Perhaps you should try some spelling variations:
nhieu viec » hieu viec, nhien viet
viec cam » viec lam, viec cua, viec va
hinh hoc » sinh hoc, tin hoc, benh hoc
tu sach » thu sach, su sach, te sach
ky lang » ky dang, ky tang, tay lang
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, luc va, xac va
tuc va » thuc va, truc va, tuc xa

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 ((ky lang) or (ky nang)) xa hoi. nhieu viec cam ((xuc va) OR (tuc va)) hinh hoc cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky lang) OR (ky nang)) xa hoi. nhieu viec cam ((xuc va) OR (tuc va)) hinh hoc cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky lang) or (ky nang)) xa hoi. nhieu viec cam ((xuc va) OR (tuc va)) hinh hoc cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky lang) or (ky nang)) xa hoi. nhieu viec cam ((xuc va) OR (tuc va)) hinh hoc cua tre*.