全文获取类型
收费全文 | 1307篇 |
免费 | 35篇 |
出版年
2024年 | 3篇 |
2023年 | 15篇 |
2022年 | 32篇 |
2021年 | 33篇 |
2020年 | 73篇 |
2019年 | 75篇 |
2018年 | 73篇 |
2017年 | 78篇 |
2016年 | 93篇 |
2015年 | 50篇 |
2014年 | 60篇 |
2013年 | 140篇 |
2012年 | 74篇 |
2011年 | 55篇 |
2010年 | 66篇 |
2009年 | 57篇 |
2008年 | 50篇 |
2007年 | 56篇 |
2006年 | 29篇 |
2005年 | 43篇 |
2004年 | 37篇 |
2003年 | 34篇 |
2002年 | 33篇 |
2001年 | 19篇 |
2000年 | 25篇 |
1999年 | 14篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
排序方式: 共有1342条查询结果,搜索用时 15 毫秒
51.
大约以公元前2200年为界, 老虎山文化可分为前、后两大期.前期稳定发展,对外影响有限;后期向南强烈扩张,其陶双鋬鬲、卜骨和细石器镞更流播至黄河中下游广大地区.老虎山文化后期对外扩张的加强和这一时期气候日渐干冷有关. 相似文献
52.
156项工程与新中国工业城市发展(1949~1957年) 总被引:1,自引:0,他引:1
“一五”时期,以156项工程为契机,新中国开始了全面的社会主义工业化建设。这些大型经济建设项目的启动,不仅改变了中国城市发展的道路、方向,而且为中国城市的快速发展提供了强劲的动力,从而推动了中国城市进入以重工业优先发展战略为导向的新阶段。在这一发展模式的作用下,中国城市的发展呈现出城市职能的经济化、城市化发展的高速化、大中城市优先发展以及区域城市发展均衡化等新特点,这种城市发展的变化既彻底改变了旧中国城市的半殖民地半封建性质,又为后来中国城市的发展奠定了全新的基础。 相似文献
53.
Major corrosion has been found at depth in carbonate hydrocarbon reservoirs from different geologic provinces. Fluid inclusion microthermometry and stable isotopic compositions of carbonate cements, predating major corrosion, constrain the interpretation of the evolution of parental fluids during progressive burial and prior to the major corrosion event. Post‐major corrosion mineral paragenesis includes pyrite (‐marcasite), anhydrite, kaolinite (dickite) and fluorite. Although the post‐corrosion mineral paragenesis represents minor volumes of rock, it may provide valuable insights into the post‐corrosion brine chemistry. Using reactive transport numerical models, the roles of cooling and/or mixing of brines on corrosion have been evaluated as controls for dolomitization, deep burial corrosion and precipitation of the post‐corrosion mineral paragenesis. Modelling results show that cooling of deep‐seated fluids moving upward along a fracture may cause minor calcite dissolution and porosity generation. Significant dolomitization along a fracture zone and nearby host‐rock only occurs when deep‐seated fluids have high salinities (4 mol Cl kg?1 of solution) and Darcian flow rates are relatively high (1 m3 m?2 year?1). Only minor volumes of quartz and fluorite precipitate in the newly formed porosity. Moreover, modelling results cannot reproduce the authigenic precipitation of kaolinite (dickite at high temperatures) by cooling. As an alternative to cooling as a cause of corrosion, mixing between two brines of different compositions and salinities is represented by two main cases. One case consists of the flow up along a fracture of deep‐seated fluids with higher salinities than the fluid in the wall rock. Dolomite does not precipitate at a fracture zone. Nevertheless, minor volumes of dolomite are formed away from the fracture. The post‐corrosion mineral paragenesis can be partly reproduced, and the results are comparable to those obtained from cooling calculations. Minor volumes of quartz and fluorite are formed, and kaolinite‐dickite does not precipitate. The major outputs of this scenario are calcite dissolution and slight net increase in porosity. A second case corresponds to the mixing of low salinity deep‐seated fluids, flowing up along fractures, with high salinity brines within the wall rock. Calculations predict major dissolution of calcite and precipitation of dolomite. The post‐corrosion mineral paragenesis can be reproduced. High volumes of quartz, fluorite and kaolinite‐dickite precipitate and may even completely occlude newly formed porosity. 相似文献
54.
流动性的增强不但意味着人口、信息、资金流动强度增加,也意味着流动范围的扩大。在此背景下,以稳定的人口构成为基础的传统地域饮食文化区的边界也开始发生变化。同时,流动性也使多元地方饮食文化在空间扩散的基础上展开了互动与交融。本研究将除港澳台地区以外的中国全域作为研究区域,基于海量餐饮服务设施POI数据,运用核密度分析方法分析中国目前的流行菜系空间扩散格局并描述其特征,并从流动性视角阐释其形成与扩散的文化地理逻辑。研究发现,中国现流行的菜系主要包括川菜、湘菜、粤菜、东北菜、徽菜、云贵菜、西北菜、鲁菜;中国流行菜系的空间扩散格局具有差异明显、多中心发展的特点。其中,川菜、湘菜、粤菜数量多分布广;鲁菜、徽菜分布集中,扩散较少;东北菜、云贵菜、西北菜数量较少但分布范围广。这种流行菜系空间扩散格局背后的文化地理逻辑与流动性密不可分,人口、资金等的流动促使地方饮食文化在空间内扩散,同时也带来了地方饮食文化间的交融互构。 相似文献
55.
在文艺复兴时期的西欧,法国的宫廷大臣、著名的政治思想家克劳德·得·塞瑟尔根据现实社会的变动,提出了系统的"新君主制"学说.在肯定君主制的价值时,他鼓吹"王权神授",但却着重于从人性的角度来强调君主制的优越性.在对"明君政治"的憧憬中,他界定了一些君主应当遵循的政治行为规范,特别强调君主实施仁政,建立各等级之间的"和谐"秩序,并提出了等级变动的合理性.同时,塞瑟尔主张君主让各等级代表参政议政,建立"君主咨政会议制".他还提出"有限君权"的主张,力图以教会、"正义"与国家法令来遏止君主的暴政.此外,他还要求君主灵活地进行外交,积极进行殖民扩张.塞氏的政治学说充满着"过渡时期"社会所赋予的复杂性与矛盾性,但受时代变迁的感召与人文主义的熏陶,他突破传统的藩篱,提出了适应民族国家发展与新兴资产阶级成长之需要的"新君主制"学说.他的政治理想,反映了西方政治思想从中世纪向近代转型的历史趋势. 相似文献
56.
江西省区域经济发展空间差异研究 总被引:20,自引:0,他引:20
区域差异历来是政府关注的重要问题,也是区域发展理论研究的主要课题。江西省受周边强经济中心的影响,经济区位边缘化趋势明显。近年来江西省突破原来农业大省的发展思路,致力引进发达地区和国外的技术和资金,工业化水平明显提高。目前江西省内部地区差异较1990年明显扩大,而且表现出各地区相对波动较大的特征。本文采用偏离一份额模型,对江西1990-2001年间11年来的发展状况分两个阶段进行分析,探讨江西省区域经济发展差异的空间结构特征,将江西划分为4种发展类型。江西省各地区区位条件的变化是其经济发展空间差异的驱动因素。 相似文献
57.
《International Journal of Osteoarchaeology》2017,27(2):143-154
Examining recently excavated burnt burials, we explore the potential of spatial analysis to contribute to the understanding of changes that human body goes through during burning and relocation to the place of secondary deposition. Artificial heat decomposition of a body is a complex process that consists of several stages of intentional manipulation with the body. Each stage can be biased by several accidental factors which then significantly change the final archaeological record. We focussed on the post‐burning stage, especially the pathways of bone fragments to secondary deposition. We investigated spatial distribution and weight of bones in urns and pits and asked whether it is possible to observe their intentional arrangement. The trend of bone arrangement could be distinguished in most cases. Bones of peripheral parts of body were typically situated at the bottom; skull bones were usually concentrated in the upper part. However, the weight underrepresentation of all investigated burials was apparent. Deposition of selected burnt bones suggests their careful collection from the pyre and complex post‐mortem manipulation. Our detailed analysis aims to reconstruct particular steps executed during funeral rites of past populations. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
58.
59.
This paper documents court‐imposed bail and sentencing conditions with spatial dimensions, such as red zones, no contact conditions, curfews and prohibitions to demonstrate, issued in the context of criminal proceedings. These conditional orders, which are growing in importance and have a significant impact on the lives of marginalized groups of people, have not received the attention they deserve in the literature. As opposed to better publicized forms of spatial regulation such as legislation or policing strategies, these conditional orders are a distinctive form of spatial tactic that rely on ancient and routinized rules of criminal procedure and the practices of the courts. In order to understand this spatial tactic, and its impact on marginalized people's rights and uses of spaces, we argue that it is necessary to pay attention to the legal rationalities, knowledge and practices that sustain them. 相似文献
60.
Massimiliano Bratti Luca De Benedictis Gianluca Santoni 《Journal of regional science》2020,60(2):249-272
This paper demonstrates the positive effect of immigrant entrepreneurs on manufacturing exports over and above that of diasporas. Using small-scale regional administrative data, our instrumental variable estimates of export gravity models imply that ceteris paribus, that is, holding constant the total number of immigrants, the expected protrade effect of a migrant becoming an entrepreneur amounts to an average increase of US$5,946 in the export flows toward her country of origin. Besides these dyadic effects, immigrant entrepreneurs unlike nonentrepreneurial immigrants raise a region's overall competitiveness and export flows toward other destinations as well. 相似文献