Perhaps you should try some spelling variations:
dat thanh » dao thanh, dat khanh, dang thanh
dao hanh » dao thanh, dang hanh, ban hanh
cao thuc » cao thuoc, bao thuc, can thuc
doi cua » dai cua, hoi cua
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va cao » va cac, va co, va dao
di cua » dai cua, de cua, do cua
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: vu sach ky nang x hoi. hieu va cao thuc ((dao hanh) or (dat thanh)) ((di cua) OR (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang x hoi. hieu va cao thuc ((dao hanh) OR (dat thanh)) ((di cua) OR (doi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang x hoi. hieu va cao thuc ((dao hanh) or (dat thanh)) ((di cua) OR (doi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang x hoi. hieu va cao thuc ((dao hanh) or (dat thanh)) ((di cua) OR (doi cua)) tre*.