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The effective elastic thickness of the lithosphere and the evolution of foreland basins 总被引:4,自引:0,他引:4
A. B. Watts 《Basin Research》1992,4(3-4):169-178
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A pilot cropland carbon sequestration program within north central Montana has allowed farmers to receive carbon credit for management adjustments associated with changing from tillage-based agricultural systems to no-till. Carbon credit can also be obtained by adopting conservation reserve, where cropland is planted into perennial vegetation. Summer fallowing is also considered within the crediting process as credit is not given in years that a field is left un-vegetated. The carbon sequestration program has been advocated as a means to mitigate climate change while providing an added source of income for Montana farmers. There is lack of data, however, pertaining to the percentage of lands within this region that have not converted to no-till management, lands under certain crop intensities (e.g. those that are cropped every growing season vs. those that use a fallow-crop-fallow system), or cropland that have converted to perennial vegetation outside of the popular Conservation Reserve Program. Data is also sparse concerning the amount of soil organic carbon that might be sequestered given a conversion to no-till or conservation reserve. This study established regional percentage estimates of cropland under no-till, various degrees of crop intensity, and conservation reserve within north central Montana. Literature-based carbon sequestration estimates were used to generate carbon gain data associated with the conversation to no-till and to conservation reserve. These estimates were then applied to the area-based cropland statistics to estimate potential regional carbon sequestration associated with these management changes. 相似文献
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Steven R. Jayne Nelson G. Hogg Stephanie N. Waterman Luc Rainville Kathleen A. Donohue D. Randolph Watts Karen L. Tracey Julie L. McClean Mathew E. Maltrud Bo Qiu Shuiming Chen Peter Hacker 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(12):2088-2099
This paper reports on the strength and structure of the Kuroshio Extension and its recirculation gyres. In the time average, quasi-permanent recirculation gyres are found to the north and south of the Kuroshio Extension jet. The characteristics of these recirculations gyres are determined from the combined observations from the Kuroshio Extension System Study (KESS) field program (June 2004–June 2006) and include current meters, pressure and current recording inverted echo sounders, and subsurface floats. The position and strength of the recirculation gyres simulated by a high-resolution numerical model are found to be consistent with the observations. The circulation pattern that is revealed is of a complex system of multiple recirculation gyres that are embedded in the crests and troughs of the quasi-permanent meanders of the Kuroshio Extension. At the location of the KESS array, the Kuroshio Extension jet and its recirculation gyres transport of about 114 Sv. This represents a 2.7-fold increase in the transport of the current compared to the Kuroshio's transport at Cape Ashizuri before it separates from the coast and flows eastward into the open ocean. This enhancement in the current's transport comes from the development of the flanking recirculation gyres. Estimates from an array of inverted echo sounders and a high-resolution ocean general circulation model are of similar magnitude. 相似文献
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M. L. Duldig J. G. Greenhill K. B. Fenton R. M. Thomas D. J. Watts 《Astrophysics and Space Science》1983,95(1):137-144
Balloon observations of the X-ray source Sco X-1 carried out in November 1978 have revealed a thermal spectrum withkT?7 keV in the 20–60 keV energy band. In addition, there was evidence of a high energy component, possibly variable, above ~50 keV. The spectral form of this component could not be determined but was hard with a 60 keV flux of ~10?4 photons (keV cm2 s)?1. 相似文献
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R. Vargas E.A. Yépez J.L. Andrade G. Ángeles T. Arredondo A.E. Castellanos J. Delgado-Balbuena J. Garatuza-Payán E. González Del Castillo W. Oechel J.C. Rodríguez A. Sánchez-Azofeifa E. Velasco E.R. Vivoni C. Watts 《Atmósfera》2013,26(3):325-336
Understanding ecosystem processes from a functional point of view is essential to study relationships among climate variability, biogeochemical cycles, and surface-atmosphere interactions. Increasingly during the last decades, the eddy covariance (EC) method has been applied in terrestrial, marine and urban ecosystems to quantify fluxes of greenhouse gases (e.g., CO2, H2O) and energy (e.g., sensible and latent heat). Networks of EC systems have been established in different regions and have provided scientific information that has been used for designing environmental and adaptation policies. In this context, this article outlines the conceptual and technical framework for the establishment of an EC regional network (i.e., MexFlux) to measure the surface-atmosphere exchange of heat and greenhouse gases in Mexico. The goal of the network is to improve our understanding of how climate variability and environmental change influence the dynamics of Mexican ecosystems. First, we discuss the relevance of CO2 and water vapor exchange between terrestrial ecosystems and the atmosphere. Second, we briefly describe the EC basis and present examples of measurements in terrestrial and urban ecosystems of Mexico. Finally, we describe the conceptual and operational goals at short-, medium-, and long-term scales for continuity of the MexFlux network. 相似文献