Perhaps you should try some spelling variations:
normal variations » normal variants
total variations » total variational, local variations, global variations
zonal variations » clonal variations, local variations, annual variations
clonal variation » somaclonal variation, seasonal variation, regional variation
tonal variation » local variation, national variation, clonal variations

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: (("total variation) or ("((((total variations) OR (normal variations))) OR (((zonal variations) OR (((tonal variation) OR (clonal variation))))))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"total variation) or (\"((((total variations) or (normal variations))) or (((zonal variations) or (((tonal variation) OR (clonal variation))))))))*".
• Removing quotes may allow a broader search: (( total variation) or ( ((((total variations) or (normal variations))) or (((zonal variations) or (((tonal variation) OR (clonal variation))))))))*.