全文获取类型
收费全文 | 28843篇 |
免费 | 1520篇 |
国内免费 | 128篇 |
专业分类
电工技术 | 468篇 |
综合类 | 233篇 |
化学工业 | 4820篇 |
金属工艺 | 790篇 |
机械仪表 | 660篇 |
建筑科学 | 786篇 |
矿业工程 | 148篇 |
能源动力 | 501篇 |
轻工业 | 3988篇 |
水利工程 | 210篇 |
石油天然气 | 135篇 |
武器工业 | 10篇 |
无线电 | 1522篇 |
一般工业技术 | 5292篇 |
冶金工业 | 7305篇 |
原子能技术 | 164篇 |
自动化技术 | 3459篇 |
出版年
2023年 | 300篇 |
2022年 | 261篇 |
2021年 | 607篇 |
2020年 | 502篇 |
2019年 | 426篇 |
2018年 | 904篇 |
2017年 | 814篇 |
2016年 | 898篇 |
2015年 | 777篇 |
2014年 | 907篇 |
2013年 | 1731篇 |
2012年 | 1336篇 |
2011年 | 1342篇 |
2010年 | 1139篇 |
2009年 | 1087篇 |
2008年 | 1221篇 |
2007年 | 1168篇 |
2006年 | 828篇 |
2005年 | 664篇 |
2004年 | 487篇 |
2003年 | 451篇 |
2002年 | 418篇 |
2001年 | 331篇 |
2000年 | 322篇 |
1999年 | 448篇 |
1998年 | 2282篇 |
1997年 | 1373篇 |
1996年 | 960篇 |
1995年 | 580篇 |
1994年 | 471篇 |
1993年 | 427篇 |
1992年 | 171篇 |
1991年 | 179篇 |
1990年 | 153篇 |
1989年 | 158篇 |
1988年 | 150篇 |
1987年 | 159篇 |
1986年 | 138篇 |
1985年 | 217篇 |
1984年 | 180篇 |
1983年 | 165篇 |
1982年 | 131篇 |
1981年 | 175篇 |
1980年 | 172篇 |
1979年 | 121篇 |
1978年 | 105篇 |
1977年 | 222篇 |
1976年 | 480篇 |
1975年 | 85篇 |
1973年 | 111篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
Cell suspensions of Escherichia coli as a model for bacterial populations in wastewaters were treated with ozone as a disinfectant in a continuously operated pilot plant with a plug flow reactor. Suspensions with an initial number of CFU (colony forming units) of 108 mL?1 were ozonized with ozone concentrations up to 12 mg/L. Metabolic activities and membrane functions break down with increasing ozone concentrations. The fluorochromization using 3′,6′-diacetylfluorescein (FDA) proved to be a suitable method for the detection of an alteration in permeability of the cell membranes and an inactivation of metabolic activity. By fluorescence microscopic and photometric investigations it could be clearly demonstrated that, in the case of disinfection with ozone, inactivation of the cells includes first of all a damage of the cell membranes. In contrast to the determination of the number of CFU, fluorochromization allows the detection of alteration in metabolic activities. 相似文献
122.
The relationship between endometriosis and infertility is observed frequently. Patients with both conditions require a conservative approach to their management. Since hormonal therapy is one of those approaches, we sought to compare the efficacy of Danazol and Gestrinone in 80 infertile patients (48 and 32, respectively). Therapy lasted 6 months in both treatment groups, and all patients studied had laboratory tests performed and were clinically evaluated and classified through laparoscopy before and after therapy. The improvement of symptoms and favorable follow-up were similar with both treatments. The reestablishment of menstrual patterns and fertility were also nearly alike in both groups. However, Gestrinone was associated with fewer secondary effects and is easier to administer than Danazol. We conclude that Gestrinone is a useful medication in the management of the infertile patient with endometriosis. 相似文献
123.
124.
125.
A. Koblischka-Veneva M. R. Koblischka K. Ogasawara F. Mücklich M. Murakami 《Journal of Superconductivity》2005,18(4):469-474
Local orientations of superconducting YBa2Cu3O
x
(123) and embedded Y2BaCuO5 (211) particles within bulk, melt-textured 123 samples are studied on a local scale by means of electron backscatter diffraction
(EBSD). The embedded Y2BaCuO5 (211) particles do not show any preferred texture, but their presence within the 123-matrix alters the growth of the 123-phase,
independent of the orientation. EBSD enables to analyse the interactions between the 123- and 211-phases in detail. 相似文献
126.
The aim of this study was to determine the tocopherol contents of wine by-products including grape seed, pomace (seed, skin and stem) and bagasse (skin and stem) by using two different extraction methods in order to evaluate the possibilities of them as natural non-polar antioxidants. Cold extraction appeared to give more tocopherol contents in seeds than hot extraction. But hot extraction was found more suitable for pomace and bagasse. α-Tocopherol was the most abundant tocopherol in the grape seed, pomace and bagasse. Although γ- and δ-tocopherols were found in the samples with low concentrations, β-tocopherol was not detected in the samples. Kalecik karası had the highest α and total tocopherol compared to the other cultivars. On the other hand, hot extracted bagasse in all cultivars gave the highest tocopherol contents. As a conclusion, wine by-products, a large scale wastes, can be evaluated both to get natural tocopherol source and to obtain economical gain. 相似文献
127.
128.
Walter Binder Ion Constantinescu Boi Faltings Klaus Haller Can Türker 《Autonomous Agents and Multi-Agent Systems》2006,12(2):219-237
This article presents an architecture to automatically create ad-hoc processes for complex value-added services and to execute
them in a reliable way. The uniqueness of ad-hoc processes is to support users not only in standardized situations like traditional
workflows do, but also in unique non-recurring situations. Based on user requirements, a service composition engine generates
such ad-hoc processes, which integrate individual services in order to provide the desired functionality. Our infrastructure
executes ad-hoc processes by transactional agents in a peer-to-peer style. The process execution is thereby performed under
transactional guarantees. Moreover, the service composition engine is used to re-plan in the case of execution failures.
The work presented in this article was supported by the Swiss National Science Foundation as part of the project MAGIC (FNRS-68155),
as well as by the Swiss National Funding Agency OFES as part of the European projects KnowledgeWeb (FP6-507482) and DIP (FP6-507483).
Authors in alphabetic order 相似文献
129.
130.