Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
thanh vi » hanh vi, thanh va, thanh ve
cao suc » cao su, cao duc
cam duc » cam xuc, cao duc, pham duc
luu tre » luu tru, cuu tre, luy tre
hieu ve » hieu va, hieu van
ty lang » tay lang, ty hang, tu lang
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ((ty lang) OR (ty xang)) xa hoi. hieu ve ((cam duc) or (cao suc)) gia thanh vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty lang) OR (ty xang)) xa hoi. hieu ve ((cam duc) OR (cao suc)) gia thanh vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ty lang) OR (ty xang)) xa hoi. hieu ve ((cam duc) or (cao suc)) gia thanh vi luu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty lang) OR (ty xang)) xa hoi. hieu ve ((cam duc) or (cao suc)) gia thanh vi luu tre*.