Perhaps you should try some spelling variations:
thieu nang » thien nang, thieu khang, thieu quang
hieu vien » hieu hien, hieu viec, thieu nien
thuc dant » thuoc dang, thuc hanh, thuc vat
thuc dan » thuc hanh, hoc dan, thuc vat
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
vien da » vien dai, hien dai
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thieu nang ma hoi. hieu vien da ((thuc dan) OR (thuc dant)) hanh vi cua vat~.
• Adding a wildcard symbol may retrieve word variants: su sach thieu nang ma hoi. hieu vien da ((thuc dan) or (thuc dant)) hanh vi cua vat*.