Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
doanh khoa » toan khoa
sach toi » sach doi, sach hoi, sach moi
toi gian » thoi gian, thi giang, don gian
cong hoc » dong hoc, cong coc, cong ho
cong hoa » dong hoa, dong hoc, hang hoa
khoa hoc » hoa hoc
tu sach » thu sach, su sach, te sach
xa phan » va phan, a phan, x phan

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach toi gian, nghien thu ((cong hoc) OR (cong hoa)) doanh khoa hoc ma hoa xa phan tu~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach toi gian, nghien thu ((cong hoc) OR (cong hoa)) doanh khoa hoc ma hoa xa phan tu".
• Adding a wildcard symbol may retrieve word variants: tu sach toi gian, nghien thu ((cong hoc) OR (cong hoa)) doanh khoa hoc ma hoa xa phan tu*.