Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
cao thuc » cao thuoc, bao thuc, can thuc
so sach » so sanh, bo sach, co sach
lang xa » lang ha, dang xay
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hang » van hang, va nang, va lang
hang vi » hang va, hanh vi, hang di
va cao » va cac, va co, va dao
vi va » vi van, vai va, vu va
thiet* » thieu*

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((lang xa) or (lang van)) hoi. hieu va cao thuc va hang vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((lang xa) OR (lang van)) hoi. hieu va cao thuc va hang vi va thiet*.