Perhaps you should try some spelling variations:
vien cam » vien cac, vien cao, vien can
vien nam » viet nam, vien dai, van nam
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
truc va » thuc va, thuc vat, trung va
va hanh » van hanh, va thanh, va danh
lai cua » hai cua, lai chau, thai cua
y nang » ky nang, ly nang, v nang

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 y nang xa hoi. hieu ((vien cam) OR (vien nam)) truc va hanh ((lai cua) or (dai cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang xa hoi. hieu ((vien cam) OR (vien nam)) truc va hanh ((lai cua) OR (dai cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang xa hoi. hieu ((vien cam) OR (vien nam)) truc va hanh ((lai cua) or (dai cua)) triet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang xa hoi. hieu ((vien cam) OR (vien nam)) truc va hanh ((lai cua) or (dai cua)) triet*.