Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hieu van » hieu va, thien van, lieu va
kho tang » cao tang
cuu tre » cua tre, cau tren, cau treo
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
van cau » van dau, van hau, van chat
ky tang » ky nang, ky dang, ky trong
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 tang) OR (kho tang)) xa hoi. hieu van cau thuc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu bach) OR (su sach)) ((ky tang) OR (kho tang)) xa hoi. hieu van cau thuc va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu bach) or (su sach)) ((ky tang) OR (kho tang)) xa hoi. hieu van cau thuc va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((vu bach) or (su sach)) ((ky tang) OR (kho tang)) xa hoi. hieu van cau thuc va hanh vi cuu tre*.