Perhaps you should try some spelling variations:
cham luc » cham soc, nhan luc, cham cuu
thi hanh » thi thanh
tinh hoi » trinh hoi, tinh hoc, tinh hai
chat cua » nhat cua, chat va, chat huu
sach thi » sach thu, sach tai, sach thieu
su sach » so sach, vu sach
hoi cua » hoi chuc
va tinh » may tinh
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet

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 hanh ((mai hoi) or (xa hoi)). hieu va ((cham luc) or (chat cua)) va tinh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thi hanh ((mai hoi) OR (xa hoi)). hieu va ((cham luc) OR (chat cua)) va tinh hoi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach thi hanh ((mai hoi) or (xa hoi)). hieu va ((cham luc) or (chat cua)) va tinh hoi cua tre*.