Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
vu khach » vu khanh, vu khac, vay khach
qua tham » qua cham, qua than, qua thanh
ve triet » va trien, su triet
mang xa » lang xa, mang may, dang xay
so sach » so sanh, bo sach, co sach
thuc va » thuc vat, thuc dan, thuc day
va tinh » may tinh
tinh vi » trinh vi, tinh voi, tinh va
nang ma » tang ma, sang ma, nang cao
vi ve » va ve, gi ve, ve ve

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu khach) or (so sach)) ty ((mang xa) or (nang ma)) hoi. hieu qua tham thuc va tinh vi ve triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (so sach)) ty ((mang xa) OR (nang ma)) hoi. hieu qua tham thuc va tinh vi ve triet.
• Adding a wildcard symbol may retrieve word variants: ((vu khach) or (so sach)) ty ((mang xa) or (nang ma)) hoi. hieu qua tham thuc va tinh vi ve triet*.