Perhaps you should try some spelling variations:
nghien thu » nghiem thuc, nghiep thuc, nghien cuu
manh tong » manh tuong, manh tung, manh long
sach hoc » cach hoc, sach hoi, mach hoc
cong hoc » dong hoc, cong hoa, cong coc
hoc manh » hoc anh, hoc hanh, hoc danh
cac nhan » ca nhan, cac nha, cam nhan
nhan dan » phan dau, gian dan, nhan tai
tu sach » thu sach, su sach, te sach
hop may » hoc may, hoa may, chop mat
voi cac » loi cach
hop ma » hoc ma, hop va, chop mat

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 hoc tap, nghien thu cong hoc manh tong ((hop ma) OR (hop may)) voi cac nhan dan~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoc tap, nghien thu cong hoc manh tong ((hop ma) OR (hop may)) voi cac nhan dan".
• Adding a wildcard symbol may retrieve word variants: tu sach hoc tap, nghien thu cong hoc manh tong ((hop ma) OR (hop may)) voi cac nhan dan*.