全文获取类型
收费全文 | 65733篇 |
免费 | 2244篇 |
国内免费 | 3065篇 |
专业分类
系统科学 | 3679篇 |
丛书文集 | 2144篇 |
教育与普及 | 2180篇 |
理论与方法论 | 527篇 |
现状及发展 | 1159篇 |
研究方法 | 196篇 |
综合类 | 61146篇 |
自然研究 | 11篇 |
出版年
2024年 | 325篇 |
2023年 | 728篇 |
2022年 | 996篇 |
2021年 | 1227篇 |
2020年 | 761篇 |
2019年 | 325篇 |
2018年 | 1144篇 |
2017年 | 1349篇 |
2016年 | 1043篇 |
2015年 | 1464篇 |
2014年 | 2048篇 |
2013年 | 1985篇 |
2012年 | 2441篇 |
2011年 | 3329篇 |
2010年 | 3143篇 |
2009年 | 3261篇 |
2008年 | 3738篇 |
2007年 | 3756篇 |
2006年 | 2547篇 |
2005年 | 2535篇 |
2004年 | 1924篇 |
2003年 | 1788篇 |
2002年 | 1832篇 |
2001年 | 1928篇 |
2000年 | 1887篇 |
1999年 | 2947篇 |
1998年 | 2603篇 |
1997年 | 2729篇 |
1996年 | 2509篇 |
1995年 | 2155篇 |
1994年 | 2039篇 |
1993年 | 1761篇 |
1992年 | 1482篇 |
1991年 | 1289篇 |
1990年 | 1137篇 |
1989年 | 1015篇 |
1988年 | 818篇 |
1987年 | 536篇 |
1986年 | 295篇 |
1985年 | 108篇 |
1984年 | 34篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1979年 | 5篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1971年 | 7篇 |
1970年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
321.
Lanju XU 《系统科学与复杂性》2007,20(1):30-40
In the present paper, we focus on constructive spherical codes. By employing algebraic geometry codes, we give an explicit construction of spherical code sequences. By making use of the idea involved in the proof of the Gilbert-Varshamov bound in coding theory, we construct a spherical code sequence in exponential time which meets the best-known asymptotic bound by Shamsiev and Wyner. 相似文献
322.
323.
介绍了AMC垃圾渗滤液处理的工艺流程,对系统单元进行了功用分析,探讨了AMC系统的特点。 相似文献
324.
对高校图书馆人力资源管理工作的几点认识 总被引:1,自引:0,他引:1
针对当前高校图书馆工作的实际,就图书馆组织结构、人员结构、工作组织方式、激励管理及培训等方面提出了一些思考。 相似文献
325.
根据计算机网络技术的特点,文章从消防设施、消防宣传、消防教育、消防行政效能建设等四个方面,阐述了网络技术在促进消防工作社会化过程中的应用前景。 相似文献
326.
327.
328.
329.
Multiple MIPS 4Kc cores based interrupt controller design and its implementation on HDTV SoC platform 总被引:2,自引:0,他引:2
A multiple MIPS 4Kc processor cores based interrupt processing system is introduced. The interrupt controller plays a key role in the high definition television (HDTV) system-on-a-chip (SoC) platform, especially when it is a multiple processor system. Based on a general introduction to the whole HDTV SoC platform, a layered interrupt controller and its implementation are discussed in detail. The proposed scheme was implemented in our FPGA verification board. The results indicate that our scheme is reliable and efficient. Meanwhile, as a functional intellectual property (IP), the interrupt controller has reusability and expandability with the layered structure. 相似文献
330.
Rein Vihalemm 《Foundations of Science》2007,12(3):223-234
The philosophical analysis of chemistry has advanced at such a pace during the last dozen years that the existence of philosophy of chemistry as an autonomous discipline cannot be doubted any more. The present paper will attempt to analyse the experience of philosophy of chemistry at the, so to say, meta-level. Philosophers of chemistry have especially stressed that all sciences need not be similar to physics. They have tried to argue for chemistry as its own type of science and for a pluralistic understanding of science in general. However, when stressing the specific character of chemistry, philosophers do not always analyse the question ‘What is science?’ theoretically. It is obvious that a ‘monistic’ understanding of science should not be based simply on physics as the epitome of science, regarding it as a historical accident that physics has obtained this status. The author’s point is that the philosophical and methodological image of science should not be chosen arbitrarily; instead, it should be theoretically elaborated as an idealization (theoretical model) substantiated on the historical practice of science. It is argued that although physics has, in a sense, justifiably obtained the status of a paradigm of science, chemistry, which is not simply a physical science, but a discipline with a dual character, is also relevant for elaborating a theoretical model of science. The theoretical model of science is a good tool for examining various issues in philosophy of chemistry as well as in philosophy of science or science studies generally. 相似文献