Perhaps you should try some spelling variations:
mmanh hai » thanh hai, lanh hai, minh hai
cao quoc » cac quoc, cao thuoc, han quoc
quoc ban » quoc bao, quoc lan, quoc quan
manh hai » lanh hai, minh hai, thanh hai
tu sach » thu sach, su sach, te sach
hieu ve » hieu van
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cuu tre » cua tre, cau tren, cau treo
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: tu sach y nang xa hoi. ((hieu ve) OR (hieu va)) cao quoc ban ((manh hai) or (mmanh hai)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang xa hoi. ((hieu ve) OR (hieu va)) cao quoc ban ((manh hai) OR (mmanh hai)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang xa hoi. ((hieu ve) OR (hieu va)) cao quoc ban ((manh hai) or (mmanh hai)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang xa hoi. ((hieu ve) OR (hieu va)) cao quoc ban ((manh hai) or (mmanh hai)) cuu tre*.