Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
dang cau » hang cau, bang cau, dang mau
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
cam luc » cau luc
cuc tre » cua tre, cuu tre, cuc thue
duc tre » duoc tren, duc tien

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky dang cau hoi. hieu van ((cam luc) or (cam xuc)) va thanh tai ((cuc tre) OR (duc tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang cau hoi. hieu van ((cam luc) OR (cam xuc)) va thanh tai ((cuc tre) OR (duc tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang cau hoi. hieu van ((cam luc) or (cam xuc)) va thanh tai ((cuc tre) OR (duc tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang cau hoi. hieu van ((cam luc) or (cam xuc)) va thanh tai ((cuc tre) OR (duc tre))*.