全文获取类型
收费全文 | 1988篇 |
免费 | 116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 | 495篇 |
金属工艺 | 35篇 |
机械仪表 | 54篇 |
建筑科学 | 86篇 |
矿业工程 | 4篇 |
能源动力 | 57篇 |
轻工业 | 226篇 |
水利工程 | 20篇 |
石油天然气 | 5篇 |
无线电 | 167篇 |
一般工业技术 | 328篇 |
冶金工业 | 193篇 |
原子能技术 | 17篇 |
自动化技术 | 368篇 |
出版年
2023年 | 13篇 |
2022年 | 48篇 |
2021年 | 87篇 |
2020年 | 41篇 |
2019年 | 35篇 |
2018年 | 58篇 |
2017年 | 50篇 |
2016年 | 69篇 |
2015年 | 50篇 |
2014年 | 76篇 |
2013年 | 120篇 |
2012年 | 81篇 |
2011年 | 129篇 |
2010年 | 102篇 |
2009年 | 120篇 |
2008年 | 118篇 |
2007年 | 102篇 |
2006年 | 85篇 |
2005年 | 66篇 |
2004年 | 63篇 |
2003年 | 62篇 |
2002年 | 52篇 |
2001年 | 33篇 |
2000年 | 31篇 |
1999年 | 29篇 |
1998年 | 64篇 |
1997年 | 48篇 |
1996年 | 33篇 |
1995年 | 16篇 |
1994年 | 21篇 |
1993年 | 19篇 |
1992年 | 16篇 |
1991年 | 7篇 |
1990年 | 12篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 10篇 |
1978年 | 4篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1910年 | 2篇 |
排序方式: 共有2108条查询结果,搜索用时 15 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.
J Antosiewicz E Damiani W Jassem M Wozniak M Orena L Greci 《Canadian Metallurgical Quarterly》1997,22(1-2):249-255
An in vitro study was carried out to verify whether the chain length of a substituent on an indolinic nitroxide could influence its antioxidant activity in different biological environments subjected to oxidative stress. Three distinct indolinic nitroxides were synthesized and compared with vitamin E and Trolox (a hydrophilic analogue of vitamin E), where the only difference between the nitroxides was the length of the hydrocarbon chain in the 2-position of indole, namely 2 (C2), 10 (C10), and 18 (C18) carbons. All the nitroxides were effective in preventing oxidation of bovine serum albumin, but to different extents, with the longer chain derivatives being more efficient. However, the C2 compound was the most efficient in preventing lipid peroxidation in microsomal membranes. The C2 and C18 compounds, Trolox, and vitamin E protected microsomal protein oxidation to the same extent at the highest concentration used (13 microM). The nitroxide with a C10 chain was less effective in this system. The influence of these compounds on the enzymatic activity of two mitochondrial proteins subjected to oxidative stress was also studied by means of oxygraph measurements. Mitochondrial rotenone-sensitive NADH oxidase and succinate oxidase responded differently to BuOOH-induced radical chemistry, and the compounds under study also protected the activity of the two enzymes but to different extents. The results clearly demonstrate that indolinic nitroxides are very efficient antioxidants, protecting both lipids and proteins from peroxidation. The indole structure influences the antioxidant efficacy in biological systems. 相似文献
8.
M Villarini M Moretti E Damiani L Greci AM Santroni D Fedeli G Falcioni 《Canadian Metallurgical Quarterly》1998,24(7-8):1310-1315
Because previous literature reports have demonstrated that nucleated trout erythrocytes in conditions of oxidative stress are subjected to both membrane damage and a decrease in the enzymatic defense systems (glutathione peroxidase), which in turn lead to hemolysis, the present study was undertaken to determine whether DNA may be affected too, prior to the hemolytic event. Impairment of DNA in stressed trout erythrocytes was assessed using the comet assay--a rapid and sensitive, single-cell gel electrophoresis technique used to detect primary DNA damage in individual cells. In addition, indolinic and quinolinic nitroxide radicals were included in the study to determine their efficacy as antioxidants against free-radical-induced DNA damage. The parameters, tail length, tail intensity, and tail moment, used as an index of DNA damage, have shown that trout erythrocytes exposed to oxidative stress experience DNA damage prior to hemolysis and that the nitroxides significantly prevent this damage. This result provides further information about the potential use of these compounds as antioxidants in biological systems. 相似文献
9.
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
10.
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