Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
dan loai » dang loai, phan loai, nhan loai
thi hang » thi hanh, thi nang, thi hong
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
cham luc » cham soc, nhan luc, cham cuu
sach thi » sach thu, sach tai, sach thieu
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
dan lai » dan lap, dan lat, dan li
hang xa » hoang xa, hang va, hang ca
luc va » duc va, tuc va, loc va

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 thi hang xa hoi. hieu van cham luc va ((dan lai) or (dan loai)) ((cua tre) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thi hang xa hoi. hieu van cham luc va ((dan lai) OR (dan loai)) ((cua tre) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: su sach thi hang xa hoi. hieu van cham luc va ((dan lai) or (dan loai)) ((cua tre) or (dau tren))*.