Okay, you know these. The only difference is that in Dialog you need to use "but not" for "not."
"As in most searching, "and" continues to be your most important tool. But in Dialog or other collections of simultaneously searched databases:
- "or" becomes more important because, unless you are looking for a specific kind (professional, scientific, lay) of language, you need to account for a greater range of ways of expressing the same concept.
- "not" (or "but not" or "and not") becomes more important because in large collections of records you have irrelevant content to exclude. This is particularly so in search engines with billions of files. Again, though, a warning that misuse or over-enthusiastic use of "not" can eliminate relevant records.
- cats and dogs
- cats or dogs
- cats but not dogs