Perhaps you should try some spelling variations:
vien cac » vien dai, vien da, gian cac
danh vai » danh sai, danh va, doanh van
vai cua » dai cua, hai cua, lai cua
va danh » va dinh, va dan, va hanh
tu sach » thu sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
lop va » lap va, hop va, nop va

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