Perhaps you should try some spelling variations:
sach tranh » canh tranh
tranh cong » thanh cong, trinh cong, tran cong
sanh nganh » anh ngan, dang nganh, sach ngan
cong khi » cong thai, khong khi, co khi
su sach » so sach, vu sach
so sanh » do sanh
y khi » ly khi, ky khi, my khi

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 tranh cong khi đong luc ) or ( so sanh nganh y khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tranh cong khi đong luc ) OR ( so sanh nganh y khi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( su sach tranh cong khi đong luc ) or ( so sanh nganh y khi đong luc ))*.