Help. Combining keywords
The search box allows three search modes:
- Keyword
- Boolean
- Exact match
They can be selected by clicking the three dots to the right of the search box:
1) Keyword. If multiple keywords are typed in the search box, the default operator is OR. Hits are displayed sorted by relevance.
Example: landing gear
This query will prioritise documents containing the string landing gear but will also include items containing either landing or gear appearing alone.
Tips: consider synonyms, spelling variants, and normally misspelled words. Take into account period usage: try to figure out how what you’re looking for was likely captured in writing. If you’re looking for a well-defined concept, place, or time, then the tools available on the home page work better.
2) Boolean. Allows finetuning by using the special characters described below:
2.1) A leading plus sign indicates that the keyword that follows must be included
Example: +Lancaster +hydraulics
This query will return all documents containing both Lancaster and hydraulics, irrespective of their positions in the document.
Tips: consider synonyms, spelling variants, normally misspelled words, and period usage. Note that this approach is prone to errors, as words may appear in different parts of the document, hence being totally unrelated. This is especially relevant to items containing substantial text such as transcribed oral history interviews and long written documents.
2.2) A leading minus sign indicates that the following word must not be included.
Example: +caravan -runway
This will return all document containing caravan but not runway, thus focusing on caravan intended as a recreational vehicle. This approach is especially useful to exclude ‘noise’ words.
Tips: consider synonyms, spelling variants, and normally misspelled words. Take into account period usage: try to figure out how what you’re looking for was likely captured in writing. If you’re looking for a well-defined concept, place, or time, then the tools available on the home page work better.
2.3) An asterisk denotes the truncation (or wildcard) operator.
Example: defen*e
This will return all documents containing either defense or defence.
Tip: put the wildcard in different positions to allow for spelling variants, typos etc.
3) Exact match.
Allow precise searches for any sequence of letters, spaces, and numbers, exactly as they are entered. This is the default mode.
Tips: This mode allows extremely focused searches but please be aware of its inflexible rigidity. Retrieval quality depends heavily on the way the phrase is typed: consider synonyms, spelling variants, and typos. For instance, Peter J Morris and Peter J. Morris are treated as two different individuals, even though they obviously are the same person. If you’re looking for a well-defined concept, place, or time, the tools available on the home page work better.
This mode also allows searching for numbers and codes.
Example: PO-
This will return all items about aircraft whose registration number starts with PO-, such as PO-L, PO-M etc.
Tips: If you are looking for very short keywords denoting squadrons (157, 617 etc.), aircraft types (109, B29 etc.), armaments (88, V2 etc.), equipment (Gee, H2S etc.), or decorations (VC, DFC etc.) the systematic list of all subject matters and topics may yield more focused results.