Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
manh hai » lanh hai, minh hai, thanh hai
quoc ban » quoc bao, quoc lan, quoc quan
anh hai » lanh hai, anh thai, anh bai
tu sach » thu sach, su sach, te sach
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
ve cac » va cac

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 y nang xa hoi. hieu ((ve cac) OR (vien cac)) quoc ban ((anh hai) or (manh hai)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. hieu ((ve cac) OR (vien cac)) quoc ban ((anh hai) OR (manh hai)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. hieu ((ve cac) OR (vien cac)) quoc ban ((anh hai) or (manh hai)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. hieu ((ve cac) OR (vien cac)) quoc ban ((anh hai) or (manh hai)) cuu tre*.