  LAMOST Data Release 5, covering $\sim$17,000 $deg^2$ from $-10^{\circ}$ to
$80^{\circ}$ in declination, contains 9 millions co-added low resolution
spectra of celestial objects, each spectrum combined from repeat exposure of
two to tens of times during Oct 2011 to Jun 2017. In this paper, We present the
spectra of individual exposures for all the objects in LAMOST Data Release 5.
For each spectrum, equivalent width of 60 lines from 11 different elements are
calculated with a new method combining the actual line core and fitted line
wings. For stars earlier than F type, the Balmer lines are fitted with both
emission and absorption profiles once two components are detected. Radial
velocity of each individual exposure is measured by minimizing ${\chi}^2$
between the spectrum and its best template. Database for equivalent widths of
spectral lines and radial velocities of individual spectra are available
online. Radial velocity uncertainties with different stellar type and
signal-to-noise ratio are quantified by comparing different exposure of the
same objects. We notice that the radial velocity uncertainty depends on the
time lag between observations. For stars observed in the same day and with
signal-to-noise ratio higher than 20, the radial velocity uncertainty is below
5km/s, and increase to 10km/s for stars observed in different nights.
