Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
dang xay » dang van, van xay
thuc van » thuc vat, thuc va, thuc hanh
sach thu » sach thue, sach thieu, sach tham
su sach » so sach, vu sach
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, nang ma
di cua » dai cua, doi cua, de cua
va dau » va dao

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 thu ((nang xa) or (dang xay)) hoi. lieu va dau ((thuc van) OR (thuc dan)) hanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach thu ((nang xa) OR (dang xay)) hoi. lieu va dau ((thuc van) OR (thuc dan)) hanh di cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach thu ((nang xa) or (dang xay)) hoi. lieu va dau ((thuc van) OR (thuc dan)) hanh di cua tre*".