To get better search results in Salesforce, it helps to understand how Salesforce search works.
When you search in Salesforce, Salesforce performs separate searches on all the objects in your default search scope. The results from these searches are then combined on your search results page.
Salesforce also reformulates your search terms using natural language analysis algorithms (tokenization, lemmatization etc.) and other techniques. Once Salesforce completes the reformulation process, it then uses the reformulated search query to find matching items in your indexes.
Finally Salesforce presents your results intelligently ranked based on your Salesforce usage (they call this “smart scoping” and “smart ordering”).
Starting in Spring ’12, Salesforce uses your usage history to personalize the search scope based on the types of objects you use and how often you use them. For example, if you frequently work with Accounts and Opportunities, those objects will likely show at the top of your search results.
Salesforce search uses operators (AND, OR, AND NOT, parentheses, quotation marks) in the search string you type. You can you override the default operator by explicitly typing your own operator.
For example: if you type Kinetic AND Growth as your search string, your results will only have items that contain both Kinetic and Growth
Salesforce search uses wildcards in search queries.
Examples of using wildcards:
Salesforce search uses lemmatization to match different forms of verbs and nouns. In addition to matches on the terms you provide, your search results include matches on the root term (called the lemma) and different forms of the root as long as they are the same part of speech.
For example: a search for the word renew (a verb) matches items containing renew, renewing, and renewed, but not renwal (a noun).
References: