Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thu sach » tu sach, thuat sach, thu hoach
hanh vai » hanh vi, hanh va, hanh tai
sang mai » sang ma, sang tai, lang mai
va hanh » van hanh, va thanh, va danh
la tren » loai tren, dua tren, dat tren
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky nang, ky dang, ky tang
ve cac » va cac, vien cac
xuc va » duc va, tuc va, luc va
vai la » tai la, vai va
ve cai » va cai, ve tai, ve cau

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