Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
cac thuc » cach thuc, cac thu, can thuc
su sach » so sach, vu sach
ky dang » ky nang
ky danh » ky anh
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu

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 (su sach)) ((ky dang) OR (ky danh)) xa hoi. hieu va cac thuc va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu khach) OR (su sach)) ((ky dang) OR (ky danh)) xa hoi. hieu va cac thuc va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu khach) or (su sach)) ((ky dang) OR (ky danh)) xa hoi. hieu va cac thuc va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((vu khach) or (su sach)) ((ky dang) OR (ky danh)) xa hoi. hieu va cac thuc va hanh vi cuu tre*.