Perhaps you should try some spelling variations:
nghien huu » nghien cuu, nguyen huu, nhiem huu
hoc sach » hoc sinh, hoc cac, hoc anh
doc sach » toc sach, nuoc sach, dac sac
hoc toan » hoc tan, hop toan, hoa toan
khoa hoc » hoa hoc
gian dan » gian lang
hoi tap » hoi dap, hoc tap, hoi tai
va gian » va gianh, van gian, va giai
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) or (doc sach)) hoi tap, nghien huu co hoc toan khoa hoc xa hoi va gian dan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (doc sach)) hoi tap, nghien huu co hoc toan khoa hoc xa hoi va gian dan.
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (doc sach)) hoi tap, nghien huu co hoc toan khoa hoc xa hoi va gian dan*.