Perhaps you should try some spelling variations:
instrumentacion didactica » instrumentos didacticos
instrumento didactico » instrumentos didacticos, instrumento pedagogico, instrumento politico
publicacion de » publicaciones de, aplicacion de
minera de » mineria de, mineral de, minerales de
y minera » y mineral, y mineria, y minero

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: publicacion de ((instrumentacion didactica) or (instrumento didactico)) y minera de espana ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: publicacion de ((instrumentacion didactica) OR (instrumento didactico)) y minera de espana ;.
• Adding a wildcard symbol may retrieve word variants: publicacion de ((instrumentacion didactica) or (instrumento didactico)) y minera de espana ;*.