Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tham duc » pham duc, tham du, than duc
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
sach ky » sac ky, sach ty, sach kem
duc van » duc va, duc tan, duc manh
doi cua » dai cua, hoi cua
di cua » dai cua, de cua, do cua
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: tu ((sach ky) or (sach y)) nang x hoi. hieu van tham duc van hanh ((di cua) OR (doi cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang x hoi. hieu van tham duc van hanh ((di cua) OR (doi cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang x hoi. hieu van tham duc van hanh ((di cua) OR (doi cua)) triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang x hoi. hieu van tham duc van hanh ((di cua) OR (doi cua)) triet*.