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41.
新型冠状病毒肺炎(COVID-19)疫情爆发以来,温州市疫情形势严峻.本文通过温州市卫生健康委员会官方网站公布的新型冠状病毒肺炎患者的具体信息,利用数据分析法、GIS技术和定量分析法对温州市新冠肺炎疫情的发展变化、分布及扩散特征进行分析.结果显示:1)温州市新冠肺炎确诊病例男性占比高于女性,且以中青年人为主,老年人位列第三,少年儿童最少.2)新冠肺炎患者主要分布在温州中部和东北部人口稠密、经济发达的地区,南部和西南部地区患者数量比较少.3)经济发展较弱的地区扩散风险较高,人群防护意识薄弱也会加剧疫情扩散.本研究可对新冠肺炎等传染性疾病疫情的防控工作起到一定的指导和借鉴作用. 相似文献
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Mixed carbonate-siliciclastic sedimentation is common in the Upper Permian-Lower Tri-assic in the western Sichuan(四川) basin.The extensional movement was strong in the Late Permian,resulting in differential uplifting of fault blocks.During this period,there was an extensive retrogres-sion.The Kangdian(康滇) ancient land progressive uplifted and enlarged,forming the major prove-nance of terrigenous clastics.In Changxingian age,mixed terrigenous-carbonate sedimentation was dis-tributed in the area between Dafeis... 相似文献
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北京市地面塌陷特征与致灾因子分析 总被引:1,自引:0,他引:1
年北京地面塌陷呈波动式上升趋势,威胁严重.在讨论其孕灾环境和时空分布特征的基础上,分析引起地面塌陷的因素.研究把此区地面塌陷分为采矿地面塌陷和工程地面塌陷两种类型.采矿地面塌陷主要分布于西山门头沟,致灾因子包括开采深度、矿体倾角、降雨、和大量疏排水.工程地面塌陷主要分布于城区,致灾因子包括管线渗漏与侵蚀、地下水过度开采... 相似文献
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A passive seismic experiment across the Longmenshan (LMS) fault belt had been conducted between August 2006 and July 2007 for the understanding of geodynamic process between the Eastern Tibet and Sichuan basin. We herein collected 3677 first P arrival times with high precision from seismograms of 288 teleseismic events so as to reconstruct the upper mantle velocity structure. Our results show that the depth of the Lithosphere–asthenosphere boundary (LAB) changes from 70 km beneath Eastern Tibet to about 110 km beneath Longquanshan, Sichuan Basin, which is consistent with the receiver function imaging results. The very thin mantle part of the lithosphere beneath Eastern Tibet may suggest the lithosphere delamination due to strong interaction between the Tibetan eastward escaping flow and the rigid resisting Sichuan basin, which can be further supported by the existences of two high-velocity anomalies beneath LAB in our imaging result. We also find there are two related low-velocity anomalies beneath the LMS fault belt, which may indicate magmatic upwelling from lithosphere delamination and account for the origin of tremendous energy needed by the devastating Wenchuan earthquake. 相似文献
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Assessment of sediment and erosion rates by using the caesium-137 technique in a Chinese polygonal karst depression 总被引:4,自引:0,他引:4
Xiaoyong Bai 《Environmental Earth Sciences》2011,64(8):2151-2158
Karst depressions comprise geomorphologically important sources and sinks for sediments and associated pollutants; yet the
sedimentology of many depressions is not well understood in the world. In this paper, the 137Cs technique was employed to estimate recent sedimentation rates in a Chinese polygonal karst depression. The results indicate
that the sediment deposition rates ranged from 0.91 to 1.97 mm year−1 from 1963 to 2007, and the average sediment deposition rate and specific deposit yield were estimated to be 1.47 mm year−1 and 20 t km−2 year−1, respectively. These results are consistent with the local monitoring data of runoff fields, which confirms the validity
of the overall approach. This shows that the soil loss rate is very low in some karst areas of Southwest China. Above all,
the approach appears to offer valuable potential to study surface erosion by estimating sediment deposition rates of karst
depressions, rather than the assessment of complicated soil erosion in stony soils of carbonate rock slopes. In addition,
the space distribution of surface soil and 137Cs inventories are affected remarkably by the inhomogeneous dissolution of limestone under the soil. It may be an important
phenomenon, which exists widely in karst areas, and it is significantly different from other places. 相似文献
48.
Previously, we had characterized several structurally interesting brominated phenols from the marine red alga Symphyocladia latiuscula collected from various sites. However, Phytochemical investigations on this species collected from the Weihai coastline of Shandong Province remains blank. Therefore, we characterized the chemical constituents of individuals of this species collected from the region. Eight bromophenols were isolated and identified. Using detailed spectroscopic techniques and comparisons with published data, these compounds were identified as 2,3-dibromo-4,5-dihydroxybenzyl methyl ether (1), 3,5-dibromo-4-hydroxybenzoic acid (2), 2,3,6-tribromo-4,5-dihydroxymethylbenzene (3), 2,3,6-tribromo-4,5-dihydroxybenzaldehyde (4), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (5), bis(2,3,6-tribromo-4,5-dihydroxyphenyl)methane (6), 1,2-bis(2,3,6-tribromo-4,5-dihydroxyphenyl)-ethane (7), and 1-(2,3,6-tribromo-4,5-dihydroxybenzyl)-pyrrolidin-2-one (8). Among these compounds, 1 and 2 were isolated for the first time from S. latiuscula. Each compound was evaluated on the ability to inhibit protein tyrosine phosphatase 1B (PTP1B), which is a potential therapeutic target in the treatment of type 2 diabetes. Bromophenols 5, 6, and 7 showed strong activities with IC50 values of 3.9, 4.3, and 3.5 μmol/L, respectively. This study provides further evidence that bromophenols are predominant among the chemical constituents of Symphyocladia, and that some of these compounds may be candidates for the development of anti-diabetes drugs. 相似文献
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