Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hau truc » hang truc, hoc truc, tu truc
hang hai » hoang hai, hang tai, thanh hai
van hang » van khang, van hoang, van thang
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma

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 ((hau truc) or (cau truc)) van hang hai ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang xa hoi. hieu van ((hau truc) OR (cau truc)) van hang hai ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang xa hoi. hieu van ((hau truc) or (cau truc)) van hang hai ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang xa hoi. hieu van ((hau truc) or (cau truc)) van hang hai ((cua tre) OR (cuu tre))*.