The codes below display in the CL: Classification field.

The general classification codes are searchable. For example, to search for records on aerospace engineering in general, enter

cl=10

To search for records on the aerospace engineering of aircraft, enter

cl=11

To search for all records with classification codes beginning with 1 (i.e., classification code 10 and all its subheadings), enter

cl=1*

10 Aerospace Engineering (General)

11 Aircraft

12 Spacecraft

13 Rockets and Missiles

14 Satellites, Probes, and Space Habitats

20 Automotive Engineering (General)

21 Automobiles, Trucks, and Buses

22 Motorcycles

23 Electric and Hybrid Vehicles

24 Tanks and Armored Vehicles

25 Earthmoving and Construction Machinery

26 Agricultural and Farm Machinery

27 Industrial and Materials Handling Machinery

28 Other Sporting and Recreational Vehicles

30 Railway Engineering (General)

31 Railroad Rails and Structures

32 Locomotives

33 Passenger, Freight, and Tank Cars

34 High Speed Trains

35 Rapid Transit Railways

36 Monorails

37 Magnetic Levitation Railways

38 Roller Coasters

40 Naval and Marine Engineering (General)

41 Shipbuilding

42 Passenger Ships

43 Cargo and Commercial Ships

44 Military Ships and Submarines

45 Non-Military Submersibles

46 Pleasure Craft

50 Mechanical Engineering for Industrial and Manufacturing Processes

51 Electric Power Generation

52 Industrial Machinery and Equipment

53 Industrial Robots and Automation

54 Health and Safety

60 Design Principles, Theory, and Analysis

61 Design Principles

62 Theoretical Mechanics and Dynamics

63 Mathematics and Computation

64 Fuels and Propellants

70 Forensic Engineering

80 Management and Marketing