Perhaps you should try some spelling variations:
hoc doanh » hoa doanh, hoc dan, hoc nganh
van thanh » ban thanh, van tuan
cuu cong » cua cong, thu cong, cac cong
hoc danh » hoc dan, hoc anh, hoc hanh
hoan hoc » hoa hoc, toan hoc, hoang hoa
bai tai » bai tap, ban tai, dai tai
hai van » thai van, ha van, hai tan
su cac » tu cac, su cao, su can
ma hai » ta hai, va hai, xa hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su cac bai tai, nghien cuu cong ((hoc doanh) OR (hoc danh)) hoan hoc ma hai van thanh san~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su cac bai tai, nghien cuu cong ((hoc doanh) OR (hoc danh)) hoan hoc ma hai van thanh san".
• Adding a wildcard symbol may retrieve word variants: su cac bai tai, nghien cuu cong ((hoc doanh) OR (hoc danh)) hoan hoc ma hai van thanh san*.