Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thuc dan » thuc hanh, hoc dan, thuc vat
cuu tre » cua tre, cau tren, cau treo
thuc va » thuc vat, thuc day
van cau » van dau, van hau, van chat
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
su sach » so sach, vu sach
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu bach) or (su sach)) ky lang xa hoi. hieu van cau ((thuc va) OR (thuc dan)) hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu bach) OR (su sach)) ky lang xa hoi. hieu van cau ((thuc va) OR (thuc dan)) hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu bach) or (su sach)) ky lang xa hoi. hieu van cau ((thuc va) OR (thuc dan)) hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((vu bach) or (su sach)) ky lang xa hoi. hieu van cau ((thuc va) OR (thuc dan)) hanh vi cuu tre*.