Perhaps you should try some spelling variations:
nuoc sach » nguoi sach, hoc sach, cuoc cach
dang dinh » dang sinh, dang dieu, dang hanh
thuc dang » thuoc dang, thuc dan, thuc dung
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
dinh va » dinh van, dinh ve, tinh va
hieu va » hieu qua
va cua » va chua, via cua, ca cua
cua te » cua tu
ma hoi » mai hoi, xa hoi, ma hoa

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