Perhaps you should try some spelling variations:
thuoc sac » thuoc sach, thuoc dac, thuoc sai
trang vai » trang va, trang tai, trang giai
thuc dan » hoc dan, thuc vat
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa
va cau » van cau, va cac, va dau
vai va » mai va, dai va, hai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sac ky nang ma hoi. hieu va cau ((thuc dan) OR (thuc hanh)) trang vai va (thiet or thieu)~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sac ky nang ma hoi. hieu va cau ((thuc dan) OR (thuc hanh)) trang vai va (thiet OR thieu).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sac ky nang ma hoi. hieu va cau ((thuc dan) OR (thuc hanh)) trang vai va (thiet or thieu)".
• Adding a wildcard symbol may retrieve word variants: thuoc sac ky nang ma hoi. hieu va cau ((thuc dan) OR (thuc hanh)) trang vai va (thiet or thieu)*.