Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
so sanh » do sanh
danh di » danh du, xanh di, danh dien
thuc va » thuc vat, thuc day
van hac » van hoc, van ha, van hai
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cuu tre » cua tre, cau tren, cau treo
sanh y » sinh y, anh y, hanh y
di cuu » di cau, di cua, dinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh y ((nang xa) or (nang ma)) hoi. hieu van hac ((thuc va) or (thuc dan)) danh di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh y ((nang xa) OR (nang ma)) hoi. hieu van hac ((thuc va) OR (thuc dan)) danh di cuu tre.
• Adding a wildcard symbol may retrieve word variants: so sanh y ((nang xa) or (nang ma)) hoi. hieu van hac ((thuc va) or (thuc dan)) danh di cuu tre*.