Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nham thu, pham thuc
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
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) or (toc sach)) ky nang xa hoi. hieu ve ((nham thuc) OR (nam thuc)) va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky nang xa hoi. hieu ve ((nham thuc) OR (nam thuc)) va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (toc sach)) ky nang xa hoi. hieu ve ((nham thuc) OR (nam thuc)) va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (toc sach)) ky nang xa hoi. hieu ve ((nham thuc) OR (nam thuc)) va hanh vai cua tre*.