Perhaps you should try some spelling variations:
cach thuc » anh thuc, cac thu
sach tien » sach tren, sach thieu
thuc thuy » thuc thuc, thu thuy, thac thuy
thuy canh » thuy anh, thu canh, thuy hanh
canh khoa » anh khoa, xanh khoa, doanh khoa
tien hoc » tin hoc, tien hoa, dien hoc
khoan he » khoan ke, khoan le, khoan hoi
so sach » so sanh, bo sach, co sach
hoc cac » hoc cao
tu cach » tu cac
khoa he » hoa he, khoa hoc, khong he

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( so sach tien hoc cac khoan he thong ) or ( tu cach thuc thuy canh khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( so sach tien hoc cac khoan he thong ) OR ( tu cach thuc thuy canh khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( so sach tien hoc cac khoan he thong ) or ( tu cach thuc thuy canh khoa he thong ))*.