diff --git a/knowledge_base.py b/knowledge_base.py
index 5dc31c8..f7a61bc 100644
--- a/knowledge_base.py
+++ b/knowledge_base.py
@@ -2,6 +2,7 @@
 
 import os
 import re
+import logging
 from pathlib import Path
 from typing import List, Tuple, Optional
 
@@ -73,9 +74,9 @@ class KnowledgeBase:
         if not self.is_ready or not query.strip():
             return []
 
-        # 短文本（< 4 个字或 <= 2 个有效词）不做搜索，避免噪音
+        # 短文本：至少 2 个字且至少有 1 个有效词才搜索
         tokens = [t for t in jieba.cut(query.strip()) if len(t) >= 2]
-        if len(query.strip()) < 4 or len(tokens) <= 1:
+        if len(query.strip()) < 2 or len(tokens) == 0:
             return []
 
         query_vec = self._vectorizer.transform([query])
@@ -88,6 +89,16 @@ class KnowledgeBase:
             if score < min_score:
                 continue
             results.append((self.docs[idx], score))
+        if results:
+            return results
+
+        # Fallback: 子串匹配（查询包含在文档标题或内容中）
+        q = query.strip()
+        for doc in self.docs:
+            if q in doc["content"] or q in doc["title"]:
+                logger = logging.getLogger("msgbot.kb")
+                logger.debug(f"子串匹配: \"{q}\" → {doc['title']}")
+                return [(doc, min_score)]
         return results
 
     def get_doc_count(self) -> int:
diff --git a/monitor.py b/monitor.py
index b3e38f9..e06df91 100644
--- a/monitor.py
+++ b/monitor.py
@@ -280,7 +280,7 @@ class MessageMonitor:
                 pass
 
     def _read_win32_texts(self, platform: str) -> list:
-        """Win32 API 直接读窗口文本（绕过 UIA 缓存）。"""
+        """Win32 API 读窗口文本，递归枚举（depth 不限）。"""
         hwnd = self._cached_hwnd.get(platform)
         if not hwnd:
             return []
@@ -289,7 +289,7 @@ class MessageMonitor:
         def enum_callback(child_hwnd, _):
             try:
                 text = win32gui.GetWindowText(child_hwnd)
-                if text and len(text.strip()) >= 4:
+                if text and len(text.strip()) >= 2:
                     texts.append(text.strip())
             except Exception:
                 pass
@@ -297,7 +297,7 @@ class MessageMonitor:
 
         try:
             main_text = win32gui.GetWindowText(hwnd)
-            if main_text and len(main_text.strip()) >= 4:
+            if main_text and len(main_text.strip()) >= 2:
                 texts.append(main_text.strip())
             win32gui.EnumChildWindows(hwnd, enum_callback, None)
         except Exception:
@@ -308,7 +308,19 @@ class MessageMonitor:
         """剪贴板法：聚焦窗口→Ctrl+A→Ctrl+C→读剪贴板（适用 Electron 应用）。
 
         稳妥可靠但会切焦点+清用户剪贴板（自动恢复原内容）。
+        自动重试 1 次若首次结果为空。
         """
+        texts = self._read_via_clipboard_once(platform)
+        if texts:
+            return texts
+        # 重试一次：再次 SetForegroundWindow + SendKeys
+        logger.debug(f"[{platform}] 剪贴板首次空，重试")
+        time.sleep(0.5)
+        texts = self._read_via_clipboard_once(platform)
+        return texts
+
+    def _read_via_clipboard_once(self, platform: str) -> list:
+        """剪贴板法单次执行。"""
         hwnd = self._cached_hwnd.get(platform)
         if not hwnd or not win32gui.IsWindow(hwnd):
             return []
@@ -359,8 +371,6 @@ class MessageMonitor:
 
         return texts
 
-    # ── 自动回复相关 ──────────────────────────────────────────
-
     def get_raw_clipboard(self, platform: str) -> str:
         """获取最近一次剪贴板读取的原始文本。"""
         return self._raw_clipboard.get(platform, "")
@@ -512,8 +522,9 @@ class MessageMonitor:
     def _read_messages(self, window, platform: str = "") -> list:
         """每轮重新定位 ListControl。"""
         if platform == "qq":
-            # QQ NT/TIM Electron: UIA 不可遍历，唯一可靠是 SetForegroundWindow + SendKeys(Ctrl+A/C)
-            # 降频到 20s 一次，减少焦点切换次数；切回原前台由 sendkeys 后自动恢复
+            # QQ NT/TIM Electron: UIA 不可遍历，剪贴板法+Win32回退
+            # 先 SendMessage 点击消息区确保焦点位置
+            self._click_message_area(platform)
             texts = self._read_via_clipboard(platform)
             if texts:
                 return texts