Perhaps you should try some spelling variations:
cua triet » cua viet, su triet, va triet
hanh tai » thanh tai, hang tai, han tai
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
tai cua » thai cua, tai cuc, tri cua
duc van » duc va, duc tan, duc manh
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
ve cam » ve cham, ve cac, ve cai
va cam » va cham, va cac, va cao

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 ky ((nang ma) or (nang x)) hoi. hieu ((ve cam) OR (va cam)) duc van hanh tai cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang ma) OR (nang x)) hoi. hieu ((ve cam) OR (va cam)) duc van hanh tai cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cam) OR (va cam)) duc van hanh tai cua triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((nang ma) or (nang x)) hoi. hieu ((ve cam) OR (va cam)) duc van hanh tai cua triet*.