Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
tang mai » tang ma, tang tai, lang mai
sach ty » sach y, sach tu, sach thu
ty tang » tay tang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
la tren » loai tren, dua tren, dat tren
cao tu » cao thu, co tu, tao tu
di la » di lam, de la, di le

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach ty tang mai hoi. hieu va ((cao tu) or (cao su)) va hanh di la tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ty tang mai hoi. hieu va ((cao tu) OR (cao su)) va hanh di la tren.
• Adding a wildcard symbol may retrieve word variants: thuat sach ty tang mai hoi. hieu va ((cao tu) or (cao su)) va hanh di la tren*.