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991.
Determination of the Concentration of Carbonic Species in Natural Waters: Results from a World‐Wide Proficiency Test
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Mahendra P. Verma Enrique Portugal Sophie Gangloff María Aurora Armienta Dornadula Chandrasekharam Mayela Sanchez Roberto E. Renderos Miguel Juanco Robert van Geldern 《Geostandards and Geoanalytical Research》2015,39(2):233-255
The results of an international interlaboratory proficiency test for the determination of carbonic species are presented. Eight laboratories analysed twelve water samples (four synthetic waters, one lake water, four geothermal waters, one seawater and two petroleum waters) by two methods: (a) individual laboratory analytical procedure and (b) acid–base titration curves in tabular form following a standardised protocol. In case (b), the concentrations of carbonic species were calculated by the organiser using the (1) Hydrologists' method, (2) Geochemists' method and/or (3) initial pH and total alkalinity method. For synthetic waters, the averaged % trueness and precision of measurement of the two methods were (trueness = 7.6, precision = 9.4) and (9.0, 3.4) for total alkalinity, and (6.6, 31.0) and (7.8, 6.1) for carbonic alkalinity, respectively. This indicates that the total alkalinity calculation procedure is in general correct in the individual laboratory method, but the carbonic alkalinity calculation procedure has serious problems. The measurements of total alkalinity for lake and seawaters were in agreement in both the methods; however, the individual laboratory measurement method for geothermal and petroleum waters was conceptually incorrect. Thus, the analytical procedures for the determination of carbonic species were reviewed. To apply the Hydrologists' and/or Geochemists' methods, the location of NaHCO3EP and H2CO3EP is necessary, even for samples with pH lower than that of NaHCO3EP, and a backward titration curve after complete removal of CO2 must be performed. The initial pH and total alkalinity method is appropriate where a complete analysis of species that contribute to the alkalinity is known. 相似文献
992.
Accurately mapped locations within multi-unit properties are useful for several organizations in today's society. Published work on geocoding methods either require detailed location reference data or does not apply to multi-unit buildings. In this research, a generalizable method is realized to map apartment addresses to their explicit locations without access to indoor location reference data based on publicly available address- and geospatial-building information. The performance of this approach is measured by conducting a comparative study between a linear interpolation baseline and gradient-boosted decision trees model. The proposed method can successfully geocode addresses across different building shapes and sizes. Furthermore, the model significantly outperforms the baseline in terms of positional accuracy proving the feasibility of approximating apartment locations by their address- and geospatial-building information. 相似文献
993.
Christiaan P. A. van Buchem Yamila Miguel Mantas Zilinskas Wim van Westrenen 《Meteoritics & planetary science》2023,58(8):1149-1161
To date, over 500 short-period rocky planets with equilibrium temperatures above 1500 K have been discovered. Such planets are expected to support magma oceans, providing a direct interface between the interior and the atmosphere. This provides a unique opportunity to gain insight into their interior compositions through atmospheric observations. A key process in doing such work is the vapor outgassing from the lava surface. LavAtmos is an open-source code that calculates the equilibrium chemical composition of vapor above a dry melt for a given composition and temperature. Results show that the produced output is in good agreement with the partial pressures obtained from experimental laboratory data as well as with other similar codes from literature. LavAtmos allows for the modeling of vaporization of a wide range of different mantle compositions of hot rocky exoplanets. In combination with atmospheric chemistry codes, this enables the characterization of interior compositions through atmospheric signatures. 相似文献
994.
The role of technology for achieving climate policy objectives: overview of the EMF 27 study on global technology and climate policy strategies 总被引:3,自引:1,他引:2
Elmar Kriegler John P. Weyant Geoffrey J. Blanford Volker Krey Leon Clarke Jae Edmonds Allen Fawcett Gunnar Luderer Keywan Riahi Richard Richels Steven K. Rose Massimo Tavoni Detlef P. van Vuuren 《Climatic change》2014,123(3-4):353-367
This article presents the synthesis of results from the Stanford Energy Modeling Forum Study 27, an inter-comparison of 18 energy-economy and integrated assessment models. The study investigated the importance of individual mitigation options such as energy intensity improvements, carbon capture and storage (CCS), nuclear power, solar and wind power and bioenergy for climate mitigation. Limiting the atmospheric greenhouse gas concentration to 450 or 550 ppm CO2 equivalent by 2100 would require a decarbonization of the global energy system in the 21st century. Robust characteristics of the energy transformation are increased energy intensity improvements and the electrification of energy end use coupled with a fast decarbonization of the electricity sector. Non-electric energy end use is hardest to decarbonize, particularly in the transport sector. Technology is a key element of climate mitigation. Versatile technologies such as CCS and bioenergy are found to be most important, due in part to their combined ability to produce negative emissions. The importance of individual low-carbon electricity technologies is more limited due to the many alternatives in the sector. The scale of the energy transformation is larger for the 450 ppm than for the 550 ppm CO2e target. As a result, the achievability and the costs of the 450 ppm target are more sensitive to variations in technology availability. 相似文献
995.
This article performs actor-network theory (ANT) to examine the development of gorilla tourism at Bwindi Impenetrable National Park, Uganda. We depict a number of translations in which gorillas were designated and enrolled as coexisting with local livelihood practices, as “trophies” in the hunting network, “man's closest neighbor” in the scientific network, “endangered species” in the conservation network, and finally, through habituation processes, became part of the tourism network. These five versions of the “gorilla” network show how gorillas are shaped in and by the relations in which they reside. By examining Bwindi in terms of ANT's notions of ordering, materiality, and multiplicity, we not only show how gorilla tourism has gained permanence and popularity, but also draw attention to new ways of thinking about actors and agency in tourism, conservation, and development. 相似文献
996.
997.
GPS-derived orbits for the GOCE satellite 总被引:5,自引:4,他引:1
Heike Bock Adrian Jäggi Ulrich Meyer Pieter Visser Jose van den IJssel Tom van Helleputte Markus Heinze Urs Hugentobler 《Journal of Geodesy》2011,85(11):807-818
The first ESA (European Space Agency) Earth explorer core mission GOCE (Gravity field and steady-state Ocean Circulation Explorer)
was launched on 17 March 2009 into a sun-synchronous dusk–dawn orbit with an exceptionally low initial altitude of about 280 km.
The onboard 12-channel dual-frequency GPS (Global Positioning System) receiver delivers 1 Hz data, which provides the basis
for precise orbit determination (POD) for such a very low orbiting satellite. As part of the European GOCE Gravity Consortium
the Astronomical Institute of the University of Bern and the Department of Earth Observation and Space Systems are responsible
for the orbit determination of the GOCE satellite within the GOCE High-level Processing Facility. Both quick-look (rapid)
and very precise orbit solutions are produced with typical latencies of 1 day and 2 weeks, respectively. This article summarizes
the special characteristics of the GOCE GPS data, presents POD results for about 2 months of data, and shows that both latency
and accuracy requirements are met. Satellite Laser Ranging validation shows that an accuracy of 4 and 7 cm is achieved for
the reduced-dynamic and kinematic Rapid Science Orbit solutions, respectively. The validation of the reduced-dynamic and kinematic
Precise Science Orbit solutions is at a level of about 2 cm. 相似文献
998.
A statistical characterization is presented of Global Positioning System (GPS) user range error as a normally distributed
random variable with non-zero mean over the length of the aircraft precision approach operation, correlated from one GPS measurement
epoch to another and from one satellite to another. This leads directly to modeling GPS error in the position domain as multivariate
normal with non-zero mean. Based on this model, a vertical composite protection level VPLc and a horizontal composite protection level HPLc are each calculated as scalar values from a univariate normal distribution displaced from the origin by the worst-case position
domain bias combination possible, given the maximum possible individual satellite bias magnitudes and the satellite geometry.
A method is then presented by which exact values—that is, values accurate to a user-defined error tolerance and consistent
with statistical assumptions—of VPLc and HPLc are obtained, and by which computationally efficient approximations may be evaluated. A statistical quadratic form under
the multivariate normal distribution is used to derive a new class of protection levels based on the probability enclosed
within a radius defined in two or more dimensions. A central Chi-square representation of this quadratic form is also presented
and is incorporated into a six-step computational procedure for the two-dimensional composite radial protection level RPLc. This procedure is extended to the spherical protection level (SPLc) and the ellipsoidal protection level (EPLc). 相似文献
999.
Detlef P. van Vuuren Elke Stehfest Michel G. J. den Elzen Tom Kram Jasper van Vliet Sebastiaan Deetman Morna Isaac Kees Klein Goldewijk Andries Hof Angelica Mendoza Beltran Rineke Oostenrijk Bas van Ruijven 《Climatic change》2011,109(1-2):95-116
The RCP2.6 emission and concentration pathway is representative of the literature on mitigation scenarios aiming to limit the increase of global mean temperature to 2°C. These scenarios form the low end of the scenario literature in terms of emissions and radiative forcing. They often show negative emissions from energy use in the second half of the 21st century. The RCP2.6 scenario is shown to be technically feasible in the IMAGE integrated assessment modeling framework from a medium emission baseline scenario, assuming full participation of all countries. Cumulative emissions of greenhouse gases from 2010 to 2100 need to be reduced by 70% compared to a baseline scenario, requiring substantial changes in energy use and emissions of non-CO2 gases. These measures (specifically the use of bio-energy and reforestation measures) also have clear consequences for global land use. Based on the RCP2.6 scenario, recommendations for further research on low emission scenarios have been formulated. These include the response of the climate system to a radiative forcing peak, the ability of society to achieve the required emission reduction rates given political and social inertia and the possibilities to further reduce emissions of non-CO2 gases. 相似文献
1000.
Malte Meinshausen S. J. Smith K. Calvin J. S. Daniel M. L. T. Kainuma J-F. Lamarque K. Matsumoto S. A. Montzka S. C. B. Raper K. Riahi A. Thomson G. J. M. Velders D.P. P. van Vuuren 《Climatic change》2011,109(1-2):213-241
We present the greenhouse gas concentrations for the Representative Concentration Pathways (RCPs) and their extensions beyond 2100, the Extended Concentration Pathways (ECPs). These projections include all major anthropogenic greenhouse gases and are a result of a multi-year effort to produce new scenarios for climate change research. We combine a suite of atmospheric concentration observations and emissions estimates for greenhouse gases (GHGs) through the historical period (1750?C2005) with harmonized emissions projected by four different Integrated Assessment Models for 2005?C2100. As concentrations are somewhat dependent on the future climate itself (due to climate feedbacks in the carbon and other gas cycles), we emulate median response characteristics of models assessed in the IPCC Fourth Assessment Report using the reduced-complexity carbon cycle climate model MAGICC6. Projected ??best-estimate?? global-mean surface temperature increases (using inter alia a climate sensitivity of 3°C) range from 1.5°C by 2100 for the lowest of the four RCPs, called both RCP3-PD and RCP2.6, to 4.5°C for the highest one, RCP8.5, relative to pre-industrial levels. Beyond 2100, we present the ECPs that are simple extensions of the RCPs, based on the assumption of either smoothly stabilizing concentrations or constant emissions: For example, the lower RCP2.6 pathway represents a strong mitigation scenario and is extended by assuming constant emissions after 2100 (including net negative CO2 emissions), leading to CO2 concentrations returning to 360 ppm by 2300. We also present the GHG concentrations for one supplementary extension, which illustrates the stringent emissions implications of attempting to go back to ECP4.5 concentration levels by 2250 after emissions during the 21st century followed the higher RCP6 scenario. Corresponding radiative forcing values are presented for the RCP and ECPs. 相似文献