Perhaps you should try some spelling variations:
khau sach » hau sach, khoa sach, pham sach
hieu van » hieu va, thien van, lieu va
van hang » van khang, van hoang, van thang
hang di » hang doi, hang vi, hang dien
luc van » luoc van, luu van, duc van
cau luc » cau truc, cau phuc
van cau » van dau, van hau, van chat
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
tu sach » thu sach, su sach, te sach
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (((tu sach) or (khau sach)))) ky tang xa hoi. hieu van cau luc van hang di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (((tu sach) OR (khau sach)))) ky tang xa hoi. hieu van cau luc van hang di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (((tu sach) or (khau sach)))) ky tang xa hoi. hieu van cau luc van hang di cua tre*.