Perhaps you should try some spelling variations:
cham thuc » nham thuc, pham thuc, tham thuc
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
cua viet » ca viet, hoa viet, cua vat
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
thuc va » thuc vat, thuc dan, thuc day
dinh vi » dinh ve, dinh viet, dinh tri

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty nang mai hoi. hieu vu cham thuc va ((dinh vi) or (chinh tri)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang mai hoi. hieu vu cham thuc va ((dinh vi) OR (chinh tri)) cua viet.
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang mai hoi. hieu vu cham thuc va ((dinh vi) or (chinh tri)) cua viet*.