Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
dang xay » dang van, van xay
nhan luc » nang luc
cau treo » cau theo, cau tren, cau triet
dau tien » van tien
lang xa » lang ha, lang van
va nhan » van nhan, ca nhan, va phan
va hanh » van hanh, va thanh, va danh
luc va » duc va, tuc va, loc va

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: thu sach y ((lang xa) OR (dang xay)) hoi. lieu va nhan luc va hanh vi ((cau treo) OR (dau tien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((lang xa) OR (dang xay)) hoi. lieu va nhan luc va hanh vi ((cau treo) or (dau tien))~".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((lang xa) OR (dang xay)) hoi. lieu va nhan luc va hanh vi ((cau treo) or (dau tien))*.