Perhaps you should try some spelling variations:
nhanh hai » nhanh thai, thanh hai, nhanh ha
nhanh hoi » nhanh hon, nhanh hoan, nhanh thai
thu sach » tu sach, thuat sach, thuoc sach
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
qua cac » cua cac
nang xa » nang x, lang xa, nang ma
lo nang » ho nang, ly nang, loai nang
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (su sach)) lo nang xa hoi. hieu qua cac duc van ((nhanh hoi) OR (nhanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (su sach)) lo nang xa hoi. hieu qua cac duc van ((nhanh hoi) OR (nhanh hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (su sach)) lo nang xa hoi. hieu qua cac duc van ((nhanh hoi) OR (nhanh hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (su sach)) lo nang xa hoi. hieu qua cac duc van ((nhanh hoi) OR (nhanh hai)) cua tre*.