Perhaps you should try some spelling variations:
thien van » thi van
nam thuc » nam thuoc, am thuc, nam thu
thuc van » thuc vat, thuc dan, thuc va
van dinh » van minh, van dich, va dinh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
dinh vi » dinh ve, dinh viet, dinh tri
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, 5 hoi

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 ky nang ((x hoi) or (x ho)). ((lieu va) or (thien van)) nam thuc van dinh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((x hoi) OR (x ho)). ((lieu va) OR (thien van)) nam thuc van dinh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((x hoi) or (x ho)). ((lieu va) or (thien van)) nam thuc van dinh vi cua tre*.