全文获取类型
收费全文 | 10283篇 |
免费 | 412篇 |
国内免费 | 81篇 |
专业分类
化学 | 7359篇 |
晶体学 | 62篇 |
力学 | 140篇 |
数学 | 1535篇 |
物理学 | 1680篇 |
出版年
2023年 | 63篇 |
2022年 | 96篇 |
2021年 | 114篇 |
2020年 | 217篇 |
2019年 | 178篇 |
2018年 | 105篇 |
2017年 | 86篇 |
2016年 | 280篇 |
2015年 | 222篇 |
2014年 | 265篇 |
2013年 | 501篇 |
2012年 | 537篇 |
2011年 | 610篇 |
2010年 | 370篇 |
2009年 | 327篇 |
2008年 | 552篇 |
2007年 | 542篇 |
2006年 | 551篇 |
2005年 | 512篇 |
2004年 | 424篇 |
2003年 | 323篇 |
2002年 | 383篇 |
2001年 | 181篇 |
2000年 | 188篇 |
1999年 | 162篇 |
1998年 | 168篇 |
1997年 | 150篇 |
1996年 | 158篇 |
1995年 | 132篇 |
1994年 | 155篇 |
1993年 | 132篇 |
1992年 | 114篇 |
1991年 | 112篇 |
1990年 | 93篇 |
1989年 | 76篇 |
1988年 | 64篇 |
1987年 | 68篇 |
1986年 | 57篇 |
1985年 | 111篇 |
1984年 | 98篇 |
1983年 | 67篇 |
1982年 | 105篇 |
1981年 | 90篇 |
1980年 | 77篇 |
1979年 | 95篇 |
1978年 | 87篇 |
1977年 | 79篇 |
1976年 | 87篇 |
1975年 | 63篇 |
1973年 | 56篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The ability of commercially available amino acid derivatives, especially Fmoc-Trp(Boc)-OH, to differentiate enantiomers of chiral phosphonates, phosphinates, phosphates, phosphine oxides, and phosphonamidates is demonstrated with (31)P, (13)C, and (1)H NMR spectroscopy. The chiral differentiation provided a rapid and convenient method for measuring the enantiomeric purity of these phosphorus compounds. 相似文献
52.
53.
Atiya MS Chiang I Frank JS Haggerty JS Ito MM Kycia TF Li KK Littenberg LS Stevens A Strand RC Louis WC Akerib DS Marlow DR Meyers PD Selen MA Shoemaker FC Smith AJ Azuelos G Blackmore EW Bryman DA Felawka L Kitching P Kuno Y Macdonald JA Numao T Padley P Poutissou J Poutissou R Roy J 《Physical review letters》1990,65(1):21-24
54.
Frank Mantlik 《Integral Equations and Operator Theory》1990,13(2):231-250
We investigate operator functionsT(x) inBanach spaces, depending differentiably (meaning of classC
orC
) on a parameterx and enjoying a certain regularity property. Iff is a given differentiable function such that the equationT(x)e=f(x) is solvable for eachx then the existence of a functione is proved which belongs to the same differentiability class asf andT, solving the equationT(x)e(x)f(x) identically inx. As an application we extend a result ofJ. Leiterer [9] and give a comprehensive answer to a question posed byJ.L. Taylor in [15] concerning the exactness of certain cochain complexes. 相似文献
55.
Nanoscale organization of the pathogen receptor DC-SIGN mapped by single-molecule high-resolution fluorescence microscopy. 总被引:3,自引:0,他引:3
Bärbel I. de Bakker Dr. Frank de Lange Dr. Alessandra Cambi Dr. Jeroen P. Korterik Erik M. H. P. van Dijk Dr. Niek F. van Hulst Prof. Carl G. Figdor Prof. Maria F. Garcia‐Parajo Prof. 《Chemphyschem》2007,8(10):1473-1480
DC-SIGN, a C-type lectin exclusively expressed on dendritic cells (DCs), plays an important role in pathogen recognition by binding with high affinity to a large variety of microorganisms. Recent experimental evidence points to a direct relation between the function of DC-SIGN as a viral receptor and its spatial arrangement on the plasma membrane. We have investigated the nanoscale organization of fluorescently labeled DC-SIGN on intact isolated DCs by means of near-field scanning optical microscopy (NSOM) combined with single-molecule detection. Fluorescence spots of different intensity and size have been directly visualized by optical means with a spatial resolution of less than 100 nm. Intensity- and size-distribution histograms of the DC-SIGN fluorescent spots confirm that approximately 80 % of the receptors are organized in nanosized domains randomly distributed on the cell membrane. Intensity-size correlation analysis revealed remarkable heterogeneity in the molecular packing density of the domains. Furthermore, we have mapped the intermolecular organization within a dense cluster by means of sequential NSOM imaging combined with discrete single-molecule photobleaching. In this way we have determined the spatial coordinates of 13 different individual dyes, with a localization accuracy of 6 nm. Our experimental observations are all consistent with an arrangement of DC-SIGN designed to maximize its chances of binding to a wide range of microorganisms. Our data also illustrate the potential of NSOM as an ultrasensitive, high-resolution technique to probe nanometer-scale organization of molecules on the cell membrane. 相似文献
56.
Donald R. Schreiber James Huebner Seyed Rahmani Frank J. Millero 《Journal of solution chemistry》1993,22(3):201-210
Enthalpies of mixing (m
H) aqueous solutions of CoCl2, CuCl2, and MnCl2 with NaCl solutions were measured at constant ionic strengths of 0.5, 1.0, and 3.0 molal at 25°C. The excess enthalpy equations of Pitzer were then fit to the resulting m
H data. The resulting parameters are the temperature derivatives of the activity coefficient mixing parameters in the Pitzer system. The heat of mixing data for CoCl2 and CuCl2 were in agreement with earlier isomolal results by other workers. 相似文献
57.
58.
59.
60.