Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
va tinh » may tinh
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ty nang » ky nang, ty hang, ly nang
ve cac » va cac, vien cac
o hoi » co hoi, o hoc, o hai
vi su » ve su, ki su, oi su

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty xang)) o hoi. hieu ve cac thuc va tinh ((vi su) OR (va su)) triet~.
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) or (ty xang)) o hoi. hieu ve cac thuc va tinh ((vi su) or (va su)) triet*.