全文获取类型
收费全文 | 787篇 |
免费 | 22篇 |
国内免费 | 2篇 |
学科分类
工业技术 | 811篇 |
出版年
2023年 | 6篇 |
2021年 | 15篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 13篇 |
2014年 | 20篇 |
2013年 | 49篇 |
2012年 | 21篇 |
2011年 | 30篇 |
2010年 | 26篇 |
2009年 | 30篇 |
2008年 | 31篇 |
2007年 | 38篇 |
2006年 | 25篇 |
2005年 | 27篇 |
2004年 | 17篇 |
2003年 | 13篇 |
2002年 | 21篇 |
2001年 | 15篇 |
2000年 | 11篇 |
1999年 | 16篇 |
1998年 | 47篇 |
1997年 | 34篇 |
1996年 | 21篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 18篇 |
1991年 | 12篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 17篇 |
1976年 | 21篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1969年 | 8篇 |
1968年 | 4篇 |
1966年 | 3篇 |
排序方式: 共有811条查询结果,搜索用时 31 毫秒
11.
Fischer U. Schenk W. Salzsieder E. Albrecht G. Abel P. Freyse E.-J. 《IEEE transactions on bio-medical engineering》1987,(8):575-582
To test the hypothesis that only an adaptive algorithm would guarantee optimal feedback control of glycemia in insulin-dependent diabetes, fasting chronically diabetic dogs at rest were subjected to short-term artificial beta cell treatment. Insulin was applied intravenously and an oral glucose load was given during the experiment. Employing the same dosing algorithm, three different control strategies were employed in a random order on different days: adaptive control (minimum variance controller, Test A), fixed command control using on-line parameter estimates (Test B), and fixed command control using off-line individually optimized dosage constants (Test C). Comparison was made to nondiabetic control animals. The glycemic profiles were entirely normal in Test A and C, but were distinctly elevated in Test B. The peripheral hyperinsulinaemia could, however, not be avoided by adaptive control. It is concluded that the restoration of physiological blood glucose control in insulin-dependent diabetes requires dosage parameters which are either continually adapted to the actual situation (adaptive control) or are optimized to meet the individual's needs. In the latter case, fixed command control may be employed. Peripheral hyperinsulinaemia cannot be avoided as long as insulin is administered by a posthepatic route. 相似文献
12.
Lisa Goedtke Heike Sprenger Ute Hofmann Felix F. Schmidt Helen S. Hammer Ulrich M. Zanger Oliver Poetz Albrecht Seidel Albert Braeuning Stefanie Hessel-Pras 《International journal of molecular sciences》2021,22(1)
Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants produced by incomplete combustion of organic matter. They induce their own metabolism by upregulating xenobiotic-metabolizing enzymes such as cytochrome P450 monooxygenase 1A1 (CYP1A1) by activating the aryl hydrocarbon receptor (AHR). However, previous studies showed that individual PAHs may also interact with the constitutive androstane receptor (CAR). Here, we studied ten PAHs, different in carcinogenicity classification, for their potential to activate AHR- and CAR-dependent luciferase reporter genes in human liver cells. The majority of investigated PAHs activated AHR, while non-carcinogenic PAHs tended to activate CAR. We further characterized gene expression, protein abundancies and activities of the AHR targets CYP1A1 and 1A2, and the CAR target CYP2B6 in human HepaRG hepatoma cells. Enzyme induction patterns strongly resembled the profiles obtained at the receptor level, with AHR-activating PAHs inducing CYP1A1/1A2 and CAR-activating PAHs inducing CYP2B6. In summary, this study provides evidence that beside well-known activation of AHR, some PAHs also activate CAR, followed by subsequent expression of respective target genes. Furthermore, we found that an increased PAH ring number is associated with AHR activation as well as the induction of DNA double-strand breaks, whereas smaller PAHs activated CAR but showed no DNA-damaging potential. 相似文献
13.
14.
15.
16.
Martin Bard Mark R. Albrecht Navyash Gupta Cynthia J. Guynn William Stillwell 《Lipids》1988,23(6):534-538
Geraniol, an olefinic terpene, was found to inhibit growth ofCandida albicans andSaccharomyces cerevisiae strains. Geraniol was shown to enhance the rate of potassium leakage out of whole cells and also was shown by fluorescence
polarization to increaseC. albicans membrane fluidity. Biophysical studies using differential scanning calorimetry, fluorescence polarization and osmotic swelling
of phospholipid vesicles demonstrated that geraniol decreased the phase-transition temperature of dipalmitoylphosphatidylcholine
vesicles, affected fluidity throughout the bilayer, particularly the central portion of the bilayers, and caused an increase
in bilayer permeability to erythritol. Geraniol may have potential use as an antifungal agent. 相似文献
17.
We have investigated the surface of thin films (thickness 2 µm) of solid H2 between 1.5 and 4.2 K by measuring the ac conductivity of surface-state electrons (SSE). The films were prepared on a glass substrate by quench condensation at 1.5 K and were therefore initially strongly disordered. In fact the surface of the virgin films before any heat treatment was so rough that no current due to SSE could be observed. Annealing the films decreased the surface roughness and gave rise to a thermal-activation-type temperature dependence of the SSE conductivity. By proper heat treatment up to 8 K the activation energy could be reduced to 10k
B.On leave from the Hyogo University of Teacher Education, Shimokume 942-1, Yashiro, 673-14, Japan. 相似文献
18.
Ivona Kafedjiska Igal Levine Artem Musiienko Natalia Maticiuc Tobias Bertram Amran Al-Ashouri Christian A. Kaufmann Steve Albrecht Rutger Schlatmann Iver Lauermann 《Advanced functional materials》2023,33(34):2302924
The performance of five hole-transporting layers (HTLs) is investigated in both single-junction perovskite and Cu(In, Ga)Se2 (CIGSe)-perovskite tandem solar cells: nickel oxide (NiOx,), copper-doped nickel oxide (NiOx:Cu), NiOx+SAM, NiOx:Cu+SAM, and SAM, where SAM is the [2-(3,-6Dimethoxy-9H-carbazol-9yl)ethyl]phosphonic acid (MeO-2PACz) self-assembled monolayer. The performance of the devices is correlated to the charge-carrier dynamics at the HTL/perovskite interface and the limiting factors of these HTLs are analyzed by performing time-resolved and absolute photoluminescence ((Tr)PL), transient surface photovoltage (tr-SPV), and X-ray/UV photoemission spectroscopy (XPS/UPS) measurements on indium tin oxide (ITO)/HTL/perovskite and CIGSe/HTL/perovskite stacks. A high quasi-Fermi level splitting to open-circuit (QFLS-Voc) deficit is detected for the NiOx-based devices, attributed to electron trapping and poor hole extraction at the NiOx-perovskite interface and a low carrier effective lifetime in the bulk of the perovskite. Simultaneously, doping the NiOx with 2% Cu and passivating its surface with MeO-2PACz suppresses the electron trapping, enhances the holes extraction, reduces the non-radiative interfacial recombination, and improves the band alignment. Due to this superior interfacial charge-carrier dynamics, NiOx:Cu+SAM is found to be the most suitable HTL for the monolithic CIGSe-perovskite tandem devices, enabling a power-conversion efficiency (PCE) of 23.4%, Voc of 1.72V, and a fill factor (FF) of 71%, while the remaining four HTLs suffer from prominent Voc and FF losses. 相似文献
19.
Raimund Kirner Jens Knoop Adrian Prantl Markus Schordan Albrecht Kadlec 《Software and Systems Modeling》2011,10(3):411-437
Worst-case execution time (WCET) analysis is concerned with computing a precise-as-possible bound for the maximum time the execution of a program can
take. This information is indispensable for developing safety-critical real-time systems, e. g., in the avionics and automotive
fields. Starting with the initial works of Chen, Mok, Puschner, Shaw, and others in the mid and late 1980s, WCET analysis
turned into a well-established and vibrant field of research and development in academia and industry. The increasing number
and diversity of hardware and software platforms and the ongoing rapid technological advancement became drivers for the development
of a wide array of distinct methods and tools for WCET analysis. The precision, generality, and efficiency of these methods
and tools depend much on the expressiveness and usability of the annotation languages that are used to describe feasible and infeasible program paths. In this article we survey the annotation languages which
we consider formative for the field. By investigating and comparing their individual strengths and limitations with respect
to a set of pivotal criteria, we provide a coherent overview of the state of the art. Identifying open issues, we encourage
further research. This way, our approach is orthogonal and complementary to a recent approach of Wilhelm et al. who provide
a thorough survey of WCET analysis methods and tools that have been developed and used in academia and industry. 相似文献
20.
Driving Automotive User Interface Research 总被引:2,自引:0,他引:2
Cars offer an interesting but challenging microcosm for pervasive computing research and, in particular, for interaction with pervasive computing systems. Increasingly, researchers are looking at interactive applications in the car and investigating human-car interaction from a computer science—rather than an ergonomics or mechanical engineering—perspective. This article reports on the International Conference on Automotive User Interfaces and Interactive Vehicular Applications, wherein participants shared presentations on topics such as aesthetics, user interaction and distraction, safety, and driver monitoring. 相似文献