Perhaps you should try some spelling variations:
thanh vinh » thanh binh, thanh tinh, than kinh
hieu van » hieu va, thien van, lieu va
cau treo » cau theo, cau tren, cau triet
tu sach » thu sach, su sach, te sach
cuu tre » cua tre, cau tren
y nang » ky nang, ly nang, v nang
x hoi » xa hoi, o hoi, x ho

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