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   136篇
  免费   2篇
化学   52篇
力学   2篇
数学   14篇
物理学   70篇
  2022年   2篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2016年   1篇
  2015年   1篇
  2014年   1篇
  2013年   4篇
  2012年   3篇
  2011年   2篇
  2010年   3篇
  2009年   1篇
  2008年   10篇
  2007年   5篇
  2006年   4篇
  2004年   2篇
  2003年   2篇
  2002年   2篇
  2001年   3篇
  2000年   8篇
  1999年   6篇
  1998年   9篇
  1997年   1篇
  1996年   7篇
  1995年   4篇
  1994年   10篇
  1993年   8篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   5篇
  1988年   5篇
  1987年   5篇
  1986年   2篇
  1985年   1篇
  1982年   1篇
  1980年   2篇
  1977年   1篇
  1969年   1篇
  1968年   1篇
  1964年   4篇
排序方式: 共有138条查询结果,搜索用时 31 毫秒
71.
We analyse different error propagation mechanisms for conservativeand nonconservative time-integrators of nonlinear Schrödingerequations. We use a geometric approach based on interpretingwaves as relative equilibria.  相似文献   
72.
We report an experimental study of the dynamics of thermal fluctuations in a 4.86 mm thick layer of CS2 heated from above. Stabilizing gradients ranged from 10.3 to 61.7 K/cm. Power spectral measurements were made over the wave vector range 9 cm(-1)相似文献   
73.
Zusammenfassung Es wird die Oxydation von Phenolen untersucht, die neben anderen Substituenten in einer o-Stellung Isopropyl-,sec.-Butylodertert.-Butylreste tragen2. Die erhaltenen o-Chinolacetate sind von Interesse, weil nach erfolgtem Umsatz aus den erhaltenen verschiedenen Reaktionsprodukten die genannten Reste entfernt werden können3.Auch aus Phenolen, die in bestimmten Stellen eine Nitrooder Phthaliminogruppe enthielten, wurden o-Chinolacetate hergestellt.Zur Trennung der bei der Oxydation erhaltenen Chinolacetate wurde die Dünnschichtchromatographie eingesetzt.Mit 1 AbbildungAuszug aus der DissertationF. Takacs, Univ. Wien, 1964.10. Mitt.:F. Wessely, J. Swoboda undV. Guth Mh. Chem.95, 649 (1964).  相似文献   
74.
75.
We have investigated water desorption from the polymer poly(methylvinylidene cyanide). The angle resolved thermal desorption spectra show large deviations from the cosn theta distribution for water desorption from poly(methylvinylidene cyanide) indicative of an activated desorption process. The Arrhenius plots obtained from Polanyi-Wigner analysis of the thermal desorption data suggest that a two-state model of desorption applies, while theory suggests that lattice strain in the polymer plays a key role in the thermal desorption of water.  相似文献   
76.
We define mAb proteomics as the global generation of disease specific antibodies that permit mass screening of biomarkers. An integrated, high-throughput, disease-specific mAb-based biomarker discovery platform has been developed. The approach readily provided new biomarker leads with the focus on large-scale discovery and production of mAb-based, disease-specific clinical assay candidates. The outcome of the biomarker discovery process was a highly specific and sensitive assay, applicable for testing of clinical validation paradigms, like response to treatment or correlation with other clinical parameters. In contrast to MS-based or systems biology-based strategies, our process produced prevalidated clinical assays as the outcome of the discovery process. By re-engineering the biomarker discovery paradigm, the encouraging results presented in this paper clearly demonstrate the efficiency of the mAb proteomics approach, and set the grounds for the next steps of studies, namely, the hunt for candidate biomarkers that respond to drug treatment.  相似文献   
77.
Background: It is well known that more than 90% of cancer deaths are due to metastases. However, the entire tumorigenesis process is not fully understood, and it is evident that cells spreading from the primary tumor play a key role in initiating the metastatic process. Tumor proliferation and invasion also elevate the concentration of regular and irregular metabolites in the serum, which may alter the normal function of the entire human homeostasis and possibly causes cancer metabolism syndrome, also referred to as cachexia. Methods: We report on the modification of commercially available hemodialysis membranes to selectively capture circulating tumor cells from the blood stream by means of immobilized human anti-EpCAM antibodies on the inner surface of the fibers. All critical steps are described that required in situ addition of the immuno-affinity feature to hemodialyzer cartridges in order to capture EpCAM positive circulating tumor cells, which represents ~80% of cancer cell types. Results: The cell capture efficiency of the suggested technology was demonstrated by spiking HCT116 cancer cells both into buffer solution and whole blood and run through on the modified cartridge. Flow cytometry was used to quantitatively evaluate the cell clearance performance of the approach. Conclusions: The suggested modification has no significant effect on the porous structure of the hemodialysis membranes; it keeps its cytokine removal capability, addressing cachexia simultaneously with CTC removal.  相似文献   
78.
Equilibrium fluctuations of thermodynamic variables, such as density or concentration, are known to be small and typically occur at a molecular length scale. In contrast, theory predicts that non-equilibrium fluctuations grow very large both in amplitude and spatial size. On earth, the presence of gravity and buoyancy forces severely limits the development of the fluctuations. We will present the results of a 14-year long international collaboration on an experiment on non-equilibrium fluctuations in a single liquid and in a polymer solution under microgravity conditions. Non-equilibrium conditions are generated by applying a temperature gradient across millimetre-size liquid slabs. Phase modulations introduced by fluctuations are measured using a quantitative shadowgraph method, with the optical axis parallel to the temperature gradient. Thousands of images are analysed and their two-dimensional power spectra yield the fluctuation structure function S(q), once data are reduced accounting for the instrumental transfer function T(q). The mean-squared amplitude of the fluctuations exhibits an impressive power-law dependence at larger q and a crossover at low q showing that the fluctuation size is limited by the sample thickness. The shape of the structure function, its increase due to removing gravity, and its dependence on applied gradient are in reasonable agreement with available theoretical predictions.  相似文献   
79.
The high source intensity of the Spallation Neutron Source (SNS), together with efficient detectors and large detector solid angles, now makes possible neutron experiments with much smaller sample volumes than previously were practical. Nested Kirkpatrick–Baez supermirror optics provide a promising and efficient way to further decrease the useable neutron sample size by focusing polychromatic neutrons into microbeams. Because the optics are nondispersive, they are ideal for spallation sources and for polychromatic and wide bandpass experiments on reactor sources. Theoretical calculations indicate that nested mirrors can preserve source brilliance at the sample for small beams and for modest divergences that are appropriate for diffraction experiments. Although the flux intercepted by a sample can be similar with standard beam-guided approaches, the signal-to-background is much improved with small beams on small samples. Here we describe the design, calibration and performance of a nested neutron mirror pair for the Spallation Neutrons At Pressure (SNAP) beamline at the SNS. High-pressure neutron diffraction is but one example of a large class of neutron experiments that will benefit from spatially-resolved microdiffraction.  相似文献   
80.
Super-concentrated “water-in-salt” electrolytes recently spurred resurgent interest for high energy density aqueous lithium-ion batteries. Thermodynamic stabilization at high concentrations and kinetic barriers towards interfacial water electrolysis significantly expand the electrochemical stability window, facilitating high voltage aqueous cells. Herein we investigated LiTFSI/H2O electrolyte interfacial decomposition pathways in the “water-in-salt” and “salt-in-water” regimes using synchrotron X-rays, which produce electrons at the solid/electrolyte interface to mimic reductive environments, and simultaneously probe the structure of surface films using X-ray diffraction. We observed the surface-reduction of TFSI at super-concentration, leading to lithium fluoride interphase formation, while precipitation of the lithium hydroxide was not observed. The mechanism behind this photoelectron-induced reduction was revealed to be concentration-dependent interfacial chemistry that only occurs among closely contact ion-pairs, which constitutes the rationale behind the “water-in-salt” concept.  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