全文获取类型
收费全文 | 140篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
化学 | 78篇 |
晶体学 | 2篇 |
力学 | 3篇 |
数学 | 28篇 |
物理学 | 32篇 |
出版年
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2013年 | 7篇 |
2012年 | 4篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 3篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 5篇 |
1996年 | 10篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1912年 | 1篇 |
排序方式: 共有143条查询结果,搜索用时 15 毫秒
51.
Application of an integrated optics (IO) microcavity (MC) for evanescent excitation of two-photon excited fluorescence (TPF) is demonstrated. The MC provides a high local intensity, which is required for the TPF, because of resonant enhancement of the intracavity power and a strong two-dimensional confinement of the guided mode. Numerical estimations show a large increase, by more than a factor of 104 of the TPF intensity at the MC compared to a conventional straight waveguide. This will lead to a significant improvement of the detection limits of UV-absorbing chromophores (down to 10−8 M) when using the MC as a biosensor. Feasibility of TPF excitation using an IO MC is confirmed experimentally for the first time. 相似文献
52.
A. Driessen D.H. Geuzebroek E.J. Klein R. Dekker R. Stoffer C. Bornholdt 《Optics Communications》2007,270(2):217-224
The propagation of short lightpulses in waveguiding structures with optical feedback, in our case optical microresonators, has been studied theoretically and experimentally. It appears that, dependent on the measurement set-up, ballistic transport or interference in the time domain of fs and ps laser pulses can be observed. The experiments are analyzed in terms of characteristic time scales of the source, the waveguide device and the detector arrangement and are related to Heisenberg’s uncertainty principle. Based on this analysis, a criterion is given for the upper bit-rate for error free data transmission through optical microresonators. 相似文献
53.
In terms of the similarity of matrices, by combining the dual operator and the linear mapping with respect to Hamiache’s associated game on the game space, the Shapley value for TU-games is axiomatized as the unique value verifying dual similar associated consistency, continuity, and the inessential game property. 相似文献
54.
The simultaneous detection of TE- as well as TM-polarized light with a photon scanning tunneling microscope leads to a quasi-interference pattern of these mutually perpendicular polarized fields. This interference pattern has been observed in the optical field distribution as a function of both position and wavelength. Comparison of experimental data with simulations confirms the interference of mutually orthogonal fields. This quasi interference is caused by conversion of the linearly polarized light of both modes into elliptically polarized light by a fiber probe. 相似文献
55.
56.
Sensor based on an integrated optical microcavity 总被引:6,自引:0,他引:6
A novel integrated optical sensor based on a cylindrical microcavity (MC) is proposed. A MC sustains so-called whispering-gallery modes (WGMs), in which the energy of the optical field can be efficiently stored. By monitoring the scattering intensity from the MC, one can detect minute changes in the refractive index of the WGM, for instance, as a result of analyte adsorption. Measurement of a change in refractive index of as little as 10(-4) is demonstrated experimentally. The MC-based integrated optical sensor may have a size of approximately 8mum , and it is rugged and inexpensive. 相似文献
57.
1H NMR‐based metabolomics exploring urinary biomarkers correlated with proteinuria in focal segmental glomerulosclerosis: a pilot study
下载免费PDF全文
![点击此处可从《Magnetic resonance in chemistry : MRC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Shiva Kalantari Mohsen Nafar Shiva Samavat Mahmoud Parvin B. Fatemeh Nobakht M.GH. Farnaz Barzi 《Magnetic resonance in chemistry : MRC》2016,54(10):821-826
Focal segmental glomerulosclerosis (FSGS) is a common glomerulonephritis, and its rates of occurrence are increasing worldwide. Proteinuria is a clinical defining feature of FSGS which correlates with the severity of podocyte injury in patients with nephrotic‐range protein excretion. Metabolite biomarkers corresponding with the level of proteinuria could be considered as non‐invasive complementary prognostic factors to proteinuria. The urine samples of 15 patients (n = 6 women and n = 9 men) with biopsy‐proven FSGS were collected and subjected to nuclear magnetic resonance (NMR) analysis for metabolite profiling. Multivariate statistical analyses, including principal component analysis and orthogonal projection to latent structure discriminant analysis, were applied to construct a predictive model based on patients with proteinuria >3000 mg/day and <3000 mg/day. In addition, random forest was performed to predict differential metabolites, and pathway analysis was performed to find the defective pathways responsible for proteinuria. Ten metabolites, significant in both statistical methods (orthogonal projection to latent structure discriminant analysis and random forest), were considered as prognostic biomarkers for FSGS: citrulline, dimethylamine, proline, acetoacetate, alpha‐ketoisovaleric acid, valine, isobutyrate, D‐Palmitylcarnitine, histidine, and N‐methylnicotinamide. Pathway analysis revealed impairment of the branched‐chain amino acid degradation pathways in patients with massive proteinuria. This study shows that metabolomics can reveal the molecular changes corresponding with disease progression in patients with FSGS and provide a new insight for pathogenic pathways. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
58.
M. D. Hoogerland J. P. J. Driessen E. J. D. Vredenbregt H. J. L. Megens M. P. Schuwer H. C. W. Beijerinck K. A. H. van Leeuwen 《Applied physics. B, Lasers and optics》1996,62(4):323-327
Using a three-step transverse laser cooling scheme, a strongly diverging flow of metastable Ne(3s
3
P
2] atoms is compressed into a well-collimated, small diameter atomic beam (e.g., 1.4 mrad HWHM divergence at 3.6 mm beam diameter) with an unmodified axial velocity distribution centered at 580 m/s. The maximum increase in beam flux 1.04 m downstream of the source is a factor 1400; the maximum increase in phase space density, i.e., brightness, is a factor 160. The laser power used is only 140 mW. The scheme is extendable to a large variety of atomic species and enables the application of bright atomic beams in many areas of physics. 相似文献
59.
PMBF2, a pyrromethene pigment, can be used in gas chromatography. Because of its fluorescence, adsorption sites on glass columns and connections can be traced in situ. The compound can be employed to check the inertness of glass surfaces after deactivation procedures. Some applications are described. 相似文献
60.
R. C. M. Brekelmans L. T. Driessen H. J. M. Hamers D. den Hertog 《Journal of Optimization Theory and Applications》2008,136(3):341-357
We use Lagrange interpolation polynomials to obtain good gradient estimations. This is e.g. important for nonlinear programming
solvers. As an error criterion, we take the mean squared error, which can be split up into a deterministic error and a stochastic
error. We analyze these errors using N-times replicated Lagrange interpolation polynomials. We show that the mean squared
error is of order
if we replicate the Lagrange estimation procedure N times and use 2d evaluations in each replicate. As a result, the order of the mean squared error converges to N
−1 if the number of evaluation points increases to infinity. Moreover, we show that our approach is also useful for deterministic
functions in which numerical errors are involved. We provide also an optimal division between the number of gridpoints and
replicates in case the number of evaluations is fixed. Further, it is shown that the estimation of the derivatives is more
robust when the number of evaluation points is increased. Finally, test results show the practical use of the proposed method.
We thank Jack Kleijnen, Gül Gürkan, and Peter Glynn for useful remarks on an earlier version of this paper. We thank Henk
Norde for the proof of Lemma 2.2. 相似文献