Perhaps you should try some spelling variations:
sach tru » sach truc, sach thu, sach tu
tru nang » tra nang, tri nang, truc nano
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
van cam » van nam, van lam, van cau
thuc va » thuc vat, thuc dan, thuc day
danh va » doanh va, hanh va, anh va
danh di » danh du, xanh di, danh dien
cua tre » cua te, cuu tre, cua triet

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach tru nang xa hoi. hieu van cam thuc va ((danh va) or (danh di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tru nang xa hoi. hieu van cam thuc va ((danh va) OR (danh di)) cua tre*.