Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh van » thanh san, thanh toan, thanh phan
sach hoc » cach hoc, sach hoi, sach duoc
mach hoc » cach hoc, dich hoc, anh hoc
cuu long » cuu cong, cuu tong, cuu nang
long soc » lon soc, luong suc, cong so
soc toan » so toan, soc trang, ngoc toan
khoa hoc » hoa hoc
hai van » thai van, ha van, hai tan
hoc xa » hoc ma
xa hai » xa thai, xua hai, xa hoi

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 cuu long soc toan khoa hoc xa hai van thanh van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach hoc) OR (mach hoc)) tap, nghien cuu long soc toan khoa hoc xa hai van thanh van".
• Adding a wildcard symbol may retrieve word variants: thu ((sach hoc) OR (mach hoc)) tap, nghien cuu long soc toan khoa hoc xa hai van thanh van*.