Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
va triet » va trien, ve triet, cua triet
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
hanh te » hanh tu, hanh ve, hanh de
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
ve cam » ve cham, ve cac, va cam
x hoi » xa hoi, o hoi, x ho
thiet » thieu

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 dan hanh te ((va triet) OR (va thiet))~.
• 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 dan hanh te ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang x hoi. hieu ((ve cam) or (vien cac)) thuc dan hanh te ((va triet) OR (va thiet))".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang x hoi. hieu ((ve cam) or (vien cac)) thuc dan hanh te ((va triet) OR (va thiet))*.