We present element-to-element abundance ratios measured from high dispersion spectra for 150 field subdwarfs and early subgiants with accurate Hipparcos parallaxes ( errors < 20 % ) .
For 50 stars new spectra were obtained with the UVES on Kueyen ( VLT UT2 ) , the McDonald 2.7m telescope , and SARG at TNG .
Additionally , literature equivalent widths were taken from the works by Nissen & Schuster , Fulbright , and Prochaska et al .
to complement our data .
The whole sample includes both thick disk and halo stars ( and a few thin disk stars ) ; most stars have metallicities in the range -2 < [ Fe/H ] < -0.6 .
We found our data , that of Nissen & Schuster , and that of Prochaska to be of comparable quality ; results from Fulbright scatter a bit more , but they are still of very good quality and are extremely useful due to the large size of his sample .
The results of the present analysis will be used in forthcoming papers to discuss the chemical properties of the dissipational collapse and accretion components of our Galaxy