Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
ky sang » ky nang, ky dang, ky tang
sang xa » song xa, lang xa, sang ma
cam tuc » cam xuc, nam thuc, dam thuc
dau tai » dai tai, dat tai, da tai
cuc tre » duc tre, cua tre, cuu tre
cam tu » cam thu, nam tu, dam tu
va dau » va dao

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 (thu hoach)) ky sang xa hoi. hieu van ((cam tuc) or (cam tu)) va dau tai cuc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu hoach)) ky sang xa hoi. hieu van ((cam tuc) OR (cam tu)) va dau tai cuc tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu hoach)) ky sang xa hoi. hieu van ((cam tuc) or (cam tu)) va dau tai cuc tre*.