Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
van hanh » ban hanh, van anh, van ban
sach ky » sach y, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
nam luc » nang luc, nhan luc, nam thuc
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
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: te ((sach ky) or (sac ky)) nang cao hoi. hieu van nam luc ((van hanh) OR (van thanh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ky) OR (sac ky)) nang cao hoi. hieu van nam luc ((van hanh) OR (van thanh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ky) or (sac ky)) nang cao hoi. hieu van nam luc ((van hanh) OR (van thanh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te ((sach ky) or (sac ky)) nang cao hoi. hieu van nam luc ((van hanh) OR (van thanh)) vi cua tre*.