Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
duc manh » suc manh, duc anh, duc minh
hanh tai » thanh tai, hang tai, han tai
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve phan » va phan, ke phan, ve phat
duc van » duc va, duc tan, duc phan
tai cua » thai cua, tai cuc, tri cua
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: ((toc sach) or (hoc sinh)) ky nang xa hoi. hieu ve phan ((duc van) OR (duc manh)) hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sinh)) ky nang xa hoi. hieu ve phan ((duc van) OR (duc manh)) hanh tai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sinh)) ky nang xa hoi. hieu ve phan ((duc van) OR (duc manh)) hanh tai cua tre*".