Perhaps you should try some spelling variations:
doanh khoa » toan khoa
dong thanh » truong thanh
thanh van » thanh san, thanh toan, thanh phan
thu mach » thu sach, thuat mach, thu hoach
mach hoc » cach hoc, dich hoc, anh hoc
cuu cong » cua cong, thu cong, cac cong
so doanh » so danh, su doanh, hoa doanh
khoa hoc » hoa hoc
cong so » cong san, cong hoa
xa thai » ca thai, a thai, xa hai
da thai » dao thai, do thai, ca thai

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu mach hoc tap, nghien cuu cong so doanh khoa hoc ((xa thai) OR (da thai)) dong thanh van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu mach hoc tap, nghien cuu cong so doanh khoa hoc ((xa thai) OR (da thai)) dong thanh van".
• Adding a wildcard symbol may retrieve word variants: thu mach hoc tap, nghien cuu cong so doanh khoa hoc ((xa thai) OR (da thai)) dong thanh van*.