全文获取类型
收费全文 | 224篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 83篇 |
晶体学 | 2篇 |
力学 | 7篇 |
数学 | 23篇 |
物理学 | 114篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 7篇 |
2012年 | 6篇 |
2011年 | 12篇 |
2010年 | 14篇 |
2009年 | 3篇 |
2008年 | 17篇 |
2007年 | 6篇 |
2006年 | 16篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 15篇 |
2001年 | 8篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 8篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1932年 | 1篇 |
1900年 | 1篇 |
排序方式: 共有229条查询结果,搜索用时 15 毫秒
41.
Eckers C Laures AM Giles K Major H Pringle S 《Rapid communications in mass spectrometry : RCM》2007,21(7):1255-1263
Many formulated products contain complex polymeric excipients such as polyethylene glycols (PEGs). Such excipients can be readily ionized by electrospray and may be present at very high concentrations, thus making it very difficult to identify trace level impurities such as degradants in samples, even if hyphenated techniques such as liquid chromatography/mass spectrometry (LC/MS) are used. Ion mobility (IM) spectrometry is a very rapid gas-phase separation technique and offers additional separation capability within the LC timeframe. This work investigates the use of an IM separator in combination with high-pressure liquid chromatography (HPLC) and MS, to improve the separation of drug-related materials from excipients, thus aiding the identification of trace-level impurities in an anti-HIV medication, Combivir. 相似文献
42.
Metabonomic/metabolomic studies can involve the analysis of large numbers of samples for the detection of biomarkers and confidence in the analytical data, generated by methods such as GC and HPLC-MS, requires active measures on the part of the analyst. However, quality control for complex multi-component samples such as biofluids, where many of the components of interest in the sample are unknown prior to analysis, poses significant problems. Here the repeat analysis of a pooled sample throughout the run, thereby enabling the analysis to be monitored and controlled using targeted inspection of the data and pattern recognition, is advocated as a pragmatic solution to this problem. 相似文献
43.
Intraperitoneal photodynamic therapy in the Fischer 344 rat using 5-aminolevulinic acid and violet laser light: a toxicity study 总被引:2,自引:0,他引:2
Major AL Rose GS Svaasand LO Lüdicke F Campana A van Gemert MJ 《Journal of photochemistry and photobiology. B, Biology》2002,66(2):107-114
OBJECTIVE: Our study was designed to investigate 5-aminolevulinic acid (ALA) as a candidate for intraperitoneal photodynamic therapy (IP-PDT). The toxicity of IP-PDT and the effects of IP-PDT on abdominal and pelvic organs, particularly the small intestine, were investigated after ALA administration and illumination with violet laser light. STUDY DESIGN AND RESULTS: The toxicity of IP-PDT was evaluated in Fischer 344 rats in two ways. In the first part of the study local PDT effects on the intestine were analyzed histologically. Violet laser light (lambda: 406-415 nm) was applied as a 2 cm diameter spot on the intestine 3 h after intraperitoneal (i.p.) administration of 50 mg/kg ALA. (A) Histological tissue samples were taken 0 min, 6 h and 1, 2 and 3 days after treatment (optical dose 3.2 J/cm(2)). Immediately after local PDT (3.2 J/cm(2), 50 mg/kg ALA) showed no effect on the intestine. However, 6 h post PDT there was complete destruction of the mesothelial lining and the outer (longitudinal) smooth muscle. Ganglion cells of the myenteric (Auerbach) plexus were also destroyed. The inner circular smooth muscle, the muscularis mucosa and the lamina propria were unharmed. Marked lymphectasia was present at this time. (B) To determine the threshold light dose of tissue destruction caused by PDT, different optical doses (1.6, 3.2, 6.4 J/cm(2)) were administered and histologic analysis of tissue samples were obtained 1 day post treatment. Destruction of the entire external musculature, submucosal structures and muscularis mucosa of the intestine at the illumination site could be observed above 1.6 J/cm(2) (50 mg/kg ALA). In the second part of the study whole peritoneal cavity PDT (WPC-PDT) was performed by illumination of the whole peritoneal cavity with 1.6 J/cm(2) violet light 3 h after ALA administration using different drug doses (200, 100 and 50 mg/kg). WPC-PDT showed lethal toxicity with a drug dose above 50 mg/kg ALA at 1.6 J/cm(2). The probable cause of death in the first 3 days after IP-PDT was rhabdomyolysis, whereas when death occurred at longer time intervals, megaintestine associated with significant damage could be observed; however, without perforation of the intestinal wall. CONCLUSION: In rats WPC-PDT with 50 mg/kg ALA, 1.6 J/cm2 at lambda=415 nm was the maximum tolerable light dose. This dose is likely to be above the threshold of destruction of ovarian cancer micrometastasis. 相似文献
44.
Nonlinear Dynamics - Port Knocking is a method for authenticating clients through a closed stance firewall, and authorising their requested actions, enabling severs to offer services to... 相似文献
45.
L. Deák L. Bottyán R. Callens R. Coussement M. Major I. Serdons Y. Yoda 《Hyperfine Interactions》2006,167(1-3):709-715
The concept of the heterodyne/stroboscopic detection of nuclear resonance scattering of synchrotron radiation is extended to the grazing incidence geometry. Model calculations for an antiferromagnetic [57Fe/Cr]20 multilayer are shown and discussed. Principles and methodological aspects of stroboscopic synchrotron Mössbauer reflectometry are briefly reviewed. 相似文献
46.
E. Widmann W. Bauer S. Connell K. Maier J. Major A. Seeger H. Stoll F. Bosch 《Zeitschrift für Physik A Hadrons and Nuclei》1991,340(2):209-218
Motivated by the observation of energy- and momentum-correlatede + e ? pairs in heavy ion collisions, a search for resonances ine + e ? scattering at the corresponding energies has been made. Thee + e ? decay channel is analyzed in a time window from ~ 10?13 s to ~ 10?11 s with a set-up optimized for low-background detection of delayede + e ? decays. The two-photon decay channel of a hypothetical resonance is investigated by measuring the two-photon annihilation-in-flight excitation function. New upper limits for the partiale + e ? decay width Γee of a few meV are derived for total centre-of-mass energies √s between 1.78 and 1.92 MeV, taking into account the dilepton as well as the two-photon decay of a neutral resonance. 相似文献
47.
K. Bharuth‐Ram R. Scheuermann I.Z. Machi S.H. Connell J. Major J.P.F. Sellschop A. Seeger 《Hyperfine Interactions》1997,105(1-4):339-344
Transverse‐field μSR spectroscopy was used to study the behaviour of positive muons implanted in polycrystalline chemical‐vapour‐deposited
(CVD) diamond. Measurements were made at sample temperatures of 10 K, 100 K, and 300 K at a magnetic field of 7.5 mT to study
the behaviour of the “normal” (isotropic) muonium state (MuT) and the diamagnetic states (μd), and at 10 K and 300 K at the so‐called “magic field” of 407.25 mT to study the anomalous (bond‐centred) muonium state (MuBC) and μd. The absolute fractions of the muonium states in the CVD diamond are observed to be close to those in high‐quality natural
type‐IIa single crystal diamond.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
48.
Er:ZBLAN玻璃的一光束上转换立体显示的初步研究 总被引:5,自引:0,他引:5
本文研究了一光束上转换三维立体显示 ,所用材料为Er:ZBLAN氟化物玻璃 ;利用 96 6nm的连续波半导体激光研究了一光束上转换三维立体显示的尺寸效应 ,且得到了它的上转换发光谱 ;尤其是发现了基于 15 2 0nm的半导体激光激发的多光子上转换一光束三维立体显示的性能有大幅度提高 ,这在国际上还未见报道。 相似文献
49.
Julius Mandl k. u. k. Major des Geniestabes 《Monatshefte für Mathematik》1900,11(1):183-192
Ohne Zusammenfassung 相似文献
50.
P. Major 《Probability Theory and Related Fields》1988,78(3):419-435
Summary Let F
n
(u) denote the empirical distribution function of a sample of i.i.d. random variables with uniform distribution on [0, 1]. Define
, and consider the integrals
where f is a bounded measurable function. We give a good upper bound on the probability
. An analogous estimate is given for multiple integrals with respect to a Poisson process. 相似文献