Perhaps you should try some spelling variations:
khoai chau » khoa chau, khoa phau, hai chau
chau thong » chau phong, khau thong, chan thuong
thay nguoi » tay nguoi, thanh nguoi, thang nguoi
nguoi sinh » nguoi binh, nguoi kinh, nguoi ninh
dan khoai » dan khai, dan khoa, dang khoi
sach thay » sach tham, sach hay, hoach thay
sinh khoa » sinh hoc, sinh hoat, anh khoa
tu sach » thu sach, su sach, te sach
nha hoc » nha thuoc, khoa hoc, nha nuoc
so sach » so sanh, bo sach, co sach
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: (( tu sach nha hoc dan khoai chau thong ) or ( so sach thay nguoi sinh khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach nha hoc dan khoai chau thong ) OR ( so sach thay nguoi sinh khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach nha hoc dan khoai chau thong ) or ( so sach thay nguoi sinh khoa he thong ))*.