China 
Africa 
- Antisense oligonucleotide
- Antisense therapy
- Antisepsis
- Antiseptics
- Antiserotonergic
- Antiserum
- Antisialagogue
- Antisocial behavior
- Antisocial personality disorder
- Antispasmodics
- Antisperm antibodies
- Antistatic agent
- Antistreptolysin
- Antisynthetase syndrome
- Antitachycardia pacing
- Antitermination
- Antithrombin
- Antithrombin III
- Antithrombin III deficiency
- Antithrombin deficiency
- Antithrombotic
- Antithrombotic agents
- Antithyroid
- Antithyroid agents
- Antitoxins
- Antitragus
- Antitrypsin
- Antitussive
- Antitussives
- Antiulcer agent
- Antivenom
- Antiviral agents
- Antiviral drugs
- Antiviral protein
- Antiviral therapy
- Antivirals
- Antivitamin K
- Antizyme
- Antler
- Antley Bixler Syndrome
- Antley-Bixler syndrome
- Anton syndrome
- Antonine Plague
- Antral
- Antral follicle
- Antral follicle count
- Antrectomy
- Anura
- Anuria
- Anxiety
- Anxiety attacks
- Anxiety disorders
- Anxiety neurosis
- Anxiety sensitivity
- Anxiogenic
- Anxiolytic agent
- Anxiolytics
- Aorta-gonad-mesonephros
- Aortic aneurysm
- Aortic arch
- Aortic arch syndrome
- Aortic arches
- Aortic bifurcation
- Aortic bodies
- Aortic body
- Aortic coarctation
- Aortic cross clamp
- Aortic cross-clamp
- Aortic dissection
- Aortic hiatus
- Aortic insufficiency
- Aortic orifice
- Aortic pressure
- Aortic regurgitation
- Aortic root
- Aortic sac
- Aortic sinus
- Aortic stenosis
- Aortic surgery
- Aortic valve
- Aortic valve replacement
- Aortic valve stenosis
- Aortic valvuloplasty
- Aortitis
- Aortocaval compression syndrome
- Aortography
- Aortoiliac occlusive disease
- Aortopexy
- Aortopulmonary window
- Ap endonuclease
- Ap4a
- Apache II
- Apafant
- Apalutamide
- Apamin
- Apathy
- Apatinib
- Apaziquone
- Ape index
- Apelin
- Apert syndrome
- Apex beat
- Apex of the heart
- Apexification
- Apgar score
- Aph-1
- Aphagia
- Aphakia
- Aphallia
- Aphasia
- Apheresis
- Aphidicolin
- Aphrodisiacs
- Aphthous stomatitis
- Aphthous ulcers
- Aphthovirus
- Apical constriction
- Apical dendrites
- Apical ectodermal ridge
- Apical foramen
- Apical ligament
- Apical membrane
- Apical membrane antigen 1
- Apicoectomy
- Apicoplasts
- Apigenin
- Apiol
- Apitherapy
- Apixaban
- Aplasia
- Aplasia cutis congenita
- Aplastic anemia
- Aplastic crisis
- Apnea
- Apnea hypopnea index
- Apnea of prematurity
- Apnea-hypopnea index
- Apoa2
- Apoa4
- Apoatropine
- Apobec3g
- Apoc3
- Apocarotenal
- Apocrine
- Apocrine gland
- Apocrine sweat gland
- Apocynin
- Apocynum cannabinum
- Apoenzyme
- Apoferritin