全文获取类型
收费全文 | 2837篇 |
免费 | 153篇 |
专业分类
化学 | 1967篇 |
晶体学 | 11篇 |
力学 | 114篇 |
数学 | 414篇 |
物理学 | 484篇 |
出版年
2023年 | 25篇 |
2022年 | 29篇 |
2021年 | 37篇 |
2020年 | 48篇 |
2019年 | 46篇 |
2018年 | 56篇 |
2017年 | 46篇 |
2016年 | 93篇 |
2015年 | 87篇 |
2014年 | 94篇 |
2013年 | 176篇 |
2012年 | 229篇 |
2011年 | 266篇 |
2010年 | 114篇 |
2009年 | 98篇 |
2008年 | 207篇 |
2007年 | 170篇 |
2006年 | 165篇 |
2005年 | 160篇 |
2004年 | 134篇 |
2003年 | 108篇 |
2002年 | 79篇 |
2001年 | 36篇 |
2000年 | 35篇 |
1999年 | 22篇 |
1998年 | 25篇 |
1997年 | 17篇 |
1996年 | 23篇 |
1995年 | 16篇 |
1994年 | 24篇 |
1993年 | 21篇 |
1992年 | 20篇 |
1991年 | 20篇 |
1990年 | 22篇 |
1989年 | 16篇 |
1988年 | 10篇 |
1987年 | 12篇 |
1985年 | 16篇 |
1984年 | 13篇 |
1982年 | 20篇 |
1981年 | 12篇 |
1980年 | 16篇 |
1979年 | 10篇 |
1978年 | 12篇 |
1977年 | 12篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有2990条查询结果,搜索用时 15 毫秒
111.
Andreea L. Turcu Antoine Versini Nadjib Khene Christine Gaillet Dr. Tatiana Cañeque Dr. Sebastian Müller Dr. Raphaël Rodriguez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(33):7369-7373
Cancer stem cells (CSC) constitute a cell subpopulation in solid tumors that is responsible for resistance to conventional chemotherapy, metastasis and cancer relapse. The natural product Salinomycin can selectively target this cell niche by directly interacting with lysosomal iron, taking advantage of upregulated iron homeostasis in CSC. Here, inhibitors of the divalent metal transporter 1 (DMT1) have been identified that selectively target CSC by blocking lysosomal iron translocation. This leads to lysosomal iron accumulation, production of reactive oxygen species and cell death with features of ferroptosis. DMT1 inhibitors selectively target CSC in primary cancer cells and circulating tumor cells, demonstrating the physiological relevance of this strategy. Taken together, this opens up opportunities to tackle unmet needs in anti-cancer therapy. 相似文献
112.
Dr. Samuel Oger Damien Schapman Dr. Romain Mougeot Dr. Stéphane Leleu Dr. Noëlle Lascoux Dr. Patrice Baldeck Dr. Magalie Bénard Dr. Thibault Gallavardin Dr. Ludovic Galas Dr. Xavier Franck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(46):10954-10964
Epicocconone 1 is a natural chromophore isolated from the fungus Epicoccum nigrum that has shown applications in proteomics and fluorescent microscopy thanks to its unique pro-fluorescence properties. The modification of the skeleton of the natural product by replacing the triene side chain by a fluorenyl scaffold can noticeably increase the fluorophore's absorption coefficient. The synthesis of the analogues of the natural product has been made possible by the use of a palladium-catalyzed carbonylation reaction, allowing the construction of the β-keto-dioxinone key intermediate. Two-photon absorption cross-section measurements of the fluorenyl epicocconone analogues show a structure dependency with values ranging from 60 to 280 GM and live cell imaging show intense staining of intracellular vesicle-like structures around the nucleus. 相似文献
113.
Guillaume Erbland Dr. Seifallah Abid Yohan Gisbert Nathalie Saffon-Merceron Yuichiro Hashimoto Leonardo Andreoni Théo Guérin Dr. Claire Kammerer Prof. Dr. Gwénaël Rapenne 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16328-16339
The design and synthesis of two families of molecular-gear prototypes is reported, with the aim of assembling them into trains of gears on a surface and ultimately achieving controlled intermolecular gearing motion. These piano-stool ruthenium complexes incorporate a hydrotris(indazolyl)borate moiety as tripodal rotation axle and a pentaarylcyclopentadienyl ligand as star-shaped cogwheel, equipped with five teeth ranging from pseudo-1D aryl groups to large planar 2D paddles. A divergent synthetic approach was followed, starting from a pentakis(p-bromophenyl)cyclopentadienyl ruthenium(II) complex as key precursor or from its iodinated counterpart, obtained by copper-catalyzed aromatic Br/I exchange. Subsequent fivefold cross-coupling reactions with various partners allowed high structural diversity to be reached and yielded molecular-gear prototypes with aryl-, carbazole-, BODIPY- and porphyrin-derived teeth of increasing size and length. 相似文献
114.
Dr. Siddhartha De Dr. Alexandrine Flambard Dr. Delphine Garnier Patrick Herson Dr. Frank H. Köhler Dr. Abhishake Mondal Dr. Karine Costuas Dr. Béatrice Gillon Prof. Rodrigue Lescouëzec Dr. Boris Le Guennic Dr. Frédéric Gendron 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(52):12120-12136
The local magnetic structure in the [FeIII(Tp)(CN)3]− building block was investigated by combining paramagnetic Nuclear Magnetic Resonance (pNMR) spectroscopy and polarized neutron diffraction (PND) with first-principle calculations. The use of the pNMR and PND experimental techniques revealed the extension of spin-density from the metal to the ligands, as well as the different spin mechanisms that take place in the cyanido ligands: Spin-polarization on the carbon atoms and spin-delocalization on the nitrogen atoms. The results of our combined density functional theory (DFT) and multireference calculations were found in good agreement with the PND results and the experimental NMR chemical shifts. Moreover, the ab-initio calculations allowed us to connect the experimental spin-density map characterized by PND and the suggested distribution of the spin-density on the ligands observed by NMR spectroscopy. Interestingly, significant differences were observed between the pseudo-contact contributions of the chemical shifts obtained by theoretical calculations and the values derived from NMR spectroscopy using a simple point-dipole model. These discrepancies underline the limitation of the point-dipole model and the need for more elaborate approaches to break down the experimental pNMR chemical shifts into contact and pseudo-contact contributions. 相似文献
115.
Laurent François Joël Dupays Dmitry Davidenko Marc Massot 《Combustion Theory and Modelling》2020,24(5):775-809
We investigate a model of solid propellant combustion involving surface pyrolysis coupled to finite activation energy gas-phase combustion. Existence and uniqueness of a travelling wave solution are established by extending dynamical system tools classically used for premixed flames, dealing with the additional difficulty arising from the surface regression and pyrolysis. An efficient shooting method allows to solve the problem in phase space without resorting to space discretisation nor fixed-point Newton iterations. The results are compared to solutions from a CFD code developed at ONERA, assessing the efficiency and potential of the method, and the impact of the modelling assumptions is evaluated through parametric studies. 相似文献
116.
117.
Thermo‐ and pH‐sensitive triblock copolymers with tunable hydrophilic/hydrophobic properties
下载免费PDF全文
![点击此处可从《Journal of polymer science. Part A, Polymer chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Christophe Pottier Gaëlle Morandi Virginie Dulong Zied Souguir Luc Picton Didier Le Cerf 《Journal of polymer science. Part A, Polymer chemistry》2015,53(22):2606-2616
Polymers consisting of poly(acrylic acid) (PAA) and statistical poly[(acrylic acid)‐co‐(tert‐butylacrylate)] (P(AA‐co‐tBA)), attached to both extremities of Jeffamine® (D series based on a poly(propylene oxide) (PPO) with one amine function at each end) using atom transfer radical polymerization (ATRP) are presented in this article. An original bifunctional amide‐based macroinitiator was first elaborated from Jeffamine®. tBA polymerization was subsequently initiated from this macroinitiator. This polymerization occurs in a well‐controlled manner leading to narrow molecular weights distribution. Amphiphilic copolymers were finally obtained after complete or partial hydrolysis of the PtBA blocks into PAA. The control of the partial hydrolysis of tBA units, conducted in a concentrated HCl/tetrahydrofuran mixture, is demonstrated. The properties of the triblock copolymers were preliminary investigated in aqueous solution by absorbance, DLS measurements and SEC/MALS/DV/DRI analysis as a function of temperature and pH modifications, providing evidences of thermo‐ and pH‐sensitive self‐assembly of the copolymers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2606–2616 相似文献
118.
Nanoparticles (NPs)-based electrochemical devices are generating a growing interest and optical microscopy has recently proven to be a powerful tool to apprehend their electrochemical behavior. Through several striking examples, this review demonstrates how label-free optical imaging coupled to an electrochemical actuation can be used to probe operando the physical and electrochemical properties of single NPs, with high resolution and sensitivity and without additional emitters. Such an approach can be particularly relevant to establish clear structure-motion/reactivity relationships required to optimize NPs exploited as electrode materials. 相似文献
119.
The Ramanujan Journal - Let $${\mathcal {A}}$$ , $${\mathcal {B}}$$ be large subsets of $$\{1,\ldots ,N\}$$ . We study the distribution of the sum of binary digits of the sums $$a+b$$ with... 相似文献
120.