Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
cau tren » cu tren, dau tren, cau treo
dinh vai » dinh van, dinh vi, dinh va
tang van » dang van, hoang van, trong van
va dinh » van dinh, va kinh, va tinh
hieu va » lieu va, hieu qua
ca tren » cu tren, la tren, co tren
van hoi » van hoa, van hoc, van hoe
ky tang » ky nang, ky dang, kho tang
tu sach » su sach, te sach, tu cach
va cam » va cham, va cac, va cao
cam o » cham o, cam lo, ca o
o va » do va, so va, co va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (tu sach)) ky tang van hoi. hieu va cam o va dinh vai ((cau tren) OR (ca tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ky tang van hoi. hieu va cam o va dinh vai ((cau tren) OR (ca tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ky tang van hoi. hieu va cam o va dinh vai ((cau tren) OR (ca tren))".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ky tang van hoi. hieu va cam o va dinh vai ((cau tren) OR (ca tren))*.