Perhaps you should try some spelling variations:
hanh hai » thanh hai, nhanh hai, hang hai
cua viet » hoa viet, cua vat, cua dieu
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
cac tru » ca tru, cac tro, cac thu
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
ca viet » va viet, co viet, hoa viet
tru va » truc va, tu va, trung va

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 xa hoi. lieu va cac tru va hanh hai ((cua tre) or (((cua viet) OR (ca viet))))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. lieu va cac tru va hanh hai ((cua tre) OR (((cua viet) OR (ca viet)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. lieu va cac tru va hanh hai ((cua tre) or (((cua viet) OR (ca viet))))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. lieu va cac tru va hanh hai ((cua tre) or (((cua viet) OR (ca viet))))*.