Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
ky dang » ky nang
ky danh » ky anh
cam luc » cau luc
cuc tre » duc tre, cua tre, cuu tre

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