Perhaps you should try some spelling variations:
sach hoc » cach hoc, sach hoi, mach hoc
cuu cong » cua cong, thu cong, cac cong
dan khoa » dang khoa, da khoa, san khoa
khoa hoc » hoa hoc
tu sach » thu sach, su sach, te sach
cuu mot » cua mot, cuu mo, huu mot
hoc mac » hoc ma, hoc may, hoc cac
cu luan » tu luan, su luan, luc luan
mac ho » bac ho, cac ho, mau ho
ho cu » cho cu, ho chu, ho cua

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 hoc tap, nghien ((cuu cong) or (cuu mot)) hoc dan khoa hoc mac ho cu luan van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach hoc tap, nghien ((cuu cong) OR (cuu mot)) hoc dan khoa hoc mac ho cu luan van.
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien ((cuu cong) or (cuu mot)) hoc dan khoa hoc mac ho cu luan van*.