Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
nam truc » nam truoc, nam thuc, nam trung
toc sach » hoc sach, doc sach, thuoc sach
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
truc va » thuc va, thuc vat, trung va
han tai » hang tai, nhan tai, van tai
cuu tre » cua tre, cau treo
su sach » so sach, vu sach
va nam » van nam, ha nam, va nay
va han » va phan, van han, va hanh

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) or (toc sach)) ky dang xa hoi. lieu va nam truc va han tai ((cuu tre) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (toc sach)) ky dang xa hoi. lieu va nam truc va han tai ((cuu tre) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (toc sach)) ky dang xa hoi. lieu va nam truc va han tai ((cuu tre) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (toc sach)) ky dang xa hoi. lieu va nam truc va han tai ((cuu tre) OR (cau tren))*.