全文获取类型
收费全文 | 4494篇 |
免费 | 426篇 |
国内免费 | 106篇 |
专业分类
电工技术 | 44篇 |
综合类 | 187篇 |
化学工业 | 2237篇 |
金属工艺 | 75篇 |
机械仪表 | 57篇 |
建筑科学 | 84篇 |
矿业工程 | 56篇 |
能源动力 | 23篇 |
轻工业 | 695篇 |
水利工程 | 4篇 |
石油天然气 | 138篇 |
武器工业 | 10篇 |
无线电 | 139篇 |
一般工业技术 | 370篇 |
冶金工业 | 106篇 |
原子能技术 | 45篇 |
自动化技术 | 756篇 |
出版年
2024年 | 13篇 |
2023年 | 82篇 |
2022年 | 142篇 |
2021年 | 177篇 |
2020年 | 141篇 |
2019年 | 169篇 |
2018年 | 138篇 |
2017年 | 135篇 |
2016年 | 166篇 |
2015年 | 196篇 |
2014年 | 226篇 |
2013年 | 313篇 |
2012年 | 295篇 |
2011年 | 271篇 |
2010年 | 193篇 |
2009年 | 252篇 |
2008年 | 231篇 |
2007年 | 224篇 |
2006年 | 246篇 |
2005年 | 221篇 |
2004年 | 191篇 |
2003年 | 148篇 |
2002年 | 159篇 |
2001年 | 130篇 |
2000年 | 100篇 |
1999年 | 88篇 |
1998年 | 75篇 |
1997年 | 51篇 |
1996年 | 49篇 |
1995年 | 48篇 |
1994年 | 33篇 |
1993年 | 25篇 |
1992年 | 21篇 |
1991年 | 14篇 |
1990年 | 7篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 6篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1976年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
1959年 | 2篇 |
1956年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有5026条查询结果,搜索用时 15 毫秒
51.
传统的用软盘收集信息的方法存在一些不足之处,本文介绍了移动代理技术,给出了用移动代理技术来实现信息收集的方法,对该方法进行了安全性分析,并说明了该方法的优点。 相似文献
52.
There is an implicit assumption in electronic commerce that induces the buyers to believe that their deals will be handled appropriately. However, after a seller has already committed to a buyer, he may be tempted by several requests though he will not be able to supply them all. We analyze markets in which a finite set of automated buyers interacts repeatedly with a finite set of automated sellers. These sellers can satisfy one buyer at a time, and they can be tempted to break a commitment they already have. We have found the perfect equilibria that exist in markets with a finite horizon, and with an unrestricted horizon. A significant result stemming from our study reveals that sellers are almost always tempted to breach their commitments. However, we also show that if markets' designers implement an external mechanism that restricts the automated buyers actions, then sellers will keep their commitments. 相似文献
53.
Due to the complexity of modern industrial systems, a conventional automation system is not capable of providing sufficient information management and high-level intelligent approaches, as achieving these functionalities requires the support of comprehensive data management and coordination between system devices and heterogenous information. This paper proposes the concept of e-Automation, in which computer networking and distributed intelligence agent technologies are applied to industrial automation systems, and presents a hardware and software architecture that implements this concept. An open infrastructure based on multi-agent systems is employed in the proposed architecture of e-Automation, which aims to allow the implementation of diverse tasks and to permit greater configurability than can be obtained from a traditional system. To evaluate our proposed e-Automation concept, this paper presents a case study of substation information management which adopts the proposed e-Automation architecture in power system domain. 相似文献
54.
55.
Antimitotic agents such as the clinically approved vinca alkaloids, taxanes and epothilone can arrest cell growth during interphase and are therefore among the most important drugs available for treating cancer. These agents suppress microtubule dynamics and thus interfere with intracellular transport, inhibit cell proliferation and promote cell death. Because these drugs target biological processes that are essential to all cells, they face an additional challenge when compared to most other drug classes. General toxicity can limit the applicable dose and therefore reduce therapeutic benefits. Photopharmacology aims to avoid these side-effects by introducing compounds that can be applied globally to cells in their inactive form, then be selectively induced to bioactivity in targeted cells or tissue during a defined time window. This review discusses photoswitchable analogues of antimitotic agents that have been developed by combining different photoswitchable motifs with microtubule-stabilizing or microtubule-destabilizing agents. 相似文献
56.
Feng Wang Frank Stappenbeck Liu-Ya Tang Ying E. Zhang Simon T. Hui Aldons J. Lusis Farhad Parhami 《International journal of molecular sciences》2022,23(10)
Inflammatory responses by the innate and adaptive immune systems protect against infections and are essential to health and survival. Many diseases including atherosclerosis, osteoarthritis, rheumatoid arthritis, psoriasis, and obesity involve persistent chronic inflammation. Currently available anti-inflammatory agents, including non-steroidal anti-inflammatory drugs, steroids, and biologics, are often unsafe for chronic use due to adverse effects. The development of effective non-toxic anti-inflammatory agents for chronic use remains an important research arena. We previously reported that oral administration of Oxy210, a semi-synthetic oxysterol, ameliorates non-alcoholic steatohepatitis (NASH) induced by a high-fat diet in APOE*3-Leiden.CETP humanized mouse model of NASH and inhibits expression of hepatic and circulating levels of inflammatory cytokines. Here, we show that Oxy210 also inhibits diet-induced white adipose tissue inflammation in APOE*3-Leiden.CETP mice, evidenced by the inhibition of adipose tissue expression of IL-6, MCP-1, and CD68 macrophage marker. Oxy210 and related analogs exhibit anti-inflammatory effects in macrophages treated with lipopolysaccharide in vitro, mediated through inhibition of toll-like receptor 4 (TLR4), TLR2, and AP-1 signaling, independent of cyclooxygenase enzymes or steroid receptors. The anti-inflammatory effects of Oxy210 are correlated with the inhibition of macrophage polarization. We propose that Oxy210 and its structural analogs may be attractive candidates for future therapeutic development for targeting inflammatory diseases. 相似文献
57.
工作流理论不断发展,工作流管理系统也逐渐成为目前研究的热点之一.而工作流执行系统作为工作流管理系统的核心部件,其工作效率也越来越引起人们的关注.通过利用代理技术,提出了一种新的工作流执行服务架构,并对工作流引擎的执行过程进行了分析. 相似文献
58.
Elbieta U. Stolarczyk Weronika Strzempek Marta aszcz Andrzej Le Elbieta Menaszek Krzysztof Stolarczyk 《International journal of molecular sciences》2022,23(14)
Isoflavonoids such as genistein (GE) are well known antioxidants. The predictive biological activity of structurally new compounds such as thiogenistein (TGE)–a new analogue of GE–becomes an interesting way to design new drug candidates with promising properties. Two oxidation strategies were used to characterize TGE oxidation products: the first in solution and the second on the 2D surface of the Au electrode as a self-assembling TGE monolayer. The structure elucidation of products generated by different oxidation strategies was performed. The electrospray ionization mass spectrometry (ESI-MS) was used for identifying the product of electrochemical and hydrogen peroxide oxidation in the solution. Fourier transform infrared spectroscopy (FT-IR) with the ATR mode was used to identify a product after hydrogen peroxide treatment of TGE on the 2D surface. The density functional theory was used to support the experimental results for the estimation of antioxidant activity of TGE as well as for the molecular modeling of oxidation products. The biological studies were performed simultaneously to assess the suitability of TGE for antioxidant and antitumor properties. It was found that TGE was characterized by a high cytotoxic activity toward human breast cancer cells. The research was also carried out on mice macrophages, disclosing that TGE neutralized the production of the LPS-induced reactive oxygen species (ROS) and exhibits ABTS (2,2′-azino-bis-3-(ethylbenzothiazoline-6-sulphonic acid) radical scavenging ability. In the presented study, we identified the main oxidation products of TGE generated under different environmental conditions. The electroactive centers of TGE were identified and its oxidation mechanisms were proposed. TGE redox properties can be related to its various pharmacological activities. Our new thiolated analogue of genistein neutralizes the LPS-induced ROS production better than GE. Additionally, TGE shows a high cytotoxic activity against human breast cancer cells. The viability of MCF-7 (estrogen-positive cells) drops two times after a 72-h incubation with 12.5 μM TGE (viability 53.86%) compared to genistein (viability 94.46%). 相似文献
59.
Within the enterprise, information infrastructure as the mean to bring together different software applications is the key component to enable cooperation and information and knowledge exchange in an open-distributed environment. The paper addresses the issues of industrial application integration in business processes using agent-enabled service-oriented architectures (SOA). In this paper, we show that agent-enabled SOA can play an important role for service integration. Our framework combines Web services (WS) and intelligent agent technologies orchestrated by a business process management system. This framework looks for unification of agent and WS service models, is grounded in a semantic SOA of an agent platform and is supported by the Component Agent Platform Over .NET Framework agent platform tools. We describe the architecture and illustrate the approach by an industrial application scenario from petroleum wells’ drilling. 相似文献
60.
Frances Brazier Anja Oskamp Corien Prins Maurice Schellekens Niek Wijngaards 《Artificial Intelligence and Law》2004,12(1-2):137-157
Software agents that play a role in E-commerce and E-government applications involving the Internet often contain information about the identity of their human user such as credit cards and bank accounts. This paper discusses whether this is necessary: whether human users and software agents are allowed to be anonymous under the relevant legal regimes and whether an adequate interaction and balance between law and anonymity can be realised from both the perspective of Computer Systems and the perspective of Law.This paper is an extended and fully revised version of Brazier, Kubbe, Oskamp and Wijngaards (2002) and Brazier, Oskamp, Prins, Schellekens and Wijngaards (2003). 相似文献