全文获取类型
收费全文 | 1505篇 |
免费 | 83篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 25篇 |
综合类 | 5篇 |
化学工业 | 357篇 |
金属工艺 | 32篇 |
机械仪表 | 49篇 |
建筑科学 | 31篇 |
能源动力 | 114篇 |
轻工业 | 142篇 |
水利工程 | 10篇 |
石油天然气 | 9篇 |
无线电 | 193篇 |
一般工业技术 | 280篇 |
冶金工业 | 75篇 |
原子能技术 | 3篇 |
自动化技术 | 268篇 |
出版年
2024年 | 6篇 |
2023年 | 33篇 |
2022年 | 76篇 |
2021年 | 116篇 |
2020年 | 91篇 |
2019年 | 76篇 |
2018年 | 120篇 |
2017年 | 84篇 |
2016年 | 79篇 |
2015年 | 52篇 |
2014年 | 71篇 |
2013年 | 125篇 |
2012年 | 71篇 |
2011年 | 85篇 |
2010年 | 62篇 |
2009年 | 52篇 |
2008年 | 47篇 |
2007年 | 43篇 |
2006年 | 36篇 |
2005年 | 28篇 |
2004年 | 12篇 |
2003年 | 17篇 |
2002年 | 9篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 29篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 15篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 9篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
排序方式: 共有1593条查询结果,搜索用时 15 毫秒
61.
62.
Zahra Shabeh tu Syed Waqar A.A. Rafiq Nouman Shah Wiqar H. Iqbal Zafar 《Protection of Metals and Physical Chemistry of Surfaces》2021,57(2):321-328
Protection of Metals and Physical Chemistry of Surfaces - Chromium oxide thin films were grown on Al2O3 substrates by ablating a pure Cr2O3 target using a KrF excimer laser. The energy density on... 相似文献
63.
V. S. Vendamani Syed Hamad V. Saikiran A. P. Pathak S. Venugopal Rao V. V. Ravi Kanth Kumar S. V. S. Nageswara Rao 《Journal of Materials Science》2015,50(4):1666-1672
We report a detailed study on the synthesis of ultra-small (1–10 nm) colloidal silicon nanoparticles (Si NPs) by ablating porous silicon (pSi) in acetone using femtosecond laser pulses. Porous silicon is considered as a target material for ablation because it contains a large number of light emitting silicon nanoparticles. The pSi samples were prepared by anodic etching of silicon in aqueous HF solution for different etching current densities. Transmission electron microscope measurements confirmed the successful formation of well-isolated spherical silicon nanoparticles. The average size of spherical NPs were estimated to be ~7.6, ~7, and ~6 nm when anodic etching current densities of 5, 10, and 20 mA/cm2 were used respectively for preparing pSi targets. The crystallinity of these Si NPs was confirmed by selective area electron diffraction and Raman spectroscopy measurements. The observed blue shift in the absorption and emission spectra are attributed to reduction in the average particle size with increase in etching current density. These Si NPs may be useful for fabricating low-dimensional microelectronic compatible photonic devices. 相似文献
64.
Frank J. Gaudet Syed R. Qasim 《The International journal of environmental studies》2013,70(1-2):127-135
Industrial wastes containing heavy metals can interfere with the normal operation of municipal wastewater treatment plants utilizing biological treatment processes. It is well known, however, that activated sludge can become acclimated to toxic levels of heavy metals if the dosages are increased gradually. Although such an acclimation procedure could prevent inhibitory effects of slug loads of toxins, the use of toxic heavy metals for normal plant operation is too perilous for consideration. It is, however, acceptable to utilize a nontoxic metal that may give general tolerance to toxic metals. Laboratory experiments were conducted to examine the use of ferric chloride acclimation for treatment against heavy metal toxicity of an activated sludge process. The oxygen uptake of acclimated and unacclimated seed was measured by respirometry to determine the inhibitory effects of Ag and Pb. The toxic effects of Ag and Pb were greatly reduced for acclimated seed. The experimental data area utilized in kinetic rate equations, and families of curves are developed to show the inhibition of Ag and Pb at a range of concentrations when the activated sludge is acclimatized at different concentrations of Fe(III). 相似文献
65.
Brajendra Kumar Singh Jeremy Coulter Mohammad Abdul Ghani Sayani Syed M. Sami Mohammad Khalid Kemal E. Tepe 《The International journal of environmental studies》2013,70(5):765-776
Communication systems are needed to integrate generated power from wind farms with the electrical grid. This paper provides a comprehensive review of available communication technologies, protocols and objectives related to wind energy and electrical grid integration. This paper summarizes the communication system solutions for wind generation. A major obstacle is an absence of unified communication architectures and standards. 相似文献
66.
Syed Jafar Mehdi Hector Rosas-Hernandez Elvis Cuevas Susan M. Lantz Steven W. Barger Sumit Sarkar Merle G. Paule Syed F. Ali Syed Z. Imam 《International journal of molecular sciences》2016,17(9)
Currently, the lack of new drug candidates for the treatment of major neurological disorders such as Parkinson’s disease has intensified the search for drugs that can be repurposed or repositioned for such treatment. Typically, the search focuses on drugs that have been approved and are used clinically for other indications. Kinase inhibitors represent a family of popular molecules for the treatment and prevention of various cancers, and have emerged as strong candidates for such repurposing because numerous serine/threonine and tyrosine kinases have been implicated in the pathobiology of Parkinson’s disease. This review focuses on various kinase-dependent pathways associated with the expression of Parkinson’s disease pathology, and evaluates how inhibitors of these pathways might play a major role as effective therapeutic molecules. 相似文献
67.
Sougata Jana Syed Ansar Ali Amit Kumar Nayak Kalyan Kumar Sen Sanat Kumar Basu 《Chemical Engineering Research and Design》2014
This article describes the development, optimization, and evaluation of Carbopol 940 topical gel containing aceclofenac-crospovidone (1:4) solid dispersion using “Quality by Design (QbD)” approach based on 23 factorial design. The effect of crospovidone, tri-ethanolamine, and ethyl alcohol amount on the drug permeation profile of the topical gel containing aceclofenac-crospovidone solid dispersion was optimized by 23 factorial design. The optimized gel showed improved permeation profile with cumulative drug permeation of 26.262 ± 2.157%, and permeation flux of 0.059 ± 0.011 μg/cm2/h. These gels were characterized by pH, viscosity, gel strength and FTIR study. The in vivo anti-inflammatory activity of the optimized gel was evaluated in rats using carrageenan-induced rat-paw oedema model and found excellent anti-inflammatory comparable with a marketed gel without producing any skin irritation. 相似文献
68.
Yagmur Esemen Mariam Awan Rabeeia Parwez Arsalan Baig Shahinur Rahman Ilaria Masala Sonia Franchini Dimitrios Giakoumettis 《International journal of molecular sciences》2022,23(5)
Glioblastoma (GBM) is the most common and malignant tumour of the central nervous system. Recent appreciation of the heterogeneity amongst these tumours not only changed the WHO classification approach, but also created the need for developing novel and personalised therapies. This systematic review aims to highlight recent advancements in understanding the molecular pathogenesis of the GBM and discuss related novel treatment targets. A systematic search of the literature in the PubMed library was performed following the PRISMA guidelines for molecular pathogenesis and therapeutic advances. Original and meta-analyses studies from the last ten years were reviewed using pre-determined search terms. The results included articles relevant to GBM development focusing on the aberrancy in cell signaling pathways and intracellular events. Theragnostic targets and vaccination to treat GBM were also explored. The molecular pathophysiology of GBM is complex. Our systematic review suggests targeting therapy at the stemness, p53 mediated pathways and immune modulation. Exciting novel immune therapy involving dendritic cell vaccines, B-cell vaccines and viral vectors may be the future of treating GBM. 相似文献
69.
Sobia Noreen Sara Hasan Shazia Akram Ghumman Syed Nasir Abbas Bukhari Bushra Ijaz Huma Hameed Huma Iqbal Afeefa Aslam Mervat Abdelaziz Mohamed Elsherif Shazia Noureen Hasan Ejaz 《International journal of molecular sciences》2022,23(5)
The rapid progression in biomaterial nanotechnology apprehends the potential of non-toxic and potent polysaccharide delivery modules to overcome oral chemotherapeutic challenges. The present study is aimed to design, fabricate and characterize polysaccharide nanoparticles for methotrexate (MTX) delivery. The nanoparticles (NPs) were prepared by Abelmoschus esculentus mucilage (AEM) and chitosan (CS) by the modified coacervation method, followed by ultra-sonification. The NPs showed much better pharmaceutical properties with a spherical shape and smooth surface of 213.4–254.2 nm with PDI ranging between 0.279–0.485 size with entrapment efficiency varying from 42.08 ± 1.2 to 72.23 ± 2.0. The results revealed NPs to possess positive zeta potential and a low polydispersity index (PDI). The in-vitro drug release showed a sustained release of the drug up to 32 h with pH-dependence. Blank AEM -CS NPs showed no in-vivo toxicity for a time duration of 14 days, accompanied by high cytotoxic effects of optimized MTX loaded NPs against MCF-7 and MD-MBA231 cells by MTT assay. In conclusion, the findings advocated the therapeutic potential of AEM/CS NPs as an efficacious tool, offering a new perspective for pH-responsive routing of anticancer drugs with tumor cells as a target. 相似文献
70.
Syed Jawad Ali Shah Haiyang Zhong Qianqian Zhang Huanxiang Liu 《International journal of molecular sciences》2022,23(5)
The formation of neurofibrillary tangles (NFT) with β-sheet-rich structure caused by abnormal aggregation of misfolded microtubule-associated protein Tau is a hallmark of tauopathies, including Alzheimer’s Disease. It has been reported that acetylation, especially K174 located in the proline-rich region, can largely promote Tau aggregation. So far, the mechanism of the abnormal acetylation of Tau that affects its misfolding and aggregation is still unclear. Therefore, revealing the effect of acetylation on Tau aggregation could help elucidate the pathogenic mechanism of tauopathies. In this study, molecular dynamics simulation combined with multiple computational analytical methods were performed to reveal the effect of K174 acetylation on the spontaneous aggregation of Tau peptide 171IPAKTPPAPK180, and the dimerization mechanism as an early stage of the spontaneous aggregation was further specifically analyzed by Markov state model (MSM) analysis. The results showed that both the actual acetylation and the mutation mimicking the acetylated state at K174 induced the aggregation of the studied Tau fragment; however, the effect of actual acetylation on the aggregation was more pronounced. In addition, acetylated K174 plays a major contributing role in forming and stabilizing the antiparallel β-sheet dimer by forming several hydrogen bonds and side chain van der Waals interactions with residues I171, P172, A173 and T175 of the corresponding chain. In brief, this study uncovered the underlying mechanism of Tau peptide aggregation in response to the lysine K174 acetylation, which can deepen our understanding on the pathogenesis of tauopathies. 相似文献