Perhaps you should try some spelling variations:
sach truc » cach thuc, sach tren, sach thu
cach khoa » bach khoa, cac khoa, cac khoan
canh sinh » canh tinh, canh binh, tinh sinh
sinh thuc » trinh thuc, sinh hoc, sinh thai
thuc cach » thuoc sach, truoc cach, thuc hanh
khoa hoc » hoa hoc
he trung » le trung, he thong, do trung
te sach » toc sach
truc ve » thuc ve, truc va, truc van
ve cach » va cach, ve cac, ve canh
tu canh » thu canh, tu chanh, tu can
khoa he » hoa he, khong he, khoa thu

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( te sach truc ve cach khoa hoc thuong ) or ( tu canh sinh thuc cach khoa he trung ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach truc ve cach khoa hoc thuong ) OR ( tu canh sinh thuc cach khoa he trung )).
• Adding a wildcard symbol may retrieve word variants: (( te sach truc ve cach khoa hoc thuong ) or ( tu canh sinh thuc cach khoa he trung ))*.