Basic STN commands | Cheat sheet | Current awareness | Quiz
Cheat sheet: STN version
Academic program hours
The CA, REG, CAOLD, and STNGUIDE files are available:
| Monday – Friday | 5pm – 5am |
| Saturday | Midnight – 3pm |
| Sunday | 3pm – 5am (Monday) |
The LCA, LREGISTRY, LCASREACT, LMARPAT, AND STNGUIDE files are available 24 hours a day.
Selected commands
All STN files, including Chemical Abstracts Service Online, are searched using the same command language. The commands used most frequently are listed below. You can use the full or abbreviated form of a command at any STN system prompt (=>).
| Command | Abbreviation | Function | Example |
|---|---|---|---|
| FILE | FIL | Enter a STN database | =>file ca =>fil reg =>fil caold |
| SEARCH | S | Search terms in database | =>search organometallics =>s organometallics |
| EXPAND | E | View search term and its neighbor in an index |
=>expand pearson w/au =>e tetrahedron/jt |
| EXPAND LEFT | E LEFT | View search term plus words where term has a prefix |
=>e left assay |
| DISPLAY | D | Display search results on screen (L#/format/record #s) |
=>display =>enter (L1), L#, or ?: L1 =>format (bib): ti =>enter answer number or range (1): 1-3 =>D L1 ti 1-3 =>d history full =>d cost full |
| HELP | ? | View online help | =>help display |
| LOGOFF | LOG | Disconnect from STN | =>log y |
Truncation and character masking symbols
Truncation is the process of using a wildcard charater to locate variant spellings and words having the same word stem. The truncation symbol can be used several ways:
| Truncation symbol | Function | Example |
|---|---|---|
| ? | Open truncation: represents any number of characters to the left or to the right of the term |
=>s analy? =>s ?assay? |
| # | Restricted: represents one or zero characters at the end of a term |
=>s polymer# |
| ! | Variable character: represents exactly one character and can be used either in the middle or at the end of a term |
=>s wave! =>s alk!ne |
Combining search terms using Boolean logic
Boolean operators are used with the SEARCH command to establish a relationship between two or more search terms.
| Boolean operator | Function | Example |
|---|---|---|
| AND | Retrieves records where both terms exist | =>s gas and chromatography |
| OR | Retrieves records where either term exists | =>s gas or liquid |
| NOT | Retrieves records where term is excluded | =>s gas not solid |
| Using >1 Boolean Operator |
If OR is used with AND or NOT in the same search statement, surround terms being ORed together with parentheses |
=>s (gas or liquid) and chromatog? |
Combining search terms using proximity operators
Proximity operators are used to specify the relative nearness or adjacency of search terms within the same record.
| Proximity operator | Function | Example |
|---|---|---|
| (W) or (nW) | Terms must occur next to each other (or within n number of words) and in the order specified |
=>s gas(w)chromatog? |
| (A) or (nA) | Terms must occur next to each other (or within n number of words) but may be in any order |
=>s gas(2a)chromatog? |
| (S) | Terms must occur within the same sentence. Useful when search terms within an abstract |
=>s gas(s)chromatog?/abs |
| (L) | Terms must be present in the same field (e.g. title, keyword, or index entry) |
=>s gas(l)chromatog? |
The CA file
The CA file contains all bibliographic references to literature cited in printed CA since 1967 and complete CA abstracts since 1969. Type FILE CA to enter the CA file. The Learning CA File (LCA) contains a fixed 5% of the full file and may be used to practice online searching.
| Subject searching | Example |
|---|---|
| * Basic Index (default; = title, abstract text, keywords & index terms) |
=>s (solar or sun) and collector? |
| * Title words only | =>s crystallograph?/ti |
| Author searching | |
|---|---|
| (Always view author index by using EXPAND command because author names are put into the CA file more than one way. Some records have first name spelled out while others contain only initials for first name.) | =>e counsell r e/au E1 5 counsell patrick j/au E2 7 counsell patrick james/au E3 13 counsell r e/au E4 20 counsell raymond e/au =>s e3-e4 |
| Chemical substance searching | |
|---|---|
| * Individual substances, use CAS Registry Number (use REG File to find CAS RN's) |
=>s 42228-92-2 |
|
|
| * Classes of compounds, use text terms | =>s ketones |
Tailoring your search
| Review papers | =>s crystallograph? and review =>s L1 and review |
| Language | =>s crystallograph? and eng/la |
| Publication year- may use 4 digits, 2 digits, or truncation |
=>s crystallograph? and 1989/py =>s crystallograph? and 89/py =>s crystallograph? and 198?/py =>s crystallograph? and 8?/py |
| Range of file- can limit one search statement or entire search session |
=>s L1 range=(1989,) =>s L1 range=(1985,1989) =>s L1 ran=(,1980) =>set ran=(1985,) =>set ran=(all) |
CA file: selected display formats
| Type of formats | Information obtained |
|---|---|
| TI | Title only |
| SAM | Sample = Title and indexing data |
| IBIB | Indented bibliographic data (all field names spelled out) |
| BIB | Bibliographic data (one line per field) |
| CBIB | Compressed bibliographic data (wordwrapped) |
| ABS | Abstract |
| ALL | BIB, ABS, and INDexing |
| CBIB ABS | Can use more than one display format at a time |
The REGISTRY file
The REGISTRY file contains chemical substance information for compounds published in the literature from 1957 to the present. It is possible to search the REGISTRY file several ways: CAS Registry Number, complete chemical name, name fragments, formula, chemical elements, and structure. Type FILE REG to enter the REGISTRY file. The Learning REGISTRY file (LREG) contains a fixed 5% of the full file and may be used to practice online searching. Search term costs are high, so verify that term exists by using EXPAND command before searching it.
| Chemical Abstracts Registry Number | =>s 1234-55-9 |
| Complete chemical name searching (/CN) | =>e sulfadiazine/cn |
| Name fragment searching (use longest possible name fragment) |
=>s amino(L)phosphono |
| Molecular formula (/MF) Arrange elements in Hill System Order: Carbons first, Hydrogens next, and then all remaining elements in alphabetical order. All elements in alpha order if no Carbon is present. |
=>e c8h10n4o2/mf |
| Chemical element searching | =>s 1-3/n (L) 6/c (L) cu>0 |
REGISTRY file: selected display formats
| Type of formats | Information obtained |
|---|---|
| IDE | Identification information (default display) |
| IDE CBIB ABS | Identification information plus display of ten most recent citations along with abstracts in compressed bibliographic citation format |
| RN CBIB | CAS Registry Number & 10 most recent citations |
Using search results from REGISTRY File as search terms in CA File
After locating CAS Registry Numbers (using techniques specified above), you can use the L# as a search term in the CA File. For example:
| Part 1: Search REGISTRY File | =>fil reg =>s sulfadiazine/cn L1 1 SULFADIAZINE/CN |
| Part 2: Use Reg File L# in CA File. (limits answers to articles on prepn of cmpd) |
=>fil ca =>s L1 =>s L1/p |
The CAOLD file
The CAOLD file covers 1957–1966 and is searchable only by CAS Registry Number. Records contain the Printed CA volume and abstract numbers, the document type for patents, and CAS Registry Numbers. You need to search Printed CA to find out where an item was published. You do not need to specify the format when viewing records, just enter DISPLAY command, L#, and number of records you want to display (e.g. D L2 1-25).