Perhaps you should try some spelling variations:
nhanh ha » thanh hoa, thanh hai, khanh hoa
thuc day » thuc dan, thuc vat
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
ha cua » hoa cua, hai cua, nha cua
van am » van nam, van lam, van dam

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 y ((nang xa) or (nang ma)) hoi. hieu van am ((thuc va) OR (thuc day)) nhanh ha cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((nang xa) OR (nang ma)) hoi. hieu van am ((thuc va) OR (thuc day)) nhanh ha cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y ((nang xa) or (nang ma)) hoi. hieu van am ((thuc va) OR (thuc day)) nhanh ha cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach y ((nang xa) or (nang ma)) hoi. hieu van am ((thuc va) OR (thuc day)) nhanh ha cua tre*.