Perhaps you should try some spelling variations:
dat thanh » dao thanh, dat khanh, dang thanh
thanh ve » hanh ve, thanh va, thanh vien
thuc dat » thuc vat, thuc dan, thuc day
nam thuc » nam thuoc, am thuc, nam thu
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
so sach » so sanh, bo sach, co sach
che tre » cho tre, khoe tre, choi tre
ve che » va che, ke che, de che

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (so sach)) ky ((nang xa) or (lang xa)) hoi. hieu van nam thuc dat thanh ve che tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (so sach)) ky ((nang xa) OR (lang xa)) hoi. hieu van nam thuc dat thanh ve che tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (so sach)) ky ((nang xa) or (lang xa)) hoi. hieu van nam thuc dat thanh ve che tre*.