Perhaps you should try some spelling variations:
hac thuc » hoc thuc, ha thuc, thach thuc
thanh va » thanh van, hanh va, thanh ha
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
cua tre » cuu tre, cua triet, dua tren
thuc va » thuc vat, thuc dan, thuc day
van hac » van hoc, van ha, van hai
sach ty » sach y, sach tu, sach thu
sac ky » cac ky, sai ky
cua te » cua tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu ((sach ty) or (sac ky)) nang x hoi. hieu van hac thuc va thanh va ((cua tre) OR (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ty) OR (sac ky)) nang x hoi. hieu van hac thuc va thanh va ((cua tre) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach ty) or (sac ky)) nang x hoi. hieu van hac thuc va thanh va ((cua tre) OR (cua te))".
• Adding a wildcard symbol may retrieve word variants: vu ((sach ty) or (sac ky)) nang x hoi. hieu van hac thuc va thanh va ((cua tre) OR (cua te))*.