Text words, also called natural language, are the words that authors use in their titles or abstracts. In Subject Searching we wrote:
Type a word or phrase into a search box and chances are something will come up. But for really effective searching, it is important to find the right language. Using subject headings, sometimes called controlled vocabulary, is one way to focus on concepts rather than on random words.
This is true if there are subject headings for the concept you are searching for. Often we have no choice but to use text words, and, in fact, good searches use a combination of subject headings (MeSH or ChiroSH, in ICL) and text words.
Use truncation (e.g. chiropract*) to retrieve all forms of a word. Enclose phrases in “quotation marks”. Also keep in mind alternate spellings (mobilization or mobilisation) or different words for the same concept (e.g. facet or zygapophyseal joint. In the MeSH browser, scroll down to see the PubMed Entry Terms, or alternative words and spellings).