Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
thanh ve » hanh ve, thanh va, thanh vien
va thanh » gia thanh, ban thanh, va tinh
sach ty » sach tu, sach thu, xach tay
ve cua » le cua, de cua, te cua
luc va » duc va, tuc va, loc va
cua te » cua tu
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: su ((sach ty) OR (sach y)) nang x hoi. hieu ((ve cac) or (vien cac)) luc va thanh ve cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ty) OR (sach y)) nang x hoi. hieu ((ve cac) OR (vien cac)) luc va thanh ve cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ty) OR (sach y)) nang x hoi. hieu ((ve cac) or (vien cac)) luc va thanh ve cua te".
• Adding a wildcard symbol may retrieve word variants: su ((sach ty) OR (sach y)) nang x hoi. hieu ((ve cac) or (vien cac)) luc va thanh ve cua te*.