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51.
Zhen-Ru Wang Min Li Yi Zhao Astronomy Department Nanjing University Nanjing Institute of Chinese Classics Nanjing University Nanjing 《中国天文和天体物理学报》2006,6(5)
Stimulated by the recent discovery of PSR J1833-1034 in SNR G21.5-0.9 and its age parameters presented by two groups of discovery, we demonstrate that the PSR J1833-1034 was born 2053 years ago from a supernova explosion, the BC 48 guest star observed in the Western Han (Early Han) Dynasty by ancient Chinese. Based on a detailed analysis of the Chinese ancient record of the BC 48 guest star and the new detected physical parameters of PSR J1833-1034, agreements on the visual position, age and distance between PSR J1833-1034 and the BC 48 guest star are obtained. The initial period P0 of PSR J1833-1034 is now derived from its historical and current observed data without any other extra assumption on P0 itself, except that the factor PP is a constant in its evolution until now. 相似文献
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Hilde Maritz H. C. C. Cloete Jacobus H. Elsenbroek 《Geostandards and Geoanalytical Research》2010,34(3):265-273
The Council for Geoscience (CGS, South Africa) has a statutory mandate to carry out regional geochemical mapping in South Africa that needs to be rapidly and accurately analysed. Both simultaneous X-ray fluorescence spectrometry (S-XRF) and a newly developed method using inductively coupled plasma-mass spectrometry (ICP-MS) were employed. Various trace elements that could not previously be analysed by S-XRF can now be analysed by ICP-MS for the regional geochemical mapping programme, e.g., Cd, Mo, Te and Li. Using both techniques, the CGS aims to report element distributions for some fifty elements. To ensure that element concentration levels correlate over map boundaries, quality control measures in the sampling, sample preparation and analyses were of critical importance. This paper aims to discuss the sample preparation and quality control measures as applied to the ∼5500 samples of the Giyani and Tzaneen 1:100000 scale map sheets sampled at a density of one soil sample per km2. ICP-MS batch- and instrumental drift-correction procedures will be discussed. As a final step, geochemical data were overlain over simplified geological maps using geographical information system software. These maps complement existing geological information of South Africa, help in the identification of exploration targets, test exploration models and initiate further geological research. 相似文献
54.
Tourmaline occurs as a minor but important mineral in the alteration zc,ne of the Archean orogenic gold deposit of Guddadarangavanahalli (G.R.Halli) in the Chitradurga greenst~ne belt of the western Dharwar craton, southern India. It occurs in the distal alteration halo of the G.R.Halli golcl deposit as (a) clusters of very fine grained aggregates which form a minor constituent in the natrix of the altered metabasalt (AMB tourmaline) and (b) in quartz-carbonate veins (vein tourmaline). ~['he vein tourmaline, based upon the association of specific carbonate minerals, is further grouped as (i) albite-tourmaline-ankerite-quartz veins (vein-1 tourmaline) and (ii) albite-tourmaline-calcite-quartz veins (vein-2 tourmaline). Both the AMB tourmaline and the vein tourmalines (vein-I and vein-2) belong to the alkali group and are clas- sified under schorl-dravite series. Tourmalines occurring in the veins are zoned while the AMB tour- malines are unzoned. Mineral chemistry and discrimination diagrams 1eveal that cores and rims of the vein tourmalines are distinctly different. Core composition of the ve:n tourmalines is similar to the composition of the AMB tourmaline. The formation of the AMB tourmaline and cores of the vein tour- malines are proposed to be related to the regional D1 deformational event associated with the emplacement of the adjoining ca. 2.61 Ga Chitradurga granite whilst rims of the vein tourmalines vis-a- vis gold mineralization is spatially linked to the juvenile magmatic accretion (2.56-2.50 Ga) east of the studied area in the western part of the eastern Dharwar craton. 相似文献
55.
魏光辉 《沙漠与绿洲气象(新疆气象)》2014,8(5):44-47
水面蒸发敏感因素的判断,对于干旱区水资源的规划与利用具有重要指导意义。文章以新疆塔额盆地内的塔城市气象站1981—2010年资料为例,采用敏感系数法对研究区多年月均水面蒸发影响因素进行敏感性分析,并与关联分析法分析的结果对比。结果表明:在塔额盆地内,温度与水汽压二因素对水面蒸发影响最为敏感;基于敏感系数法的敏感因素研究结果与关联分析的结果基本一致,尤其在主要影响因子的判定上。 相似文献
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W. W. Tian M. Haverkorn † H. Y. Zhang 《Monthly notices of the Royal Astronomical Society》2007,378(4):1283-1286
New images of the supernova remnant (SNR) G351.7+0.8 are presented based on 21-cm H i -line emission and continuum emission data from the Southern Galactic Plane Survey. SNR G351.7+0.8 has a flux density of 8.4 ± 0.7 Jy at 1420 MHz. Its spectral index is 0.52 ± 0.25 ( S = v −α ) between 1420 and 843 MHz, typical of adiabatically expanding shell-like remnants. H i observations show structures possibly associated with the SNR in the radial velocity range of −10 to −18 km s−1 , and suggest a distance of 13.2 kpc and a radius of 30.7 pc. The estimated Sedov age for G351.7+0.8 is less than 6.8×104 yr . A young radio pulsar PSR J1721−3532 lies close to SNR G351.7+0.8 on the sky. The new distance and age of G351.7+0.8 and recent proper motion measurements of the pulsar strongly argue against an association between SNR G351.7+0.8 and PSR J1721−3532. There is an unidentified, faint X-ray point source 1RXS J172055.3−353937 which is close to G351.7+0.8. This may be a neutron star potentially associated with G351.7+0.8. 相似文献
58.
土地卫片执法检查是政府实施土地严格管理的重要手段.本文以绵阳市2009年度遥感土地执法检查为例,选用2008年和2009年两个时相的中巴资源卫星02B遥感图像作为信息源,对3G与3S集成技术在土地利用执法检查中应用方法进行了研究.该方法利用RS获取土地利用变化信息,利用VRS-GPS技术采集变化图斑空间与属性特征信息,... 相似文献
59.
Haishen Lü Xiaoli Li Zhongbo Yu Robert Horton Yonghua Zhu Zhenchun Hao Long Xiang 《水文研究》2010,24(25):3648-3660
Root zone soil water content impacts plant water availability, land energy and water balances. Because of unknown hydrological model error, observation errors and the statistical characteristics of the errors, the widely used Kalman filter (KF) and its extensions are challenged to retrieve the root zone soil water content using the surface soil water content. If the soil hydraulic parameters are poorly estimated, the KF and its extensions fail to accurately estimate the root zone soil water. The H‐infinity filter (HF) represents a robust version of the KF. The HF is widely used in data assimilation and is superior to the KF, especially when the performance of the model is not well understood. The objective of this study is to study the impact of uncertain soil hydraulic parameters, initial soil moisture content and observation period on the ability of HF assimilation to predict in situ soil water content. In this article, we study seven cases. The results show that the soil hydraulic parameters hold a critical role in the course of assimilation. When the soil hydraulic parameters are poorly estimated, an accurate estimation of root soil water content cannot be retrieved by the HF assimilation approach. When the estimated soil hydraulic parameters are similar to actual values, the soil water content at various depths can be accurately retrieved by the HF assimilation. The HF assimilation is not very sensitive to the initial soil water content, and the impact of the initial soil water content on the assimilation scheme can be eliminated after about 5–7 days. The observation interval is important for soil water profile distribution retrieval with the HF, and the shorter the observation interval, the shorter the time required to achieve actual soil water content. However, the retrieval results are not very accurate at a depth of 100 cm. Also it is complex to determine the weighting coefficient and the error attenuation parameter in the HF assimilation. In this article, the trial‐and‐error method was used to determine the weighting coefficient and the error attenuation parameter. After the first establishment of limited range of the parameters, ‘the best parameter set’ was selected from the range of values. For the soil conditions investigated, the HF assimilation results are better than the open‐loop results. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
60.