Perhaps you should try some spelling variations:
thien van » thi van
cam thuc » nam thuc, cam thu, can thuc
danh hai » dang hai, lanh hai, manh hai
cau treo » cau theo, cau tren, cau triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
va danh » va dinh, va dan, va hanh
hai cau » hai chau, hai chu, hai hau

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 ky nang ((ma hoa) or (xa hoi)). thien van ((cam thuc) OR (am thuc)) va danh hai cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((ma hoa) OR (xa hoi)). thien van ((cam thuc) OR (am thuc)) va danh hai cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((ma hoa) or (xa hoi)). thien van ((cam thuc) OR (am thuc)) va danh hai cau treo".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((ma hoa) or (xa hoi)). thien van ((cam thuc) OR (am thuc)) va danh hai cau treo*.