Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
minh vai » minh va, minh hai, minh ai
vai cua » dai cua, hai cua, lai cua
luc van » luoc van, luu van, duc van
nam luc » nang luc, nhan luc, nam thuc
hieu va » lieu va, hieu qua
te sach » toc sach
sach ly » sach y, sach lo, sach ty
cao hoc » co hoc, cho hoc, chat hoc
cao hoi » cau hoi, co hoi, tao hoi
ly nang » ky nang, ly hang, ly vang
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: te sach ly nang ((cao hoi) or (cao hoc)). ((hieu van) or (hieu va)) nam luc van minh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ly nang ((cao hoi) OR (cao hoc)). ((hieu van) OR (hieu va)) nam luc van minh vai cua tre.
• Adding a wildcard symbol may retrieve word variants: te sach ly nang ((cao hoi) or (cao hoc)). ((hieu van) or (hieu va)) nam luc van minh vai cua tre*.