The next step is to create your search strings. Each search string will represent a theme/concept of your research. Search strings are a combination of keywords that are synonymous or related terms, along with acronyms and variant spellings. Your aim is to capture as much of the relevant literature as possible and search strings will help you do that.
There are a number of tools and search operators that you can use to improve the efficacy of your search strings.
Note: Not all databases search using the same syntax, check the search tips of the database to check they accept wildcards, truncation, phrase-searching, etc. and adjust your search string accordingly.
Combining your keywords and search strings: search operators
Watch this Boolean operators video to learn more about using them to connect your keywords and other commands such as quotation marks, question marks and asterisks which will all help you to improve your search results.
Further guidance from Kings College London on advanced search techniques.
A search strategy is simply your search strings combined to address each of your review questions, to answer your overarching research topic. Search strings are usually combined with a Boolean operator or a proximity operator, as described above.