全文获取类型
收费全文 | 77368篇 |
免费 | 8609篇 |
国内免费 | 5007篇 |
专业分类
电工技术 | 7600篇 |
技术理论 | 5篇 |
综合类 | 9249篇 |
化学工业 | 6427篇 |
金属工艺 | 2542篇 |
机械仪表 | 4311篇 |
建筑科学 | 8829篇 |
矿业工程 | 3334篇 |
能源动力 | 2332篇 |
轻工业 | 6026篇 |
水利工程 | 3297篇 |
石油天然气 | 6968篇 |
武器工业 | 1215篇 |
无线电 | 7269篇 |
一般工业技术 | 7154篇 |
冶金工业 | 2743篇 |
原子能技术 | 1134篇 |
自动化技术 | 10549篇 |
出版年
2024年 | 176篇 |
2023年 | 1099篇 |
2022年 | 1926篇 |
2021年 | 2674篇 |
2020年 | 2670篇 |
2019年 | 2162篇 |
2018年 | 2132篇 |
2017年 | 2480篇 |
2016年 | 2975篇 |
2015年 | 3158篇 |
2014年 | 5012篇 |
2013年 | 4789篇 |
2012年 | 5931篇 |
2011年 | 6241篇 |
2010年 | 4595篇 |
2009年 | 4760篇 |
2008年 | 4423篇 |
2007年 | 5327篇 |
2006年 | 4777篇 |
2005年 | 4142篇 |
2004年 | 3369篇 |
2003年 | 2900篇 |
2002年 | 2309篇 |
2001年 | 2087篇 |
2000年 | 1634篇 |
1999年 | 1322篇 |
1998年 | 1006篇 |
1997年 | 891篇 |
1996年 | 764篇 |
1995年 | 651篇 |
1994年 | 544篇 |
1993年 | 380篇 |
1992年 | 288篇 |
1991年 | 244篇 |
1990年 | 204篇 |
1989年 | 200篇 |
1988年 | 149篇 |
1987年 | 86篇 |
1986年 | 55篇 |
1985年 | 54篇 |
1984年 | 63篇 |
1983年 | 37篇 |
1982年 | 31篇 |
1981年 | 28篇 |
1980年 | 17篇 |
1979年 | 19篇 |
1964年 | 16篇 |
1962年 | 13篇 |
1961年 | 16篇 |
1959年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
This paper proposes a method for the coordinated control of power factor by means of a multiagent approach. The proposed multiagent system consists of two types of agent: single feeder agent (F_AG) and bus agent (B_AG). In the proposed system, an F_AG plays as an important role, which decides the power factors of all distributed generators by executing the load flow calculations repeatedly. The voltage control strategies are implemented as the class definition of Java into the system. In order to verify the performance of the proposed method, it has been applied to a typical distribution model system. The simulation results show that the system is able to control very violent fluctuation of the demands and the photovoltaic (PV) generations. 相似文献
12.
13.
Collaboration with artificial intelligence (AI) is a growing trend even in the field of creativity. This paper examines which quantitative metrics can be used to comparatively analyse human-computer co-creativity with children. To study this question, 24 schoolchildren of age 10–11 wrote a poem with three co-creative poetry writing processes: a human-computer, a human-human, and a human-human-computer process. The computational participant in the processes was an AI-based application called the Poetry Machine. The children were asked to evaluate their user experience with a 5-point Likert-type questionnaire after each writing process and a comparative questionnaire after finishing all processes. The metrics used in the evaluation were immediate fun, long-term enjoyment, creativity, self-expression, outcome satisfaction, ease of starting and finishing writing, quality of ideas and support from others, and ownership.
Significant differences were found in fun, long-term enjoyment, quality of ideas, support, and ownership. The high number of statistically relevant results was enabled by exposing all participants to all writing processes, and the comparative questionnaire. The human-human-computer process was evaluated the best in long-term enjoyment and the human-computer process the weakest in support and idea quality. Creativity and ease of finishing writing turned out to be outlining metrics for the co-creative processes. 相似文献
14.
Jie-Long He An-Te Chen Jyong-Huei Lee Shih-Kang Fan 《International journal of molecular sciences》2015,16(9):22319-22332
The basic structural and functional unit of a living organism is a single cell. To understand the variability and to improve the biomedical requirement of a single cell, its analysis has become a key technique in biological and biomedical research. With a physical boundary of microchannels and microstructures, single cells are efficiently captured and analyzed, whereas electric forces sort and position single cells. Various microfluidic techniques have been exploited to manipulate single cells through hydrodynamic and electric forces. Digital microfluidics (DMF), the manipulation of individual droplets holding minute reagents and cells of interest by electric forces, has received more attention recently. Because of ease of fabrication, compactness and prospective automation, DMF has become a powerful approach for biological application. We review recent developments of various microfluidic chips for analysis of a single cell and for efficient genetic screening. In addition, perspectives to develop analysis of single cells based on DMF and emerging functionality with high throughput are discussed. 相似文献
15.
乳腺疾病已严重危害女性身心健康,其中乳腺癌更位居全球范围内女性癌症发病率和死亡率首位,因此乳腺癌的早期发现意义重大。传统结构影像学早期检测疾病具有一定局限性,而红外热成像作为功能成像技术可为乳腺癌的早期筛查提供有效线索。因此本文主要就红外热成像在乳腺疾病的早期检测及预后评估的应用价值进行综述。 相似文献
16.
17.
Dr. Tomasz Ratajczyk Prof. Dr. Gerd Buntkowsky Dr. Torsten Gutmann Dr. Bartłomiej Fedorczyk Dr. Adam Mames Dr. Mariusz Pietrzak Zuzanna Puzio Piotr Grzegorz Szkudlarek 《Chembiochem : a European journal of chemical biology》2021,22(5):855-860
The biorelevant PyFALGEA oligopeptide ligand, which is selective towards the epidermal growth factor receptor (EGFR), has been successfully employed as a substrate in magnetic resonance signal amplification by reversible exchange (SABRE) experiments. It is demonstrated that PyFALGEA and the iridium catalyst IMes form a PyFALGEA:IMes molecular complex. The interaction between PyFALGEA:IMes and H2 results in a ternary SABRE complex. Selective 1D EXSY experiments reveal that this complex is labile, which is an essential condition for successful hyperpolarization by SABRE. Polarization transfer from parahydrogen to PyFALGEA is observed leading to significant enhancement of the 1H NMR signals of PyFALGEA. Different iridium catalysts and peptides are inspected to discuss the influence of their molecular structures on the efficiency of hyperpolarization. It is observed that PyFALGEA oligopeptide hyperpolarization is more efficient when an iridium catalyst with a sterically less demanding NHC ligand system such as IMesBn is employed. Experiments with shorter analogues of PyFALGEA, that is, PyLGEA and PyEA, show that the bulky phenylalanine from the PyFALGEA oligopeptide causes steric hindrance in the SABRE complex, which hampers hyperpolarization with IMes. Finally, a single-scan 1H NMR SABRE experiment of PyFALGEA with IMesBn revealed a unique pattern of NMR lines in the hydride region, which can be treated as a fingerprint of this important oligopeptide. 相似文献
18.
在分析传统单片机教学存在问题的基础上,提出面向工程应用,聚焦企业需要,构建能力递进、面向应用的内容体系,搭建资源共享、实践创新、师生互动的自主学习平台,组建培养兴趣,突出技能的“双师型”教学团队,实践表明,在传授知识的同时,能有效提升学习兴趣,优化人才素质结构。 相似文献
19.
20.
电网的安全水平主要取决于其使用产品的质量是否过关。如果产品的质量较好,则能建造出优质的电网,电网的安全水平便会随之提高。因此,应加强对产品质量的监督管理,从而提高电网的安全水平。我们可建立质量监督管理系统,及时抽检出质量不过关的产品,从而消除电网运行过程中潜在的安全隐患。 相似文献