Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham tuc » tham thuc, thai tuc, nham thuc
sach ky » sac ky, sach y, sach ty
cua tre » cuu tre, cua triet, dua tren
va danh » va dinh, va hanh, dia danh
nang xa » nang x, lang xa, nang ma
va dan » ca dan, va dao, va dau
cua te » cua tu

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

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