Perhaps you should try some spelling variations:
dang than » dang thanh, sang than, dang tran
cua triet » cua viet, su triet, va triet
bac nuoc » cac nuoc, bach tuoc, sach nuoc
thi van » thi lan, thi hanh, thi nang
van bac » van ban, van bao, van hac
va dang » van dang, va nang, va lang
cua tre » cua te, cuu tre, dua tren
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 ((cua tre) OR (cua triet))~.
• 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 ((cua tre) OR (cua triet)).
• 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 ((cua tre) OR (cua triet))".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sac ky) or (sach y)) nang x hoi. thi van bac nuoc va dang than ((cua tre) OR (cua triet))*.