Perhaps you should try some spelling variations:
van thiet » va thiet, dan thiet, can thiet
vien cac » vien bach, vien dai, vien da
tinh voi » trinh voi, tinh doi, binh voi
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
va tinh » may tinh
voi van » vi van, voi can, doi van
ve cac » va cac
bac va » ban va, bac ha, bao va
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 cac) or (vien cac)) bac va tinh voi van thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang x hoi. hieu ((ve cac) OR (vien cac)) bac va tinh voi van thiet.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu ((ve cac) or (vien cac)) bac va tinh voi van thiet*.