Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
nang tai » hang tai, tang tai, sang tai
hieu van » thien van, lieu va, hieu ve
nam thuc » nam thuoc, am thuc, nam thu
thuc dan » thuc hanh, hoc dan, thuc vat
dan hanh » dang hanh, dan khanh, dan thanh
cua viet » ca viet, hoa viet, cua dieu
sach ho » sach hoi, sach ha, sach lo
ho nang » thi nang, kha nang, cao nang
tai hoi » tai khoi, dai hoi, tai hai
hieu va » lieu va, hieu qua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ho nang tai hoi. ((hieu van) or (hieu va)) nam thuc dan hanh vi ((cua viet) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ho nang tai hoi. ((hieu van) OR (hieu va)) nam thuc dan hanh vi ((cua viet) OR (cua vat)).
• Adding a wildcard symbol may retrieve word variants: thu sach ho nang tai hoi. ((hieu van) or (hieu va)) nam thuc dan hanh vi ((cua viet) or (cua vat))*.