Perhaps you should try some spelling variations:
su sach » so sach
vu sach » vu bach, vu khach
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
cac tru » ca tru, cac tro, cac thu
va hanh » van hanh, va thanh, va danh
ca viet » va viet, co viet, hoa viet
y nang » ky nang, ly nang, v nang
tru va » truc va, tu va, trung va
vi ca » vit ca, li ca, va ca

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) or (vu sach)) y nang xa hoi. ((hieu va) or (lieu va)) cac tru va hanh vi ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y nang xa hoi. ((hieu va) OR (lieu va)) cac tru va hanh vi ca viet.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) y nang xa hoi. ((hieu va) or (lieu va)) cac tru va hanh vi ca viet*.