Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
doan van » doan va, hoang van, luan van
sach ky » sac ky, sach y, sach ty
anh van » anh va, thanh van, doanh van
qua cau » quan cau, qua cac, qua ca
cau loc » hau loc, cau hoc, cau luc
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
loc va » hoc va, luc va
di cua » dai cua, doi cua, de cua
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: thu sach ky ((anh van) or (doan van)) hoi. hieu qua cau loc va danh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((anh van) OR (doan van)) hoi. hieu qua cau loc va danh di cua te.
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((anh van) or (doan van)) hoi. hieu qua cau loc va danh di cua te*.