Keyword Factory
This tool helps you to expand your technical vocabulary using the arXiv dataset.
Note that terms which occur infrequently in arXiv articles will not return good (if any) results.
Read about our method here.
hpa
is associated with:
hypothalamic-pituitary-adrenal,   
twta,   
predistorter,   
traveling-wave-tube,   
geopotential-height,   
air-fluorescence,   
cortisol,   
predistortion,   
ecmwf,   
troposphere,   
deexcitation,   
sea-level,   
stratospheric,   
papr,   
peak-to-average,   
amplifier,   
air,   
dry,   
fluorescence
Using these keywords in combination
with hpa will
help you expand your search horizons.