Perhaps you should try some spelling variations:
dan thanh » dang thanh, danh thanh, ban thanh
hieu van » hieu va, thien van, lieu va
thanh ha » thanh hoa, thanh hai, nhanh ha
thuc dan » thuc hanh, hoc dan, thuc vat
cam thuc » am thuc, nam thuc, cam thu
van cam » van nam, van lam, van cau
su sach » so sach, vu sach
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, dang xay, lang van
nang xa » nang x, mang xa, ang xa
cua tre » cua te, cuu tre, cua triet
ha cua » hoa cua, hai cua, nha cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y ((((nang xa) or (lang xa))) or (nang ma)) hoi. hieu van cam thuc dan thanh ha cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y ((((nang xa) OR (lang xa))) OR (nang ma)) hoi. hieu van cam thuc dan thanh ha cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach y ((((nang xa) or (lang xa))) or (nang ma)) hoi. hieu van cam thuc dan thanh ha cua tre*.