Perhaps you should try some spelling variations:
sach thu » sach thue, sach thieu, sach tham
van hanh » van thanh, ban hanh, van anh
cham luc » cham soc, nhan luc, cham cuu
tu sach » thu sach, su sach, te sach
su tien » su hien, tu tieng, dau tien
luc van » luoc van, luu van, duc van
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
nang ma » tang ma, sang ma, nang cao
kien » bien, vien, dien

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 thu ((nang ma) or (nang x)) hoi. hieu ve cham luc van hanh vi ((su tien) or (su kien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu ((nang ma) OR (nang x)) hoi. hieu ve cham luc van hanh vi ((su tien) OR (su kien)).
• Adding a wildcard symbol may retrieve word variants: tu sach thu ((nang ma) or (nang x)) hoi. hieu ve cham luc van hanh vi ((su tien) or (su kien))*.