Perhaps you should try some spelling variations:
thien van » thi van
cam thuc » am thuc, nam thuc, can thuc
va manh » van manh, va danh, va hanh
hai hau » hai chau, dai hau, hai hai
hai cau » hai chau, hai chu, hoi cau
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cam thu » nam thu, cac thu, ca thu

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