Perhaps you should try some spelling variations:
"genotype variation method" » "genotypic variation method", "phenotypic variation method", "genetic variation method", "genotype variational method", "genotype radiation method", "genotype variational methods"
"genome variation method" » "genome variational method", "genome radiation method", "genome variational methods", "genetic variation method", "time variation method", "some variations method"
"isotope dilution method" » "isotope solution method", "isotope solution methods", "isotope evaluation method"

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("isotope dilution method") or ((("genotype variation method") OR ("genome variation method"))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("isotope dilution method") OR ((("genotype variation method") OR ("genome variation method")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"isotope dilution method\") or (((\"genotype variation method\") OR (\"genome variation method\"))))".
• Removing quotes may allow a broader search: (( isotope dilution method ) or ((( genotype variation method ) OR ( genome variation method )))).
• Adding a wildcard symbol may retrieve word variants: (("isotope dilution method") or ((("genotype variation method") OR ("genome variation method"))))*.