全文获取类型
收费全文 | 2313篇 |
免费 | 84篇 |
国内免费 | 8篇 |
专业分类
化学 | 1491篇 |
晶体学 | 17篇 |
力学 | 39篇 |
数学 | 439篇 |
物理学 | 419篇 |
出版年
2023年 | 12篇 |
2022年 | 22篇 |
2021年 | 46篇 |
2020年 | 60篇 |
2019年 | 52篇 |
2018年 | 25篇 |
2017年 | 34篇 |
2016年 | 75篇 |
2015年 | 63篇 |
2014年 | 70篇 |
2013年 | 123篇 |
2012年 | 156篇 |
2011年 | 144篇 |
2010年 | 81篇 |
2009年 | 82篇 |
2008年 | 132篇 |
2007年 | 150篇 |
2006年 | 128篇 |
2005年 | 112篇 |
2004年 | 98篇 |
2003年 | 91篇 |
2002年 | 87篇 |
2001年 | 46篇 |
2000年 | 32篇 |
1999年 | 31篇 |
1998年 | 26篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 28篇 |
1993年 | 25篇 |
1992年 | 27篇 |
1991年 | 18篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 16篇 |
1984年 | 12篇 |
1983年 | 16篇 |
1982年 | 16篇 |
1981年 | 14篇 |
1980年 | 12篇 |
1979年 | 8篇 |
1978年 | 15篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 16篇 |
1974年 | 15篇 |
1972年 | 7篇 |
排序方式: 共有2405条查询结果,搜索用时 15 毫秒
151.
Marcus V. P. dos Santos Eduardo C. Aguiar João Bosco P. da Silva Ricardo L. Longo 《Journal of computational chemistry》2013,34(8):611-621
A new approach Procedure for Investigating Categories of Vibrations (PICVib) for estimating vibrational frequencies of selected modes using only the structure and energy calculations at a more demanding computational level is presented and explored. The PICVib has an excellent performance at only a small fraction of the computational demand required for a complete analytical calculation. The errors are smaller than ca. 0.5% when DFT functionals are combined with high level ab initio methods. The approach is general because it can use any quantum chemical program and electronic structure method. It is very robust because it was validated for a wide range of frequency values (ca. 20–4800 cm–1) and systems: XH3 (D3h) with X = B, Al, Ga, N, P, As, O, S, and Se, YH4 (D4h) with Y = C, Si, and Ge, conformers of RDX, SN2 and E2 reactions, [W(dppe)2(NNC5H10)] complex, carbon nanotubes, and hydrogen‐bonded complexes including guanine‐cytosine pair. © 2012 Wiley Periodicals, Inc. 相似文献
152.
Isabel V. L. Wilkinson Kelly J. Perkins Hannah Dugdale Lee Moir Aini Vuorinen Maria Chatzopoulou Sarah E. Squire Sebastian Monecke Alexander Lomow Marcus Geese Philip D. Charles Peter Burch Jonathan M. Tinsley Graham M. Wynne Stephen G. Davies Francis X. Wilson Fraydoon Rastinejad Shabaz Mohammed Kay E. Davies Angela J. Russell 《Angewandte Chemie (International ed. in English)》2020,59(6):2420-2428
Duchenne muscular dystrophy (DMD) is a fatal muscle‐wasting disease arising from mutations in the dystrophin gene. Upregulation of utrophin to compensate for the missing dystrophin offers a potential therapy independent of patient genotype. The first‐in‐class utrophin modulator ezutromid/SMT C1100 was developed from a phenotypic screen through to a Phase 2 clinical trial. Promising efficacy and evidence of target engagement was observed in DMD patients after 24 weeks of treatment, however trial endpoints were not met after 48 weeks. The objective of this study was to understand the mechanism of action of ezutromid which could explain the lack of sustained efficacy and help development of new generations of utrophin modulators. Using chemical proteomics and phenotypic profiling we show that the aryl hydrocarbon receptor (AhR) is a target of ezutromid. Several lines of evidence demonstrate that ezutromid binds AhR with an apparent KD of 50 nm and behaves as an AhR antagonist. Furthermore, other reported AhR antagonists also upregulate utrophin, showing that this pathway, which is currently being explored in other clinical applications including oncology and rheumatoid arthritis, could also be exploited in future DMD therapies. 相似文献
153.
FUNDAMENTALS OF TRANSMISSION FLUCTUATION SPECTROMETRY WITH VARIABLE SPATIAL AVERAGING 总被引:4,自引:0,他引:4
JianqiShen UlrichRiebel MarcusBreitenstein UdoKraeuter 《中国颗粒学报》2003,1(6):242-246
Transmission signal of radiation in suspension of particles performed with a high spatial and temporal resolution shows significant fluctuations,which are related to the physical properties of the particles and the process of spatial and temporal averaging.Exploiting this connection,it is possible to calculate the particle size distribution (PSD) and particle concentration.This paper provides an approach of transmission fluctuation spectrometry (TFS) with variable spatial averaging,The transmission fluctuations are expressed in terms of the expectancy of transmission square (ETS) and are obtained as a spectrum,which is a function of the variable beam diameter.The reversal point and the depth of the spectrum contain the information of particle size and particle concentration,respectively. 相似文献
154.
Paula R. Cable Mark Parker R. Kenneth Marcus Joseph M. Pochkowski 《Journal of the American Society for Mass Spectrometry》1995,6(2):140-147
The use of a two-dimensional charge injection device (CID) to directly image the spatial profile of impingent positively charged ions is described. By this approach, no prior conversion from an ion beam to a photon image is required. Because of the positive response of the device to plasma photons, ions that emanated from the radiofrequency glow discharge source were diverted around a photon stop and focused onto the CID. The resultant ion images were digitized via an external image processor and corrected for dark current contributions. Two-dimensional ion images and single pixel line profiles are presented. 相似文献
155.
Harishandra JadhavEsben Taarning Christian Marcus PedersenMikael Bols 《Tetrahedron letters》2012,53(8):983-985
The formation of hydroxymethylfurfural (HMF) from glucose was studied. It was found that the CrCl2-catalyzed conversion in the ionic liquid, butylmethylimidazolium chloride ([Bmim]Cl) leads to negligible quantities of 3-deoxyglucosone confirming that fructose is the main intermediate. It was found that the environmentally unfriendly chromium salt could be replaced with zeolite (H-ZSM-5) leading to a 45% yield of HMF. It was also found that the solvent [Bmim]Cl could be replaced with non-toxic tetrabutylammonium chloride (TBAC) giving a 56% yield of HMF. 相似文献
156.
157.
158.
159.
Alberto Caprara Marcus Oswald Gerhard Reinelt Robert Schwarz Emiliano Traversi 《Mathematical Programming Computation》2011,3(3):261-280
We solve for the first time to proven optimality the small instances in the classical literature benchmark of Minimum Linear
Arrangement. This is achieved by formulating the problem as an ILP in a somehow unintuitive way, using variables expressing
the fact that a vertex is between two other adjacent vertices in the arrangement. Using (only) these variables appears to
be the key idea of the approach. Indeed, with these variables already the use of very simple constraints leads to good results,
which can however be improved with a more detailed study of the underlying polytope. 相似文献
160.