全文获取类型
收费全文 | 537篇 |
免费 | 45篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
综合类 | 2篇 |
化学工业 | 194篇 |
金属工艺 | 7篇 |
机械仪表 | 14篇 |
建筑科学 | 58篇 |
矿业工程 | 2篇 |
能源动力 | 14篇 |
轻工业 | 72篇 |
石油天然气 | 1篇 |
无线电 | 24篇 |
一般工业技术 | 110篇 |
冶金工业 | 21篇 |
原子能技术 | 2篇 |
自动化技术 | 61篇 |
出版年
2023年 | 10篇 |
2022年 | 25篇 |
2021年 | 36篇 |
2020年 | 17篇 |
2019年 | 14篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 32篇 |
2015年 | 28篇 |
2014年 | 22篇 |
2013年 | 44篇 |
2012年 | 38篇 |
2011年 | 26篇 |
2010年 | 41篇 |
2009年 | 26篇 |
2008年 | 32篇 |
2007年 | 38篇 |
2006年 | 26篇 |
2005年 | 22篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 3篇 |
排序方式: 共有583条查询结果,搜索用时 15 毫秒
501.
Katrin Bidmon Sebastian Grottel Fabian Bös Jürgen Pleiss Thomas Ertl 《Computer Graphics Forum》2008,27(3):935-942
Water is known to play a crucial role in protein structure, flexibility and activity. The use of molecular dynamics simulations allows detailed studies of complex protein‐solvent interactions. Cluster analysis and density‐based approaches have been successfully used for the identification and analysis of conserved water molecules and hydration patterns of proteins. However, appropriate tools for analysing long‐time molecular dynamics simulations with respect to tracking and visualising the paths of solvent molecules are lacking. Our method focuses on visualising the solvent paths entering and leaving cavities of the protein and allows to study the route and dynamics of the exchange of tightly bound internal water molecules with the bulk solvent. The proposed visualisation also represents dynamic properties such as direction and velocity in the solvent. Especially, by clustering similar path‐lines with respect to designated properties the visualisation can be abstracted to represent the principal paths of solvent molecules through the cavities. Its application in the analysis of long‐time scale molecular dynamics simulations not only confirmed conjectures based on previous manual observations made by chance, but also led to novel insights into the dynamical and structural role of water molecules and its interplay with protein structure. 相似文献
502.
Detlev Fritsch Karsten Kuhr Katrin Mackenzie Frank-Dieter Kopinke 《Catalysis Today》2003,82(1-4):105-118
A polymer-based catalytic membrane reactor was developed and applied for hydrodechlorination of chlorobenzene as a model compound of ground and waste water contaminants. The catalytically active membrane consists of a non-porous, thin film (about 3–7 μm) of poly(dimethylsiloxane) (PDMS) loaded with nano-sized Pd clusters. They were built-in either directly or as nano-sized, supported catalysts. A composite membrane, consisting of porous poly(acrylonitrile) (PAN) support and a Pd-loaded thin PDMS film, was fabricated on a coating machine. Defect-free membrane envelopes of 0.1 m2 were produced and fitted into a membrane test cell. Gaseous hydrogen as reductant for hydrodechlorination is fed from the membrane’s back side directly to the catalyst, embedded in the PDMS layer. The chemical reactions at the Pd surface are accompanied by absorption of chlorobenzene from the water phase into the PDMS layer and desorption of benzene and HCl back to the water phase. The specific activity of supported catalysts decreased only slightly by PDMS incorporation, e.g., from 31 l/g(Pd) min for Pd/Fe on titania to 16 l/g(Pd) min for the same catalyst built-in a 7 μm thick supported PDMS membrane and measured in the membrane test cell. Directly built-in Pd clusters are less active and more difficult to prepare on a larger scale. Some catalyst deactivation was observed and may be balanced by development of more suited nano-sized supported catalysts. 相似文献
503.
504.
Katrin Schlack Laura-Maria Krabbe Manfred Fobker Andres Jan Schrader Axel Semjonow Martin Boegemann 《International journal of molecular sciences》2016,17(9)
The purpose of this study was to evaluate the prognostic ability of early changes of total prostate specific antigen (tPSA), free PSA (fPSA), [−2]proPSA and the Prostate Health Index (PHI) following initiation of Abiraterone-therapy in men with castration resistant prostate cancer (mCRPC). In 25 patients, PSA-subforms were analyzed before and at 8–12 weeks under therapy as prognosticators of progression-free-survival (PFS) and overall survival (OS). Comparing patients with a PFS < vs. ≥12 months by using Mann–Whitney–Wilcoxon Tests, the relative-median-change of tPSA (−0.1% vs. −86.8%; p = 0.02), fPSA (12.1% vs. −55.3%; p = 0.03) and [−2]proPSA (8.1% vs. −59.3%; p = 0.05) differed significantly. For men with ≤ vs. >15 months of OS there was a non-significant trend for a difference in the relative-median-change of fPSA (17.0% vs. −46.3%; p = 0.06). In Kaplan–Meier analyses, declining fPSA and [−2]proPSA were associated with a longer median PFS (13 months, 95% confidence interval (CI): 9.6–16.4 vs. 10 months, 95% CI: 3.5–16.5; p = 0.11), respectively. Correspondingly, decreasing fPSA and [−2]proPSA values indicated an OS of 32 months (95% CI: not reached (NR)) compared to 21 months in men with rising values (95% CI: 7.7–34.3; p = 0.14), respectively. We concluded that the addition of fPSA- and [−2]proPSA-changes to tPSA-information might be further studied as potential markers of early Abiraterone response in mCRPC patients. 相似文献
505.
506.
507.
Diana Nanova Michael Scherer Felix Schell Johannes Zimmermann Tobias Glaser Anne Katrin Kast Christian Krekeler Annemarie Pucci Wolfgang Kowalsky Rasmus R. Schröder Robert Lovrinčić 《Advanced functional materials》2015,25(41):6511-6518
It is shown that the effect of substrate heating on the photo conversion efficiency in vacuum‐deposited small molecule organic solar cells is closely related to the improved free charge generation in ordered C60 regions. The formation of these ordered regions strongly depends on the deposition sequence in the device and differs therefore between inverted and noninverted cells. Substrate‐induced local fullerene ordering is found in small molecule:C60 bulk heterojunctions (BHJs) deposited on pristine C60 at elevated temperatures. This does not occur for BHJs deposited under identical conditions on pristine donor molecule layers, despite similar degrees of phase separation in both cases. These findings point to a hitherto unidentified advantage of inverted over noninverted solar cells that manifests itself in a higher charge separation efficiency. 相似文献
508.
Literature has identified formal and informal channels in university knowledge and technology transfer (KTT). While formal KTT typically involves a legal contract on a patent or on collaborative research activities, informal transfer channels refer to personal contacts and hence to the tacit dimension of knowledge transfer. Research is, however, scarce regarding the interaction of formal and informal transfer mechanisms. In this paper, we analyze whether these activities are mutually reinforcing, i.e., complementary. Our analysis is based on a comprehensive data-set of more than 2,000 German manufacturing firms and confirms a complementary relationship between formal and informal KTT modes: using both transfer channels contributes to higher innovation performance. The management of the firm should therefore strive to maintain close informal relationships with universities to realize the full potential of formal KTT. 相似文献
509.