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41.
提为初值问题的数值预报在通过改进数值模式、观测手段及分析方法而改进预报的同时,仍然面临着两大困难,即模式误差和初值不完整。然而我们有大量的气候演变的历史观测资料,其中蕴含着关于气候系统的信息。本文针对这两个困难,系统地提出充分利用历史资料反演订正模式和初值进而改进数值预报的三类反问题,并给出数值解法。最后将三类反问题应用于一个简单模式进行反演预报的数值试验,其数值试验结果将在本文的第二部分给出。 相似文献
42.
For energy‐based seismic design, energy demand in the form of absorbed energy spectra was established by an attenuation relationship. The absorbed energy is proposed for evaluating the energy demand in an inelastic system because the absorbed energy is directly related to the pseudo‐velocity in the elastic case. Based on a total of 273 ground motion records from 15 significant earthquakes in California, an attenuation relationship of the absorbed energy was established from a two‐stage non‐linear regression analysis. This relationship was established for a given earthquake magnitude, source‐to‐site distance, site class, and ductility factor. A similar expression for the normalized absorbed energy was also developed. This study showed that the absorbed energy for near‐field ground motions can be significantly larger than that predicted by the attenuation relationship for normal ground motions. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
43.
青海玉树地震差分干涉雷达同震形变测量 总被引:1,自引:0,他引:1
2010-04-14青海玉树发生7.1级地震后,作者利用震前和震后获取的日本ALOS卫星PALSAR遥感数据,开展了差分干涉雷达(D-InSAR)地震同震形变测量与分析。结果表明:玉树地震引起较大范围地表变形,地震变形沿玉树—甘孜断裂带向南东东方向扩展,在N33.7°,E96.81°附近达到最大形变量,D-InSAR监测到雷达视向上的最大形变量为35cm。地表形变特征对于评价玉树地震破坏程度、推断断层性质、研究地震形变和地震孕育特征具有重要的参考价值。 相似文献
44.
Complexity analysis of rainfall and runoff time series based on sample entropy in different temporal scales 总被引:5,自引:3,他引:2
Chien-Ming Chou 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(6):1401-1408
This study applied sample entropy (SampEn) to rainfall and runoff time series to investigate the complexity of different temporal scales. Rainfall and runoff time series with intervals of 1, 10, 30, 90, and 365 days for the Wu-Tu upstream watershed were used. Thereafter, SampEn was computed for the five rainfall and runoff time series. The results show that for the various temporal scales, comparisons of the complexity between the rainfall and runoff time series based on the SampEn are inconsistent. Calculating the dynamic SampEn further elucidated variations of the complexity in the rainfall and runoff time series. In addition, the results show that SampEn measures of the rainfall and runoff time series are typically higher than the approximate entropy measures of the rainfall and runoff time series for a specific temporal scale. The complexity increases when the sample size increases for a specific temporal scale. Furthermore, temporal scales with low complexity and high predictability are obtained from the variations of SampEn for the rainfall and runoff time series with different temporal scales, thereby providing a reference for determining the appropriate temporal scale for rainfall and runoff time series forecasting. 相似文献
45.
46.
The study of trace metal speciation has benefited from a great deal of interest leading to the development and the diversification of sequential extraction schemes (SES), which triggered the need for harmonization by the standard, measurements and testing programme (SM & T). However, some uncertainties still persist in the application of the harmonized 3-step protocol, because of the difficulty in conceptualizing a technique that can be applied to environmental samples irrespective of their nature. The alternative method proposed in this study is based on the solubility of the sample components progressively dissolved during the course of an acidimetric titration by 1 mol L−1 HCl. The major HCl-reactive mineralogical components are identified using mass balance calculation of H+ consumed by their dissolution together with the amount of major elements released into solution. The speciation of minor and trace elements is investigated by comparing their titrations to those of the major elements. This approach is much simpler than SES because it uses simple non-selective H+ at room temperature instead of a complex experimental design of so-called specific reagents. The different mineral components of the solid are no longer operationally defined and the problem of selectivity is irrelevant to the titration approach. The method was applied to several sediment samples from the Scheldt estuary and the particulate phase was further examined by Scanning Electron Microprobe and X-ray Diffraction techniques. The nearly complete consumption of H+ in the suspension is balanced by the total dissolution of carbonates and Fe-oxyhydroxides. In contrast to the speciation inferred from the Tessier SES, the acidimetric titration has demonstrated that the carbonate phase does not significantly contain trace metals with the exceptions of 40% of the Mn and 30% of the Co. In contrast, the Fe-oxyhydroxides seem to play a major role and account for 70% of Pb and 20% of Cr, in addition to 60% of P and additional amounts of 20% Co and 40% Mn. 70% of the Cu also occur in the oxyhydroxide phase, more likely coprecipitated with gibbsite. 90% of the Cd and 85% of Zn can be attributed to the Acid Volatile Sulfide (AVS) phase as evidenced from S titration. The acidimetric titration method not only provides information on the speciation of trace metals but also allows the quantification of their reactivity and mobility, if one considers that the titration roughly mimics pH changes that may occur as a result of chemical disequilibrium in the environment. The results demonstrate the potential of the acidimetric titration as an alternative to SES protocols in geochemical and environmental regulation studies. This method is applicable to a wide variety of environmental materials with little or minor adjustments. 相似文献
47.
K.Y. Chang S.S. He C.C. Chou S.L. Kao A.S. Chiou 《International journal of geographical information science》2013,27(8):1375-1393
To plan undeveloped optimal routes between Asia and Europe via the Arctic Northeast Passages using a 3D geographic information system (GIS), voyage paths are simulated in a 3D visual form. This ensures that the distances are calculated accurately, and that other voyage data such as water depths, sea ice distribution, and seashore topology are also easily deciphered, giving a more direct and clear demonstration compared to simplified presentations on an Electronic Chart Display & Information System (ECDIS). This article also implements a higher-geometry maze router in ice zone areas to obtain the optimal path in relation to safety and costs. This article compares the optimal Arctic Northeast Passages with traditional routes through the Suez Canal for dynamic analyses of the cost efficiency (including time costs, fuel costs, and other factors) of travel between major ports in Asia and Europe. The average benefit assessment is around 30–45% in a bulk carrier comparison. Thus, a 3D GIS can easily obtain and demonstrate safe navigation routes, providing a very convenient tool for initial planning. 相似文献
48.
Silva Vinicius Oliveira de Mello Carlos Rogério Chou Sin Chan 《Theoretical and Applied Climatology》2022,148(3-4):1289-1302
Theoretical and Applied Climatology - South of Minas Gerais state, in Southeast Brazil, is known for the coffee crop production (more than 30% of country’s production) and hydroelectricity... 相似文献
49.
L. H. Shih T. Y. Chou 《International Journal of Environmental Science and Technology》2011,8(3):523-532
Although solar power systems are considered as one of the most promising renewable energy sources, some uncertain factors as well as the high cost could be barriers which create customer resistance. Leasing instead of purchase, as one type of product service system, could be an option to reduce consumer concern on such issues. This study focuses on consumer concerns about uncertainty and willingness to pay for leasing solar power systems. Conjoint analysis method is used to find part worth utilities and estimate gaps of willingness to pay between attribute levels, including various leasing time lengths. The results show the part worth utilities and relative importance of four major attributes, including leasing time. Among concerns about uncertainties, government subsidy, electricity price, reliability, and rise of new generation solar power systems were found to be significantly related to the additional willingness-to-pay for a shorter leasing time. Cluster analysis is used to identify two groups standing for high and low concerns about uncertainty. People with more concerns tend to pay more for a shorter lease time. 相似文献
50.
Keh‐Chyuan Tsai Chung‐Che Chou Chi‐Lon Lin Pei‐Ching Chen Sheng‐Jhih Jhang 《地震工程与结构动力学》2008,37(4):627-645
This paper first presents the force–deformation relationship of a post‐tensioned (PT) steel beam‐to‐column connection constructed with bolted web friction devices (FDs). This paper then describes the test program conducted in the National Center for Research on Earthquake Engineering, Taiwan, on four bolted FDs and four full‐scale PT beam‐to‐column moment connection subassemblies using the FDs. Tests confirm that (1) the hysteretic behavior of four bolted FDs is very stable, (2) the friction coefficient between the steel plate and the brass shim is about 0.34, (3) the proposed force–deformation relationships reasonably predict the experimental responses of the PT connections under cyclically increasing deformations up to a beam peak rotation of 0.05 rad, and (4) the decompression moments do not degrade as beam cyclic deformations increase. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献