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
tonal variation » clonal variation, local variation, vocal variation

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))))))*.
• 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))))))*".
• Removing quotes may allow a broader search: (( total variation) or ( ((((total variations) OR (normal variations))) or (((zonal variations) or (tonal variation))))))*.