Perhaps you should try some spelling variations:
sach tranh » canh tranh
sach vien » sach tien, sach viet, sinh vien
tranh lao » tranh lam, trinh lao, tranh luan
khoa hoc » hoa hoc
lao khoa » lo khoa, tai khoa, san khoa
su sach » so sach, vu sach
vien da » vien dai, hien dai
te sach » toc sach
tu mach » tu cach, tu manh, tu hach
mach xu » cach xu, sach xu, mach cua

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 vien da khoa hoc ) or ( te sach tranh lao khoa hoc ))) or ( tu mach xu ly khoa hoc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (((( su sach vien da khoa hoc ) OR ( te sach tranh lao khoa hoc ))) OR ( tu mach xu ly khoa hoc )).
• Adding a wildcard symbol may retrieve word variants: (((( su sach vien da khoa hoc ) or ( te sach tranh lao khoa hoc ))) or ( tu mach xu ly khoa hoc ))*.