Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
van thanh » ban thanh, van tuan
sach hoc » cach hoc, sach hoi, sach duoc
mach hoc » cach hoc, dich hoc, anh hoc
toan hoa » toan khoa, toan hoat, toan hoc
cong so » cong san, cong hoa
so toan » so tan, so than, bao toan
hoc xua » hoc cua, hoc xa, hoc lua
xua hai » qua hai, cua hai, xa hai
hai van » thai van, ha van, hai tan

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach hoc) OR (mach hoc)) tap, nghien thu cong so toan hoa hoc xua hai van thanh san~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach hoc) OR (mach hoc)) tap, nghien thu cong so toan hoa hoc xua hai van thanh san".
• Adding a wildcard symbol may retrieve word variants: thu ((sach hoc) OR (mach hoc)) tap, nghien thu cong so toan hoa hoc xua hai van thanh san*.