全文获取类型
收费全文 | 494篇 |
免费 | 19篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 7篇 |
综合类 | 2篇 |
化学工业 | 139篇 |
金属工艺 | 20篇 |
机械仪表 | 28篇 |
建筑科学 | 25篇 |
矿业工程 | 4篇 |
能源动力 | 23篇 |
轻工业 | 47篇 |
水利工程 | 2篇 |
无线电 | 30篇 |
一般工业技术 | 98篇 |
冶金工业 | 27篇 |
原子能技术 | 4篇 |
自动化技术 | 62篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 45篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 19篇 |
2017年 | 14篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 24篇 |
2013年 | 41篇 |
2012年 | 33篇 |
2011年 | 47篇 |
2010年 | 29篇 |
2009年 | 25篇 |
2008年 | 24篇 |
2007年 | 18篇 |
2006年 | 18篇 |
2005年 | 15篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有518条查询结果,搜索用时 15 毫秒
501.
Treatment of symptomatic coronary artery disease in patients with end‐stage renal disease on hemodialysis with paclitaxel‐eluting TAXUS stent 下载免费PDF全文
Szymon L. Wiernek R. Stefan Kiesz Barbara K. Wiernek Piotr P. Buszman Adam Janas Jack L. Martin Blazej Trela Robert G. Szewc Pawel E. Buszman 《Hemodialysis international. International Symposium on Home Hemodialysis》2015,19(3):402-411
Percutaneous coronary intervention (PCI) utilizing drug‐eluting stents is becoming a very common revascularization technique in the dialysis cohort; therefore, we sought to identify the impact of dialysis on outcomes in this group of patients. This is a multicenter registry comparing results of 290 patients (186 with normal kidney function, 104 on dialysis) who underwent PCI with exclusive use of paclitaxel‐eluting TAXUS stent. The primary endpoint was an assessment of major adverse cardiac events (MACE) at 1‐ and 2‐year observation. Mean follow‐up was 23.3 ± 6.1 months. Results at 12 months showed: MACE 11.8% vs. 7.7% (P = not significant [ns]), composite major adverse cardiac and cerebrovascular events (MACCE) 12.4% vs. 11.5% (P = ns), all‐cause death 2.7% vs. 8.6% (P < 0.05), cardiac death 2.7% vs. 1.9% (P = ns), target vessel revascularization (TVR) 9.1% vs. 6.7% (P = ns), acute myocardial infarction (AMI) 3.8% vs. 2.9% (P = ns), cerebrovascular events (CVA) 0.5% vs. 1.0% (P = ns); and results at 24 months showed: MACE 17.7% vs. 18.3% (P = ns), MACCE 21.5% vs. 26.0% (P = ns), all‐cause death 4.3% vs. 14.4% (P < 0.01), cardiac death 3.2% vs. 1.9% (P = ns), TVR 14.0% vs. 16.3% (P = ns), AMI 5.4% vs. 5.8% (P = ns), CVA 3.2% vs. 2.9% (P = ns) for non–end‐stage renal disease (ESRD) and dialysis group, respectively. Prior coronary artery bypass graft (CABG) was found to be single risk factor for MACE, TVR, and MACCE in patients with ESRD, while dialysis and prior CABG were found to be single risk factors for death in the entire population. PCI with TAXUS is a feasible procedure and presents promising results in dialysis‐dependent patients. 相似文献
502.
The design and measurement results of a micro-power successive approximation charge redistribution ADC implemented in CMOS 180 nm technology are presented. The project has been optimized for very low area occupancy in order to utilize it in multichannel neural signal recording pixel systems for future application. The design has been fabricated, experimentally characterized and it exhibits good performance, especially from the silicon area occupation point of view. The presented converter achieves 500 kS/s sampling rate with ENOB of 6.54 at 4.45 μW and occupies only 90 μm×95 μm of silicon area. 相似文献
503.
David J. Burke Nicole Pietrasiak Shu F. Situ Eric C. Abenojar Mya Porche Pawel Kraj Yutthana Lakliang Anna Cristina S. Samia 《International journal of molecular sciences》2015,16(10):23630-23650
In this study, we investigated the effect of positively and negatively charged Fe3O4 and TiO2 nanoparticles (NPs) on the growth of soybean plants (Glycine max.) and their root associated soil microbes. Soybean plants were grown in a greenhouse for six weeks after application of different amounts of NPs, and plant growth and nutrient content were examined. Roots were analyzed for colonization by arbuscular mycorrhizal (AM) fungi and nodule-forming nitrogen fixing bacteria using DNA-based techniques. We found that plant growth was significantly lower with the application of TiO2 as compared to Fe3O4 NPs. The leaf carbon was also marginally significant lower in plants treated with TiO2 NPs; however, leaf phosphorus was reduced in plants treated with Fe3O4. We found no effects of NP type, concentration, or charge on the community structure of either rhizobia or AM fungi colonizing plant roots. However, the charge of the Fe3O4 NPs affected both colonization of the root system by rhizobia as well as leaf phosphorus content. Our results indicate that the type of NP can affect plant growth and nutrient content in an agriculturally important crop species, and that the charge of these particles influences the colonization of the root system by nitrogen-fixing bacteria. 相似文献
504.
Starting from the classical centrifugal compressor, cone shaped in meridional cross section, two modifications are considered on the basis of results from 2D and 3D flow models. The first modification is the change of the meridional cross section to hyperbolically shaped channel. The second modification, proposed on the basis of 2D axisymmetric solution, concerns the shape of blading. On the strength of this solution the blades are formed as 3D shaped blades, coinciding with the recent tendency in 3D designs. Two aims were considered for the change of meridional compressor shape. The first was to remove the separation zone which appears as the flow turns from axial to radial direction. The second aim is to uniformize the flow at exit of impeller. These two goals were considered within the frame of 2D axisymmetric model. Replacing the cone shaped compressor by a hyperbolically shaped one, the separation at the corner was removed. The disc and shroud shape of the compressor was chosen in the way which sat 相似文献
505.
Abstract In this paper a semi-classical model of the nonlinear operation of a laser is extended to describe a laser with a Gaussian mirror. Modified nonlinear self-consistent equations including transverse and longitudinal field dependence, gain saturation, spatial hole burning and nonlinear dispersion effects are derived. With the help of an energy theorem an approximate solution for steady-state single mode operation is presented, which relates the small signal gain to the output power and the laser system characteristic parameters. The laser output power characteristics are presented for various cavity configurations, especially, revealing an influence of the Gaussian mirror parameter on the power efficiency of the laser. 相似文献
506.
Peteris Prusis Helgi B. Schiöth Ruta Muceniece Pawel Herzyk Mohammad Afshar Roderick E. Hubbard Jarl E.S. Wikberg 《Journal of molecular graphics & modelling》1997,15(5):307-317
A model is presented of the melanocortin 1 receptor (MC1R), constructed by use of an unbiased, objective method. The model is created directly from data derived from multiple sequence analysis, a low-resolution EM-projection map of rhodopsin, and the approximate membrane thickness. The model agrees well with available data concerning natural mutations of MC1Rs occurring in different species. A model is also presented of the most rigid ligand for this receptor, the cyclic pentapeptide cHFRWG, shown docked in the receptor model. The receptor–ligand complex model agrees well with available experimental data. The ligand is located between transmembrane region 1 (TM1), TM2, TM3, TM6, and TM7 of the receptor. Multiple interactions occur between ligand and receptor, including interactions with Leu-48 (TM1), Ser-52 (TM1), Glu-55 (TM1), Asn-91 (TM2), Glu-94 (TM2), Thr-95 (TM2) Ile-98 (TM2), Asp-121 (TM3), Thr-124 (TM3), Phe-257 (TM6), Phe-283 (TM7), Asn-290 (TM7), and Asp-294 (TM7) of the receptor. 相似文献
507.
Anna Dzimitrowicz Piotr Jamroz Pawel Pohl Weronika Babinska Dominik Terefinko Wojciech Sledz Agata Motyka-Pomagruk 《International journal of molecular sciences》2021,22(9)
To the present day, no efficient plant protection method against economically important bacterial phytopathogens from the Pectobacteriaceae family has been implemented into agricultural practice. In this view, we have performed a multivariate optimization of the operating parameters of the reaction-discharge system, employing direct current atmospheric pressure glow discharge, generated in contact with a flowing liquid cathode (FLC-dc-APGD), for the production of a plasma-activated liquid (PAL) of defined physicochemical and anti-phytopathogenic properties. As a result, the effect of the operating parameters on the conductivity of PAL acquired under these conditions was assessed. The revealed optimal operating conditions, under which the PAL of the highest conductivity was obtained, were as follows: flow rate of the solution equaled 2.0 mL min−1, the discharge current was 30 mA, and the inorganic salt concentration (ammonium nitrate, NH4NO3) in the solution turned out to be 0.50% (m/w). The developed PAL exhibited bacteriostatic and bactericidal properties toward Dickeya solani IFB0099 and Pectobacterium atrosepticum IFB5103 strains, with minimal inhibitory and minimal bactericidal concentrations equaling 25%. After 24 h exposure to 25% PAL, 100% (1−2 × 106) of D. solani and P. atrosepticum cells lost viability. We attributed the antibacterial properties of PAL to the presence of deeply penetrating, reactive oxygen and nitrogen species (RONS), which were, in this case, OH, O, O3, H2O2, HO2, NH, N2, N2+, NO2−, NO3−, and NH4+. Putatively, the generated low-cost, eco-friendly, easy-to-store, and transport PAL, exhibiting the required antibacterial and physicochemical properties, may find numerous applications in the plant protection sector. 相似文献
508.
Leif Holmlid Andrzej Kotarba Pawel Stelmachowski 《International Journal of Hydrogen Energy》2021,46(35):18466-18480
Condensation of hydrogen Rydberg atoms (highly electronically excited) into the lowest energy state of condensed hydrogen i.e. the ultra-dense hydrogen phase, H(0), has gained increased attention not only from the fundamental aspects but also from the applied point of view. The physical properties of ultra-dense hydrogen H(0) were recently reviewed (Physica Scripta 2019 https://doi.org/10.1088/1402-4896/ab1276), summarizing the results reported in 50 publications during the last ten years. The main application of H(0) so far is as the fuel and working medium in nuclear particle generators and nuclear fusion reactors which are under commercial development. The first fusion process showing sustained operation above break-even was published in 2015 (AIP Advances) and used ultra-dense deuterium D(0) as fuel. The first generator giving a high-intensity muon flux intended for muon-catalyzed fusion reactors was patented in 2017, using H(0) as the working medium. Here, we first focus on the different nuclear processes using hydrogen isotopes for energy generation, and then on the detailed processes of formation of H(0). The production of H(0) employs heterogeneous catalysts which are active in hydrogen transfer reactions. Iron oxide-based, alkali promoted catalysts function well, but also platinum group metals and carbon surfaces are active in this process. The clusters of highly excited Rydberg hydrogen atoms H(l) are formed upon interaction with alkali Rydberg matter. The final conversion step from ordinary hydrogen Rydberg matter H(l) to H(0) is spontaneous and does not require a solid surface. It is concluded that the exact choice of catalyst is not very important. It is also concluded that the crucial feature of the catalyst is to provide excited alkali atoms at a sufficiently high surface density and in this way enabling formation and desorption of H(0) clusters. Finally, the relation to industrial catalytic processes which use H(0) formation catalysts is described and some important consequences like the muon and neutron radiation from H(0) are discussed. 相似文献
509.
Anna de Corde-Skurska Pawel Krzascik Anna Lesniak Mariusz Sacharczuk Lukasz Nagraba Magdalena Bujalska-Zadrozny 《International journal of molecular sciences》2021,22(8)
One of the key strategies for effective pain management involves delaying analgesic tolerance. Early clinical reports indicate an extraordinary effectiveness of off-label disulfiram—an agent designed for alcohol use disorder—in potentiating opioid analgesia and abrogation of tolerance. Our study aimed to determine whether sustained µ-opioid signaling upon disulfiram exposure contributes to these phenomena. Wistar rats were exposed to acute and chronic disulfiram and morphine cotreatment. Nociceptive thresholds were assessed with the mechanical Randal-Selitto and thermal tail-flick tests. µ-opioid receptor activation in brain structures important for pain processing was carried out with the [35S]GTPγS assay. The results suggest that disulfiram (12.5–50 mg/kg i.g.) augmented morphine antinociception and diminished morphine (25 mg/kg, i.g.) tolerance in a supraspinal, opioid-dependent manner. Disulfiram (25 mg/kg, i.g.) induced a transient enhancement of µ-opioid receptor activation in the periaqueductal gray matter (PAG), rostral ventromedial medulla (RVM), hypothalamus, prefrontal cortex and the dorsal striatum at day 1 of morphine treatment. Disulfiram rescued µ-opioid receptor signaling in the nucleus accumbens and caudate-putamen 14 days following morphine and disulfiram cotreatment. The results of this study suggest that striatal µ-opioid receptors may contribute to the abolition of morphine tolerance following concomitant treatment with disulfiram. 相似文献
510.
This paper explores the use of Jaya algorithm for the single- and multi-objective design optimization of plate-fin heat exchangers (PFHEs). Design of PFHEs involves a number of geometric and physical parameters with high complexity. The general design approaches are based on trial and error and become tedious and time consuming and do not guarantee the achievement of an optimal design. Therefore, advanced optimization algorithms are preferred. The Jaya algorithm is a newly developed simple algorithm and it does not have any algorithmic-specific parameters to be tuned and this aspect reduces the designer's effort in tuning the parameters to arrive at the optimum value of the objective function. The Jaya algorithm is proposed for the design optimization of PFHEs by minimizing the total surface area of heat transfer, total annual cost, and total pressure drop of the system and maximizing the effectiveness. Seven design parameters are considered which are imposed by constraints on the design. Single- as well as multi-objective design optimization is carried out using the proposed algorithm. The results obtained by Jaya algorithm are compared with the results of latest reported algorithms. These comparisons revealed that the Jaya algorithm can be successfully applied for the design optimization of PFHEs. 相似文献