Unable to see anything after importing .obj file I try to import .obj files from this project: http://dbarchive.biosciencedbc.jp/en/bodyparts3d/download.html -
the files contain Polygon Mesh Data.

When I import the obj file into blender, the outliner shows a new mesh added, but nothing is visible in the 3D viewport:





Any help will be appreciated.
Imported objects from other file formats, are some times really small, off centered, or very far away from scene origin, compared to the default scene scale.
First step is to make sure anything was actually imported. Look in the Outliner for new objects under current collection (geometry should be of mesh type). If there are any, use the outliner to select them.

Then with the mouse over the 3D View press the Numpad . (Period) key, or go to View &gt; Frame Selected for 2.8+, to view selected objects.
This will zoom in tightly on the selected object.