Perhaps you should try some spelling variations:
cau treo » cau theo, cau tren, cau triet
dang hai » dang khai, hang hai, dung hai
lanh hai » manh hai, thanh hai, lang chai
hieu van » hieu va, thien van, lieu va
thuc va » thuc vat, thuc dan, thuc day
su sach » so sach, vu sach
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi
van am » van nam, van lam, van dam

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach y nang ((ma hoi) OR (ma hoa)). hieu van am thuc va ((lanh hai) or (dang hai)) cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang ((ma hoi) OR (ma hoa)). hieu van am thuc va ((lanh hai) OR (dang hai)) cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang ((ma hoi) OR (ma hoa)). hieu van am thuc va ((lanh hai) or (dang hai)) cau treo".
• Adding a wildcard symbol may retrieve word variants: su sach y nang ((ma hoi) OR (ma hoa)). hieu van am thuc va ((lanh hai) or (dang hai)) cau treo*.