Merge pull request #1 from kimmking/patch-1

Update qos.md
diff --git a/dubbo-user-book/references/qos.md b/dubbo-user-book/references/qos.md
index 0979957..4fa8bef 100644
--- a/dubbo-user-book/references/qos.md
+++ b/dubbo-user-book/references/qos.md
@@ -138,7 +138,7 @@
 dubbo>offline
 OK
 
-//根据正则,上线部分服务
+//根据正则,下线部分服务
 dubbo>offline com.*
 OK
 ```