全文获取类型
收费全文 | 1638篇 |
免费 | 52篇 |
国内免费 | 11篇 |
专业分类
化学 | 1045篇 |
晶体学 | 23篇 |
力学 | 45篇 |
数学 | 308篇 |
物理学 | 280篇 |
出版年
2023年 | 9篇 |
2022年 | 13篇 |
2021年 | 30篇 |
2020年 | 27篇 |
2019年 | 39篇 |
2018年 | 21篇 |
2017年 | 20篇 |
2016年 | 58篇 |
2015年 | 53篇 |
2014年 | 53篇 |
2013年 | 83篇 |
2012年 | 121篇 |
2011年 | 122篇 |
2010年 | 68篇 |
2009年 | 68篇 |
2008年 | 94篇 |
2007年 | 117篇 |
2006年 | 94篇 |
2005年 | 99篇 |
2004年 | 94篇 |
2003年 | 69篇 |
2002年 | 56篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 8篇 |
1997年 | 11篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 12篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1976年 | 3篇 |
1973年 | 4篇 |
1960年 | 5篇 |
1911年 | 2篇 |
排序方式: 共有1701条查询结果,搜索用时 15 毫秒
1.
2.
Dr. Alberto Lena Dr. Alessandra Benassi Michele Stasi Christine Saint-Pierre Prof. Mauro Freccero Dr. Didier Gasparutto Dr. Sophie Bombard Prof. Filippo Doria Dr. Daniela Verga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(35):e202200734
Combining the selectivity of G-quadruplex (G4) ligands with the spatial and temporal control of photochemistry is an emerging strategy to elucidate the biological relevance of these structures. In this work, we developed six novel V-shaped G4 ligands that can, upon irradiation, form stable covalent adducts with G4 structures via the reactive intermediate, quinone methide (QM). We thoroughly investigated the photochemical properties of the ligands and their ability to generate QMs. Subsequently, we analyzed their specificity for various topologies of G4 and discovered a preferential binding towards the human telomeric sequence. Finally, we tested the ligand ability to act as photochemical alkylating agents, identifying the covalent adducts with G4 structures. This work introduces a novel molecular tool in the chemical biology toolkit for G4s. 相似文献
3.
Marcio David Bocelli Deyber Arley Vargas Medina Julie Paulin García Rodriguez Fernando Mauro Lanças Álvaro José Santos-Neto 《Electrophoresis》2022,43(15):1567-1576
Dynamic single-drop microextraction (SDME) was automatized employing an Arduino-based lab-made Cartesian robot and implemented to determine parabens in wastewater samples in combination with liquid chromatography–tandem mass spectrometry. A dedicated Arduino sketch controls the auto-performance of all the stages of the SDME process, including syringe filling, drop exposition, solvent recycling, and extract collection. Univariate and multivariate experiments investigated the main variables affecting the SDME performance, including robot-dependent and additional operational parameters. Under selected conditions, limit of detections were established at 0.3 µg/L for all the analytes, and the method provided linear responses in the range between 0.6 and 10 µg/L, with adequate reproducibility, measured as intraday relative standard deviations (RSDs) between 5.54% and 17.94%, (n = 6), and inter-days RSDs between 8.97% and 16.49% (n = 9). The robot-assisted technique eased the control of dynamic SDME, making the process more feasible, robust, and reliable so that the developed setup demonstrated to be a competitive strategy for the automated extraction of organic pollutants from water samples. 相似文献
4.
Rodolfo G. Figueroa Mauro Valente Jaime Guarda Jorge Leiva Eduardo Quilaguilque Bryan Casanelli Fernando Leyton 《X射线光谱测定》2022,51(3):251-261
A novel and suitable energy-dispersive X-ray fluorescent (EDXRF) device, currently at the prototype stage, the Project OXIRIS (Orthovoltage X-Ray–Induced Radiation System), is presented for the simultaneous detection and treatment of cancer diseases. Monte Carlo simulation and experimental results of EDXRF signals from a small deep artificial tumor consisting of a solution of gold nanoparticles bio-targeted and immersed in a tissue-bioequivalent matrix are presented and compared. Briefly, the device consists of a dynamic orthovoltage X-ray fluence concentration coupled to confocal with an EDXRF system along with a sample holder for 3D scanning; all integrated and controlled by a dedicated software capable of controlling the whole operation functionalities: the X-ray source, the rotating arm, the sample holder, and the detection system. The software also includes dedicated subroutines for X-ray fluorescent spectra processing to correlate K-lines signal at each acquisition position with the corresponding high atomic number elements' concentration to produce a 3D distribution according to the user-defined grid. The confocal configuration ensures that the detected signal comes exclusively from the excited volume as defined by the bulk of the focal spot. Hence, the 3D image is achieved by scanning the sample holder through the movement of the sample-carrier stretcher moved by step motors in the 3 coordinated axes. The feasibility of the proposed methodology and the design of the prototype have been successfully demonstrated experimentally, targeting gold nanoparticles in water-equivalent phantoms. 相似文献
5.
6.
Khan A. Valezi D. F. Picinato M. T. Vicentin B. L. S. Netto A. M. Mantovani A. C. G. Di Mauro E. 《Journal of Applied Spectroscopy》2022,89(1):186-190
Journal of Applied Spectroscopy - This study aimed to investigate the molecular mobility of crude oils using the linewidth of the free radical electron paramagnetic resonance signal (EPR) as a... 相似文献
7.
Gianluca Ambrosi Mauro Micheloni Daniele Paderni Mauro Formica 《Supramolecular chemistry》2020,32(2):139-149
ABSTRACTThe new macrocyclic ligand L (28,29-dimethoxy-27-oxa-8,11,14,17,25,26-hexaazatetracyclo[22.2.1.1(2,6).1(19,23)]nonacosa-2,4,6(28),19,21,23(29),24,26(1)-octaene) has been synthesised. It contains a tetramine chain and the 2,5-bis(2-methoxy-3-metyl-phenyl)-1,3,4-oxadiazole (PPD-OMe) chromophore, acting as coordinating and sensing units, respectively.The fluorescent emission of L depends on the pH being highly fluorescent at pH = 2 and not emitting from pH >10. The studies highlighted that L is a PET mediated emitting chemosensor, being the PET effect regulated by the degree of the tetraamine protonation.L coordinates metal ions (Cu(II), Zn(II) and Cd(II)) in water giving rise to an OFF-ON fluorescent response for the presence of Zn(II) ion thus signalling its presence in the medium. This response is particularly notable at pH = 9 allowing to extend the Zn(II) sensing also in the alkaline pH field. 相似文献
8.
9.
Michele Menotta Sara Biagiotti Laura Streppa Luigia Rossi Mauro Magnani 《Analytica chimica acta》2015
In the present paper we describe an atomic force microscopy (AFM)-based method for the quantitative analysis of FK506 (Tacrolimus) in whole blood (WB) samples. Current reference methods used to quantify this immunosuppressive drug are based on mass spectrometry. In addition, an immunoenzymatic assay (ELISA) has been developed and is widely used in clinic, even though it shows a small but consistent overestimation of the actual drug concentration when compared with the mass spectrometry method. The AFM biosensor presented herein utilises the endogen drug receptor, FKBP12, to quantify Tacrolimus levels. The biosensor was first assayed to detect the free drug in solution, and subsequently used for the detection of Tacrolimus in blood samples. The sensor was suitable to generate a dose–response curve in the full range of clinical drug monitoring. A comparison with the clinically tested ELISA assay is also reported. 相似文献
10.