China 
Africa 
- Apolipoprotein
- Apolipoprotein A
- Apolipoprotein A1
- Apolipoprotein B
- Apolipoprotein B100
- Apolipoprotein B48
- Apolipoprotein C
- Apolipoprotein D
- Apolipoprotein E
- Apolipoprotein E4
- Apolipoprotein H
- Apolipoprotein L
- Apolipoprotein L1
- Apomorphine
- Aponeurosis
- Aponeurotic fibroma
- Apophysomyces
- Apoplexy
- Apoprotein
- Apoptosis
- Apoptosis-inducing factor
- Apoptosome
- Apoptotic DNA fragmentation
- Aporia
- Aporphine
- Aporphine alkaloids
- Aposematism
- Apotransferrin
- Apparent diffusion coefficient
- Apparent leukonychia
- Apparent life threatening event
- Apparent life-threatening event
- Appeal to nature
- Appendages
- Appendectomy
- Appendiceal cancer
- Appendicitis
- Appendicular skeleton
- Appendix
- Appendix testis
- Apperception
- Apperceptive agnosia
- Appetite
- Appetite stimulants
- Applicability domain
- Application site reaction
- Applied behavior analysis
- Applied physiology
- Apprehension
- Approach-avoidance conflict
- Approximants
- Apraclonidine
- Apramycin
- Apraxia
- Apraxia of lid opening
- Apraxia of speech
- Apremilast
- Aprepitant
- Apricot oil
- Aprosodia
- Aprotinin
- Apt test
- Aptamers
- Apudoma
- Apurinic site
- Apyrase
- Apyrimidinic site
- Aqua regia
- Aquabacterium
- Aquagenic pruritus
- Aquaglyceroporins
- Aquamid
- Aquaporin
- Aquaporin 1
- Aquaporin 2
- Aquaporin 3
- Aquaporin 4
- Aquaporin 5
- Aquaporin-5
- Aquaretic
- Aquatic therapy
- Aqueductal stenosis
- Aqueous cream
- Aqueous humor
- Aquifex
- Aquifex aeolicus
- Aquifoliaceae
- Ara h 3
- Ara h1
- Arabinitol
- Arabinogalactan
- Arabinose
- Arabinoside
- Arabinosyltransferase
- Arabinoxylan
- Arabitol
- Arable land
- Arachidic acid
- Arachidonate 12 lipoxygenase
- Arachidonate 12-lipoxygenase
- Arachidonate 5 lipoxygenase
- Arachidonate 5-lipoxygenase
- Arachidonic acid
- Arachidonic acid metabolism
- Arachis hypogaea
- Arachis oil
- Arachnodactyly
- Arachnoid
- Arachnoid cysts
- Arachnoid granulations
- Arachnoid mater
- Arachnoid trabeculae
- Arachnoiditis
- Aralkylamine N-acetyltransferase
- Aramchol
- Arbekacin
- Arbidol
- Arbitrary inference
- Arbor vitae
- Arbovirus
- Arcade of Frohse
- Arcanobacterium
- Archaea
- Archaebacteria
- Archaeol
- Archetypes
- Arcobacter
- Arctigenin
- Arctium
- Arctium lappa
- Arctostaphylos uva ursi
- Arctostaphylos uva-ursi
- Arcuate arteries
- Arcuate eminence
- Arcuate fasciculus
- Arcuate foramen
- Arcuate line
- Arcuate nucleus
- Arcuate uterus
- Arcuate vein
- Arcuate veins
- Arcus senilis
- Area postrema
- Areca
- Areca catechu
- Areca nut
- Arecaidine
- Arecoline
- Areflexia
- Arenaviridae