Perhaps you should try some spelling variations:
sach hoi » sach moi, cach thoi, hoach hoi
sach doi » sach moi, sach dao, sach bai
cuu dong » cuu cong, cuu tong, cuu long
co thanh » cho thanh, o thanh, co tranh
cong hoc » dong hoc, cong hoa, cong coc
hoa lang » hoa dan, hoa van
lang dau » hang dau, xang dau, nang dau
hoi hoa » hoi khoa, hoc hoa, hoi hoc
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: tu ((sach hoi) or (sach doi)) dap, nghien cuu dong co thanh cong hoc xa hoi hoa lang dau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach hoi) OR (sach doi)) dap, nghien cuu dong co thanh cong hoc xa hoi hoa lang dau.
• Adding a wildcard symbol may retrieve word variants: tu ((sach hoi) or (sach doi)) dap, nghien cuu dong co thanh cong hoc xa hoi hoa lang dau*.