difficulty processing difficulty rating difficulty reaching difficulty reading difficulty recognizing difficulty recruiting difficulty relating difficulty remembering difficulty saying difficulty seeing difficulty setting difficulty settings difficulty sleeping difficulty speaking difficulty standing difficulty starting difficulty staying difficulty swallowing difficulty talking difficulty thinking difficulty trusting difficulty understanding difficulty understanding what difficulty urinating difficulty using difficulty walking difficulty when difficulty will difficulty writing diffidence diffident diffie diffie-hellman diffracted diffraction diffraction analysis diffraction data diffraction diagram diffraction efficiency diffraction grating diffraction gratings diffraction limit diffraction lines diffraction method diffraction of light diffraction pattern diffraction patterns diffraction peaks diffraction spectrum diffraction studies diffraction techniques diffractive diffractive optical diffractogram diffractograms diffractometer diffserv diffuse diffuse axonal injury diffuse essential diffuse it diffuse large b-cell diffuse light diffuse pollution diffuse reflectance diffuse reflection diffuse sources diffuse the situation diffused diffused light diffuser diffuser can diffuser plate diffusers diffuses diffusing diffusion diffusion barrier diffusion barriers diffusion bonding diffusion can diffusion cell diffusion cells diffusion coefficient diffusion coefficients diffusion device diffusion electrode diffusion equation diffusion layer diffusion length diffusion means diffusion method diffusion model diffusion occurs diffusion of information diffusion of innovation diffusion of innovations diffusion of knowledge diffusion of new