首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   892篇
  免费   78篇
  国内免费   8篇
电工技术   8篇
综合类   2篇
化学工业   202篇
金属工艺   11篇
机械仪表   83篇
建筑科学   12篇
矿业工程   1篇
能源动力   35篇
轻工业   117篇
水利工程   2篇
石油天然气   3篇
无线电   113篇
一般工业技术   206篇
冶金工业   25篇
原子能技术   6篇
自动化技术   152篇
  2024年   10篇
  2023年   46篇
  2022年   89篇
  2021年   116篇
  2020年   81篇
  2019年   91篇
  2018年   76篇
  2017年   54篇
  2016年   74篇
  2015年   45篇
  2014年   47篇
  2013年   53篇
  2012年   42篇
  2011年   39篇
  2010年   18篇
  2009年   16篇
  2008年   8篇
  2007年   9篇
  2006年   10篇
  2005年   6篇
  2004年   6篇
  2001年   2篇
  2000年   3篇
  1999年   2篇
  1998年   3篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   3篇
  1993年   2篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
  1989年   4篇
  1988年   3篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1968年   1篇
排序方式: 共有978条查询结果,搜索用时 0 毫秒
91.
92.
93.
Over the last few years, vehicular ad hoc networks (VANETs) have gained popularity for their interesting applications. To make efficient routing decisions, VANET routing protocols require road traffic density information for which they use density estimation schemes. This paper presents a distributed mechanism for road vehicular density estimation that considers multiple road factors, such as road length and junctions. Extensive simulations are carried out to analyze the effectiveness of the proposed technique. Simulation results suggested that, the proposed technique is more accurate compared to the existing technique. Moreover, it facilitate VANET routing protocols to increase packet delivery ratio and reduce end-to-end delay.  相似文献   
94.
We report on the fabrication and performance of vacuum-processed organic field effect transistors utilizing evaporated low-density polyethylene (LD-PE) as a dielectric layer. With C60 as the organic semiconductor, we demonstrate low operating voltage transistors with field effect mobilities in excess of 4 cm2/Vs. Devices with pentacene showed a mobility of 0.16 cm2/Vs. Devices using tyrian Purple as semiconductor show low-voltage ambipolar operation with equal electron and hole mobilities of ~0.3 cm2/Vs. These devices demonstrate low hysteresis and operational stability over at least several months. Grazing-angle infrared spectroscopy of evaporated thin films shows that the structure of the polyethylene is similar to solution-cast films. We report also on the morphological and dielectric properties of these films. Our experiments demonstrate that polyethylene is a stable dielectric supporting both hole and electron channels.  相似文献   
95.
Vincristine (VCR) is a widely used chemotherapy drug that induced peripheral painful neuropathy. Yet, it still lacks an ideal therapeutic strategy. The transient receptor potential (TRP) channels, purinergic receptor (P2Y), and mitogen-activated protein kinase (MAPK) signaling play a crucial role in the pathogenesis of neuropathic pain. Withametelin (WMT), a potential Phytosteroid isolated from datura innoxa, exhibits remarkable neuroprotective properties. The present investigation was designed to explore the effect of withametelin on VCR-induced neuropathic pain and its underlying molecular mechanism. Initially, the neuroprotective potential of WMT was confirmed against hydrogen peroxide (H2O2)-induced PC12 cells. To develop potential candidates for neuropathic pain treatment, a VCR-induced neuropathic pain model was established. Vincristine (75 μg/kg) was administered intraperitoneally (i.p.) for 10 consecutive days (day 1–10) for the induction of neuropathic pain. Gabapentin (GBP) (60 mg/kg, i.p.) and withametelin (0.1 and 1 mg/kg i.p.) treatments were given after the completion of VCR injection on the 11th day up to 21 days. The results revealed that WMT significantly reduced VCR-induced pain hypersensitivity, including mechanical allodynia, cold allodynia, and thermal hyperalgesia. It reversed the VCR-induced histopathological changes in the brain, spinal cord, and sciatic nerve. It inhibited VCR-induced changes in the biochemical composition of the myelin sheath of the sciatic nerve. It markedly downregulated the expression levels of TRPV1 (transient receptor potential vanilloid 1); TRPM8 (Transient receptor potential melastatin 8); and P2Y nociceptors and MAPKs signaling, including ERK (Extracellular Signal-Regulated Kinase), JNK (c-Jun N-terminal kinase), and p-38 in the spinal cord. It suppressed apoptosis by regulating Bax (Bcl2-associated X-protein), Bcl-2 (B-cell-lymphoma-2), and Caspase-3 expression. It considerably attenuated inflammatory cytokines, oxidative stress, and genotoxicity. This study suggests that WMT treatment suppressed vincristine-induced neuropathic pain by targeting the TRPV1/TRPM8/P2Y nociceptors and MAPK signaling.  相似文献   
96.
Poly(glycerol sebacate) (PGS) is a new biodegradable polymer with good biocompatibility used in many fields of biomedicine and drug delivery. Sunitinib‐loaded PGS/gelatine nanoparticles were prepared by the de‐solvation method for retinal delivery and treatment of diabetic retinopathy. The nanoparticles were characterised by Fourier‐transform infrared and differential scanning calorimetry. The effects of different formulation variables including drug‐to‐carrier ratio, gelatine‐to‐PGS ratio, and glycerine‐to‐sebacate ratio were assessed on the encapsulation efficiency (EE%), particle size, release efficiency (RE), and zeta potential of the nanoparticles. The in vitro cytotoxicity of PGS/gelatine nanoparticles was studied on L929 cells. Draize test on rabbit eyes was also done to investigate the possible allergic reactions caused by the polymer. Glycerine/sebacic acid was the most effective parameter on the EE and RE. Gelatine‐to‐PGS ratio had the most considerable effect on the particle size while the RE was more affected by the glycerine/sebacic acid ratio. The optimised formulation (S1 G0.7 D21.2) exhibited a particle size of 282 nm, 34.6% EE, zeta potential of −8.9 mV, and RE% of about 27.3% for drug over 228 h. The 3‐(4,5‐dimethylthuazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay indicated PGS/gelatine nanoparticles were not cytotoxic and sunitinib‐loaded nanoparticles were not toxic at concentrations <36 nM.Inspec keywords: polymers, differential scanning calorimetry, toxicology, drug delivery systems, solvation, eye, encapsulation, particle size, drugs, biodegradable materials, nanofabrication, nanomedicine, nanoparticles, gelatin, Fourier transform infrared spectraOther keywords: gelatine‐to‐PGS ratio, glycerine‐to‐sebacate ratio, particle size, zeta potential, sunitinib‐loaded nanoparticles, biodegradable polymer, retinal delivery, differential scanning calorimetry, drug‐to‐carrier ratio, allergic reactions, physicochemistry, cytotoxicity, poly(glycerol sebacate) nanoparticles, sunitinib ocular delivery, drug delivery, sunitinib‐loaded PGS‐gelatine nanoparticles, Fourier‐transform, in vitro cytotoxicity, biocompatibility, Draize test, rabbit eyes, 3‐(4,5‐dimethylthuazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay  相似文献   
97.
98.
An in vitro capsule dissolution rate problem was encountered during scale-up of cofadroxil monohydrate, a water-soluble drug product. Initial formulation development had been carried out on a Zanasi LZ-64 with a blend containing 1.0% magnesium stearate lubricant. Scale-up capsules manufactured using a Hoflinger-Karg model GFK-1500 (H&K) showed a significantly slower dissolution rate when compared to those produced on a Zanasi LZ-64. Analysis of the problem indicated that during encepsulation on the H&K capsule machine, powder was being sheared resulting in slower in vitro capsule dissolution rate.

Shear simulation studies were conducted to select the level of magnesium stearate for encapsulation on the H&K which would maintain a satisfactory in capsule dissolution rate. A 0.3% level of magnesium stearate was selected on the basis of the simulation studies. At this lubricant level, capsules have been routinely produced on the H&K with satisfactory dissolution and encapsulation characteristics.  相似文献   
99.
Instruments and Experimental Techniques - An Erratum to this paper has been published: https://doi.org/10.1134/S0020441221050249  相似文献   
100.
The rapid adoption of FPGA-based systems in space and avionics demands dependability rules from the design to the layout phases to protect against radiation effects. Triple Modular Redundancy is a widely used fault tolerance methodology to protect circuits against radiation-induced Single Event Upsets implemented on SRAM-based FPGAs. The accumulation of SEUs in the configuration memory can cause the TMR replicas to fail, requiring a periodic write-back of the configuration bit-stream. The associated system downtime due to scrubbing and the probability of simultaneous failures of two TMR domains are increasing with growing device densities. We propose a methodology to reduce the recovery time of TMR circuits with increased resilience to Cross-Domain Errors. Our methodology consists of an automated tool-flow for fine-grain error detection, error flags convergence and non-overlapping domain placement. The fine-grain error detection logic identifies the faulty domain using gate-level functions while the error flag convergence logic reduces the overwhelming number of flag signals. The non-overlapping placement enables selective domain reconfiguration and greatly reduces the number of Cross-Domain Errors. Our results demonstrate an evident reduction of the recovery time due to fast error detection time and selective partial reconfiguration of faulty domains. Moreover, the methodology drastically reduces Cross-Domain Errors in Look-Up Tables and routing resources. The improvements in recovery time and fault tolerance are achieved at an area overhead of a single LUT per majority voter in TMR circuits.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号