全文获取类型
收费全文 | 1462篇 |
免费 | 29篇 |
出版年
2024年 | 3篇 |
2023年 | 14篇 |
2022年 | 10篇 |
2021年 | 17篇 |
2020年 | 43篇 |
2019年 | 18篇 |
2018年 | 26篇 |
2017年 | 27篇 |
2016年 | 20篇 |
2015年 | 43篇 |
2014年 | 23篇 |
2013年 | 82篇 |
2012年 | 98篇 |
2011年 | 125篇 |
2010年 | 125篇 |
2009年 | 144篇 |
2008年 | 111篇 |
2007年 | 114篇 |
2006年 | 103篇 |
2005年 | 96篇 |
2004年 | 23篇 |
2003年 | 56篇 |
2002年 | 39篇 |
2001年 | 31篇 |
2000年 | 34篇 |
1999年 | 19篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 10篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
排序方式: 共有1491条查询结果,搜索用时 15 毫秒
21.
The quick and accurate identification of post-earthquake rescue objects can minimize the casualties and property loss caused by earthquakes. With the rapid development of remote sensing technology, rescue objects can be identified through high-resolution remote sensing images. There are two main categories of approaches to identify rescue object through high-resolution images: automatic extraction by a computer and visual judgment by professionals. Although results can be obtained quickly by using automatic extraction, the accuracy of the results is unacceptably low. For visual judgment, the large demands for time and professionals restrict its wide practical application. In this study, we introduce crowdsourcing into the identification of post-earthquake rescue objects. First, we integrate the advantages of the computer and crowdsourcing, which means that the computer takes advantage of the speed of information processing, while crowdsourcing makes full use of human recognition capabilities. Second, we take visual judgment tasks out of the hands of professionals and entrust the tasks to workers in a crowdsourcing platform. Not only are the human resources infinite, but we can also improve the efficiency of identifying rescue objects. Third, we propose a crowdsourcing model that improves the quality of the results and saves human resources. Finally, experimental results demonstrate that our solution is feasible. 相似文献
22.
23.
24.
25.
Z. Liu A. Mehta N. Tamura D. Pickard B. Rong T. Zhou P. Pianetta 《Journal of archaeological science》2007
Until the 19th century, most pigments were based on naturally occurring colored minerals and dyes, with three significant exceptions: Egyptian Blue, Chinese Blue/Purple and Maya Blue. The former two are alkaline-earth copper silicates, and because of this similarity it has been proposed that the Chinese pigments were derived from Egyptian Blue. Herein, we analyzed clumps of pigment from the Qin warriors and discovered that in spite of the structural similarity to Egyptian Blue, the micro-structural morphology of Chinese Purple is very different. Therefore, we believe that the synthesis technology for the Chinese pigments was a by-product of high-refractive index glasses (artificial jades) produced by Taoist monks. Further, the disappearance of these pigments from Chinese art and monuments concurrently with the decline of Taoism not only substantiates the link between the two, but also gives a striking example of how cultural changes in the society affected the scientific developments in ancient China. 相似文献
26.
宋太祖开宝三年(970),南唐清辉殿学士张洎奉命使宋,纪录宋典客、左补阙贾黄中谈话,撰成<贾氏谈录>一书.此书虽记唐代琐事,又仅一卷,"篇帙无多,然如牛李之党其初肇衅于口语,为史所未及,而<周秦行纪>一书,晁公武亦尝据此录以辨韦璀之诬. 相似文献
27.
28.
平底碟是晚期定窑瓷器中的一种非常常见的器型,也是最传统、最保守的一种器型,自北宋晚期以来直至金代,平底碟在各地不同时代的早晚均有发现,体现了一定的演变规律,这也为我们整体上探讨其发展演变提供了可能.对其进行探讨,从中也可以体现同时期整个定窑器物演变上的某些线索. 相似文献
29.
宋钱版别研究珍贵史料——读叶适《淮西论铁钱五事状》 总被引:1,自引:1,他引:0
叶适(1150~1223),字正则,学者称水心先生,浙江永嘉(今浙江温州)人,为南宋著名思想家、文学家、政论家,是与朱熹的道学派、陆九渊的心学派并列为南宋三大学派的永嘉学派的集大成者和主要代表。南宋淳熙五年(1178),叶适以进士第二名及第,后历任吏部员外郎、吏部侍郎、江东安抚使兼沿江制置使等职,官至宝文阁学士、光禄大夫。 相似文献
30.
从《申报》看苏州的私钱与禁私(1827-1877) 总被引:1,自引:1,他引:0
清代实行银钱平行本位,大数用银,小数用钱。制钱是民间主要的流通货币,银两只不过是国家财政和大宗贸易的计算出纳单位以及富裕人家的储藏手段。在清朝统治者入关前,就曾铸有“天命”、“天聪”两种铜钱,自顺治进关,到辛亥革命,前后历经十代皇帝,铸有十种年号钱。康熙、乾隆时代的铜钱质量、重量都很规范。 相似文献