diff --git a/pastastore/store.py b/pastastore/store.py
index b2a2954..20eabde 100644
--- a/pastastore/store.py
+++ b/pastastore/store.py
@@ -1496,7 +1496,7 @@ def search(
         case_sensitive: bool = True,
         sort=True,
     ):
-        """Search for names of time series or models starting with `s`.
+        """Search for names of time series or models containing string `s`.
 
         Parameters
         ----------
@@ -1515,30 +1515,45 @@ def search(
             list of names that match search result
         """
         if libname == "models":
-            lib_names = self.model_names
+            lib_names = {"models": self.model_names}
         elif libname == "stresses":
-            lib_names = self.stresses_names
+            lib_names = {"stresses": self.stresses_names}
         elif libname == "oseries":
-            lib_names = self.oseries_names
+            lib_names = {"oseries": self.oseries_names}
+        elif libname is None:
+            lib_names = {
+                "oseries": self.oseries_names,
+                "stresses": self.stresses_names,
+                "models": self.model_names,
+            }
         else:
             raise ValueError("Provide valid libname: 'models', 'stresses' or 'oseries'")
 
-        if isinstance(s, str):
-            if case_sensitive:
-                matches = [n for n in lib_names if s in n]
-            else:
-                matches = [n for n in lib_names if s.lower() in n.lower()]
-        if isinstance(s, list):
-            m = np.array([])
-            for sub in s:
+        result = {}
+        for lib, names in lib_names.items():
+            if isinstance(s, str):
                 if case_sensitive:
-                    m = np.append(m, [n for n in lib_names if sub in n])
+                    matches = [n for n in names if s in n]
                 else:
-                    m = np.append(m, [n for n in lib_names if sub.lower() in n.lower()])
-            matches = list(np.unique(m))
-        if sort:
-            matches.sort()
-        return matches
+                    matches = [n for n in names if s.lower() in n.lower()]
+            elif isinstance(s, list):
+                m = np.array([])
+                for sub in s:
+                    if case_sensitive:
+                        m = np.append(m, [n for n in names if sub in n])
+                    else:
+                        m = np.append(m, [n for n in names if sub.lower() in n.lower()])
+                matches = list(np.unique(m))
+            else:
+                raise TypeError("s must be str or list of str!")
+            if sort:
+                matches.sort()
+            result[lib] = matches
+
+        if len(result) == 1:
+            return result[lib]
+        else:
+            return result
 
     def get_model_timeseries_names(
         self,