全文获取类型
收费全文 | 11411篇 |
免费 | 645篇 |
国内免费 | 57篇 |
专业分类
化学 | 8267篇 |
晶体学 | 38篇 |
力学 | 292篇 |
数学 | 1858篇 |
物理学 | 1658篇 |
出版年
2023年 | 91篇 |
2022年 | 77篇 |
2021年 | 183篇 |
2020年 | 291篇 |
2019年 | 305篇 |
2018年 | 144篇 |
2017年 | 166篇 |
2016年 | 436篇 |
2015年 | 476篇 |
2014年 | 489篇 |
2013年 | 648篇 |
2012年 | 919篇 |
2011年 | 922篇 |
2010年 | 570篇 |
2009年 | 493篇 |
2008年 | 734篇 |
2007年 | 704篇 |
2006年 | 645篇 |
2005年 | 629篇 |
2004年 | 495篇 |
2003年 | 405篇 |
2002年 | 379篇 |
2001年 | 107篇 |
2000年 | 80篇 |
1999年 | 77篇 |
1998年 | 83篇 |
1997年 | 123篇 |
1996年 | 100篇 |
1995年 | 86篇 |
1994年 | 79篇 |
1993年 | 91篇 |
1992年 | 66篇 |
1991年 | 69篇 |
1990年 | 54篇 |
1989年 | 64篇 |
1988年 | 43篇 |
1987年 | 36篇 |
1986年 | 42篇 |
1985年 | 58篇 |
1984年 | 48篇 |
1983年 | 48篇 |
1982年 | 51篇 |
1981年 | 58篇 |
1980年 | 42篇 |
1979年 | 47篇 |
1978年 | 44篇 |
1977年 | 44篇 |
1976年 | 50篇 |
1975年 | 42篇 |
1973年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Kapil Shyam Lokare Nicolas Frank Beatrice Braun‐Cula Itziar Goikoetxea Joachim Sauer Christian Limberg 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2016,128(40):12513-12517
To gain molecular level insights into the properties of certain functions and units of extended oxides/hydroxides, suitable molecular model compounds are needed. As an attractive route to access such compounds the trapping of early intermediates during the hydrolysis of suitable precursor compounds with the aid of stabilizing ligands is conceivable, which was tested for the aluminum(III)/water system. Indeed, trisilanols proved suitable trapping reagents: their presence during the hydrolysis of AliBu2H in dependence on the amount of water used allowed for the isolation of tri‐ and octanuclear aluminum hydroxide cluster complexes [Al3(μ2‐OH)3(THF)3(PhSi(OSiPh2O)3)2] ( 1 ) and [Al8(μ3‐OH)2(μ2‐OH)10(THF)3(p‐anisylSi(OSiPh2O)3)4] ( 2 ). 1 can be regarded as the Al(OH)3 cyclic trimer, where six protons have been replaced by silyl residues. While 2 features a unique [Al8(μ3‐OH)2(μ2‐OH)10]12+ core. In contrast to most other known aggregates of this type, 1 and 2 can be readily prepared at reasonable scales, dissolve in common solvents, and retain an intact framework even in the presence of excessive amounts of water. This finding paves the way to future research addressing the reactivity of the individual functional groups. 相似文献
72.
73.
Christian W. Pester Justin E. Poelma Benjaporn Narupai Shrayesh N. Patel Gregory M. Su Thomas E. Mates Yingdong Luo Christopher K. Ober Craig J. Hawker Edward J. Kramer 《Journal of polymer science. Part A, Polymer chemistry》2016,54(2):253-262
In an attempt to create a polymer brush-based platform for the systematic study for anti-biofouling surfaces, the benefits of surface initiated, visible light-mediated radical polymerization are utilized to fabricate well-defined, chemically ambiguously patterned surfaces. A variety of analytical tools are used to illustrate the precise tuning of surface chemistry and thoroughly characterize spatially well-defined, hydrophilic/hydrophobic surfaces composed of poly(ethylene glycol methacrylate) and poly(trifluoroethyl methacrylate) with chemical definition on the micron scale. Advantages of both visible light-mediated photopolymerization and traditional copper-catalyzed atom transfer radical polymerization are combined to achieve both high spatial control and expanded monomer tolerance. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 253–262 相似文献
74.
Back Cover: Activation of Elemental Sulfur at a Two‐Coordinate Platinum(0) Center (Chem. Eur. J. 36/2016) 下载免费PDF全文
75.
Christian Schlereth Christine Eckert René Schaaf Bernd Skiera 《European Journal of Operational Research》2014
Self-explicated approaches are popular preference measurement approaches for products with many attributes. This article classifies previous self-explicated approaches according to their evaluation types, i.e. trade-off- versus non-trade-off-based, and outlines their advantages and disadvantages. In addition, it proposes a new method, the presorted adaptive self-explicated approach that is based on Netzer and Srinivasan’s (2011) adaptive self-explicated approach and that combines trade-off- and non-trade-off-based evaluation types. Two empirical studies compare this new method with the most popular existing self-explicated approaches, including the adaptive self-explicated approach and paired comparison preference measurement. The new method overcomes the insufficient discrimination between importance weights, as usually found in non-trade-off-based evaluation types; discourages respondents’ simplification strategies, as are frequently encountered in trade-off evaluation types; is easy to implement; and yields high predictive validity compared with other popular self-explicated approaches. 相似文献
76.
Analyse von Protease‐Inhibitor‐Interaktionen unter Nutzung evolvierbarer tricyclischer Microviridine
77.
An operator Riccati equation from systems theory is considered in the case that all entries of the associated Hamiltonian are unbounded. Using a certain dichotomy property of the Hamiltonian and its symmetry with respect to two different indefinite inner products, we prove the existence of nonnegative and nonpositive solutions of the Riccati equation. Moreover, conditions for the boundedness and uniqueness of these solutions are established. 相似文献
78.
Back Cover: Constrained Peptides with Target‐Adapted Cross‐Links as Inhibitors of a Pathogenic Protein–Protein Interaction (Angew. Chem. Int. Ed. 9/2014) 下载免费PDF全文
79.
Inside Back Cover: Reversible Photochemical and Thermal Isomerization of Azaboratabisnorcaradiene to Azaborabenzotropilidene (Angew. Chem. Int. Ed. 34/2014) 下载免费PDF全文
80.
A Filled‐Honeycomb‐Structured Crystal Formed by Self‐Assembly of a Janus Polyoxometalate–Silsesquioxane (POM–POSS) Co‐Cluster 下载免费PDF全文
Chi Ma Han Wu Zi‐Han Huang Dr. Ruo‐Hai Guo Dr. Min‐Biao Hu Dr. Christian Kübel Prof. Dr. Li‐Tang Yan Prof. Dr. Wei Wang 《Angewandte Chemie (International ed. in English)》2015,54(52):15699-15704
Clusters with diverse structures and functions have been used to create novel cluster‐assembled materials (CAMs). Understanding their self‐assembly process is a prerequisite to optimize their structure and function. Herein, two kinds of unlike organo‐functionalized inorganic clusters are covalently linked by a short organic tether to form a dumbbell‐shaped Janus co‐cluster. In a mixed solvent of acetonitrile and water, it self‐assembles into a crystal with a honeycomb superstructure constructed by hexagonal close‐packed cylinders of the smaller cluster and an orderly arranged framework of the larger cluster. Reconstruction of these structural features via coarse‐grained molecular simulations demonstrates that the cluster crystallization and the nanoscale phase separation between the two incompatible clusters synergistically result in the unique nano‐architecture. Overall, this work opens up new opportunities for generating novel CAMs for advanced future applications. 相似文献