Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van dinh » van minh, van dich, xuan dinh
va trien » va truyen, va thiet, va tuyen
cam duc » cam xuc, cao duc, nam duoc
sach ky » sac ky, sach y, sach ty
va dinh » va kinh, va tinh, vu dinh
x hoi » xa hoi, o hoi, x ho
cu va » cuu va, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ky nang x hoi. hieu van ((cam duc) OR (pham duc)) ((van dinh) or (va dinh)) cu va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang x hoi. hieu van ((cam duc) OR (pham duc)) ((van dinh) OR (va dinh)) cu va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang x hoi. hieu van ((cam duc) OR (pham duc)) ((van dinh) or (va dinh)) cu va trien".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x hoi. hieu van ((cam duc) OR (pham duc)) ((van dinh) or (va dinh)) cu va trien*.