Perhaps you should try some spelling variations:
khong thuoc » khang thuoc, hong phuoc, dong thuoc
hoc nhanh » hoc nganh, hoc phan
khong hoc » khung hoc, thong hoc, khong chuc
sach doi » sach hoi, sach moi, sach dao
hai tran » thai tran, hai tan, ha tran
tran han » tran hanh, tran hoan, tran nhan
tu sach » thu sach, su sach, te sach
doi tap » doi tac, doi dap, doi tai
xua hai » qua hai, cua hai, xa hai
han van » phan van, nhan van, hanh van
mo hoc » mon hoc, co hoc

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 doi tap, nghien cuu mo hoc nhanh ((khong hoc) or (khong thuoc)) xua hai tran han van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach doi tap, nghien cuu mo hoc nhanh ((khong hoc) OR (khong thuoc)) xua hai tran han van*.