Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
sach nuoc » sach duoc, cac nuoc, bach tuoc
danh hoc » dan hoc, danh hoa, anh hoc
hieu van » hieu va, thien van, lieu va
va danh » va dinh, va dan, va hanh
sach ky » sac ky, sach y, sach kem
nang xa » nang x, lang xa, nang ma
sach ty » sach y, sach tu, sach thu
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 ky) or (sach ty)) nang xa hoi. ((hieu viec) or (hieu van)) sach nuoc va danh hoc cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sach ty)) nang xa hoi. ((hieu viec) OR (hieu van)) sach nuoc va danh hoc cua tre.
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sach ty)) nang xa hoi. ((hieu viec) or (hieu van)) sach nuoc va danh hoc cua tre*.