Perhaps you should try some spelling variations:
instituto tecnico » instituto politecnico, instituto tecnologico, instituto medio
publicacion de » publicaciones de, aplicacion de
de instituto » del instituto, el instituto, e institutos
minerales en » generales en
tecnico de » tecnica de, tecnicas de
mineral de » general de, mineria de, mineral y

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

• If you are trying to use Boolean operators, they must be ALL CAPS: publicacion de instituto tecnico de ((mineral de) OR (minerales en)) espana ;~.
• Adding a wildcard symbol may retrieve word variants: publicacion de instituto tecnico de ((mineral de) or (minerales en)) espana ;*.