-
769.
Petroleum industry and trade
Subjects
Energy industries
-
770.
Petroleum pipelines
Subjects
Pipe
-
771.
Petroleum prospecting
Subjects
Petroleum engineeringProspecting
-
772.
Petroleum refineries
Subjects
Petroleum refining
-
773.
Pharmaceutical technology
Subjects
-
774.
Phase-locked loops
Subjects
Electric oscillators
-
775.
Philosophy of technology
Subjects
-
776.
Phonograph
Subjects
-
777.
Phonograph records
Subjects
Sound recordings
-
778.
Photoelectric cells
Subjects
-
779.
Photographic equipment
Subjects
-
780.
Photographic industry
Subjects
-
781.
Photorefractive materials
Subjects
-
782.
Photovoltaic cells
Subjects
Photoelectric cells
-
783.
Photovoltaic effect
Subjects
Photoelectricity
-
784.
Photovoltaic power generation
Subjects
Direct energy conversionSolar energyPhotovoltaic effect
-
785.
Photovoltaic power systems
Subjects
Solar power plants
-
786.
Physical instruments
Subjects
Scientific apparatus and instruments
-
787.
Piezoelectricity
Subjects
CrystallographyElectricity
-
788.
Pilot guides
Subjects
NavigationPilotage
-
789.
Pilotage
Subjects
Maritime contractsHarbors
-
790.
Pipe
Subjects
Hydraulic structuresTransportation
-
791.
Pistols
Subjects
WeaponsFirearms
-
792.
Plant biotechnology
Subjects
Agricultural biotechnology
Last updated dated: 06/09/2025