  The experiment Neutrino-4 had started in 2014 with a detector model and then
was continued with a full-scale detector in 2016 - 2021. In this article we
describe all steps of preparatory work on this experiment. We present all
results of the Neutrino-4 experiment with increased statistical accuracy
provided to date. The experimental setup is constructed to measure the flux and
spectrum of the reactor antineutrinos as a function of distance to the center
of the active zone of the SM-3 reactor (Dimitrovgrad, Russia) in the range of 6
- 12 meters. Using all the collected data, we performed a model-independent
analysis to determine the oscillation parameters $\Delta m_{14}^2$ and
$\sin^22\theta_{14}$. The method of coherent summation of measurement results
allows to directly demonstrate the oscillation effect. We present the analysis
of possible systematic errors and the MC model of the experiment, which
considers the possibility of the effect manifestation at the present precision
level. As a result of the analysis, we can conclude that at currently available
statistical accuracy we observe the oscillations at the $2.9\sigma$ level with
parameters $\Delta m_{14}^2=(7.3\pm0.13_{st}\pm1.16_{sys})\text{eV}^2 =
(7.3\pm1.17)\text{eV}^2$ and $\sin^22\theta_{14}=
0.36\pm0.12_{stat}(2.9\sigma)$. Monte Carlo based statistical analysis gave
estimation of confidence level at $2.7\sigma$. We plan to improve the currently
working experimental setup and create a completely new setup in order to
increase the accuracy of the experiment by 3 times. We also provide a brief
analysis of the general experimental situation in the search for sterile
neutrinos.
