Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
thuoc van » thuoc va, thuc van, thuoc ban
hieu quan » lieu quan, thien quan, lien quan
manh hai » lanh hai, minh hai, thanh hai
van manh » van minh, van anh, van hanh
tu sach » thu sach, te sach, tu cach
hai cuu » hai cua, hai chu, hai cuc
cuu tre » cua tre, cau tren, cau treo
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (su sach)) ky nang ma hoi. ((hieu quan) or (hieu qua)) nam thuoc van manh hai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky nang ma hoi. ((hieu quan) OR (hieu qua)) nam thuoc van manh hai cuu tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky nang ma hoi. ((hieu quan) or (hieu qua)) nam thuoc van manh hai cuu tre*.