diff --git a/backend/app/api/articles.py b/backend/app/api/articles.py
index 5eb6d38..1799c4d 100644
--- a/backend/app/api/articles.py
+++ b/backend/app/api/articles.py
@@ -43,8 +43,10 @@ async def list_articles(
     # 公共筛选条件(用于 list + count)
     filters = [Article.duplicate_of.is_(None)]
 
-    # 默认过去 24h
-    if since is None and until is None:
+    # 默认过去 24h — 但**搜索时(q 不为空)不限时间**,搜全量历史
+    # (用户的搜索意图是"找到含某关键字的文章",跟时间无关;
+    #  想限定时间显式传 since/until)
+    if not q and since is None and until is None:
         since = _default_since_24h()
 
     if since: