Perhaps you should try some spelling variations:
quoc quan » qua quan, luc quan, hoc quan
cac quoc » cac nuoc, cac cuoc, cao quoc
toc sach » hoc sach, doc sach, thuoc sach
quan anh » quan hanh, quang anh, tuan anh
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
hieu ve » hieu va, hieu van
y nang » ky nang, ly nang, v nang
vi cua » di cua
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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) or (toc sach)) y nang x hoi. hieu ve cac quoc quan anh ((vi cua) or (vai cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) y nang x hoi. hieu ve cac quoc quan anh ((vi cua) OR (vai cua)) tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) y nang x hoi. hieu ve cac quoc quan anh ((vi cua) or (vai cua)) tre*.