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481.
Climate change is a significant concern for nature conservation in the 21?st century. One of the goals of the 2014 Scottish Climate Change Adaptation Programme is to identify the consequences of climate change for protected areas and to put in place adaptation or mitigation measures. As a contribution to the process, this paper develops a methodology to identify the relative level of risk to nationally and internationally important geological and geomorphological sites in Scotland from the impacts of climate change. The methodology is based on existing understanding of the likely responses of different types of geosite to specific aspects of climate change, such as changes in rainfall, rising sea levels or increased storminess, and is applied to assess the likelihood of damaging impacts on groups of similar geoheritage features in sites with similar characteristics. The results indicate that 80 (8.8%) of the ~900 nationally and internationally important geoheritage sites in Scotland are at ‘high’ risk from climate change. These include active soft-sediment coastal and fluvial features, finite Quaternary sediment exposures and landforms in coastal and river locations, active periglacial features, sites with palaeoenvironmental records, finite or restricted rock exposures and fossils. Using this risk-based assessment, development of indicative geoheritage climate-change actions have been prioritised for these sites. Depending on the characteristics of the sites, management options may range from ‘do nothing’ to rescue excavations and posterity recording. Monitoring is an essential part of the management process to trigger evidence-based interventions.  相似文献   
482.
正The idea that plate tectonics may not have operated deep in Earth's Precambrian past has a long legacy.What predated plate tectonics is unknown,and advances in data-from geochemical,geological and tectonic,to paleomagnetic,as well as modelling ap-  相似文献   
483.
484.
Micron and submicron-sized dust particles can be lifted from the lunar surface due to continual micrometeoroid bombardment and electrostatic charging. The characteristics of these dust populations are of scientific interest and engineering importance for the design of future equipment to operate on the lunar surface. The mobilized grains are expected to have a low velocity, which makes their detection difficult by traditional methods that are based on momentum transfer or impact energy. We describe a newly developed instrument concept, the Electrostatic Lunar Dust Analyzer (ELDA), which utilizes the charge on the dust for detection and analysis. ELDA consists of an array of wire electrodes combined with an electrostatic deflection field region, and measures the mass, charge, and velocity vector of individual dust grains. The first basic prototype of the ELDA instrument has been constructed, tested and characterized in the laboratory. The instrument is set up to measure over a velocity range 1–100 m/s and is sensitive to particles from an approximate mass range from 2×10−16 to 10−11 kg, depending on the charge state and velocity.  相似文献   
485.
The National Ignition Facility (NIF) is capable of creating new and novel high-energy-density (HED) systems relevant to astrophysics. Specifically, a system could be created that studies the effects of a radiative shock on a hydrodynamically unstable interface. These dynamics would be relevant to the early evolution after a core-collapse supernova of a red supergiant star. Prior to NIF, no HED facility had enough energy to perform this kind of experiment. The experimental target will include a 340 ??m predominantly plastic ablator followed by a low-density SiO2 foam. The interface will have a specific, machined pattern that will seed hydrodynamic instabilities. The growth of the instabilities in a radiation-dominated environment will be observed. This experiment requires a ??300?eV hohlraum drive and will be diagnosed using point projection pinhole radiography, which have both been recently demonstrated on NIF.  相似文献   
486.
This research provides a comparative examination of Ottawa as an archetype of a knowledge city. Among Canada’s four largest cities, Ottawa is unique in terms of the characteristics of its labor force, the nature of its employment mix, and its infrastructure. Since the high-tech downturn of 2001, some of Ottawa’s options as a knowledge city seem to be contracting, despite some simultaneously encouraging signs (like recovering employment levels in the high-tech sector). This raises a question about Ottawa’s potential longevity as a knowledge center. The challenge is to understand the inventory of obstacles faced by the city, and address the sort of alchemy required to maintain and improve its competitiveness as a knowledge city.  相似文献   
487.
Abstract– We have used synchrotron Fe‐XANES, XRS, microRaman, and SEM‐TEM analyses of Stardust track 41 slice and track 121 terminal area slices to identify Fe oxide (magnetite‐hematite and amorphous oxide), Fe‐Ti oxide, and V‐rich chromite (Fe‐Cr‐V‐Ti‐Mn oxide) grains ranging in size from 200 nm to ~10 μm. They co‐exist with relict FeNi metal. Both Fe‐XANES and microRaman analyses suggest that the FeNi metal and magnetite (Fe2O3FeO) also contain some hematite (Fe2O3). The FeNi has been partially oxidized (probably during capture), but on the basis of our experimental work with a light‐gas gun and microRaman analyses, we believe that some of the magnetite‐hematite mixtures may have originated on Wild 2. The terminal samples from track 121 also contain traces of sulfide and Mg‐rich silicate minerals. Our results show an unequilibrated mixture of reduced and oxidized Fe‐bearing minerals in the Wild 2 samples in an analogous way to mineral assemblages seen in carbonaceous chondrites and interplanetary dust particles. The samples contain some evidence for terrestrial contamination, for example, occasional Zn‐bearing grains and amorphous Fe oxide in track 121 for which evidence of a cometary origin is lacking.  相似文献   
488.
新疆伊犁吐拉苏地区的线性构造及控矿特征   总被引:4,自引:0,他引:4  
肖龙  HaywardNick 《地球科学》2003,28(2):191-195
采用多种数值图像进行线性构造解译,其中DEM和NOAA主要用于区域尺度,TM用于勘探区尺度,地面磁法数据用于靶区范围的解译分析。研究认为该区线性构造与金矿床的空间分布关系密切,表现为:(1)区域尺度的一级控矿构造为NEE、NE和NW向构造的交汇部位;吐拉苏地区的一级控矿构造为WNW和NNW及NE方向构造的交汇部位;(2)吐拉苏地区的次级控矿构造为NNE和环形构造的交汇部位;(3)靶区的一级控矿构造为NE、SN和环形构造。线性构造异常分析结果显示,当线性构造的优益度大于40时,有较大的成矿可能性。  相似文献   
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