全文获取类型
收费全文 | 2355篇 |
免费 | 147篇 |
出版年
2024年 | 9篇 |
2023年 | 62篇 |
2022年 | 25篇 |
2021年 | 35篇 |
2020年 | 101篇 |
2019年 | 130篇 |
2018年 | 161篇 |
2017年 | 157篇 |
2016年 | 131篇 |
2015年 | 85篇 |
2014年 | 109篇 |
2013年 | 391篇 |
2012年 | 151篇 |
2011年 | 120篇 |
2010年 | 104篇 |
2009年 | 111篇 |
2008年 | 106篇 |
2007年 | 101篇 |
2006年 | 84篇 |
2005年 | 47篇 |
2004年 | 35篇 |
2003年 | 39篇 |
2002年 | 39篇 |
2001年 | 27篇 |
2000年 | 30篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1978年 | 3篇 |
排序方式: 共有2502条查询结果,搜索用时 15 毫秒
21.
South Africa has a coal-based energy system and extractive economy, largely responsible for its high emission levels relative to countries with similar GDP. This extractive, coal-based economy began during British colonisation and today shows few signs of transitioning rapidly to limit climate change. This paper interrogates the role of coloniality in climate delay, given that colonisation is responsible for establishing fossil fuel dependence in South Africa. Combining theory on decolonisation, specifically colonial hierarchies of power, with a critical discourse analysis, this research uses interview and policy data to show how colonial power hierarchies can lead to climate delay in South Africa, through normalising emissions intensive development and silencing alternatives. In doing so, it highlights the need to recognise the colonial foundations of climate change and the potential for a coalition between decolonisation and climate action to motivate for radical change both in South Africa and at a global level. 相似文献
22.
E. J. Fagan 《政策研究杂志》2023,51(2):243-263
This paper develops a theory of the relationship between policy disasters and political institutions. Policy disasters, defined as avoidable, unintended extreme negative policy outcomes, are important political, and historical events above that receive relatively little attention from political scientists and scholars of public policy. Using the predictions of punctuated equilibrium theory, I argue that systems with higher error accumulation will experience more policy disasters. Systems with more veto players and weaker information flows will experience more policy disasters, but information flows will have a stronger impact than veto players. I test this theory using data on financial crises and natural and technological disasters across 70 countries over 60 years. I find strong evidence that systems with weaker information flows and more veto players tend to have greater policy disaster risk. 相似文献
23.
In Westminster systems, governments enjoy a privileged position in the lawmaking process that they can use to deliver on their campaign promises and achieve their policy goals. What policy areas do governments seek to affect through lawmaking? How stable is the executive lawmaking agenda? How responsive is that agenda to changes triggered by elections or by transitions in prime minister? This study uses a dataset of 3982 Australian bills introduced between 2000 and 2017 to answer these questions. While it finds considerable stability in the policy content of executive lawmaking agendas, the analysis also indicates that Australia's executive lawmaking agenda is more responsive to changes in prime minister than to changes in the party in power. As the first application of the comparative policy agendas approaches to government bills in Australia, this article offers new insights into executive lawmaking priorities during an especially turbulent period in Australian politics. 相似文献
24.
明墓出土的历书,粘连固结成块,脆硬易于折断。通过实验分析研究,探明其主要原因可能是木质素选择性地吸附的钙铁离子与蛋白质的分解物形成复杂物质,沉积在纸上,渗入书内所致。故揭取该历书的关键是去除钙离子,EDTA二钢,碱性过氧化氢、气相二氧化硅等的分步处理,使脆硬的纸张软化,再逐页分离揭取,然后再去除色素沉淀物,终于恢复了书的原貌。 相似文献
25.
Jeanne E. Arnold 《Journal of Archaeological Method and Theory》1996,3(1):77-126
Archaeologists' reconstructions of paths to complexity have all too often excluded complex hunter-gatherers. However, recent theoretical contributions and long-term field research programs in several regions of the world have now significantly advanced our understanding of complex hunter-gatherers. A discussion of definitions of complexity and a review of current models of the emergence of complexity provide a framework for analyses of complex hunter-gatherers and important cultural phenomena such as sedentism, political integration, prestige economies, feasting, and ideology. 相似文献
26.
本文采用因子生态分析方法剖析多伦多都市区的居住空间结构。主成分分析表明,家庭构成、年龄构成、职业构成是形成城市居住分异的主要因素。聚类分析表明,家庭构成和年龄构成的分异呈同心园格局,职业构成的分异呈扇形格局。形成这种居住分异格局的机制包括动力机制、管理机制和行为机制三个方面。 相似文献
27.
Empirical aspects of the movement of strontium through the food chain suggest that the level of bone strontium can be used as an indicator of the percentage of meat in human diet. In general, skeletal remains from agricultural peoples are expected to have high bone strontium levels relative to hunter-gatherers from the same geographical region because plants contain relatively higher amounts of strontium when compared with animal products. The results of the study described in this paper, however, indicate that the inclusion of molluscs as a component of the diet may produce the opposite of the expected strontium values. Burials from an Archaic (c. 2500 BC) hunting-gathering population excavated from Luo25, an archaeological site in northern Alabama, USA, exhibit a mean bone strontium level (
atomic absorption;
neutron activation) that is higher than the mean level from an agricultural Mississippian (c. AD 1400) population (
atomic absorption;
neutron activation) that was buried at the same site. The samples were analysed by two techniques (atomic absorption spectrometry and neutron activation analysis) and the results compared favourably; therefore, the results can be accepted as valid rather than being due to technique error. We propose that the ingestion of molluscs, whose meat is known to contain large amounts of strontium, has produced this reversal from expected results. 相似文献
28.
About 200 analyses have been made on late Roman and Sassanian silver objects using energy-dispersive X-ray fluorescence. This has shown that the main feature of the composition of the silver throughout the period and across the geographical area studied was towards high fineness (average silver percentage about 95%). Compositional differences are found between Roman and Sassanian silversmiths' products for the elements copper and lead. Much of the material analysed came from hoards, and using a statistical technique on the analytical data (Discriminant Analysis) broad compositional differences between hoards were found to emerge. The use of different compositions of silver for different joined parts of a single object are discussed. 相似文献
29.
The Chemical Composition and Production Area of Early Western Zhou Proto‐Porcelain Unearthed from Yejiashan Cemetery,Suizhou, China
下载免费PDF全文
![点击此处可从《Archaeometry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The bodies and glazes of 27 early Western Zhou proto‐porcelain samples from Yejiashan cemetery, Hubei Province, were analysed using LA‐ICP–AES, SEM, XRD, a thermal expansion instrument and other analytical methods. The results indicated that the bodies of all samples were characterized by high silicon and low aluminium, and were made with porcelain stone raw materials found in the south of China. The glazes are typical of high‐temperature calcium glazes of the CaO (MgO) – K2O (Na2O) – Al2O3 – SiO2 series, with relatively high Mn and P content, which was probably caused by the addition of plant ashes. The physical properties and phase compositions of Yejiashan proto‐porcelain show that firing processes were still in the early stages of development in ancient China. Multivariate statistical analyses indicated that Yejiashan proto‐porcelain might have come from the Deqing area, in Zhejiang Province. These results provide new archaeological evidence for research on issues related to material flow in the Western Zhou dynasty. 相似文献
30.
Investigating Human Migration and Horse‐Trading in Yelang (夜郎) Through Strontium Isotope Analysis of Skeletons from Zhougshui Sites,South‐West China (1300 bc – ad 25)
下载免费PDF全文
![点击此处可从《Archaeometry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Yelang (夜郎), a mysterious state located in the south‐western area of early China and dating from the Bronze Age to the Early Iron Age (1300 bc – ad 25), is a cultural interactive junction between the Yunnan–Guizhou Plateau and the Yangtze River Basin. The Zhongshui Basin in Weining County, Guizhou Province, was one of the important distribution areas of the Yelang civilization. This area, which includes sites at Jigongshan (鸡公山; 1300 – 800 bc ), Hongyingpan (红营盘; 700 – 400 bc ) and Yinzitan (银子坛; 400 bc – ad 25), has provided a very integrated chronology, spanning from the Bronze Age to the Early Iron Age in the eastern Yunnan – western Guizhou area. To investigate human migration and horse‐trading at these Yelang sites, we conducted a strontium isotopic analysis on the teeth enamel of humans and horses unearthed from these three sites. The results indicated the following: (1) people at the earlier sites (Jigongshan and Hongyingpan) were all indigenous, whereas in the Yinzitan cemetery, there was a more immigrant population, and all the people who were buried in an upper limb flexed supine position were non‐local; and (2) most of the horses found at the Jigongshan and Yinzitan sites show different provenances, probably related to the famous Dian (滇) and Zuo (筰) horses recorded in historical documents, providing more clues for further study on horse‐trading in South‐West China during the Bronze Age and the Early Iron Age. 相似文献