Perhaps you should try some spelling variations:
dat thanh » dao thanh, dat khanh, dang thanh
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
nam thuc » nam thuoc, nam thu, nam tu
te sach » toc sach
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
so sach » so sanh, bo sach, co sach
cuu tre » cua tre, cau tren, cau treo
ma hoi » mai hoi, xa hoi, ma hoa
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (so sach)) ky sang ma hoi. hieu van ((nam thuc) OR (am thuc)) dat thanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (so sach)) ky sang ma hoi. hieu van ((nam thuc) OR (am thuc)) dat thanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (so sach)) ky sang ma hoi. hieu van ((nam thuc) OR (am thuc)) dat thanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (so sach)) ky sang ma hoi. hieu van ((nam thuc) OR (am thuc)) dat thanh vi cuu tre*.