Perhaps you should try some spelling variations:
dang xay » dang van, van xay
cau tren » cu tren, dau tren, ca tren
sach ty » sach y, sach tu, sach thu
xay hoi » xa hoi, tay hoi, cay phoi
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach kem
nam xuc » cam xuc, nam xua, nam thuc
va hanh » van hanh, va thanh, ban hanh
va danh » va dinh, va dan, dia danh
vi cau » va cau, ve cau, di cau
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc ((sach ky) or (sach ty)) dang xay hoi. hieu va nam xuc ((va hanh) OR (va danh)) vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sach ky) OR (sach ty)) dang xay hoi. hieu va nam xuc ((va hanh) OR (va danh)) vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sach ky) or (sach ty)) dang xay hoi. hieu va nam xuc ((va hanh) OR (va danh)) vi cau tren".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sach ky) or (sach ty)) dang xay hoi. hieu va nam xuc ((va hanh) OR (va danh)) vi cau tren*.