Perhaps you should try some spelling variations:
sang than » cang thang, dang thanh, sang tao
dang than » dang thanh, dang tran, dan than
bac nuoc » cac nuoc, bach tuoc, sach nuoc
van bac » van ban, van bao, van hac
thi van » thi lan, thi hanh, thi nang
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
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: thuoc ((sac ky) or (sach y)) nang x hoi. thi van bac nuoc va ((dang than) OR (sang than)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sac ky) OR (sach y)) nang x hoi. thi van bac nuoc va ((dang than) OR (sang than)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sac ky) or (sach y)) nang x hoi. thi van bac nuoc va ((dang than) OR (sang than)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sac ky) or (sach y)) nang x hoi. thi van bac nuoc va ((dang than) OR (sang than)) cua tre*.