Perhaps you should try some spelling variations:
doanh vien » doanh tien, doanh chien, thanh vien
vien cac » vien bach, vien dai, vien da
kho tang » cao tang
thuc va » thuc vat, thuc dan, thuc day
truc va » thuc vat, trung va
tu sach » thu sach, su sach, te sach
ky tang » ky nang, ky dang, ky trong
qua ca » qua cac, qua cua, qua cai

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) OR (kho tang)) xa hoi. hieu qua ca ((truc va) or (thuc va)) doanh vien cac tro~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky tang) OR (kho tang)) xa hoi. hieu qua ca ((truc va) OR (thuc va)) doanh vien cac tro.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky tang) OR (kho tang)) xa hoi. hieu qua ca ((truc va) or (thuc va)) doanh vien cac tro".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky tang) OR (kho tang)) xa hoi. hieu qua ca ((truc va) or (thuc va)) doanh vien cac tro*.