Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
vien cac » vien bach, vien dai, vien da
hanh via » hanh vi, hanh va, anh va
sach ky » sac ky, sach y, sach ty
duc van » duc tan, duc manh, duc phan
via cua » gia cua, gian cua, giau cua
cua tre » cua te, cuu tre, cua triet
ve cac » va 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: thu sach ky nang x hoi. hieu ((ve cac) or (vien cac)) ((duc van) OR (duc va)) hanh via cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky nang x hoi. hieu ((ve cac) OR (vien cac)) ((duc van) OR (duc va)) hanh via cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky nang x hoi. hieu ((ve cac) or (vien cac)) ((duc van) OR (duc va)) hanh via cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach ky nang x hoi. hieu ((ve cac) or (vien cac)) ((duc van) OR (duc va)) hanh via cua tre*.