Perhaps you should try some spelling variations:
trinh thuc » trinh tu, trinh thi
canh trinh » canh tranh, hanh trinh, canh tinh
sach tren » sach tien, sach tranh
thuc cach » thuoc sach, truoc cach, thuc hanh
cach khoa » bach khoa, cac khoan, anh khoa
cac khoa » cac khoan, cac khoi, dac khoa
khoa hoc » hoa hoc
he trong » he thong, he trung, le trong
te sach » toc sach
tren ve » tren xe, tren he, tren vi
tu canh » thu canh, tu chanh, tu can
khoa he » hoa he, khong he, khoa thu
ve cac » va cac, vien cac

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 tren ve cac khoa hoc thuong ) or ( tu canh trinh thuc cach khoa he trong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( te sach tren ve cac khoa hoc thuong ) OR ( tu canh trinh thuc cach khoa he trong )).
• Adding a wildcard symbol may retrieve word variants: (( te sach tren ve cac khoa hoc thuong ) or ( tu canh trinh thuc cach khoa he trong ))*.