全文获取类型
收费全文 | 214238篇 |
免费 | 3920篇 |
国内免费 | 236篇 |
专业分类
电工技术 | 2914篇 |
综合类 | 154篇 |
化学工业 | 35475篇 |
金属工艺 | 10310篇 |
机械仪表 | 6588篇 |
建筑科学 | 4533篇 |
矿业工程 | 1969篇 |
能源动力 | 3826篇 |
轻工业 | 15094篇 |
水利工程 | 3107篇 |
石油天然气 | 8830篇 |
武器工业 | 16篇 |
无线电 | 17116篇 |
一般工业技术 | 46251篇 |
冶金工业 | 38076篇 |
原子能技术 | 7143篇 |
自动化技术 | 16992篇 |
出版年
2021年 | 2757篇 |
2020年 | 2105篇 |
2019年 | 2456篇 |
2018年 | 4718篇 |
2017年 | 4811篇 |
2016年 | 5160篇 |
2015年 | 2931篇 |
2014年 | 4637篇 |
2013年 | 9419篇 |
2012年 | 7048篇 |
2011年 | 8145篇 |
2010年 | 6506篇 |
2009年 | 6822篇 |
2008年 | 7041篇 |
2007年 | 6726篇 |
2006年 | 5557篇 |
2005年 | 5017篇 |
2004年 | 4713篇 |
2003年 | 4490篇 |
2002年 | 4321篇 |
2001年 | 4030篇 |
2000年 | 3924篇 |
1999年 | 3879篇 |
1998年 | 10332篇 |
1997年 | 7150篇 |
1996年 | 5173篇 |
1995年 | 3719篇 |
1994年 | 3280篇 |
1993年 | 3372篇 |
1992年 | 2480篇 |
1991年 | 2550篇 |
1990年 | 2651篇 |
1989年 | 2542篇 |
1988年 | 2517篇 |
1987年 | 2372篇 |
1986年 | 2450篇 |
1985年 | 2502篇 |
1984年 | 2390篇 |
1983年 | 2271篇 |
1982年 | 2136篇 |
1981年 | 2371篇 |
1980年 | 2217篇 |
1979年 | 2378篇 |
1978年 | 2541篇 |
1977年 | 2622篇 |
1976年 | 3511篇 |
1975年 | 2324篇 |
1974年 | 2367篇 |
1973年 | 2419篇 |
1972年 | 2202篇 |
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
11.
Automation and Remote Control - A linear-quadratic positional differential game of three persons is considered. Coefficient criteria are established under which there is no Nash equilibrium... 相似文献
12.
Blagoveshchenskii D. I. Kozlovskii V. N. Vasin S. A. 《Russian Engineering Research》2021,41(12):1255-1259
Russian Engineering Research - Digital tools for managing improvements in automobile production are developed. An operative tool provides warnings regarding the operational quality of the vehicles... 相似文献
13.
Angelika Varga Zoltn Mszr Mikls Sivad Tímea Bcskai Bence Vgh va Kkai Istvn Nagy Pter Szücs 《International journal of molecular sciences》2021,22(5)
The phosphorylation of serine 10 in histone 3 (p-S10H3) has recently been demonstrated to participate in spinal nociceptive processing. However, superficial dorsal horn (SDH) neurons involved in p-S10H3-mediated nociception have not been fully characterized. In the present work, we combined immunohistochemistry, in situ hybridization with the retrograde labeling of projection neurons to reveal the subset of dorsal horn neurons presenting an elevated level of p-S10H3 in response to noxious heat (60 °C), causing burn injury. Projection neurons only represented a small percentage (5%) of p-S10H3-positive cells, while the greater part of them belonged to excitatory SDH interneurons. The combined immunolabeling of p-S10H3 with markers of already established interneuronal classes of the SDH revealed that the largest subset of neurons with burn injury-induced p-S10H3 expression was dynorphin immunopositive in mice. Furthermore, the majority of p-S10H3-expressing dynorphinergic neurons proved to be excitatory, as they lacked Pax-2 and showed Lmx1b-immunopositivity. Thus, we showed that neurochemically heterogeneous SDH neurons exhibit the upregulation of p-S10H3 shortly after noxious heat-induced burn injury and consequential tissue damage, and that a dedicated subset of excitatory dynorphinergic neurons is likely a key player in the development of central sensitization via the p-S10H3 mediated pathway. 相似文献
14.
Dr. Laurent David Dr. Mark Wenlock Dr. Patrick Barton Dr. Andreas Ritzén 《ChemMedChem》2021,16(17):2669-2685
Chameleonic properties, i. e., the capacity of a molecule to hide polarity in non-polar environments and expose it in water, help achieving sufficient permeability and solubility for drug molecules with high MW. We present models of experimental measures of polarity for a set of 24 FDA approved drugs (MW 405-1113) and one PROTAC (MW 1034). Conformational ensembles in aqueous and non-polar environments were generated using molecular dynamics. A linear regression model that predicts chromatographic apparent polarity (EPSA) with a mean unsigned error of 10 Å2 was derived based on separate terms for donor, acceptor, and total molecular SASA. A good correlation (R2=0.92) with an experimental measure of hydrogen bond donor potential, Δlog Poct-tol, was found for the mean hydrogen bond donor SASA of the conformational ensemble scaled with Abraham's A hydrogen bond acidity. Two quantitative measures of chameleonic behaviour, the chameleonic efficiency indices, are introduced. We envision that the methods presented herein will be useful to triage designed molecules and prioritize those with the best chance of achieving acceptable permeability and solubility. 相似文献
15.
Zhuchkov V. I. Nazansky S. L. Frolkova A. K. Ganina K. D. 《Theoretical Foundations of Chemical Engineering》2021,55(4):786-791
Theoretical Foundations of Chemical Engineering - Using gas–liquid chromatography, the activity coefficients upon the infinite dilution of the components of the reaction mixture for obtaining... 相似文献
16.
Olga Yu Kurapova Sergey M. Shugurov Evgenia A. Vasil'eva Daniil A. Savelev Vladimir G. Konakov Sergey I. Lopatin 《Ceramics International》2021,47(8):11072-11079
Ceria-based solid solutions are important materials for high- and medium-temperature electrochemical applications. However, the stabilities of both binary and ternary ceria-based solid solutions are insufficient at elevated temperatures, which limits their application as solid electrolytes or SOFC cathodes. Data on the high-temperature stability of ceria-based ceramics are unavailable in the literature. In the present study, we report a thermodynamic stability investigation of Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions. The thermal prehistories of binary and ternary systems were investigated using STA, XRD, and ESCA techniques. The vaporization processes were investigated in the temperature range of 1577–2227°С via the Knudsen effusion mass spectrometry technique. Using data on the component activity in solid-phase thermodynamic properties of Y2O3-CeO2 solid solutions, which is represented as the Gibbs energy, the excess Gibbs energy was calculated as a function of the ceria mol. %. It was shown that the reduction of Ce4+ to Ce3+ in Y2O3-CeO2 and Y2O3-ZrO2-CeO2 solid solutions corresponds to less-negative Gibbs energy compared to ZrO2-CeO2 solid solutions. 相似文献
17.
Journal of Signal Processing Systems - Convolutional Neural Networks (CNNs) have improved several computer vision applications, like object detection and classification, when compared to other... 相似文献
18.
Matteo Di Giosia Alice Soldà Markus Seeger Andrea Cantelli Fabio Arnesano Maria I. Nardella Vincenzo Mangini Francesco Valle Marco Montalti Francesco Zerbetto Stefania Rapino Matteo Calvaresi Vasilis Ntziachristos 《Advanced functional materials》2021,31(20):2101527
Fullerenes are candidates for theranostic applications because of their high photodynamic activity and intrinsic multimodal imaging contrast. However, fullerenes suffer from low solubility in aqueous media, poor biocompatibility, cell toxicity, and a tendency to aggregate. C70@lysozyme is introduced herein as a novel bioconjugate that is harmless to a cellular environment, yet is also photoactive and has excellent optical and optoacoustic contrast for tracking cellular uptake and intracellular localization. The formation, water-solubility, photoactivity, and unperturbed structure of C70@lysozyme are confirmed using UV-visible and 2D 1H, 15N NMR spectroscopy. The excellent imaging contrast of C70@lysozyme in optoacoustic and third harmonic generation microscopy is exploited to monitor its uptake in HeLa cells and lysosomal trafficking. Last, the photoactivity of C70@lysozyme and its ability to initiate cell death by means of singlet oxygen (1O2) production upon exposure to low levels of white light irradiation is demonstrated. This study introduces C70@lysozyme and other fullerene-protein conjugates as potential candidates for theranostic applications. 相似文献
19.
20.
Isabel Fernandes Cecília Melo-Alvim Raquel Lopes-Brs Miguel Esperana-Martins Luís Costa 《International journal of molecular sciences》2021,22(2)
Osteosarcoma (OS) is a rare condition with very poor prognosis in a metastatic setting. Basic research has enabled a better understanding of OS pathogenesis and the discovery of new potential therapeutic targets. Phase I and II clinical trials are already ongoing, with some promising results for these patients. This article reviews OS pathogenesis and new potential therapeutic targets. 相似文献