全文获取类型
收费全文 | 1824篇 |
免费 | 135篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 99篇 |
综合类 | 4篇 |
化学工业 | 490篇 |
金属工艺 | 29篇 |
机械仪表 | 36篇 |
建筑科学 | 67篇 |
矿业工程 | 7篇 |
能源动力 | 51篇 |
轻工业 | 153篇 |
水利工程 | 9篇 |
石油天然气 | 3篇 |
无线电 | 157篇 |
一般工业技术 | 339篇 |
冶金工业 | 177篇 |
原子能技术 | 7篇 |
自动化技术 | 333篇 |
出版年
2023年 | 45篇 |
2022年 | 69篇 |
2021年 | 102篇 |
2020年 | 81篇 |
2019年 | 70篇 |
2018年 | 71篇 |
2017年 | 67篇 |
2016年 | 68篇 |
2015年 | 54篇 |
2014年 | 96篇 |
2013年 | 132篇 |
2012年 | 91篇 |
2011年 | 120篇 |
2010年 | 77篇 |
2009年 | 79篇 |
2008年 | 78篇 |
2007年 | 68篇 |
2006年 | 67篇 |
2005年 | 42篇 |
2004年 | 33篇 |
2003年 | 41篇 |
2002年 | 32篇 |
2001年 | 18篇 |
2000年 | 9篇 |
1999年 | 22篇 |
1998年 | 60篇 |
1997年 | 48篇 |
1996年 | 14篇 |
1995年 | 14篇 |
1994年 | 17篇 |
1993年 | 25篇 |
1992年 | 10篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 10篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 3篇 |
1974年 | 4篇 |
1973年 | 12篇 |
1972年 | 4篇 |
1943年 | 4篇 |
1942年 | 3篇 |
1940年 | 3篇 |
排序方式: 共有1961条查询结果,搜索用时 10 毫秒
11.
Jan Haas Karen S. Frese Farbod Sedaghat-Hamedani Elham Kayvanpour Rewati Tappu Rouven Nietsch Oguz Firat Tugrul Michael Wisdom Carsten Dietrich Ali Amr Tanja Weis Torsten Niederdrnk Michael P. Murphy Thomas Krieg Marcus Drr Uwe Vlker Jens Fielitz Norbert Frey Stephan B. Felix Andreas Keller Hugo A. Katus Benjamin Meder 《International journal of molecular sciences》2021,22(4)
With more than 25 million people affected, heart failure (HF) is a global threat. As energy production pathways are known to play a pivotal role in HF, we sought here to identify key metabolic changes in ischemic- and non-ischemic HF by using a multi-OMICS approach. Serum metabolites and mRNAseq and epigenetic DNA methylation profiles were analyzed from blood and left ventricular heart biopsy specimens of the same individuals. In total we collected serum from n = 82 patients with Dilated Cardiomyopathy (DCM) and n = 51 controls in the screening stage. We identified several metabolites involved in glycolysis and citric acid cycle to be elevated up to 5.7-fold in DCM (p = 1.7 × 10−6). Interestingly, cardiac mRNA and epigenetic changes of genes encoding rate-limiting enzymes of these pathways could also be found and validated in our second stage of metabolite assessment in n = 52 DCM, n = 39 ischemic HF and n = 57 controls. In conclusion, we identified a new set of metabolomic biomarkers for HF. We were able to identify underlying biological cascades that potentially represent suitable intervention targets. 相似文献
12.
F.J. Medellín‐Rodríguez J.M. Mata‐Padilla B.S. Hsiao M.A. Waldo‐Mendoza E. Ramírez‐Vargas S. Sánchez‐Valdes 《Polymer Engineering and Science》2007,47(11):1889-1897
The influence of organomodified nanoclay (montmorillonite) on the crystallization and melting mechanisms of isotactic polypropylene (iPP) was studied. Films of both neat polymer and clay nanocomposites were prepared after molecular weight optimization through melt extrusion. Products exhibited the tactoidlike morphology since no compatibilizers were used. The effect of introduction of nanoclay within the polymer was studied through isothermal crystallization and linear heating. The results indicated that low nanoclay concentrations induce the formation of the β‐crystalline structure, its formation being inhibited with high nanoclay contents. Dynamic nonisothermal bulk crystallization experiments indicated that nanoclays act as nucleating agents of iPP. Isothermal, bulk crystallization studies indicated that the crystallization process (induction time and crystallization kinetics) is proportionally accelerated by the nanoclay presence. There was also an accelerated formation of secondary crystallization when nanoclays were present in high concentrations. POLYM. ENG. SCI., 47:1889–1897, 2007. © 2007 Society of Plastics Engineers 相似文献
13.
We show that the model checking problem for intuitionistic propositional logic with one variable is complete for logspace-uniform AC 1. For superintuitionistic logics with one variable, we obtain NC 1-completeness for the model checking problem. 相似文献
14.
Felix Schmutzler Christopher Zschiesche Juliane Titus David Poppitz Jens Freiding Rainer Rakoczy Andreas Reitzmann Roger Gläser 《化学,工程师,技术》2021,93(6):981-989
The hydroisomerization of two long-chain n-alkane mixtures was investigated over bifunctional Pt/H-ZSM-5 catalysts before and after dealumination of preshaped zeolite/binder pellets. The hydroisomerization over the dealuminated catalysts leads to more isomers and less cracking products. Consequently, higher ratios of multi- to mono-branched isomerization products are formed as expected for large- rather than medium-pore zeolites. This indicates a higher availability of space in the vicinity of the active sites and provides an attractive route to make medium-pore zeolites suitable for upgrading higher boiling hydrocarbon feeds. 相似文献
15.
Christoph Windmeier Felix Flegiel Alexander Döß Ronald Franz Eckhard Schleicher Michael Wiezorek Markus Schubert Uwe Hampel 《化学,工程师,技术》2021,93(7):1119-1125
An optimized equipment design for natural gas processing and liquefaction plants becomes increasingly difficult with changing process conditions: Particularly low values of surface tension create rising challenges on the design of phase separators and column internals. The TERESA test rig at HZDR was designed to allow the investigation of multiphase thermohydraulics and phase separator performance under critical fluid properties in industrial dimensions. A versatile pipe test section is available in DN200 and equipment internals may be tested in a sectional DN300/DN500 test separator. The applied test fluid shows a high vapor-liquid density difference between 1470 and 940 kg m−3, viscosity as low as 0.12 mm2s−1, and surface tension down to 1.3 mN m−1. Volumetric liquid and vapor flow rates may be varied up to 9 and 530 m3h−1 in the test rig, respectively. 相似文献
16.
Thomas Fehn Felix Kugler Beatrice Tübke Rainer Schweppe Phillip Mebert Wolfgang Krcmar Ulrich Teipel 《化学,工程师,技术》2021,93(5):771-780
Due to the growing energy requirements, the proportion of external thermal insulation composite systems (ETICS) installed has increased significantly during the past 50 years. Due to the longevity of these systems, ETICS waste is currently accumulating. Owing to the complex construction as well as a multitude of differently installed materials and substances of the past generations, there are many uncertainties and problems with the clean and low-pollutant processing of such systems. In the frame of this work, the ETICS were processed and sorted before being screened for ingredients or pollutants as well as for the purity of the recovered material fractions. 相似文献
17.
Đurović Gordana Van Neerbos Francine A. C. Bossaert Sofie Herrera-Malaver Beatriz Steensels Jan Arnó Judit Wäckers Felix Sobhy Islam S. Verstrepen Kevin J. Jacquemyn Hans Lievens Bart 《Journal of chemical ecology》2021,47(8-9):788-798
Journal of Chemical Ecology - There is increasing evidence that microorganisms, particularly fungi and bacteria, emit volatile compounds that mediate the foraging behaviour of insects and therefore... 相似文献
18.
We present an algorithm for combining the elements of subsequences of a sequence with an associative operator. The subsequences are given by a sliding window of varying size. Our algorithm is greedy and computes the result with the minimal number of operator applications. 相似文献
19.
20.
Kirsten Bobzin Erich Lugscheider Felix Ernst Reimo Nickel Nazlim Bagcivan Daniel Parkot Arne Schlegel Stefania Ferrara Tatyana Kashko Noémi Leick 《Microsystem Technologies》2008,14(12):1887-1894
Nowadays, micro components have to fulfill rising optical requirements for different scientific and industrial fields like
astronomy, medicine or multimedia. For this purpose, advanced miniaturized chip-cameras are produced for the microsystems
engineering market. The assembly and joining technologies play a very important role in the production of these micro components.
Several challenges are associated with the joining of chip-cameras. In this study, the application of the soldering technology
has been considered in order to face these challenges. Two joining technologies have been investigated: active soldering and
transient liquid phase (TLP) bonding. Both soldering processes have shown a big potential for hybrid microsystems joining
in previous studies. For both processes, soldering alloys and parameters have been conceived in order to fulfill the joining
requirements of the micro camera components. For instance, the joining temperature represents a major challenge because the
chip-camera consists of a plastic material, polymethyl methacrylate (PMMA). Therefore, particular attention has been directed
to the soldering as well as to the coating temperature. The experimental investigations concerning the solders application
through physical vapor deposition (PVD) have been supported by finite element method (FEM) simulations. The analysis of the
temperature distribution in the micro components during the coating process was the focus of the calculations. Possible undesirable
local overheated areas of the chip-camera components can be detected through simulation.
相似文献
Tatyana KashkoEmail: |