Perhaps you should try some spelling variations:
doanh vien » doanh tien, doanh chien, thanh vien
thuc day » thuc dan, thuc vat
vien cac » vien bach, vien dai, vien da
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
qua cai » qua hai, qua cac, qua ca
truc va » thuc vat, trung va
thuc va » thuc vat, thuc dan
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 ky tang ma hoi. hieu qua cai ((truc va) or (((thuc va) OR (thuc day)))) doanh vien cac tro~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang ma hoi. hieu qua cai ((truc va) OR (((thuc va) OR (thuc day)))) doanh vien cac tro.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang ma hoi. hieu qua cai ((truc va) or (((thuc va) OR (thuc day)))) doanh vien cac tro".
• Adding a wildcard symbol may retrieve word variants: tu sach ky tang ma hoi. hieu qua cai ((truc va) or (((thuc va) OR (thuc day)))) doanh vien cac tro*.