a pair of observations

abundant observations

adjustment of indirect observations

aircraft（-based） observations

altitude observations of a celestial body

Astronomical Observations

Borehole strainmeter observations

calculus of observations

carrier observations

censored observations

clinical observations

COMBINATION OBSERVATIONS

combination of observations

Conjugate observations

Constellation occultation observations

correlated observations

Curative effect observations

cytological observations

decoding observations

dependent observations