Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
doanh khoa » toan khoa
den thanh » de thanh, dinh thanh, dong thanh
thu mach » thu sach, thuat mach, thuc cach
so doanh » so danh, su doanh, hoa doanh
khoa hoc » hoa hoc
cong so » cong san, cong hoa
xa thai » ca thai, a thai, da thai
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: ((thu mach) OR (thu hoach)) hoc tap, nghien thu cong so doanh khoa hoc xa thai den thanh san~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu mach) OR (thu hoach)) hoc tap, nghien thu cong so doanh khoa hoc xa thai den thanh san".
• Adding a wildcard symbol may retrieve word variants: ((thu mach) OR (thu hoach)) hoc tap, nghien thu cong so doanh khoa hoc xa thai den thanh san*.