Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
cua triet » cua viet, su triet, va triet
hieu van » thien van, lieu va, hieu ve
cam truc » cau truc, nam truc, lam truoc
truc van » truc va, thuc van, truc ban
thanh di » thanh doi, thanh de, thanh do
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, dua tren

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 xa hoi. ((hieu van) or (hieu va)) cam truc van thanh di ((cua tre) or (cua triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. ((hieu van) OR (hieu va)) cam truc van thanh di ((cua tre) OR (cua triet)).
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. ((hieu van) or (hieu va)) cam truc van thanh di ((cua tre) or (cua triet))*.