全文获取类型
收费全文 | 636篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
化学 | 367篇 |
晶体学 | 4篇 |
力学 | 15篇 |
数学 | 127篇 |
物理学 | 139篇 |
出版年
2022年 | 10篇 |
2021年 | 12篇 |
2020年 | 12篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 4篇 |
2016年 | 19篇 |
2015年 | 16篇 |
2014年 | 11篇 |
2013年 | 35篇 |
2012年 | 33篇 |
2011年 | 34篇 |
2010年 | 28篇 |
2009年 | 20篇 |
2008年 | 30篇 |
2007年 | 33篇 |
2006年 | 30篇 |
2005年 | 29篇 |
2004年 | 21篇 |
2003年 | 20篇 |
2002年 | 26篇 |
2001年 | 8篇 |
2000年 | 11篇 |
1999年 | 7篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 9篇 |
1989年 | 4篇 |
1988年 | 8篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1970年 | 3篇 |
1969年 | 3篇 |
1967年 | 3篇 |
1909年 | 4篇 |
1908年 | 3篇 |
排序方式: 共有652条查询结果,搜索用时 15 毫秒
31.
32.
Parviz Holakooei Umberto Tessari Massimo Verde Carmela Vaccaro 《Journal of Thermal Analysis and Calorimetry》2014,118(1):165-176
In this paper, the general rules of phase transformations in calcareous clay bodies during firing were used to estimate the equivalent firing temperature (EFT) of seventeenth century polychrome Persian haft rang tiles based on their X-ray diffraction (XRD) patterns. The novelty of this work is, however, that it handles the XRD patterns of archaeological clay bodies with principal component analysis (PCA) in order to have a new look at their firing and thermal behaviour. Statistically handling the XRD patterns, different clusters were discriminated in the clay bodies whose mineralogical composition showed various proportions of amorphous and quartz contents. The results showed interesting trends in the different clusters in terms of the EFT, quartz content and the density of the bodies. The present work uses PCA to have a new look at XRD patterns of archaeological clay bodies and, moreover, to interpret the PCA results in order to estimate the EFT of a large number of archaeological clay bodies. 相似文献
33.
Nicholas Favalli Gabriele Bassi Tania Zanetti Jrg Scheuermann Dario Neri 《Helvetica chimica acta》2019,102(4)
The construction of DNA‐encoded chemical libraries (DECLs) crucially relies on the availability of chemical reactions, which are DNA‐compatible and which exhibit high conversion rates for a large number of diverse substrates. In this work, we present our optimization and validation procedures for three copper and palladium‐catalyzed reactions (Suzuki cross‐coupling, Sonogashira cross‐coupling, and copper(I)‐catalyzed alkyne‐azide cycloaddition (CuAAC)), which have been successfully used by our group for the construction of large encoded libraries. 相似文献
34.
Synthesis and Biological Evaluation of RGD Peptidomimetic–Paclitaxel Conjugates Bearing Lysosomally Cleavable Linkers
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alberto Dal Corso Dr. Michele Caruso Dr. Laura Belvisi Dr. Daniela Arosio Prof. Dr. Umberto Piarulli Dr. Clara Albanese Dr. Fabio Gasparri Dr. Aurelio Marsiglio Dr. Francesco Sola Dr. Sonia Troiani Dr. Barbara Valsasina Dr. Luca Pignataro Dr. Daniele Donati Prof. Dr. Cesare Gennari 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6921-6929
Two small‐molecule–drug conjugates (SMDCs, 6 and 7 ) featuring lysosomally cleavable linkers (namely the Val–Ala and Phe–Lys peptide sequences) were synthesized by conjugation of the αvβ3‐integrin ligand cyclo[DKP–RGD]‐CH2NH2 ( 2 ) to the anticancer drug paclitaxel (PTX). A third cyclo[DKP–RGD]–PTX conjugate with a nonpeptide “uncleavable” linker ( 8 ) was also synthesized to be tested as a negative control. These three SMDCs were able to inhibit biotinylated vitronectin binding to the purified αVβ3‐integrin receptor at nanomolar concentrations and showed good stability at pH 7.4 and pH 5.5. Cleavage of the two peptide linkers was observed in the presence of lysosomal enzymes, whereas conjugate 8 , which possesses a nonpeptide “uncleavable” linker, remained intact under these conditions. The antiproliferative activities of the conjugates were evaluated against two isogenic cell lines expressing the integrin receptor at different levels: the acute lymphoblastic leukemia cell line CCRF‐CEM (αVβ3?) and its subclone CCRF‐CEM αVβ3 (αVβ3+). Fairly effective integrin targeting was displayed by the cyclo[DKP–RGD]–Val–Ala–PTX conjugate ( 6 ), which was found to differentially inhibit proliferation in antigen‐positive CCRF‐CEM αVβ3 versus antigen‐negative isogenic CCRF‐CEM cells. The total lack of activity displayed by the “uncleavable” cyclo[DKP–RGD]–PTX conjugate ( 8 ) clearly demonstrates the importance of the peptide linker for achieving the selective release of the cytotoxic payload. 相似文献
35.
36.
Cherubini Umberto Mulinacci Sabrina 《Methodology and Computing in Applied Probability》2021,23(1):143-163
Methodology and Computing in Applied Probability - In this paper we show how to extend a simple common shock model with Archimedean dependence of the hidden variables to the non-exchangeable case.... 相似文献
37.
Marina M. Carrozzo Umberto M. Battisti Giuseppe Cannazza Cinzia Citti Carlo Parenti Luigino Troisi 《Tetrahedron letters》2012,53(24):3023-3026
Chloroacylaminobenzensulfonamides regioselectively thermally cyclize under solvent free conditions to 1,2,4-benzothiadiazines with five- and six-membered rings fused on face b. 相似文献
38.
Nikolaus Krall Dr. Jörg Scheuermann Prof. Dario Neri 《Angewandte Chemie (International ed. in English)》2013,52(5):1384-1402
The targeted delivery of potent cytotoxic agents has emerged as a promising strategy for the treatment of cancer and other serious conditions. Traditionally, antibodies against markers of disease have been used as drug‐delivery vehicles. More recently, lower molecular weight ligands have been proposed for the generation of a novel class of targeted cytotoxics with improved properties. Advances in this field crucially rely on efficient methods for the identification and optimization of organic molecules capable of high‐affinity binding and selective recognition of target proteins. The advent of DNA‐encoded chemical libraries allows the construction and screening of compound collections of unprecedented size. In this Review, we survey developments in the field of small ligand‐based targeted cytotoxics and show how innovative library technologies will help develop the drugs of the future. 相似文献
39.
40.
Umberto Raucci Fulvio Perrella Greta Donati Maria Zoppi Alessio Petrone Nadia Rega 《Journal of computational chemistry》2020,41(26):2228-2239
Solute–solvent interactions are proxies for understanding how the electronic density of a chromophore interacts with the environment in a more exhaustive way. The subtle balance between polarization, electrostatic, and non-bonded interactions need to be accurately described to obtain good agreement between simulations and experiments. First principles approaches providing accurate configurational sampling through molecular dynamics may be a suitable choice to describe solvent effects on solute chemical–physical properties and spectroscopic features, such as optical absorption of dyes. In this context, accurate energy potentials, obtained by hybrid implicit/explicit solvation methods along with employing nonperiodic boundary conditions, are required to represent bulk solvent around a large solute–solvent cluster. In this work, a novel strategy to simulate methanol solutions is proposed combining ab initio molecular dynamics, a hybrid implicit/explicit flexible solvent model, nonperiodic boundary conditions, and time dependent density functional theory. As case study, the robustness of the proposed protocol has been gauged by investigating the microsolvation and electronic absorption of the anionic green fluorescent protein chromophore in methanol and aqueous solution. Satisfactory results are obtained, reproducing the microsolvation layout of the chromophore and, as a consequence, the experimental trends shown by the optical absorption in different solvents. 相似文献