全文获取类型
收费全文 | 889篇 |
免费 | 48篇 |
专业分类
电工技术 | 17篇 |
综合类 | 1篇 |
化学工业 | 214篇 |
金属工艺 | 14篇 |
机械仪表 | 16篇 |
建筑科学 | 34篇 |
矿业工程 | 7篇 |
能源动力 | 37篇 |
轻工业 | 30篇 |
水利工程 | 3篇 |
石油天然气 | 2篇 |
无线电 | 74篇 |
一般工业技术 | 235篇 |
冶金工业 | 67篇 |
原子能技术 | 4篇 |
自动化技术 | 182篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 14篇 |
2019年 | 26篇 |
2018年 | 24篇 |
2017年 | 22篇 |
2016年 | 29篇 |
2015年 | 27篇 |
2014年 | 27篇 |
2013年 | 59篇 |
2012年 | 40篇 |
2011年 | 78篇 |
2010年 | 53篇 |
2009年 | 79篇 |
2008年 | 42篇 |
2007年 | 53篇 |
2006年 | 52篇 |
2005年 | 52篇 |
2004年 | 38篇 |
2003年 | 13篇 |
2002年 | 29篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 17篇 |
1998年 | 14篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1988年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1966年 | 2篇 |
1961年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1943年 | 1篇 |
1942年 | 1篇 |
排序方式: 共有937条查询结果,搜索用时 31 毫秒
141.
Nikola Kanas Sathya Prakash Singh Magnus Rotan Mohsin Saleemi Michael Bittner Armin Feldhoff Truls Norby Kjell Wiik Tor Grande Mari-Ann Einarsrud 《Journal of the European Ceramic Society》2018,38(4):1592-1599
Due to high figure of merit, Ca3Co4 ? xO9 + δ (CCO) has potential as p-type material for high-temperature thermoelectrics. Here, the influence of processing including solid state sintering, spark plasma sintering and post-calcination on stability, microstructure and thermoelectric properties is reported. By a new post-calcination approach, single-phase materials were obtained from precursors to final dense ceramics in one step. The highest zT of 0.11 was recorded at 800 °C for CCO with 98 and 72% relative densities. In situ high-temperature X-ray diffraction in air and oxygen revealed a higher stability of CCO in oxygen (~970 °C) than in air (~930 °C), with formation of Ca3Co2O6 which also showed high stability in oxygen, even at 1125 °C. Since achievement of phase pure high density CCO by post-calcination method in air is challenging, the phase stability of CCO in oxygen is important for understanding and further improvement of the method. 相似文献
142.
Jonas Ahlstedt Thuy A. Tran Sven-Erik Strand Magnus Gram Bo ?kerstr?m 《International journal of molecular sciences》2015,16(12):30309-30320
Peptide receptor radionuclide therapy (PRRT) has been in clinical use for 15 years to treat metastatic neuroendocrine tumors. PRRT is limited by reabsorption and retention of the administered radiolabeled somatostatin analogues in the proximal tubule. Consequently, it is essential to develop and employ methods to protect the kidneys during PRRT. Today, infusion of positively charged amino acids is the standard method of kidney protection. Other methods, such as administration of amifostine, are still under evaluation and show promising results. α1-microglobulin (A1M) is a reductase and radical scavenging protein ubiquitously present in plasma and extravascular tissue. Human A1M has antioxidation properties and has been shown to prevent radiation-induced in vitro cell damage and protect non-irradiated surrounding cells. It has recently been shown in mice that exogenously infused A1M and the somatostatin analogue octreotide are co-localized in proximal tubules of the kidney after intravenous infusion. In this review we describe the current situation of kidney protection during PRRT, discuss the necessity and implications of more precise dosimetry and present A1M as a new, potential candidate for renal protection during PRRT and related targeted radionuclide therapies. 相似文献
143.
Nylin Magnus Johansson Westberg Jimmy Lundberg Jonas 《Cognition, Technology & Work》2022,24(2):261-273
Cognition, Technology & Work - Lack of support for handling a reduction of autonomy in a highly autonomous automation may lead to a stressful situation for a human when forced to take over. We... 相似文献
144.
145.
Maximilian Moser Tania Cecilia Hidalgo Jokubas Surgailis Johannes Gladisch Sarbani Ghosh Rajendar Sheelamanthula Quentin Thiburce Alexander Giovannitti Alberto Salleo Nicola Gasparini Andrew Wadsworth Igor Zozoulenko Magnus Berggren Eleni Stavrinidou Sahika Inal Iain McCulloch 《Advanced materials (Deerfield Beach, Fla.)》2020,32(37):2002748
A series of glycolated polythiophenes for use in organic electrochemical transistors (OECTs) is designed and synthesized, differing in the distribution of their ethylene glycol chains that are tethered to the conjugated backbone. While side chain redistribution does not have a significant impact on the optoelectronic properties of the polymers, this molecular engineering strategy strongly impacts the water uptake achieved in the polymers. By careful optimization of the water uptake in the polymer films, OECTs with unprecedented steady-state performances in terms of [μC*] and current retentions up to 98% over 700 electrochemical switching cycles are developed. 相似文献
146.
Nicola Zani Magnus Ekh Anders Ekberg Angelo Mazz 《Fatigue & Fracture of Engineering Materials & Structures》2022,45(1):222-238
A semianalytical model is introduced to assess rolling contact fatigue problems in railway applications. The constitutive law is based on the nonlinear kinematic and isotropic hardening model of Chaboche–Lemaitre, which allows the cyclic elastoplastic strain under the contact surface to be evaluated. The much higher computational effectiveness in comparison with finite element (FE) analyses is quantified. The Dang Van multiaxial fatigue criterion is implemented to evaluate the rolling contact fatigue in the subsurface elastic region where cracking is relatively rare but more dangerous than surface cracks. The influence of the presence of sulfides in the wheel matrix in decreasing fatigue strength is also assessed by means of Murakami's approach. The model is used to compare conditions under small-scale twin-disk experiments to full-scale wheel/rail contact conditions. It is found that, for the same Hertzian pressure, the small-scale contact is more conservative in that it causes a deeper plasticized layer as compared with the elliptical full-scale contact. In the investigated cases, crack initiation is also not expected according to Dang Van criterion in neither of the studied contact conditions. 相似文献
147.
Magnus Oskarsson 《Journal of Mathematical Imaging and Vision》2017,57(2):225-238
The field of high dynamic range imaging addresses the problem of capturing and displaying the large range of luminance levels found in the world, using devices with limited dynamic range. In this paper we present a novel tone mapping algorithm that is based on K-means clustering. Using dynamic programming we are able to not only solve the clustering problem efficiently, but also find the global optimum. Our algorithm runs in \(\hbox {O}(N^2K)\) for an image with N input luminance levels and K output levels. We show that our algorithm gives comparable results to state-of-the-art tone mapping algorithms, but with the additional large benefit of a minimum of parameters. We show how to extend the method to handle video input. We test our algorithm on a number of standard high dynamic range images and video sequences and give qualitative and quantitative comparisons to a number of state-of-the-art tone mapping algorithms. 相似文献
148.
F. Cynthia Martin Monika Hiller Pietro Spitali Stijn Oonk Hans Dalebout Magnus Palmblad Amina Chaouch Michela Guglieri Volker Straub Hanns Lochmüller Erik H. Niks Jan J. G. M. Verschuuren Annemieke Aartsma-Rus André M. Deelder Yuri E. M. van der Burgt Peter A. C. 't Hoen 《Proteomics. Clinical applications》2014,8(3-4):269-278
149.
Nabeel Ali Khan Sadiq Ali Magnus Jansson 《Multidimensional Systems and Signal Processing》2018,29(2):503-521
Time-frequency distributions (TFDs) allow direction of arrival (DOA) estimation algorithms to be used in scenarios when the total number of sources are more than the number of sensors. The performance of such time–frequency (t–f) based DOA estimation algorithms depends on the resolution of the underlying TFD as a higher resolution TFD leads to better separation of sources in the t–f domain. This paper presents a novel DOA estimation algorithm that uses the adaptive directional t–f distribution (ADTFD) for the analysis of close signal components. The ADTFD optimizes the direction of kernel at each point in the t–f domain to obtain a clear t–f representation, which is then exploited for DOA estimation. Moreover, the proposed methodology can also be applied for DOA estimation of sparse signals. Experimental results indicate that the proposed DOA algorithm based on the ADTFD outperforms other fixed and adaptive kernel based DOA algorithms. 相似文献
150.
Brain natriuretic peptide (BNP) might be of importance during heart development and is described to be increasingly expressed in congestive heart failure and to affect the progress of this condition. However, details in the normal expression of BNP are still unclear in various parts of the adult and growing heart, including the conduction system. In this study, we investigated the expression of BNP in relation to that of atrial natriuretic peptide (ANP) in the growing as well as in the adult rat heart. The effects of chemical sympathectomy in adult rats were also examined. Contrary to previous BNP immunohistochemical studies, the BNP antiserum was preabsorbed with an excess of ANP before staining to abolish the crossreactivity with ANP. There was a pronounced BNP immunoreaction in the auricles, the trabeculated ventricular walls, and the peripheral parts of the conduction system at 0-1 days postnatally. The degree of immunoreaction gradually decreased with increasing age. A similar developmental pattern was seen concerning ANP expression, but the magnitude of the latter clearly exceeded that for BNP. Immunoreaction for BNP was never detected in the atrioventricular (AV) node and AV bundle at any stage. In contrast to the situation for ANP previously observed, no obvious changes in BNP immunoreaction patterns were observed in response to sympathectomy. This is the first study to thoroughly demonstrate the expression of BNP in the various regions of the rat heart during growth and in the normal and sympathectomized adult stage. The observations are related to possible functions of natriuretic peptides in the growing and adult heart. 相似文献