Perhaps you should try some spelling variations:
nghien cua » nghien cuu, nghiep cua, nghiep vua
hang khoa » dung khoa
sach hoc » cach hoc, sach hoi, mach hoc
cong coc » cong cuoc, cong cac, cong co
coc hang » hoc hang, oc hang, moc hoang
dap nhan » dap nha, dac nhan, dam nhan
su sach » so sach, vu sach
nhan va » nhan tai, nhan dan, nhan tao

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 hoc tap, nghien cua cong coc hang khoa ((hoc xa) or (hoc ma)) hoi dap nhan va~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach hoc tap, nghien cua cong coc hang khoa ((hoc xa) OR (hoc ma)) hoi dap nhan va.
• Adding a wildcard symbol may retrieve word variants: su sach hoc tap, nghien cua cong coc hang khoa ((hoc xa) or (hoc ma)) hoi dap nhan va*.