Perhaps you should try some spelling variations:
cach khoan » cac khoan, cach hoan, bach khoa
khoan khau » khoanh khac, khoa kham, khoa phau
sach pham » sach tham, sach phat, sach phap
pham thuc » phap thuc, pham chuc, nham thuc
thuc cach » thuoc sach, truoc cach, thuc hanh
khau tong » khau thong, khau cong, khau thuong
sach tri » sach tai, sach tren, sach bai
tri thuc » tri tue
thuc dai » thuc dan, thuc day, thuc tai
dai khoa » da khoa, tai khoa, dac khoa
khoa hoc » hoa hoc
hoc hong » hoc huong, hoc khong, hoc cong
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( tu sach pham thuc cach khoan khau tong ) or ( tu sach tri thuc dai khoa hoc hong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach pham thuc cach khoan khau tong ) OR ( tu sach tri thuc dai khoa hoc hong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach pham thuc cach khoan khau tong ) or ( tu sach tri thuc dai khoa hoc hong ))*.