Perhaps you should try some spelling variations:
cham luc » cham soc, cham cuu, chat lua
nhan luc » nang luc
su sach » so sach, vu sach
cua tre » cua te, cua triet, dua tren
va hanh » van hanh, va thanh, va danh
sach ty » sach y, sach tu, sach thu
cuu tre » cau tren, cau treo
hieu va » lieu va, hieu qua
ty hang » ly hang, ty xang, thi hang
va hoi » xa hoi, va hoc, va hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty hang va hoi. hieu va ((cham luc) OR (nhan luc)) va hanh vi ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty hang va hoi. hieu va ((cham luc) OR (nhan luc)) va hanh vi ((cua tre) or (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: su sach ty hang va hoi. hieu va ((cham luc) OR (nhan luc)) va hanh vi ((cua tre) or (cuu tre))*.