全文获取类型
收费全文 | 558篇 |
免费 | 3篇 |
专业分类
561篇 |
出版年
2025年 | 1篇 |
2024年 | 4篇 |
2023年 | 4篇 |
2022年 | 15篇 |
2021年 | 16篇 |
2020年 | 22篇 |
2019年 | 6篇 |
2018年 | 15篇 |
2017年 | 18篇 |
2016年 | 24篇 |
2015年 | 16篇 |
2014年 | 19篇 |
2013年 | 23篇 |
2012年 | 28篇 |
2011年 | 41篇 |
2010年 | 35篇 |
2009年 | 27篇 |
2008年 | 31篇 |
2007年 | 39篇 |
2006年 | 33篇 |
2005年 | 24篇 |
2004年 | 20篇 |
2003年 | 26篇 |
2002年 | 22篇 |
2001年 | 11篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有561条查询结果,搜索用时 15 毫秒
151.
ARZHANG ALIMORADI SHAHRAM PEZESHK FARZAD NAEIM HICHEM FRIGUI 《Journal of Earthquake Engineering》2013,17(3):307-332
Classification of earthquake strong ground motion (SGM) records is performed using fuzzy pattern recognition to exploit knowledge in the data that is utilised in a genetic algorithm (GA) search and scaling program. SGM records are historically treated as “fingerprints” of certain event magnitude and mechanism of faulting systems recorded at different distances on different soil types. Therefore, databases of SGM records of today present data of complex nature in high dimensions (many of the dimensions—or SGM parameters in time and frequency domain—are presently available from different archives). In this study, simple ground motion parameters were used but were combined and scaled nonlinearly such that the physical properties of the data could be preserved while reducing its dimensionality. The processed data was then analysed using fuzzy c-means (FCM) clustering method to explore the possibility of meaningfully representing earthquake SGM data in lower dimensions through finding subsets of mathematically similar vectors in a benchmark database. This representation can be used in practical applications and has a direct influence on the processes of synthesising ground motion records, identifying unknown ground motion parameters (e.g. soil type in this study), improving the quality of matching SGM records to design target spectra, and in rule generalisation for response. The results showed that the stochastic behaviour of earthquake ground motion records can be accurately simplified by having only a few of motion parameters. The very same parameters may also be utilised to derive unknown characteristics of the motion when the classification task on “training” records is performed carefully. The clusters are valid and stable in time and frequency domain and are meaningful even with respect to seismological features that were not included in the classification task. 相似文献
152.
MARTIN A. ANDRESEN 《The Canadian geographer》2010,54(2):139-157
Interregional trade between Canada and the United States has undergone significant change since the inception of free trade. However, the magnitude of that change for the different regions in Canada and the United States has not been properly identified because of a lack of an appropriate measure. This paper introduces the concept of a quasi‐point and employs a spatial point pattern test to measure the degree of change in the interregional trade of Canadian provinces and US states, with an emphasis of that change on Ontario. It is found that the degree of change in the interregional trade flows is related to the degree of change in the provincial tariff rates. 相似文献
153.
Donald J. Dietrich 《History of European Ideas》2013,39(3):376-377
While discussions of the debate between Karl Löwith and Hans Blumenberg over ‘secularisation’ focus primarily on the methodological utility of the concept, the difference between them was also one of the philosophical commitments and substantive claims about modernity. This difference is not always obvious. One way of bringing it out is to address the different contexts in which they produced their most famous statements about secularisation. But another, and one that will be pursued here, is to consider the critical dialogue that both thinkers engaged in with Nietzsche. Put briefly, while Löwith thought that Nietzsche misunderstood the ancients, Blumenberg thought that he misunderstood the moderns. For Löwith, Nietzsche's doctrine of the eternal return is not Greek, but an aggressive countergospel that owes much to the Christian culture it seeks to oppose; for Blumenberg, Nietzsche assumes, wrongly, that the self-belittlement of man by theology has been succeeded by the self-belittlement of man by science. In addition, Blumenberg – unlike both Nietzsche and Löwith – thinks that he can mount a robust defence of both modern science and progress. 相似文献
154.
155.
Sarah Cameron 《Australian journal of political science》2020,55(2):170-190
ABSTRACT Satisfaction with democracy has declined rapidly in Australia, reaching the lowest level recorded since the 1970s in 2019. Whereas Australian citizens used to be among the most satisfied democrats in the world, there is now evidence of widespread dissatisfaction. What explains this rapid decline in political support? Comparative studies emphasise the role of government performance, both political and economic, in shaping citizens’ attitudes towards the political system. This paper examines the role of government performance in shaping satisfaction with democracy in Australia, using Australian Election Study data from 1996 to 2019. The results demonstrate that frequent changes of prime minister, which a majority of voters disapproved of, and rising economic pessimism contributed to the decline of democratic satisfaction in Australia. 相似文献
156.
《太平州芜湖县新学记》碑记载了北宋时期州县置学(政府办学)的具体措施,丰富了科举史研究资料,同时该碑由米芾晚年所书,具有较高的历史艺术价值。 相似文献
157.
The globalisation of retailing has intensified since the mid‐1990s with the rise of a group of international retailers. Foreign retailers have greatly impacted the Chinese retail market since the opening up of the retail sector in 1992. This study aims to examine spatial inequality and dynamics of foreign hypermarket retailers at different geographic scales in China. Although the relative gaps in foreign hypermarkets among Chinese regions are narrowing, the absolute gaps are widening. Logistic regression models are used to identify locational determinants of foreign retailers Carrefour, Wal‐Mart, and RT‐Mart at the intercity level. Carrefour prefers cities with larger urban district populations, longer time of being open to international retailers, and more foreign investment. While urban district populations are significant to Wal‐Mart and RT‐Mart as well, they favour cities where people have higher annual salaries and aim to achieve internal economies of scale at the provincial level. The three leading foreign retailers also have different first‐city and city size preferences in their provincial expansions. 相似文献
158.
文章从国际尺度和国家尺度对近代中国的经济格局进行考察,认为1800年前中国是世界经济中心之一,近代中国则成为欧美制成品的销售地和原材料的来源地,中国由此转变为世界经济的边缘。这种世界经济格局又影响中国内部的经济格局,原来南北经济差距转变为东西差距,东部沿海成为中国经济的中心区,西部则成为中国经济的边缘。 相似文献
159.
Ping Yu Fan Kwok Pan Chun Ana Mijic Mou Leong Tan Wei Zhai Omer Yetemen 《Geographical analysis》2024,56(2):284-302
While the land use-street network nexus is well acknowledged, evidence for the one-way impacts of land-use patterns on street accessibility is still inadequate. The measurements of land-use patterns and street accessibility lack systematic knowledge. Their empirical correlations also lack geographical variability, constraining site-specific land-use practices. Therefore, this study overcame the aforementioned limitations by examining the two-level spatial models to formulate accessibility-oriented land plans, using a well-developed Chinese city as an example. Firstly, two landscape metrics—Euclidean Nearest-Neighbor Distance (ENN) and Similarity Index (SIMI)—were used to quantify the intra- and inter-land-use configurations, respectively. Both city-level and local accessibility were measured using spatial design network analysis. Performing both ordinary least squares (OLS) and geographically weighted regression (GWR) models, results identified the statistically significant effects of inter-land-use patterns on two-level street accessibility. An exception was that land-use configurations within residential and industrial regions were irrelevant to street accessibility. We also found GWR was a better-fitting model than OLS when estimating locally-varied accessibility, suggesting hierarchical multiscale land-use planning. Overall, locally heterogeneous evidence in this study can substantialize land use-street network interactions and support the decision-making and implementation of place-specific accessibility-oriented land use. 相似文献
160.
陕西榆林地区夏代文化遗存考察 总被引:1,自引:0,他引:1
本文依据目前发现的考古资料,对陕西榆林地区的夏代文化遗存作了初步分析,考察了文化因素及其来源,认定了文化性质,对该地区夏代文化的内涵和特征提出了新认识。 相似文献