Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
tinh doi » trinh doc, trinh do, tinh hoc
dang xay » dang van, van xay
cac toc » cac toi, cac nuoc, cac thoi
doi cua » dai cua, hoi cua
va tinh » may tinh
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
cac tuc » cac tu, cac tac, cac nuoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((nang x) or (dang xay)) hoi. hieu va ((cac tuc) OR (cac toc)) va tinh doi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang x) OR (dang xay)) hoi. hieu va ((cac tuc) OR (cac toc)) va tinh doi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang x) or (dang xay)) hoi. hieu va ((cac tuc) OR (cac toc)) va tinh doi cua triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang x) or (dang xay)) hoi. hieu va ((cac tuc) OR (cac toc)) va tinh doi cua triet*.