Perhaps you should try some spelling variations:
sach thue » sach thieu, sach tham, cach thuc
van hanh » van thanh, ban hanh, van anh
hanh hai » thanh hai, nhanh hai, hang hai
sach thu » sach thieu, sach tham, cach thuc
qua cham » qua hai, qua cac, va cham
cham luc » cham soc, nhan luc, cham cuu
hai cua » thai cua, dai cua, hoi cua
van hoi » van hoc, van hoe, van loi
luc van » luoc van, luu van, duc van
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach thu) or (sach thue)) tang ((van hoi) OR (van hoa)). hieu qua cham luc van hanh hai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach thu) OR (sach thue)) tang ((van hoi) OR (van hoa)). hieu qua cham luc van hanh hai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach thu) or (sach thue)) tang ((van hoi) OR (van hoa)). hieu qua cham luc van hanh hai cua te".
• Adding a wildcard symbol may retrieve word variants: so ((sach thu) or (sach thue)) tang ((van hoi) OR (van hoa)). hieu qua cham luc van hanh hai cua te*.