全文获取类型
收费全文 | 1019篇 |
免费 | 60篇 |
国内免费 | 219篇 |
专业分类
测绘学 | 10篇 |
大气科学 | 81篇 |
地球物理 | 232篇 |
地质学 | 657篇 |
海洋学 | 112篇 |
天文学 | 98篇 |
综合类 | 10篇 |
自然地理 | 98篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 16篇 |
2020年 | 18篇 |
2019年 | 22篇 |
2018年 | 26篇 |
2017年 | 34篇 |
2016年 | 34篇 |
2015年 | 38篇 |
2014年 | 33篇 |
2013年 | 69篇 |
2012年 | 47篇 |
2011年 | 70篇 |
2010年 | 50篇 |
2009年 | 56篇 |
2008年 | 58篇 |
2007年 | 72篇 |
2006年 | 72篇 |
2005年 | 137篇 |
2004年 | 68篇 |
2003年 | 44篇 |
2002年 | 40篇 |
2001年 | 25篇 |
2000年 | 42篇 |
1999年 | 19篇 |
1998年 | 14篇 |
1997年 | 18篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 12篇 |
1993年 | 12篇 |
1992年 | 13篇 |
1991年 | 16篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1968年 | 2篇 |
1933年 | 2篇 |
排序方式: 共有1298条查询结果,搜索用时 0 毫秒
81.
Molcard Anne Gramoullé Anthony Mazoyer Camille Bourg Natacha Ourmières Yann 《Ocean Dynamics》2021,71(10):993-1009
Ocean Dynamics - Coastal regions are vulnerable areas with often high population density, as well as tourism and maritime activities that may have negative impact on the environment. From a... 相似文献
82.
Anne Vogelpohl 《Urban geography》2018,39(9):1345-1365
These days, it is often claimed that democratic procedures are under threat. The detachment of policy decisions from political debates is partly a result of the increasing influence of non-elected organizations and experts. Following a conceptual discussion of the spatiality of democracy, this paper focuses on management consultants as constraint on collective political participation in urban development; namely on McKinsey and Roland Berger. (De-)democratization is assessed alongside processes of inclusion and exclusion of both topics and people from political decisions. Based on a comparison of strategy-making projects in six German cities, the findings reveal three different types of urban policymaking ranging between expert-led and participatory versions. Despite the differences, each of the projects relied on a notion of passive citizens, who primarily need to be “gotten on board” and who lack the power to make decisions. This paper exposes the political tactics involved in an expert-influenced curtailment of democratic procedures. 相似文献
83.
Oryński Szymon Klityński Wojciech Neska Anne Ślęzak Katarzyna 《Studia Geophysica et Geodaetica》2019,63(2):273-289
Studia Geophysica et Geodaetica - A fundamental tectonic boundary between the Precambrian East European Craton (EEC) and the younger Phanerozoic mountain belts of Europe runs through Poland.... 相似文献
84.
85.
Despite several decades of discussion and debate around the role of GIS in the discipline of Geography, it would be a stretch to argue that GIS has not irreversibly altered the discipline, both in the scope of research and teaching as well as in the wider imagination of a general public. However, it remains a challenge to incorporate the range of geographic knowledge, born of a diversity of modalities, into operational insights and analytical pre‐conditions in a GIS. To be certain, some irreconcilability between GIS and geographical inquiry is to be expected, epistemologically speaking. In what follows, we consider what might be meant by a shift to geographic analysis as scholars from disciplines in the humanities and social sciences turn to GIS as a method of observation, interpretation, analysis, and representation. In this context, we engage in a thought experiment and offer some commentary, fixing the notion of information system, while opening the geographic in GIS to more variable understanding. The point is to pursue greater development of GIS theory and method, encompassing, while not reducing, scientific, social scientific, and humanities research. 相似文献
86.
Estela M. Reynoso † Simon Johnston Anne J. Green Bärbel S. Koribalski 《Monthly notices of the Royal Astronomical Society》2006,369(1):416-424
We have observed the supernova remnant (SNR) G290.1−0.8 in the 21-cm H i line and the 20-cm radio continuum using the Australia Telescope Compact Array (ATCA). The H i data were combined with data from the Southern Galactic Plane Survey to recover the shortest spatial frequencies. In contrast, H i absorption was analysed by filtering extended H i emission, with spatial frequencies shorter than 1.1 kλ. The low-resolution ATCA radio continuum image of the remnant shows considerable internal structure, resembling a network of filaments across its 13-arcmin diameter. A high-resolution ATCA radio continuum image was also constructed to study the small-scale structure in the SNR. It shows that there are no structures smaller than ∼17 arcsec, except perhaps for a bright knot to the south, which is probably an unrelated object. The H i absorption study shows that the gas distribution and kinematics in front of SNR G290.1−0.8 are complex. We estimate that the SNR probably lies in the Carina arm, at a distance 7 (±1) kpc. In addition, we have studied nearby sources in the observed field using archival multiwavelength data to determine their characteristics. 相似文献
87.
88.
渤海海水中悬浮体的研究 总被引:29,自引:5,他引:29
陆源悬浮体是边缘海海底沉积物的主要来源.所以,悬浮体(suspended matter)的调查研究是解决边缘海海底沉积作用的一个重要环节.当我们研究河口附近海域以及海底沉积物的通量平衡过程时,也必须对悬浮体的分布及其数量变化等进行调查. 相似文献
89.
Reinforced concrete structure may exhibit significant inelastic hysteretic behavior when subject to strong earthquake excitation. To investigate such an inelastic behavior, in this study, a new system identification technique is applied by using the deteriorating distributed element (DDE) model to simulate the hysteretic behavior of a degrading structure. Through the advanced signal processing technique, the multiple singular spectrum analysis (SSA) and the nonlinear SSA, the recorded inelastic restoring force of a deteriorating structure can be decomposed into several independent additive components in its sequentially degrading order and with decreasing weight. With each decomposed hysteresis loop, the model parameters of the DDE model are identified. The evolutionary properties of the progressive stiffness degradation behavior of reinforced concrete structure can be observed from the identified model parameters. Finally, comparison on the physical properties of the identified DDE model with respect to the seismic response data of the deteriorating structure is also discussed. The result shows that the proposed identification technique can have a good estimation on the seismic behavior of the degrading structure. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
90.
广东河源盆地蛋化石 总被引:3,自引:0,他引:3
河源盆地沉积了白垩系-古近系,笔者将这套地层划分为3个岩石地层单位,新建仙塘组和东源组,沿用格岭组。在河源除发现恐龙骨骼、恐龙脚印、龟鳖化石外,于白垩系东源组中还产有大量蛋化石。该组蛋化石的分布,下部以圆形蛋为主,中-上部多见长形蛋。报道了三王坝村副圆形蛋(新种)Paraspheroolithus sanwangbacunensis Fang sp.nov.、风光村树枝蛋(新种)Dendroolithus fengguangcunensis Fang sp.nov.和瑶屯巨形蛋Macroolithus yaotunensis、长形长形蛋Elongatoolithus elongates。 相似文献