Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
toc sach » hoc sach, doc sach, thuoc sach
tang mai » tang ma, tang tai, lang mai
cua tre » cua te, cuu tre, cua triet
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
ve nham » ve nha, ve cham
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
ky tang » ky nang, ky dang, kho tang
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu bach) or (toc sach)) ky tang mai hoi. hieu ve nham thuc ((va hanh) or (va danh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu bach) OR (toc sach)) ky tang mai hoi. hieu ve nham thuc ((va hanh) OR (va danh)) vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((vu bach) or (toc sach)) ky tang mai hoi. hieu ve nham thuc ((va hanh) or (va danh)) vi cua tre*.