首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   296篇
  免费   15篇
  2023年   9篇
  2022年   6篇
  2021年   12篇
  2020年   9篇
  2019年   20篇
  2018年   14篇
  2017年   13篇
  2016年   12篇
  2015年   12篇
  2014年   19篇
  2013年   37篇
  2012年   17篇
  2011年   21篇
  2010年   9篇
  2009年   16篇
  2008年   12篇
  2007年   6篇
  2006年   12篇
  2005年   9篇
  2004年   5篇
  2003年   8篇
  2002年   11篇
  2001年   7篇
  2000年   8篇
  1999年   2篇
  1997年   1篇
  1996年   1篇
  1986年   1篇
  1985年   1篇
  1982年   1篇
排序方式: 共有311条查询结果,搜索用时 15 毫秒
41.
编写《中国文学史》,总爱用我们今天的文艺理论来评价古代的文学家与他们的作品,这当然是必要的,因为学术总得与时俱进。但阅读评论古代的作品,必须知其人,而知其人,又必须论及世。我们对那些特定的时代是否能有正确深入的了解,光靠泛泛而言的所谓时代背景介绍是不够的,因此通过宋人的记载与议论去感受那个时代的社会风尚以及领会当时的思想与眼光,这样。我们才能逐渐贴近那个时代,较为正确认识这些作家与作品,以及其时发生的种种事件。本文企图通过宋人三大笔记的相关记载与议论,谈谈北宋文学史的编写问题。  相似文献   
42.
随仲嬭加鼎的发现具有重要意义,但其非考古发掘品,需要考察其制作年代。在楚系青铜器大背景下,本文通过对该鼎器形、纹饰、铭文以及工艺等时代特征的观察,并对比分析相关楚系青铜器,认为该鼎制作年代在春秋中期无疑。  相似文献   
43.
芮田生  阎洪 《旅游科学》2011,25(3):14-23
对一个地区的旅游竞争力进行评价有助于客观地了解该地区旅游业的发展状况,而科学合理的评价依赖于评价指标和评价方法的选择。本文提出了合理选择指标的原则,并在所构建的旅游竞争力评价指标体系中引入了"软"指标。由于单一评价模型的评价结果各不相同,本文引入组合评价模型对西部十二省、自治区、直辖市的旅游竞争力进行评价,然后采用斯皮尔曼等级相关系数对组合评价结果进行检验,结果显示本文采用的组合评价方法与其它评价方法的一致性最高,说明该方法能比较客观综合地反映旅游竞争力状况。最后,通过聚类分析,进一步验证了本文方法的有效性。  相似文献   
44.
Wetlands are common in Coastal Western Hemlock forests yet the hydrologic processes that generate runoff from small swamps are not completely understood. Direct field observations, hydrologic, and electrical conductivity data were collected from a gently sloping forested swamp complex from July to November 2009. Swamps occupied depressions between raised mounds (0.1 to 3 m high) and were connected by an ephemeral creek. Runoff was controlled by antecedent moisture conditions and influenced by basin microtopography. Two hydrologic regimes occurred during the study period and different runoff processes dominated each regime. Runoff was generated by subsurface flow during dry antecedent conditions as swamps remained hydrologically disconnected from each other. Runoff was generated by surface outflow from hydrologically connected swamps during wet antecedent conditions as ponded water spilled out of the depressions. The forested swamp complex produced a faster but limited hydrologic response during dry antecedent conditions compared to a slower but greater hydrologic response during wet antecedent conditions. Stormwater runoff and runoff ratios were up to two orders of magnitude higher in wet conditions than during similarly sized events in dry conditions. These factors should be considered when designing monitoring programs or runoff models in forested swamps with significant microtopography. Field surveys and estimates of hydrologic inputs and outputs may be useful in predicting the potential hydrologic connectivity of isolated forested swamps.  相似文献   
45.
Intra-household time transfer is an important intergenerational support, less emphasised but more prominent than monetary transfers in the Indian family system. This paper attempts to study, empirically, the nature and pattern of time transfers between co-residing and non-co-residing parents and their adult married children in an urban setting in India. From the analysis of 673 representative sampled households, we have found that reciprocative time transfers between adult children and their parents constitute a central feature of the intergenerational support system, regardless of co-residency status. Significant correlates of time transfers to elderly parents are age, presence of other siblings in the household, headship status, and monetary support received from and made to parents. However, there is no evidence of inter-substitution between time and money between the two generations, i.e. married adult children and their parents. Time support is more frequent and intense when parents reside in the same city, whereas monetary transfers dominate when parents reside in a distant city or village.  相似文献   
46.
This article discusses from a specifically German point of view the “spatial turn” in history and the approaches of this forum. Many recent interventions have suggested that “space” (as opposed to “time”) was for many years a marginalized category in the German historiographical debate because of the ideological contamination of the category “space” by the Nazis. In the context of the vivid, lively “provincial” or “regional” history practiced in Germany, however, “space” has always played an important role. The debates around the spatial turn nevertheless provide the opportunity for deliberate reconceptualization. This comment proposes a relational understanding of “space” as the core of the new approach and identifies some central elements and terms for it: the differentiation of “spaces,”“places,” and “locations”; movement in space; the division of space in the form of boundaries; finally, the ordering and classification of space in the form of written or visual representations.  相似文献   
47.
At the end of the nineteenth century, Ludwig Edinger completed the first comparative survey of the microscopic anatomy of vertebrate brains. He is regarded as the founder of the field of comparative neuroanatomy. Modern commentators have misunderstood him to have espoused an anti-Darwinian linear view of brain evolution, harkening to the metaphysics of the scala naturae. This understanding arises, in part, from an increasingly contested view of nineteenth-century morphology in Germany. Edinger did espouse a progressionist, though not strictly linear, view of forebrain evolution, but his work also provided carefully documented evidence that brain stem structures vary in complexity independently from one another and across species in a manner that is not compatible with linear progress. This led Edinger to reject progressionism for all brain structures other than the forebrain roof, based on reasoning not too dissimilar from those his successors used to dismiss it for the forebrain roof.  相似文献   
48.
The rock art in Altamira Cave was the first ensemble of Palaeolithic parietal art to be identified scientifically (Sautuola, 1880). Due to the great thematic, technical and stylistic variety of the art in the cave, which constitutes one of the most complete Palaeolithic art ensembles, Altamira was listed as World Heritage by UNESCO in 1985. Uranium-series dating has recently been applied to figures on the decorated ceiling in the cave. Several motifs are partly covered by thin layers of calcite precipitates, whose formation process is datable by this method. The results provide the date when the calcite formed, which gives a minimum age for the underlying depictions. These results confirm that the parietal art at Altamira was produced during a prolonged period of time, at least 20,000 years (between 35,000 and 15,200 years ago), and that part of the ensemble corresponds to the Aurignacian period.  相似文献   
49.
This paper presents the results of a comprehensive comparison study between the analytically predicted and experimentally identified dynamics of the shaking table system built recently in the Structural Engineering Laboratory at Rice University in Houston, Texas. The primary objectives of the research presented here are two-fold: (1) to shed light into the dynamic performance of asmall-tc-medium size, uni-axial, servo-hydraulic, displacement-controlled shaking table system, and (2) to validate a linearised dynamic model of the system (in the form of the total shaking table transfer function) developed earlier by the authors from basic principles. The analytical model incorporates the inherent dynamic characteristics of the various components of the shaking table system (i.e. controller, servovalve, actuator, test specimen, and reaction mass) and their dynamic interaction.

The test-analysis correlation study performed over a wide range of operating and payload conditions provides useful information on the sensitivity of the shaking table transfer function to control gain parameters and how it can be used to tune the shaking table controller for optimum performance under various payload conditions. The good test-analysis correlation results obtained validate the analytical shaking table model, show its robustness, and provide keen insight into the underlying coupled dynamics of a shaking table system. In order to achieve this good test-analysis correlation, it was crucial to include a time delay in the analytical model of the shaking table system (innovative feature of the model to account for the time lag in the response of the servovalve-actuator system). The expected significant dynamic interaction between payload and shaking table is also confirmed by this study.  相似文献   
50.
本文在分析三门峡秦人墓中洞室墓各型式的基础上,对各型式墓葬的年代分别进行了讨论,进而认为,三门峡秦人墓中的洞室墓最早出现于战国晚期,并一直延续到西汉中期.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号