Perhaps you should try some spelling variations:
nang tao » nang cao, sang tao, nang tai
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hai cua » thai cua, dai cua, hoi cua
dan hai » doan hai, dang hai, dan khai
cac luc » cau luc, coc luc, cac nuoc
hieu va » hieu qua
hieu ve » hieu van
tao hoi » tao khoi, tao boi, tay hoi
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau

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 tao hoi. ((hieu ve) or (((hieu va) OR (lieu va)))) cac luc va dan hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang tao hoi. ((hieu ve) OR (((hieu va) OR (lieu va)))) cac luc va dan hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang tao hoi. ((hieu ve) or (((hieu va) OR (lieu va)))) cac luc va dan hai cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang tao hoi. ((hieu ve) or (((hieu va) OR (lieu va)))) cac luc va dan hai cua tre*.