Perhaps you should try some spelling variations:
cach thiet » cac thiet, cach thien, sach thieu
thiet cong » thien cong, thi cong, nhiet dong
sach nganh » sach ngan, sach tranh, cac nganh
nganh nong » nganh cong
thu cach » thuc cach, thu canh, tu cach
cong khi » cong thai, khong khi, co khi
nong khi » dong khi, nong thi, khong khi
so sach » so sanh, bo sach, co sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( thu cach thiet cong khi đong luc ) or ( so sach nganh nong khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thu cach thiet cong khi đong luc ) OR ( so sach nganh nong khi đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( thu cach thiet cong khi đong luc ) or ( so sach nganh nong khi đong luc ))*.