Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
hieu va » lieu va, hieu qua
lam loc » lam duoc, lam ngoc
danh di » danh du, danh dien, danh gia
xanh di » vanh dai, xanh tai
loc va » hoc va, luc va
va lam » van lam, va lap

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 di) OR (xanh di)) cau 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 di) OR (xanh di)) cau 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 di) OR (xanh di)) cau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang ma) or (tang ma)) hoi. hieu va lam loc va ((danh di) OR (xanh di)) cau tren*.