全文获取类型
收费全文 | 4460篇 |
免费 | 171篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 53篇 |
综合类 | 14篇 |
化学工业 | 1236篇 |
金属工艺 | 74篇 |
机械仪表 | 61篇 |
建筑科学 | 232篇 |
矿业工程 | 8篇 |
能源动力 | 90篇 |
轻工业 | 428篇 |
水利工程 | 15篇 |
石油天然气 | 5篇 |
无线电 | 295篇 |
一般工业技术 | 859篇 |
冶金工业 | 621篇 |
原子能技术 | 36篇 |
自动化技术 | 607篇 |
出版年
2023年 | 44篇 |
2022年 | 28篇 |
2021年 | 93篇 |
2020年 | 54篇 |
2019年 | 76篇 |
2018年 | 61篇 |
2017年 | 62篇 |
2016年 | 109篇 |
2015年 | 108篇 |
2014年 | 138篇 |
2013年 | 209篇 |
2012年 | 209篇 |
2011年 | 262篇 |
2010年 | 205篇 |
2009年 | 196篇 |
2008年 | 219篇 |
2007年 | 203篇 |
2006年 | 173篇 |
2005年 | 165篇 |
2004年 | 125篇 |
2003年 | 106篇 |
2002年 | 99篇 |
2001年 | 88篇 |
2000年 | 78篇 |
1999年 | 95篇 |
1998年 | 180篇 |
1997年 | 135篇 |
1996年 | 87篇 |
1995年 | 74篇 |
1994年 | 75篇 |
1993年 | 57篇 |
1992年 | 57篇 |
1991年 | 58篇 |
1990年 | 38篇 |
1989年 | 39篇 |
1988年 | 43篇 |
1987年 | 43篇 |
1986年 | 42篇 |
1985年 | 33篇 |
1984年 | 40篇 |
1983年 | 25篇 |
1982年 | 18篇 |
1981年 | 34篇 |
1980年 | 30篇 |
1979年 | 30篇 |
1978年 | 29篇 |
1977年 | 41篇 |
1976年 | 50篇 |
1975年 | 27篇 |
1974年 | 17篇 |
排序方式: 共有4634条查询结果,搜索用时 78 毫秒
81.
Sascha Stanic Thomas Koch Klaus Schmid Simone Knaus Vasiliki-Maria Archodoulaki 《应用聚合物科学杂志》2021,138(28):50659
The influence of two peroxides (peroxydicarbonate/dilauroyl peroxide) with various concentrations (10–200 mmol/kg PP) and their effective opportunity to introduce long chain branched (LCB) were investigated. The dependence of a single and double extrusion step and the changes of the properties were studied. Experiments were carried out in a single screw extruder at 180°C for the first extrusion step (modification) and at 240°C for the second extrusion step (processing simulation). Melt flow rate and dynamic rheological properties were studied at a measuring temperature of 230°C. For the definitive determination of long chain branched polypropylene (LCB-PP) served the extensional rheology measurements. The mechanical properties were examined via tensile test and impact tensile test. Summarized, LCB (melt strength) could be observed via extensional rheology for all modified specimens and the mechanical properties were maintained or even improved for the modified samples. Particularly, samples containing dilauroyl peroxide display excellent mechanical properties in this study. 相似文献
82.
To minimize costs in the manufacture of ring-shaped products, the ring-rolling process must be controlled efficiently. Toward this end, a recently developed control system allows nearly unattended operation of ring-rolling machines. The control system determines optimum preform geometry, thereby minimizing scrap; it also continuously monitors the process to adjust for deviations from set conditions. Various operations can be controlled, and process efficiency and quality are greatly improved. 相似文献
83.
84.
Ulrich Stelzl 《Proteomics. Clinical applications》2013,7(11-12):727-732
Protein–protein interaction networks are typically generated in standard cell lines or model organisms as it is prohibitively difficult to record large interaction datasets from specific tissues or disease models at a reasonable pace. Although the interaction data are of high confidence, they thus do not reflect in vivo relationships as such. A wealth of physiologically relevant protein information, obtained under different conditions and from different systems, is available including information on genetic variation, protein levels, and PTMs. However, these data are difficult to assess comprehensively because the relationships between the entities remain elusive from the measurements. Here, we exemplarily highlight recent studies that gained deeper insight from genetic variation, protein, and PTM measurements using interaction information pointing toward the importance and potential of interaction networks for the interpretation of sequencing and proteomics data. 相似文献
85.
Rawn CJ Leeman JR Ulrich SM Alford JE Phelps TJ Madden ME 《The Review of scientific instruments》2011,82(2):024501
A fiber optic-based distributed sensing system (DSS) has been integrated with a large volume (72 l) pressure vessel providing high spatial resolution, time-resolved, 3D measurement of hybrid temperature-strain (TS) values within experimental sediment-gas hydrate systems. Areas of gas hydrate formation (exothermic) and decomposition (endothermic) can be characterized through this proxy by time series analysis of discrete data points collected along the length of optical fibers placed within a sediment system. Data are visualized as an animation of TS values along the length of each fiber over time. Experiments conducted in the Seafloor Process Simulator at Oak Ridge National Laboratory clearly indicate hydrate formation and dissociation events at expected pressure-temperature conditions given the thermodynamics of the CH(4)-H(2)O system. The high spatial resolution achieved with fiber optic technology makes the DSS a useful tool for visualizing time-resolved formation and dissociation of gas hydrates in large-scale sediment experiments. 相似文献
86.
Zeolite based trace humidity sensor for high temperature applications in hydrogen atmosphere 总被引:1,自引:0,他引:1
We present a humidity sensor based on H-ZSM-5 type zeolite that is suitable to detect traces of humidity (10–110 ppmV) under harsh conditions, e.g. reducing atmosphere (H2) and high temperature (up to 600 °C). By means of complex impedance spectroscopy (IS) we show that the zeolite sensor responds linearly towards minimal changes in humidity. Therefore this result indicates that the zeolite sensor is capable to detect traces of humidity in processes where high temperatures in a hydrogen environment are required. 相似文献
87.
For “on board” diagnosis purposes of the injected fuel quantity flow sensitive elements based on the thermo-resistive measurement
principle were integrated into finished Common Rail injection nozzles of valve-covered orifice (VCO) or mini-sac hole (MSH)
class. Electron-discharge machining as well as electron beam welding technique are key technologies for a reliable integration
procedure. To demonstrate negligible influence on the hydraulic performance of the nozzle after modification an optical measurement
set-up is used to record temporally resolved the propagation of the spray patterns ejected from the six injection holes simultaneously.
From these investigations the impact on the structural distortion of the valve caused by the welding seam is proved as its
position can be directly linked to any chances in spray performance of each individual injection hole. Reducing the energy
input during the electron beam welding lowers substantially the asymmetry in spray patterns from hole to hole as the needle
uncovers the six injection holes more symmetrically. Besides this important finding, the numerical calculations indicate that
the implementation of the sensor chip slightly amplifies the asymmetry induced by the welding process due to an additional
weakening of the nozzle body which is confirmed experimentally. Despite these challenges, however, it is demonstrated that
appropriate parameters for the integration procedure can be found affecting the hydraulic performance negligible compared
to the original state. 相似文献
88.
Scherer HU Wang J Toes RE van der Woude D Koeleman CA de Boer AR Huizinga TW Deelder AM Wuhrer M 《Proteomics. Clinical applications》2009,3(1):106-115
In several autoimmune disorders, including rheumatoid arthritis (RA), autoantibodies are thought to be the driving force of pathogenicity. Glycosylation of the Fc-part of human Igs is known to modulate biological activity. Hitherto, glycosylation of human IgG-Fc has been analyzed predominantly at the level of total serum IgG, revealing reduced galactosylation in RA. Given the pathogenic relevance of autoantibodies in RA, we wished, in the present study, to address the question whether distinct Fc-glycosylation features are observable at the level of antigen-specific IgG subpopulations. For this purpose, we have developed a method for the microscale purification and Fc-glycosylation analysis of anti-citrullinated peptide antibodies (ACPA). ACPA represent a group of autoantibodies that occur with unique specificity in RA patients. Their presence is associated with increased inflammatory disease activity and rapid joint destruction. Results indicate that ACPA of the IgG1 subclass vary considerably from total serum IgG1 with respect to Fc-galactosylation, with galactosylation being higher on ACPA than on serum IgG1 for some patients, while other patients show higher galactosylation on serum IgG1 than on ACPA. Using this method, studies can be performed on the biological and clinical relevance of ACPA glycosylation within RA patient cohorts. 相似文献
89.
Nesterov A König K Felgenhauer T Lindenstruth V Trunk U Fernandez S Hausmann M Bischoff FR Breitling F Stadler V 《The Review of scientific instruments》2008,79(3):035106
We examined the high precision deposition of toner and polymer microparticles with a typical size of approximately 10 microm on electrode arrays with electrodes of 100 microm and below using custom-made microelectronic chips. Selective desorption of redundant particles was employed to obtain a given particle pattern from preadsorbed particle layers. Microparticle desorption was regulated by dielectrophoretic attracting forces generated by individual pixel electrodes, tangential detaching forces of an air flow, and adhesion forces on the microchip surface. A theoretical consideration of the acting forces showed that without pixel voltage, the tangential force applied for particle detachment exceeded the particle adhesion force. When the pixel voltage was switched on, however, the sum of attracting forces was larger than the tangential detaching force, which was crucial for desorption efficiency. In our experiments, appropriately large dielectrophoretic forces were achieved by applying high voltages of up to 100 V on the pixel electrodes. In addition, electrode geometries on the chip's surface as well as particle size influenced the desorption quality. We further demonstrated the compatibility of this procedure to complementary metal oxide semiconductor chip technology, which should allow for an easy technical implementation with respect to high-resolution microparticle deposition. 相似文献
90.
A nematic polymer liquid crystal is used to construct wave plates for use at 1054 nm. Three methods of wave-plate construction are discussed: double substrate with fiber spacers in homogeneous distribution, double substrate with fiber spacers in annular distribution, and single substrate. The polymer liquid crystal shows high laser-damage resistance, making it particularly useful for high-peak-power laser applications. Alignment techniques and measurement of birefringence for the highly viscous polymer are described. 相似文献