全文获取类型
收费全文 | 2335篇 |
免费 | 113篇 |
国内免费 | 12篇 |
专业分类
化学 | 2017篇 |
晶体学 | 10篇 |
力学 | 16篇 |
数学 | 242篇 |
物理学 | 175篇 |
出版年
2023年 | 15篇 |
2022年 | 34篇 |
2021年 | 61篇 |
2020年 | 62篇 |
2019年 | 56篇 |
2018年 | 29篇 |
2017年 | 43篇 |
2016年 | 89篇 |
2015年 | 75篇 |
2014年 | 84篇 |
2013年 | 128篇 |
2012年 | 161篇 |
2011年 | 178篇 |
2010年 | 102篇 |
2009年 | 101篇 |
2008年 | 145篇 |
2007年 | 136篇 |
2006年 | 150篇 |
2005年 | 120篇 |
2004年 | 103篇 |
2003年 | 95篇 |
2002年 | 84篇 |
2001年 | 31篇 |
2000年 | 20篇 |
1999年 | 21篇 |
1998年 | 18篇 |
1997年 | 12篇 |
1996年 | 23篇 |
1995年 | 21篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 13篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 9篇 |
1978年 | 3篇 |
1976年 | 5篇 |
1973年 | 3篇 |
1958年 | 55篇 |
1957年 | 20篇 |
1934年 | 4篇 |
排序方式: 共有2460条查询结果,搜索用时 15 毫秒
991.
Lise Negrel Raymonde Baltenweck Gerard Demangeat Franoise Le Bohec-Dorner Camille Rustenholz Amandine Velt Claude Gertz Eva Bieler Markus Dürrenberger Pascale Gombault Philippe Hugueney Olivier Lemaire 《Molecules (Basel, Switzerland)》2022,27(10)
The grapevine fanleaf virus (GFLV), responsible for fanleaf degeneration, is spread in vineyards by the soil nematode Xiphinema index. Nematicide molecules were used to limit the spread of the disease until they were banned due to negative environmental impacts. Therefore, there is a growing interest in alternative methods, including plant-derived products with antagonistic effects to X. index. In this work, we evaluated the nematicidal potential of the aerial parts and roots of four Fabaceae: sainfoin (Onobrychis viciifolia), birdsfoot trefoil (Lotus corniculatus), sweet clover (Melilotus albus), and red clover (Trifolium pratense), as well as that of sainfoin-based commercial pellets. For all tested plants, either aerial or root parts, or both of them, exhibited a nematicidal effect on X. index in vitro, pellets being as effective as freshly harvested plants. Comparative metabolomic analyses did not reveal molecules or molecule families specifically associated with antagonistic properties toward X. index, suggesting that the nematicidal effect is the result of a combination of different molecules rather than associated with a single compound. Finally, scanning electron microscope observations did not reveal the visible impact of O. viciifolia extract on X. index cuticle, suggesting that alteration of the cuticle may not be the primary cause of their nematicidal effect. 相似文献
992.
993.
Eva Miranda 《Central European Journal of Mathematics》2014,12(2):240-270
The main purpose of this paper is to present in a unified approach to different results concerning group actions and integrable systems in symplectic, Poisson and contact manifolds. Rigidity problems for integrable systems in these manifolds will be explored from this perspective. 相似文献
994.
995.
Cover Picture: Paenilamicin: Structure and Biosynthesis of a Hybrid Nonribosomal Peptide/Polyketide Antibiotic from the Bee Pathogen Paenibacillus larvae (Angew. Chem. Int. Ed. 40/2014)
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)
996.
997.
Ion transfer at aqueous-organogel interfaces enables the non-redox detection of ions and ionisable species by voltammetry. In this study, a non-thermal method for preparation of an organogel was employed and used for the detection of hen-egg-white-lysozyme (HEWL) via adsorptive stripping voltammetry at an array of aqueous-organogel microinterfaces. Tetrahydrofuran solvent casting was employed to prepare the organogel mixture, hence removing the need for heating of the solution to be gelled, as used in previous studies. Cyclic voltammetry of HEWL at the microinterface array revealed a broad adsorption process on the forward scan, at positive applied potentials, followed by a desorption peak at ca. 0.68 V, indicating the detection of HEWL in this region. Application of an adsorption step, where a constant optimized potential of 0.95 V was applied, followed by voltammetric detection provided for a linear response range of 0.02–0.84 μM and a detection limit of 0.030 μM for 300 s adsorption. The detection limit was further improved by utilizing differential pulse stripping voltammetry, resulting in detection limits of 0.017 μM, 0.014 μM, and 0.010 μM for adsorptive pre-concentration times of 60, 120 and 300 s, respectively, in unstirred solutions. These results are an improvement over other methods for the detection of HEWL at aqueous–organic interfaces and offers a basis for the label-free detection of protein. 相似文献
998.
999.
Thiomaltol‐Based Organometallic Complexes with 1‐Methylimidazole as Leaving Group: Synthesis,Stability, and Biological Behavior
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)
Carmen M. Hackl Maria S. Legina Dr. Verena Pichler Dr. Melanie Schmidlehner Alexander Roller Dr. Orsolya Dömötör Dr. Eva A. Enyedy Dr. Michael A. Jakupec Dr. Wolfgang Kandioller Prof. Dr. Dr. Bernhard K. Keppler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(48):17269-17281
Thiomaltol, a potential S,O‐coordinating molecule, has been utilized for the complexation of four different organometallic fragments, yielding the desired RuII, OsII, RhIII, and IrIII complexes having a “piano‐stool” configuration. In addition to the synthesis of these compounds with a chlorido leaving group, the analogous 1‐methylimidazole derivatives have been prepared, giving rise to thiomaltol‐based organometallics with enhanced stability under physiological conditions. The organometallic compounds have been characterized by NMR spectroscopy, elemental analysis, and X‐ray diffraction analysis. Their behavior in aqueous solution and their interactions with certain amino acids have been studied by ESI mass spectrometry. Their pH‐dependent stability has been investigated by 1H NMR in aqueous solution, and their cytotoxicity against three different cancer cell lines has been investigated. Furthermore, their capacity as topoisomerase IIα inhibitors as well as their effect on the cell cycle distribution and reactive oxygen species (ROS) generation have been elucidated. 相似文献
1000.