Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
danh vai » danh sai, danh va, doanh van
cau tren » cu tren, dau tren, ca tren
ky tang » ky nang, ky dang, kho tang
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, duy sang
vai cau » va cau, van cau, vai cac
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, truc va, tuc xa

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 sang) or (ky tang)) mai hoi. hieu ve cam ((tuc va) or (duc va)) danh vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((ky sang) OR (ky tang)) mai hoi. hieu ve cam ((tuc va) OR (duc va)) danh vai cau tren.
• Adding a wildcard symbol may retrieve word variants: thu sach ((ky sang) or (ky tang)) mai hoi. hieu ve cam ((tuc va) or (duc va)) danh vai cau tren*.