  We present the largest sample of giant radio quasars (GRQs), which are
defined as having a projected linear size greater than 0.7 Mpc. The sample
consists of 272 GRQs, of which 174 are new objects discovered through
cross-matching the NRAO VLA Sky Survey (NVSS) and the Sloan Digital Sky Survey
14$^{\rm th}$ Data Release Quasar Catalogue (DR14Q) and confirmed using Faint
Images of the Radio Sky at Twenty-Centimeters (FIRST) radio maps. In our
analysis we compare the GRQs with 367 smaller, lobe-dominated radio quasars
found using our search method, as well as with quasars from the SDSS DR14
Quasar Catalogue, investigating the parameters characterizing their radio
emission (i.e. total and core radio luminosity, radio core prominence), optical
properties (black hole masses, accretion rates, distribution in Eigenvector 1
plane) and infrared colours. For the GRQs and smaller radio quasars we find a
strong correlation between [OIII] luminosity and radio luminosity at 1.4 GHz,
indicating a strong connection between radio emission and conditions in the
narrow-line region. We spot no significant differences between GRQs and smaller
radio quasars, however we show that most extended radio quasars belong to a
quasar population of evolved AGNs with large black hole masses and low
accretion rates. We also show that GRQs have bluer W2-W3 colours compared to
SDSS quasars with FIRST detections, indicating differences in the structure of
the dusty torus.
