Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
trinh kxy » trinh ky, trinh ly, trinh ke
kxy thuat » ki thuat, my thuat, ky thua
sach han » sach tham, sach danh, sach nang
toan hoc » toan khoa, van hoc, hoa hoc
tu sach » thu sach, su sach, te sach
thuat o » thuat do
tu hanh » du hanh, lu hanh, thuc hanh
han ky » hanh ky, than ky, nhan ky
o hoc » co hoc, mo hoc, so hoc

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 han ky thuat o hoc ) or ( tu hanh trinh kxy thuat toan hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach han ky thuat o hoc ) OR ( tu hanh trinh kxy thuat toan hoc )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach han ky thuat o hoc ) or ( tu hanh trinh kxy thuat toan hoc ))*.