Perhaps you should try some spelling variations:
sach tranh » canh tranh
sach hanh » sach danh, sach han, sac hanh
kxy thuat » ki thuat, my thuat, ky thua
sach dao » lanh dao
thuat du » thuat dau, thuat do, thuat tu
toan hoc » toan khoa, van hoc, hoa hoc
su sach » so sach, vu sach
du hoc » tu hoc, duoc hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( su ((sach hanh) or (sach dao)) ky thuat du hoc ) or ( su sach tranh kxy thuat toan hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su ((sach hanh) OR (sach dao)) ky thuat du hoc ) OR ( su sach tranh kxy thuat toan hoc )).
• Adding a wildcard symbol may retrieve word variants: (( su ((sach hanh) or (sach dao)) ky thuat du hoc ) or ( su sach tranh kxy thuat toan hoc ))*.