全文获取类型
收费全文 | 6017篇 |
免费 | 153篇 |
国内免费 | 46篇 |
专业分类
化学 | 3763篇 |
晶体学 | 35篇 |
力学 | 208篇 |
数学 | 1274篇 |
物理学 | 936篇 |
出版年
2022年 | 54篇 |
2021年 | 57篇 |
2020年 | 65篇 |
2019年 | 67篇 |
2018年 | 58篇 |
2017年 | 49篇 |
2016年 | 97篇 |
2015年 | 117篇 |
2014年 | 135篇 |
2013年 | 311篇 |
2012年 | 296篇 |
2011年 | 325篇 |
2010年 | 223篇 |
2009年 | 208篇 |
2008年 | 311篇 |
2007年 | 321篇 |
2006年 | 311篇 |
2005年 | 284篇 |
2004年 | 271篇 |
2003年 | 218篇 |
2002年 | 209篇 |
2001年 | 99篇 |
2000年 | 92篇 |
1999年 | 98篇 |
1998年 | 73篇 |
1997年 | 67篇 |
1996年 | 91篇 |
1995年 | 68篇 |
1994年 | 73篇 |
1993年 | 84篇 |
1992年 | 70篇 |
1991年 | 44篇 |
1990年 | 77篇 |
1989年 | 60篇 |
1988年 | 47篇 |
1987年 | 53篇 |
1986年 | 50篇 |
1985年 | 69篇 |
1984年 | 84篇 |
1983年 | 51篇 |
1982年 | 79篇 |
1981年 | 79篇 |
1980年 | 94篇 |
1979年 | 75篇 |
1978年 | 80篇 |
1977年 | 76篇 |
1976年 | 71篇 |
1975年 | 51篇 |
1974年 | 38篇 |
1973年 | 58篇 |
排序方式: 共有6216条查询结果,搜索用时 15 毫秒
991.
By using a recently developed Monte Carlo algorithm and an exact numerical method, we calculate the translocation probability and the average translocation time for charged heterogeneous polymers driven through a nanopore by an external electric field. The heteropolymer chains are composed of two types of monomers (A and B) which differ only in terms of their electric charge. We present an exhaustive study of chains composed of eight monomers by calculating the average translocation time associated with the 256 possible arrangements for various ratios of the monomer charges (lambda(A)lambda(B)) and electric field intensities E. We find that each sequence leads to a unique value of the translocation probability and time. We also show that the distribution of translocation times is strongly dependent on the two forces felt by the monomers ( approximately lambda(A)E and approximately lambda(B)E). Finally, we present results that highlight the effect of having repetitive patterns by studying the translocation times of various block copolymer structures for a very long chain composed of N=2(18) monomers (all with the same number of A and B monomers). 相似文献
992.
Souhir Boujday Romain Briandet Michèle Salmain Jean-Marie Herry Pierre-Guy Marnet Michel Gautier Claire-Marie Pradier 《Mikrochimica acta》2008,163(3-4):203-209
We describe the elaboration of ultra-sensitive immunosensors, to detect the bacterial pathogen Staphylococcus aureus. We utilized commercially available polyclonal anti-S. aureus antibody as receptor. Immunosensors were elaborated by building a self-assembled monolayer (SAM) of thiolamine onto planar gold-coated sensor chips. Then, Protein A was covalently linked to the thiolated SAM using glutaraldehyde as cross-linking agent. After a blocking step by Bovine Serum Albumin (BSA), the antibody was immobilized by affinity to Protein A. This step-by-step construction was monitored by Polarization Modulation Reflection Absorption Infrared Spectroscopy (PM-RAIRS) and Quartz Crystal Microbalance with Dissipation (QCM-D). In a first stage, the parameters of immunosensor elaboration were optimized using a model rabbit IgG. The accessibility of receptors and the homogeneity of their distribution were checked by PM-RAIRS, QCM-D, and by immuno-gold scanning electron microscopy. Then, the specific rabbit anti-S. aureus antibody was immobilized and the resulting sensing layer was applied to the detection of the pathogen target. Independent detection of bacteria immobilized on the sensors by fluorescent imaging allowed validation of the specificity of recognition toward the pathogen as well as a quantitative response of the sensor. Using PM-RAIRS as transducing technique allowed us to enhance sensitivity and reach a very competitive detection level (105 CFU mL?1). 相似文献
993.
Stefano Barranco Federico Cuccu Dayi Liu Dr. Sylvie Robin Dr. Régis Guillot Prof. Dr. Francesco Secci Dr. Valérie Brenner Dr. Michel Mons Prof. Dr. Pierluigi Caboni Prof. Dr. David J. Aitken Prof. Dr. Angelo Frongia 《European journal of organic chemistry》2023,26(16):e202300183
A stereoselective one-pot double derivatization of cyclobutene-1-carboxylic acid via a mild organic base catalyzed amidation/aza-Michael addition of benzo[d]oxazol-2(3H)-ones has been developed. This unprecedented tandem reaction provides access to novel β-N-heterocyclic cyclobutane carboximide derivatives with a trans geometry. The carboximide moiety reacts smoothly with nucleophiles, allowing access to diverse derivatives of trans-β-N-heterocyclic cyclobutanecarboxylic acid, including peptidomimetic structures. 相似文献
994.
Qiang Ma Heng Zhang Chongwang Zhou Liping Zheng Pengfei Cheng Prof. Jin Nie Prof. Wenfang Feng Prof. Yong‐Sheng Hu Prof. Hong Li Prof. Xuejie Huang Prof. Liquan Chen Prof. Michel Armand Prof. Zhibin Zhou 《Angewandte Chemie (International ed. in English)》2016,55(7):2521-2525
A novel single lithium‐ion (Li‐ion) conducting polymer electrolyte is presented that is composed of the lithium salt of a polyanion, poly[(4‐styrenesulfonyl)(trifluoromethyl(S‐trifluoromethylsulfonylimino)sulfonyl)imide] (PSsTFSI?), and high‐molecular‐weight poly(ethylene oxide) (PEO). The neat LiPSsTFSI ionomer displays a low glass‐transition temperature (44.3 °C; that is, strongly plasticizing effect). The complex of LiPSsTFSI/PEO exhibits a high Li‐ion transference number (tLi+=0.91) and is thermally stable up to 300 °C. Meanwhile, it exhibits a Li‐ion conductivity as high as 1.35×10?4 S cm?1 at 90 °C, which is comparable to that for the classic ambipolar LiTFSI/PEO SPEs at the same temperature. These outstanding properties of the LiPSsTFSI/PEO blended polymer electrolyte would make it promising as solid polymer electrolytes for Li batteries. 相似文献
995.
High‐Pressure Raman and Calorimetry Studies of Vanadium(III) Alkyl Hydrides for Kubas‐Type Hydrogen Storage
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Leah Morris Dr. Michel L. Trudeau Dr. Daniel Reed Prof. David Book Prof. David M. Antonelli 《Chemphyschem》2016,17(6):822-828
Reversible hydrogen storage under ambient conditions has been identified as a major bottleneck in enabling a future hydrogen economy. Herein, we report an amorphous vanadium(III) alkyl hydride gel that binds hydrogen through the Kubas interaction. The material possesses a gravimetric adsorption capacity of 5.42 wt % H2 at 120 bar and 298 K reversibly at saturation with no loss of capacity after ten cycles. This corresponds to a volumetric capacity of 75.4 kgH2 m?3. Raman experiments at 100 bar confirm that Kubas binding is involved in the adsorption mechanism. The material possesses an enthalpy of H2 adsorption of +0.52 kJ mol?1 H2, as measured directly by calorimetry, and this is practical for use in a vehicles without a complex heat management system. 相似文献
996.
Michel Grabisch 《TOP》2016,24(2):301-326
Set functions are widely used in many domains of operations research (cooperative game theory, decision under risk and uncertainty, combinatorial optimization) under different names (TU-game, capacity, nonadditive measure, pseudo-Boolean function, etc.). Remarkable families of set functions form polyhedra, e.g., the polytope of capacities, the polytope of p-additive capacities, the cone of supermodular games, etc. Also, the core of a set function, defined as the set of additive set functions dominating that set function, is a polyhedron which is of fundamental importance in game theory, decision-making and combinatorial optimization. This survey paper gives an overview of these notions and studies all these polyhedra. 相似文献
997.
998.
Synthesis and Characterization of GaIII,YIII, and LuIII Complexes with Etifenin and Analogues
下载免费PDF全文
![点击此处可从《无机化学与普通化学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Michel Pfeifer‐Leeg Gergely Szabó Zsolt Baranyai Tobias Niksch Wolfgang Weigand Martin Freesmeyer 《无机化学与普通化学杂志》2016,642(6):486-491
Complexes of etifenin ( 1a ), disofenin ( 1b ), and mebrofenin ( 1c ) with GaIII, YIII, and LuIII were synthesized and characterized by NMR spectroscopy and UV/Vis spectroscopy. Stability and protonation constants of the complexes of 1a were determined by potentiometry and distribution diagrams were calculated. It was shown that the YIII and LuIII species are most stable as bis chelates at higher pH, whereas the GaIII complex degrades at pH < 4.5. 相似文献
999.
Dynamic Nuclear Polarization Provides New Insights into Chromophore Structure in Phytochrome Photoreceptors
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Daniel Stöppler Dr. Chen Song Dr. Barth‐Jan van Rossum Michel‐Andreas Geiger Christina Lang Prof. Dr. Maria‐Andrea Mroginski Dr. Anil Pandurang Jagtap Prof. Dr. Snorri Th. Sigurdsson Prof. Dr. Jörg Matysik Prof. Dr. Jon Hughes Prof. Dr. Hartmut Oschkinat 《Angewandte Chemie (International ed. in English)》2016,55(52):16017-16020
1000.
Huynh Van Ngai Nguyen Huu Tron Michel Théra 《Journal of Optimization Theory and Applications》2016,168(3):785-801
This paper studies the first-order behavior of the value function of a parametric optimal control problem with nonconvex cost functions and control constraints. By establishing an abstract result on the Fréchet subdifferential of the value function of a parametric minimization problem, we derive a formula for computing the Fréchet subdifferential of the value function to a parametric optimal control problem. The obtained results improve and extend some previous results. 相似文献