Perhaps you should try some spelling variations:
thanh dai » thanh hai, thanh tai, thanh dat
cau tren » cu tren, dau tren, ca tren
va thanh » gia thanh, ban thanh, va tinh
hieu van » hieu va, thien van, lieu va
cam duc » cam xuc, cao duc, pham duc
cuu tre » cua tre, cau treo
sach ky » sac ky, sach ty, sach kem
cao hoi » cau hoi, co hoi, cao hoc
van cam » van nam, van lam, van cau

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