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   628篇
  免费   23篇
  2024年   2篇
  2023年   9篇
  2022年   2篇
  2021年   2篇
  2020年   14篇
  2019年   16篇
  2018年   27篇
  2017年   33篇
  2016年   25篇
  2015年   19篇
  2014年   25篇
  2013年   141篇
  2012年   19篇
  2011年   20篇
  2010年   25篇
  2009年   20篇
  2008年   11篇
  2007年   15篇
  2006年   9篇
  2005年   9篇
  2004年   5篇
  2003年   10篇
  2002年   13篇
  2001年   9篇
  2000年   12篇
  1999年   39篇
  1998年   30篇
  1997年   10篇
  1996年   3篇
  1995年   6篇
  1994年   5篇
  1993年   2篇
  1992年   4篇
  1991年   4篇
  1990年   3篇
  1989年   4篇
  1988年   4篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1983年   4篇
  1982年   4篇
  1981年   4篇
  1980年   6篇
  1979年   2篇
  1978年   4篇
  1977年   6篇
  1975年   3篇
  1966年   1篇
排序方式: 共有651条查询结果,搜索用时 15 毫秒
31.
Grasslands pose a particular problem for archaeological survey involving artifact assessment, as no material is plowed up to the surface. Although finds in molehills are often the only source of information available on sites with such low visibility, an archaeology of molehills has thus far been largely disregarded. Yet, by applying a low-cost and time-efficient methodology, both the potential and the pitfalls of molehill archaeology come to the forefront. At the medieval harbor site of Monnikerede, it was possible to assess material culture and to locate certain structural elements. However, when artifact densities were compared with the underlying geophysical anomalies, a more complex relationship appeared at the level of individual features.  相似文献   
32.
The Aterian lithic techno-complex that characterizes the late Middle Stone Age in North Africa is well known especially for its tanged or stemmed points. Recent techno-morphological and use-wear analyses have added new data to support the identification of the tang as the hafted portion of an artifact. They have also highlighted the presence of this attribute on tools other than projectile points, in contrast with the widespread idea that the tanged point is the Aterian fossile directeur. The design of this specific device, the tang, for hafting purposes is regarded as a great technical innovation that underlines a modern behavior. Our work provides new use-wear and experimental data, aiming at discussing the cognitive preconditions of this technical innovation that could have originated from a specific functional unit: the notch. Notches are quite abundant in the Aterian techno-complex. Our systematic study of this tool category from Aterian sites of the Jebel Gharbi allowed defining the notch per se as a techno-morpho-functional unit that was “applied” to different types of blanks, including “reused blanks,” which show a heavy patina on their surface. This functional unit has been used for various types of activities and can be found either alone on a blank or with multiple other units on the same blank, creating different tool morphologies. According to this interpretation, the tang could have been considered by Aterian populations as a new resulting variant of various possible combinations of notches, for defining and/or transforming the shape of a tool.  相似文献   
33.
Roman plasters sampled from different houses at the archaeological site of Herculaneum, Italy, (2010–12) were studied by means of petrography, thermal analysis and X‐ray fluorescence. Herculaneum plasters are composed by preparatory layers (arriccio) with a thickness of several centimetres and are based on a calcitic binder and volcanic scoriae as aggregates, covered by a thin final layer characterized by a low granulometry. Most of the sampled plasters can be placed into two groups based on the aggregate composition and classified as marmorino or intonachino. However, a similar aggregate composition did not induce superimposable thermal behaviour, thus suggesting that the samples underwent different ageing/weathering processes, with a consequent change of the ratio among the components.  相似文献   
34.
Radon (Rn) is a potentially toxic gas in soil which may affect human health. Assessing Rn levels in soil gas usually requires enormous efforts in terms of time and costs, since the sampling protocol is very complex. In most cases, the variable under study is sparsely sampled over the domain and this could affect the reliability of the spatial predictions. For this reason, it is useful to incorporate, into the estimation procedure, some auxiliary variables, correlated with the in soil gas Rn concentrations (primary variable) and more densely available over the domain. On the basis of this latter aspect, it is even better if the covariates are derived from a geographical information system (GIS). In this article, the Rn sampling protocol used during a measurement campaign planned over a risk area is described and the process of deriving GIS covariates considered as secondary information for predicting the primary variable is clarified. Then, multivariate modeling and prediction of the Rn concentrations over the domain of interest are discussed and a comparative study regarding the performance of the prediction procedures is presented. Rn prone areas are also analyzed with respect to urban and school density. All these aspects can clearly support decisions on environmental and human safeguard.  相似文献   
35.
The most recent national Census demonstrated that Australian Muslims continue to occupy a socioeconomically disadvantaged position. On key indicators of unemployment rate, income, type of occupation and home ownership, Muslims consistently under-perform the national average. This pattern is evident in the last three Census data (2001, 2006 and 2011). Limited access to resources and a sense of marginalisation challenge full engagement with society and the natural growth of emotional affiliation with Australia. Muslim active citizenship is hampered by socioeconomic barriers. At the same time, an increasingly proactive class of educated Muslim elite has emerged to claim a voice for Muslims in Australia and promote citizenship rights and responsibilities.

最近的全国普查显示,澳大利亚的穆斯林仍处于社会经济的弱势地位。在诸如失业率、收入、就业类型、家居拥有等关键指标看,穆斯林一直位于国家平均水平之下。这一模式在最近三次普查(2001、2006、2011)中非常明显。获得资源渠道的有限以及边缘化感觉阻碍着他们充分参与社会,以及在情感上融入澳大利亚。穆斯林的公民意识受困于社会经济障碍。与此同时,也出现了一班受到良好教育的穆斯林精英,这个积极进取的阶层开始为澳大利亚的穆斯林代言,促进他们的公民权利和义务。  相似文献   

36.
Small angle neutron scattering and neutron phase analysis techniques have been for the first time jointly employed to extract microscopic parameters of ceramic samples prepared under controlled conditions, in an attempt to establish a protocol for deriving information on the firing process. Data have also been collected on two series of early medieval samples from the Italian regions of Cuma and Miseno. The variation of the microscopic features observed on these samples could mirror some technological evolution in the period spanning from the 6th to the 12th century AD.  相似文献   
37.
This article analyses the history of Italian industrial districts (IDs) to identify lessons to help small and medium‐sized enterprise (SME) clusters in developing countries to move to higher stages of development. Transforming the 1990 seminal work of Brusco on distinct models of SME clustering into a stage approach, this article identifies a sequence of different maturity stages which the IDs passed through: initial craft production; industrialization through large firms; the fragmentation of production followed by the growth of smaller specialized units; and, finally, new routes to innovation and competitiveness. These phases help explain how development is a stage process which needs to be carefully considered and not rushed, through attempting to cross too many stages at once. Realistic steps are always necessary to create an effective base for growth. Furthermore, a theoretical framework is presented, which identifies three factorial levels that have intervened in the ID development process over the past 50 years. Economic, policy and social factors are identified and presented as drivers that work together to produce the structural changes that explain an effective development process. The final section emphasizes the relevance that this kind of analysis can have on the policy‐making schemes being applied in developing countries, with special reference to less developed types of clusters.  相似文献   
38.
宋德金 《史学集刊》2004,3(4):82-87
忠孝是中国古代伦理的重要内容 ,中国传统文化的组成部分。契丹、女真早期本无忠孝观念。辽金建立后 ,随着社会的发展 ,儒学的传播 ,统治者的倡导 ,民族的融合等 ,忠孝观念逐渐形成和发展起来。忠孝在辽金及后来元人那里 ,超越了民族、地区和国别的畛域 ,人们对外族、邻国、敌国乃至前朝的忠臣孝子同样表现出尊重和崇敬。 1 0 - 1 3世纪 ,忠孝已成为汉、契丹、女真、蒙古等各民族一致认同的伦理道德观念和行为规范 ,从而体现了中国传统文化的历史继承性和强大凝聚力。  相似文献   
39.
"吧国公堂"档案之《公案簿》述略   总被引:4,自引:1,他引:3  
<公案簿>是现存吧国公堂(巴达维亚华人评议会)档案中的核心部分,所涵盖的时间范围大约为150年(1787-1940年)左右.<公案簿>的内容主要有两个方面一是对吧国公堂有关华人的各类案件的会审记录;二是对有关吧城华人社区重要事件和重大决议的记录.对涵盖这一时期最为原始的记事录的内容及案例加以考察和分析,一方面可以洞察一个处在多种变革时期具有代表性的华人社区的社会生活及其行政管理的内幕,另一方面也可以从中了解各个历史阶段荷印殖民政策的变化及其对当地华人社会的影响.  相似文献   
40.
A high correlation between chronometric determinations based on aspartic acid racemization ratios and radioactive dating methods is described from samples of cave bear (Ursus deningeri and Ursus spelaeus) dentine. For samples from a very restrictive environment, as deep cave bear sites are (in view of their highly stable geochemical and thermal history), an age calculation algorithm was obtained. It has been found that there is a very close relationship between collagen preservation, from total aspartic acid in the > 3500 D fraction, and the amino acid racemization.  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