Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
thi van » thi lan, thi hanh, thi nang
van cam » van nam, van lam, van cau
duc bao » du bao, duc dao, duc ban
benh ve » benh va, benh vien, benh viem
cua tre » cua te, cuu tre, cua triet
duc ba » duc ban, duc va, duc ha
ve cua » le cua, de cua, te cua
x hoi » xa hoi, o hoi, x ho

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 tu nang x hoi. thi van cam ((duc ba) or (duc bao)) benh ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu nang x hoi. thi van cam ((duc ba) OR (duc bao)) benh ve cua tre*.