WHO's essential drugs concept.
D001290:Attitude; D003906:Developing Countries; D006291:Health Policy; D006297:Health Services Accessibility / Q000639:trends*; D004364:Pharmaceutical Preparations / Q000600:supply & distribution*; D011320:Primary Health Care / Q000639:trends*; D015397:Program Evaluation; D014944:World Health Organization
D004364:Pharmaceutical Preparations