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121.
Dairy farmers face increasing pressure to decrease environmental impact while remaining economically viable. Adaptation of farm management practices in response to seasonal climate forecasts may be one means of achieving these objectives. This paper describes the interactive and iterative process by which farmers, researchers, extension agents, regulatory agencies, and other stakeholders collaborated to create, calibrate, and validate the Dynamic North Florida Dairy Farm model (DyNoFlo), a whole-farm decision support system to decrease nitrogen leaching while maintaining profitability under variable climate conditions. Participatory modeling may enhance the creation of adoptable and adaptable user-friendly models that include environmental, economic and biophysical components. By providing farmers, policy makers, and other stakeholders with a more holistic view of current practices, common ground among them was more easily identified and collaboration was fostered. Farmer values included willingness to be good environmental stewards when they are profitable. The participatory research and development process enhanced understanding of and potential adaptation to seasonal climate variability conditioned to the El Niño Southern Oscillation (ENSO) phases in light of increasing environmental regulations and economic challenges. Adoption of the collaboratively-developed DyNoFlo is expected to be higher than usual because stakeholders feel greater ownership of the final product.  相似文献   
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The preservation of the organic-walled microbiota of the Lakhanda Lagerstätte in the Kumakha mudstone succession of the late Mesoproterozoic Lakhanda Group (Uchur-Maya region, southeast Siberia) is a result of unusually favorable paleoecologic, taphonomic, and diagenetic conditions. Well known for its marked taxonomic diversity and exquisite preservation, the biota inhabited a warm, shallow, epicontinental basin rich in nutrients into which were dispersed clay minerals, from weathering of continental crust, and minor amounts of volcanic detritus. The fossils were preserved by compression in fine-grained smectite–illite–kaolinite mudstones deposited in a sulfur-deficient disoxic and anoxic environment. Subsequently, the long-term (1 Ga) tectonic stability of the southeast margin of the Siberian platform has provided an exceptional environment for the preservation of the microfossil assemblage without significant diagenetic alteration. Conclusions drawn here from studies of the paleoecology, taphonomy, and diagenesis of the Lakhanda Lagerstätte may provide a globally useful model in the search for additional evidence of the Precambrian rise to dominance of eukaryotes in the Earth's biosphere.  相似文献   
124.
Presented paper describes the basic principles and features of the implementation of a robotic network of optical telescopes MASTER, designed to study the prompt (simultaneous with gamma radiation) optical emission of gamma-ray bursts and to perform the sky survey to detect unknown objects and transient phenomena. With joint efforts of Sternberg astronomical institute, High altitude astronomical station of the Pulkovo observatory, Ural state university, Irkutsk state university, Blagoveshchensk pedagogical university, the robotic telescopes MASTER?II near Kislovodsk, Yekaterinburg, Irkutsk and Blagoveshchensk were installed and tested. The network spread over the longitudes is greater than 6?h. A further expansion of the network is considered.  相似文献   
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Water Resources - The Queima Pé Stream Basin (QPSB) and Ararão River Basin (ARB) in central Brazil have had recurrent problems with water scarcity. This may get worse under anthropogenic...  相似文献   
126.
Inlet stabilization is a common practice in Brazil, as it is worldwide. In this paper we present results of the analysis of the stabilization practices of the Camacho Inlet, located in Santa Catarina State, southern Brazil. This inlet is maintained intermittently, in accordance with a regime designed to benefit both local fishermen and rice farmers. Fishermen require this inlet to be open as a navigation channel during the fishing season; rice farmers needs it closed during the irrigation period to allow the pumping of fresh water from the Congonhas River which drains into the Camacho’s backbarrier lagoon. An additional complication arises from the tendency of this inlet to close naturally due to infilling by dune migration. Aerial images spanning a 65 year time period (1938-2003) were analyzed, demonstrating the variability in the inlet’s width between 0 (closed) and 360 m. The analysis of inlet stability and user needs indicate that an appropriate solution is the implementation of an annual inlet dredging program in the austral autumn. This would allow for the inlet to remain open from May to September and then close naturally for the rest of the year, providing for a backbarrier fresh water reservoir during the irrigation period.  相似文献   
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Global travertine deposition modulated by oscillations in climate   总被引:1,自引:0,他引:1  
Travertine deposits are important records of past fluid flow in the Earth's crust, and document fluid migration through both tectonic activity and changes in climate. While many studies hint at possible relationships between travertine formation and global climate, none have investigated these connections on a global scale. Here we compile 1649 published travertine ages from six continents to test the hypothesis that global and/or regional changes in climate regulate travertine deposition. Peaks in bedded travertine ages occur with main frequencies that correspond to 100‐kyr changes in global climate, where most peaks occur during glacial terminations or interglacial periods, including a large peak that coincides with the Early Holocene climatic optimum. Time–series analysis also suggests a possible connection with 41‐kyr obliquity cycles. At regional scales, many peaks also correspond with local times of high precipitation or wet conditions. This can be attributed to higher groundwater recharge rates, providing the necessary water to form travertine. Many bedded travertine‐depositing systems may therefore be water‐limiting and sufficient CO2 may be present even during times of no travertine deposition. Exceptions to this conclusion are banded vein travertine deposits, which typically form during times of dry climate when water tables are low. Copyright © 2019 John Wiley & Sons, Ltd.  相似文献   
129.
Mathematical Geosciences - High-order sequential simulation methods have been developed as an alternative to existing frameworks to facilitate the modeling of the spatial complexity of non-Gaussian...  相似文献   
130.
The late Quaternary evolution of central-eastern Brazil has been under-researched. Questions remain as to the origin of the Cerrado, a highly endangered biome, and other types of vegetation, such as the Capões – small vegetation islands of semi-deciduous and mountain forests. We investigated the factors that influenced the expansion and contraction of the Cerrado and Capões during the late Quaternary (last ~35 ka), using a multi-proxy approach: stable isotopes (δ13C, δ15N), geochemistry, pollen and multivariate statistics derived from a peat core (Pinheiro mire, Serra do Espinhaço Meridional). Five major shifts in precipitation, temperature, vegetation and landscape stability occurred at different timescales. Our study revealed that changes in the South Atlantic Convergence Zone (SACZ) seem to have been coeval with these shifts: from the Late Glacial Maximum to mid-Holocene the SACZ remained near (~29.6 to ~16.5k cal a bp ) and over (~16.5 to ~6.1 k cal a bp ) the study area, providing humidity to the region. This challenges previous research which suggested that climate was drier for this time period. At present, the Capões are likely to be a remnant of a more humid climate; meanwhile, the Cerrado biome seems to have stablished in the late Holocene, after ~3.1 k cal a bp .  相似文献   
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