Perhaps you should try some spelling variations:
candidate snps » candidate snp, candidate sets, candidate sars
candidate skip » candidate ska, candidate snp, candidate asking
candidate spp » candidate snp, candida spp, candidate set

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (((((( candidate spp ) OR ( candidate snps ))) OR ( candidate skip ))) OR ( candida _ )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((((( candidate spp ) OR ( candidate snps ))) or ( candidate skip ))) or ( candida _ ))".
• Adding a wildcard symbol may retrieve word variants: (((((( candidate spp ) OR ( candidate snps ))) or ( candidate skip ))) or ( candida _ ))*.