Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
cau tren » cu tren, dau tren, ca tren
sang mai » sang ma, sang tai, lang mai
mai hoi » mai khoi, dai hoi, lai hoi
sach ky » sac ky, sach y, sach ty
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
ky sang » ky nang, ky dang, ky tang
vai cau » va cau, van cau, vai cac
ve cai » va cai, ve tai, ve cau
ve cac » va cac, vien cac

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 mai hoi. hieu ((ve cai) or (ve cac)) xuc ((va hanh) OR (va danh)) vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky sang mai hoi. hieu ((ve cai) OR (ve cac)) xuc ((va hanh) OR (va danh)) vai cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky sang mai hoi. hieu ((ve cai) or (ve cac)) xuc ((va hanh) OR (va danh)) vai cau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ky sang mai hoi. hieu ((ve cai) or (ve cac)) xuc ((va hanh) OR (va danh)) vai cau tren*.