Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
hoc sach » hoc sinh, hoc cac, hoc anh
sach hoc » cach hoc, sach hoi, mach hoc
khoa hoc » hoa hoc
phap dau » phan dau, phap day, pham dau
hoc tan » hoc tang, hoc dan, hoc can
hoc tai » hoc dai, hoc bai, hoc giai
va phap » va phat, ban phap
hoc xa » hoc ma

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach hoc tap, nghien cua mot ((hoc tan) or (hoc tai)) khoa hoc xa hoi va phap dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach hoc tap, nghien cua mot ((hoc tan) OR (hoc tai)) khoa hoc xa hoi va phap dau.
• Adding a wildcard symbol may retrieve word variants: hoc sach hoc tap, nghien cua mot ((hoc tan) or (hoc tai)) khoa hoc xa hoi va phap dau*.