Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va danh » va dinh, va hanh, dia danh
lam loc » lam duoc, lam ngoc
hieu va » lieu va, hieu qua
cu tren » tu tren, dua tren
nang ma » sang ma, nang cao, mang may
tang ma » mang may, tang van
va dan » ca dan, va dao, va dau
va lam » van lam, va lap
di cu » di cau, di cua, di du

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 y ((nang ma) or (tang ma)) hoi. hieu va lam loc ((va danh) OR (va dan)) di cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang ma) OR (tang ma)) hoi. hieu va lam loc ((va danh) OR (va dan)) di cu tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((nang ma) or (tang ma)) hoi. hieu va lam loc ((va danh) OR (va dan)) di cu tren".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang ma) or (tang ma)) hoi. hieu va lam loc ((va danh) OR (va dan)) di cu tren*.