Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
danh kien » dinh kien, danh viet, linh kien
dan danh » van danh, han danh, ban danh
kien cua » khien cua, dien cua, tien cua
doc hai » hoc hai, duc hai, do hai
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
hieu va » hieu qua
hai ky » thai ky, hoi ky, hai ly
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hai ky lang xa hoi. ((hieu va) OR (lieu va)) ((tham thuc) or (am thuc)) dan danh kien cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hai ky lang xa hoi. ((hieu va) OR (lieu va)) ((tham thuc) OR (am thuc)) dan danh kien cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hai ky lang xa hoi. ((hieu va) OR (lieu va)) ((tham thuc) or (am thuc)) dan danh kien cua te".
• Adding a wildcard symbol may retrieve word variants: doc hai ky lang xa hoi. ((hieu va) OR (lieu va)) ((tham thuc) or (am thuc)) dan danh kien cua te*.