Perhaps you should try some spelling variations:
thuc tuan » thu tuan, thuc huan, thuc luan
cam thuc » am thuc, nam thuc, cam thu
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu van
hieu va » lieu va, hieu qua
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky
vi hoc » va hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky nang cao hoi. ((hieu ve) or (hieu va)) cam thuc tuan anh ((vi hoc) or (li hoc)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky nang cao hoi. ((hieu ve) OR (hieu va)) cam thuc tuan anh ((vi hoc) OR (li hoc)) viet.
• Adding a wildcard symbol may retrieve word variants: su sac ky nang cao hoi. ((hieu ve) or (hieu va)) cam thuc tuan anh ((vi hoc) or (li hoc)) viet*.