Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
sach thi » sach thu, sach tai, sach thieu
thi hanh » thi thanh
hanh cua » manh cua, hang cua, hanh sua
su triet » su viet, su tien, ve triet
cua hoi » cua moi
cac toc » cac toi, cac nuoc, cac thoi
xa hanh » xa thanh, xa khanh, da hanh
va hanh » van hanh, va thanh, ban hanh

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach thi hanh cua hoi. lieu va ((cac toc) or (hoc nuoc)) ((xa hanh) or (va hanh)) va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach thi hanh cua hoi. lieu va ((cac toc) OR (hoc nuoc)) ((xa hanh) OR (va hanh)) va su triet.
• Adding a wildcard symbol may retrieve word variants: doc sach thi hanh cua hoi. lieu va ((cac toc) or (hoc nuoc)) ((xa hanh) or (va hanh)) va su triet*.