Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
nang mai » nang ma, nang tai, lang mai
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu va » hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
vi cua » vai cua, di cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thuoc sach)) ky nang mai hoi. ((hieu va) OR (lieu va)) nam thuc va hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) ky nang mai hoi. ((hieu va) OR (lieu va)) nam thuc va hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) ky nang mai hoi. ((hieu va) OR (lieu va)) nam thuc va hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) ky nang mai hoi. ((hieu va) OR (lieu va)) nam thuc va hanh vi cua te*.