Perhaps you should try some spelling variations:
van trien » van tien, va trien, van tren
day thanh » dao thanh, dat thanh, da thanh
vien cac » vien bach, vien dai, vien da
thuc day » thuc dan, thuc vat
thanh de » hanh de, thanh ve, thanh do
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ve cam » ve cham, ve cac, va cam
de van » le van, do van, ve van
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 ky nang x hoi. hieu ((ve cam) or (vien cac)) thuc day thanh de van trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x hoi. hieu ((ve cam) OR (vien cac)) thuc day thanh de van trien.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu ((ve cam) or (vien cac)) thuc day thanh de van trien*.