Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
ky dang » ky danh
cam tuc » cam xuc, nam thuc, dam thuc
dan tai » van tai, dan thi, han tai
tai cua » thai cua, tai cuc, tri cua
cua tre » cua te, cuu tre, cua triet
cam tu » cam thu, nam tu, dam tu
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 ((ky nang) or (ky dang)) xa hoi. hieu van ((cam tuc) OR (cam tu)) va dan tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky nang) OR (ky dang)) xa hoi. hieu van ((cam tuc) OR (cam tu)) va dan tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky nang) or (ky dang)) xa hoi. hieu van ((cam tuc) OR (cam tu)) va dan tai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky nang) or (ky dang)) xa hoi. hieu van ((cam tuc) OR (cam tu)) va dan tai cua tre*.