Reactive power compensation technology

Reactor (electricity)

Reactor neutrino experiments

Reactor physics

Real variable

Reappraisal of early dinosaur radiation

Rearrangement reaction

Recent advances in tornado observations

Reciprocating aircraft engine

Reciprocity principle

Recombinant fungal biotechnology

Recombination (genetics)

Rectifier

Rectilinear motion

Recursive function

Recycling technology

Red dwarf star

Red Sea

Red yeast rice

Redbeds

Redox-active ligands

Redshift

Redtop grass

Reduction of diesel engine particulate emissions

Redwood

Reef

Reengineering

Reference electrode

Reference printing conditions

Reference value and reference interval

Reflecting microscope

Reflection and transmission coefficients

Reflection of electromagnetic radiation

Reflection of sound

Reflex

Reforestation

Reforming processes

Refraction of waves

Refractometric analysis

Refractory material

Refrigeration

Refrigeration cycle

Refrigerator

Regeneration (engineering)

Regenerative biology

Regional anatomy

Regolith

Regular polytopes

Regularia

Regulation of cotton lint growth

Regulation of fruit ripening

Regulation of leaf shape

Regulator

Reheating

Reinforced concrete

Relapsing fever

Relations among structure, properties, and function in biological materials

Relative atomic mass

Relative molecular mass

Relative motion

Relativistic electrodynamics

Relativistic heavy-ion collisions

Relativistic mechanics

Relativistic quantum theory

Relativity

Relaxation time of electrons

Relay

Reliability, availability, and maintainability

Reluctance

Reluctance motor

Remipedia

Remote manipulator

Remote sensing

Remote sensing with small unmanned aircraft systems

Remote-control system

Renal denervation as therapy for hypertension

Renewable resource

Renner-Teller effect

Rennin

Renormalization

Repressed memories

Reproductive behavior

Reproductive immunology

Reproductive system

Reproductive system disorders

Reptilia

Repulsion motor

Reservoir

Resin

Resistance heating

Resistance measurement

Resistance welding

Resistor

Resolving power (optics)

Resonance (acoustics and mechanics)

Resonance (alternating-current circuits)

Resonance (molecular structure)

Resonance (quantum mechanics)

Resonance ionization spectroscopy

Respiration