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101.
Rajmal Jain Hemant Dave A. B. Shah N. M. Vadher Vishal M. Shah G. P. Ubale K. S. B. Manian Chirag M. Solanki K. J. Shah Sumit Kumar S. L. Kayasth V. D. Patel Jayshree J. Trivedi M. R. Deshpande 《Solar physics》2005,227(1):89-122
The first space-borne solar astronomy experiment of India, namely Solar X-ray Spectrometer (SOXS), was successfully launched on 08 May 2003 on board geostationary satellite GSAT-2 of India. The SOXS is composed of two independent payloads, viz. SOXS Low-Energy Detector (SLD) Payload and SOXS High-Energy Detector (SHD) Payload. The SOXS aims to study the full-disk integrated X-ray emission in the energy range from 4 keV to 10 MeV. In this paper we present the first report on the SLD instrumentation and its in-orbit performance. The SLD payload was designed and developed at the Physical Research Laboratory in collaboration with various centers of Indian Space Research Organisation (ISRO). The basic scientific aim of the SLD payload is to study solar flares in the energy range from 4 to 60 keV with high spectral and temporal resolution. To meet these requirements, the SLD payload employs state-of-the-art solid state detectors, the first time for a solar astronomy experiment, viz. Si PIN (4 –25 keV), and cadmium–zinc–telluride (4 –60 keV). With their superb high-energy resolution characteristics, SLD can observe iron and iron–nickel complex lines that are visible only during solar flares. In view of its 3.4 FOV, the detector package is mounted on a Sun Aspect System, for the first time, to get uninterrupted observations in a geostationary orbit. The SLD payload configuration, its in-flight operation, and the response of the detectors are presented. We also present the first observations of solar flares made by the SLD payload and briefly describe their temporal and spectral mode results. 相似文献
102.
The Yaoan vein-type gold deposit is located in the Ailaoshan-Jinshajiang alkaline intrusive belt, Yunnan Province, China, and is associated both in time and space with 33.5±1.0-Ma-old alkaline intrusions. The gold mineralization is associated with potassic wall-rock alteration. The REE distribution patterns of secondary K-feldspar are generally similar to those of the igneous perthite but with about seven times higher total REE abundances. The alteration is ascribed to a high-REE magmatic fluid derived from the Yaoan alkaline intrusive suite. The hydrothermal Yaoan gold deposit formed during two gold-bearing stages, i.e. a sulfide (pyrite) stage and a sulfide-oxide stage (pyrite-specularite). The REE abundance of early stage I pyrite is relatively high with strong enrichment in LREE, (La/Yb)n of 40–290, generally positive Eu anomalies (Eu/Eu*=0.86–1.55), and REE patterns very similar to those of secondary feldspar. In contrast, the later stage II pyrite has much lower REE concentrations and lower (La/Yb)n of 5.5–11.8, Eu/Eu* of 0.49–0.76, and flat chondrite-normalized spidergram patterns. The stage I pyrite has 34S in the range of –2.2 to +3.2, and overlaps with regionally distributed pyrite in least-altered syenite porphyry. In contrast, stage II pyrite has much higher 34S values between +7.8 and +16.5. Carbon isotope data for four samples from stage II revealed 13C (PDB) values between –6 and –8. These stable isotope and REE data suggest that magmatic fluids of the alkaline intrusions caused both potassic alteration and stage I sulfide mineralization. The system evolved from stage I to stage II mineralization by influx of meteoric fluids with relatively heavier sulfur, although calcite carbon isotope data suggest that the CO2 remained dominantly of magmatic origin.Editorial handling: B. Lehmann 相似文献
103.
104.
Dr. Dave Fultz 《Pure and Applied Geophysics》1950,17(3-4):88-93
Summary Laboratory-scale experiments on a small cylindrical barrier capable of being moved zonally with respect to a rotating hemispherical shell of liquid are described. When the cylinder is moved west relative to the shell at rates approximating 1/10 of the basic rotation a strong anticyclonic circulation developes around the cylinder and pronounced wave motions appear in the remainder of the liquid. When the cylinder is moved eastward at the same relative rates there is no net circulation around it and rapid motions toward the east occur in the latitude zone that it occupies. Velocity discontinuity surfaces on which occasional vortices develop divide this zone from the remainder of the liquid on both sides where much less developed motions occur. General implications of these and certain other types of experiments for problems of flow over large mountain masses are pointed out. 相似文献
105.
106.
Dave Kolas 《Transactions in GIS》2008,12(Z1):5-18
Though the intersection of spatial data and semantic web technologies holds significant promise, there are still many challenges before this promise can be realized. One of these challenges is query representation. History suggests that an appropriate solution is a specialized query language for spatial data; however, with a broad interpretation of the SPARQL specification and extensions that would be useful outside the spatial realm, one can use SPARQL to query spatial concepts effectively. This article establishes a set of desiderata for a query language capable of dealing with spatial Semantic Web‐based data, discusses the challenges facing such a query language, and addresses these challenges with straightforward solutions that are broadly applicable. The effectiveness of these extensions is demonstrated using example queries. 相似文献
107.
In recent years numerical investigations of tsunami wave propagation have been spurred by the magnitude 9.3 earthquake along
the Andaman–Sumatra fault in December, 2004. Visualization of tsunami waves being modeled can yield a much better physical
understanding about the manner of wave propagation over realistic seafloor bathymetries. In this paper we will review the
basic physics of tsunami wave propagation and illustrate how these waves can be visualized with the Amira visualization package.
We have employed both the linear and nonlinear versions of the shallow-water wave equation. We will give various examples
illustrating how the files can be loaded by Amira, how the wave-heights of the tsunami waves can be portrayed and viewed with
illumination from light sources and how movies can be used to facilitate physical understanding and give important information
in the initial stages of wave generation from interaction with the ambient geological surroundings. We will show examples
of tsunami waves being modeled in the South China Sea, Yellow Sea and southwest Pacific Ocean near the Solomon Islands. Visualization
should be a part of any training program for teaching the public about the potential danger arising from tsunami waves. We
propose that interactive visualization with a web-portal would be useful for understanding more complex tsunami wave behavior
from solving the 3-D Navier–Stokes equation in the near field. 相似文献
108.
Rita D. Winkler Diana M. Allen Tim R. Giles Brian A. Heise R. Dan Moore Todd E. Redding Dave L. Spittlehouse Xiaohua Wei 《水文研究》2021,35(5):e14123
Over the past 35 years, the Upper Penticton Creek (UPC) Watershed Experiment has supported forest hydrology research in south-central British Columbia (BC), Canada. This paper provides a synthesis of research results, highlights the challenges facing UPC and identifies new research directions. Clearcutting approximately 50% of two small, snow-dominated (Dfb Koppen classification) watersheds advanced the timing of snowmelt-generated high flows and decreased late-summer low flows, relative to predictions based on pre-treatment regressions. Changes in high flows did not have a significant effect on stream channels due to low stream power, coarse substrate, and limited riparian disturbance. Changes in summer low flows reduced modelled useable fish habitat by 20%–50%. Evaporation averaged 52% of the annual precipitation in the mature forest, was reduced to 30% in a clearcut, and recovered to 40% and 47% in a 10 and 25 year-old stand, respectively. Groundwater recharge to the bedrock was estimated at 19% of annual precipitation, indicating that, even with the large uncertainty associated with this estimate, deep groundwater should not be ignored in the water balance. Suspended sediment, turbidity, and colour increased post-logging; however, chemical surface water quality did not change. Aquatic community structure changed post-logging; and although this affected the processing of organic matter, the effects on habitat quality were considered minimal. The information gained at UPC has supported provincial policies, management guidelines, forest stewardship plans and watershed risk assessments. The undisturbed control watershed, re-growing treatment watersheds and ongoing long-term hydrometric monitoring continue to provide opportunities for future research addressing issues such as the effects of young forests on streamflow and hydrologic recovery, and the influence of climate change on the hydrologic regime. 相似文献
109.
Colin Neal Brian Reynolds James W. Kirchner Phil Rowland Dave Norris Darren Sleep Alan Lawlor Clive Woods Sarah Thacker Hayley Guyatt Colin Vincent Kathryn Lehto Simon Grant Jeremy Williams Margaret Neal Heather Wickham Sarah Harman Linda Armstrong 《水文研究》2013,27(17):2531-2539
This scientific briefing announces the availability of a new multi‐element high‐frequency water quality data set that is openly accessible to the research community. The data set comprises up to 2 years of 7‐hourly water quality data for two streams and one rainfall site in the Upper Severn catchment at Plynlimon in Mid‐Wales. The measurements cover 50 analytes ranging from H+ to U and spanning six orders of magnitude in concentration, including major, minor and trace elements as well as nutrients, and they complement decades of weekly measurements of the same analytes at the Upper Severn. Together, the weekly and 7‐hourly time series provide a unique data set for studying both long‐term trends and short‐term dynamics. The data show complex behaviour over a wide range of timescales, challenging our understanding of catchment processes and informing future modelling efforts. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
110.
The nutrient rich fractions in wastewater originating from human urine and can be recovered as solids for more efficient recycling, facilitated handling and storage for reuse in agriculture. Freezing and thawing can be used to concentrate the urine nutrients. Phosphorus (P) and nitrogen (N) can be precipitated as struvite [(Mg,Ca)(K,NH4)(PO4)·6H2O] by adding MgO and additional nitrogen can be recovered by using zeolites. The zeolite in this study was pretreated in two ways: (i) washed and (ii) washed and thermally treated. The P recovery was high (> 97%) and the N recovery was ca. 50 to 60%. There was no significant difference in the nitrogen recovery among the different pretreated zeolites or between the pretreated and the untreated zeolite. Freezing had a positive effect on the nutrient concentration. The acute toxicity of the supernatants was tested on Daphnia magna to evaluate the possibilities of discharging the remaining supernatants to a recipient. The supernatants from the frozen treatments and from the unfrozen and washed zeolites were much less toxic than those of the original urine. The minerals acted as slow‐release fertilizers in climate chamber tests on spring wheat. 相似文献