全文获取类型
收费全文 | 1947篇 |
免费 | 113篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 50篇 |
综合类 | 3篇 |
化学工业 | 518篇 |
金属工艺 | 33篇 |
机械仪表 | 54篇 |
建筑科学 | 85篇 |
矿业工程 | 4篇 |
能源动力 | 56篇 |
轻工业 | 208篇 |
水利工程 | 21篇 |
石油天然气 | 5篇 |
无线电 | 165篇 |
一般工业技术 | 322篇 |
冶金工业 | 181篇 |
原子能技术 | 16篇 |
自动化技术 | 343篇 |
出版年
2023年 | 19篇 |
2022年 | 84篇 |
2021年 | 90篇 |
2020年 | 38篇 |
2019年 | 33篇 |
2018年 | 59篇 |
2017年 | 46篇 |
2016年 | 67篇 |
2015年 | 45篇 |
2014年 | 69篇 |
2013年 | 115篇 |
2012年 | 79篇 |
2011年 | 125篇 |
2010年 | 99篇 |
2009年 | 114篇 |
2008年 | 109篇 |
2007年 | 99篇 |
2006年 | 81篇 |
2005年 | 65篇 |
2004年 | 61篇 |
2003年 | 59篇 |
2002年 | 49篇 |
2001年 | 27篇 |
2000年 | 32篇 |
1999年 | 28篇 |
1998年 | 51篇 |
1997年 | 42篇 |
1996年 | 34篇 |
1995年 | 15篇 |
1994年 | 21篇 |
1993年 | 20篇 |
1992年 | 14篇 |
1991年 | 7篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 3篇 |
1910年 | 2篇 |
排序方式: 共有2064条查询结果,搜索用时 218 毫秒
1.
Galli Carlo Sala Roberto Colangelo Maria Teresa Guizzardi Stefano 《Scientometrics》2022,127(7):3879-3910
Scientometrics - A literature search on the in vitro testing of anti-inflammatory compounds of natural origin revealed a considerable number of studies adopting a similar template for data... 相似文献
2.
Alessandro Lucidi Danilo Buca Carlo Ronsini Sara Tinari Giuseppina Bologna Davide Buca Martina Leombroni Marco Liberati Francesco DAntonio Giovanni Scambia Paola Lanuti Marco Petrillo 《International journal of molecular sciences》2020,21(22)
Extracellular vesicles (EVs) are a heterogeneous group of cell-derived submicron vesicles released under physiological or pathological conditions. EVs mediate the cellular crosstalk, thus contributing to defining the tumor microenvironment, including in epithelial ovarian cancer (EOC). The available literature investigating the role of EVs in EOC has been reviewed following PRISMA guidelines, focusing on the role of EVs in early disease diagnosis, metastatic spread, and the development of chemoresistance in EOC. Data were identified from searches of Medline, Current Contents, PubMed, and from references in relevant articles from 2010 to 1 April 2020. The research yielded 194 results. Of these, a total of 36 papers, 9 reviews, and 27 original types of research were retained and analyzed. The literature findings demonstrate that a panel of EV-derived circulating miRNAs may be useful for early diagnosis of EOC. Furthermore, it appears clear that EVs are involved in mediating two crucial processes for metastatic and chemoresistance development: the epithelial–mesenchymal transition, and tumor escape from the immune system response. Further studies, more focused on in vivo evidence, are urgently needed to clarify the role of EV assessment in the clinical management of EOC patients. 相似文献
3.
Francesco Di Girolamo Andrea Masotti Isabella Lante Margherita Scapaticci Cosima Damiana Calvano Carlo Zambonin Maurizio Muraca Lorenza Putignani 《International journal of molecular sciences》2015,16(9):20896-20912
Extra virgin olive oil (EVOO) with its nutraceutical characteristics substantially contributes as a major nutrient to the health benefit of the Mediterranean diet. Unfortunately, the adulteration of EVOO with less expensive oils (e.g., peanut and corn oils), has become one of the biggest source of agricultural fraud in the European Union, with important health implications for consumers, mainly due to the introduction of seed oil-derived allergens causing, especially in children, severe food allergy phenomena. In this regard, revealing adulterations of EVOO is of fundamental importance for health care and prevention reasons, especially in children. To this aim, effective analytical methods to assess EVOO purity are necessary. Here, we propose a simple, rapid, robust and very sensitive method for non-specialized mass spectrometric laboratory, based on the matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) coupled to unsupervised hierarchical clustering (UHC), principal component (PCA) and Pearson’s correlation analyses, to reveal corn oil (CO) adulterations in EVOO at very low levels (down to 0.5%). 相似文献
4.
Giulio Croce Paola Dagaro Carlo Nonino 《International Journal of Heat and Mass Transfer》2007,50(25-26):5249-5259
5.
We describe a Gauss–Seidel algorithm for optimizing a three‐dimensional unstructured grid so as to conform to a given metric. The objective function for the optimization process is based on the maximum value of an elemental residual measuring the distance of any simplex in the grid to the local target metric. We analyse different possible choices for the objective function, and we highlight their relative merits and deficiencies. Alternative strategies for conducting the optimization are compared and contrasted in terms of resulting grid quality and computational costs. Numerical simulations are used for demonstrating the features of the proposed methodology, and for studying some of its characteristics. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
6.
7.
Manual responses can be defined by differing response parameters. Any of them may generate a Simon effect. For all those response parameters, the same implementation of the Simon effect (in terms of subserving mechanism) is assumed. In 3 experiments, subjects had to respond with either fingers or sticks. Temporal properties of the Simon effect changed with response parameters relevant in a task. The Simon effect for manual responses decayed. For stick responses, in which the action goal differed from the anatomical mapping of the acting hand, a sustained Simon effect was observed. However, if the action goal for stick responses was not instrumental for selecting the correct response, the Simon effect decayed. The findings are consistent with the notion of different mechanisms involved in generating a Simon effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
We exhibit small size measure-once one-way quantum finite automata (mo-1qfa’s) inducing multiperiodic stochastic events. Moreover, for certain classes of multiperiodic languages, we exhibit: (i) isolated cut point mo-1qfa’s whose size logarithmically depends on the periods; (ii) Monte Carlo mo-1qfa’s whose size logarithmically depends on the periods and polynomially on the inverse of the error probability. 相似文献
9.
Claudio Sacchi Gianluca Gera Carlo S. Regazzoni 《International Journal of Satellite Communications and Networking》2004,22(2):193-215
This paper aims at focusing on the aspects concerning the physical layer design for an innovative satellite communication experiment. Such an experiment, denoted by the acronym DAVID–DCE (Data and Video Interactive Distribution—Data Collection Experiment) is based on the exploitation of the W‐band (75–110 GHz) for high‐bit‐rate satellite transmission. The potential advantages of using of the W‐band are mainly related to the great bandwidth availability, and to the absence of interference. Moreover, an expected result of the experiment is a substantive improvement in the communication system's performances in the presence of meteorological phenomena (e.g. rain) as compared with the more conventional Ka‐band satellite transmission. On the other hand, problems to be faced concern the non‐ideal behaviours of hardware devices employed for high‐frequency digital transmission. In particular, carrier recovery and timing recovery are the most crucial signal‐processing tasks to be carefully considered in the design of the physical level of the system, because they considerably suffer from hardware impairments. The purpose of this work is to illustrate the proposed solutions in terms of the most critical modulation, demodulation and synchronization design issues, together with the effects of non‐ideal behaviours of hardware components on BER performances. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
10.
Carlo Bertucci Piero Salvadori Francesco Ciardelli Graziella Fatti 《Polymer Bulletin》1985,13(5):469-472
Summary Circular dichroism of isotactic samples of poly-(S)-4-methyl-1-hexene and poly-(R)-3,7-dimethyl-1-octene, have been measured in the vacuum ultraviolet spectral region (200-140 nm). The c.d. band at about 160. nm accounts for the optical activity in the visible region and reflects the presence of one screw sense helical conformation of the sample examined.The authors thank Prof. W.C. Johnson, Jr., Department of Biochemistry and Biophysics, Oregon State University, for allowing them to use the vacuum u.v. spectrometer. This work has been partially supported by a N.A.T.O. grant, and by Ministero Pubblica Istruzione (MPI), Roma — Italy. 相似文献