Perhaps you should try some spelling variations:
hieu cac » hieu luc, hieu va, hieu van
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
dan vai » dan va, dan tai, dan vat
vai cua » dai cua, hai cua, lai cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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: tu sach y nang xa hoi. hien ((hieu cac) or (lieu va)) nuoc va dan vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hien ((hieu cac) OR (lieu va)) nuoc va dan vai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hien ((hieu cac) or (lieu va)) nuoc va dan vai cua tre*.