Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
cham luc » cham soc, nhan luc, cham cuu
nang doc » nang luc
hieu tuc » hieu thuc, hieu luc, hieu thuoc
tu sach » thu sach, te sach, tu cach
luc van » luoc van, luu van, duc van
hieu tu » chieu tu, hien tu, lieu tu
doc hoi » duoc hoi, hoc hoi, doc hai
tu nang » tru nang, tu nong, tu nano
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
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: ((tu sach) or (su sach)) tu nang doc hoi. ((hieu tu) OR (hieu tuc)) cham luc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) tu nang doc hoi. ((hieu tu) OR (hieu tuc)) cham luc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (su sach)) tu nang doc hoi. ((hieu tu) OR (hieu tuc)) cham luc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) tu nang doc hoi. ((hieu tu) OR (hieu tuc)) cham luc van hanh vi cua tre*.