全文获取类型
收费全文 | 1831篇 |
免费 | 475篇 |
国内免费 | 132篇 |
专业分类
化学 | 621篇 |
晶体学 | 17篇 |
力学 | 136篇 |
综合类 | 36篇 |
数学 | 127篇 |
物理学 | 1501篇 |
出版年
2024年 | 2篇 |
2023年 | 27篇 |
2022年 | 51篇 |
2021年 | 92篇 |
2020年 | 64篇 |
2019年 | 56篇 |
2018年 | 57篇 |
2017年 | 94篇 |
2016年 | 108篇 |
2015年 | 88篇 |
2014年 | 164篇 |
2013年 | 133篇 |
2012年 | 114篇 |
2011年 | 115篇 |
2010年 | 100篇 |
2009年 | 107篇 |
2008年 | 116篇 |
2007年 | 99篇 |
2006年 | 118篇 |
2005年 | 90篇 |
2004年 | 80篇 |
2003年 | 72篇 |
2002年 | 65篇 |
2001年 | 53篇 |
2000年 | 42篇 |
1999年 | 67篇 |
1998年 | 43篇 |
1997年 | 30篇 |
1996年 | 32篇 |
1995年 | 25篇 |
1994年 | 22篇 |
1993年 | 18篇 |
1992年 | 18篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 12篇 |
1986年 | 9篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1975年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有2438条查询结果,搜索用时 562 毫秒
91.
92.
We realized a series of experiments to study the physics of laser–plasma interaction in an intensity regime of interest for the novel “Shock Ignition” approach to Inertial Fusion. Experiments were performed at the Prague Asterix Laser System laser in Prague using two laser beams: an “auxiliary” beam, for pre-plasma creation, with intensity around 7?×?1013?W/cm2 (250?ps, 1ω, λ?=?1315?nm) and the “main” beam, up to 1016?W/cm (250?ps, 3ω, λ?=?438?nm), to launch a shock. The main goal of these experiments is to study the process of the formation of a very strong shock and the influence of hot electrons in the generation of very high pressures. The shock produced by the ablation of the plastic layer is studied by shock breakout chronometry. The generation of hot electrons is analyzed by imaging Kα emission. 相似文献
93.
Pulsed microwave-driven argon plasma jet with distinctive plume patterns resonantly excited by surface plasmon polaritons 下载免费PDF全文
Atmospheric lower-power pulsed microwave argon cold plasma jets are obtained by using coaxial transmission line resonators in ambient air.The plasma jet plumes are generated at the end of a metal wire placed in the middle of the dielectric tubes.The electromagnetic model analyses and simulation results suggest that the discharges are excited resonantly by the enhanced electric field of surface plasmon polaritons.Moreover,for conquering the defect of atmospheric argon filamentation discharges excited by 2.45-GHz of continued microwave,the distinctive patterns of the plasma jet plumes can be maintained by applying different gas flow rates of argon gas,frequencies of pulsed modulator,duty cycles of pulsed microwave,peak values of input microwave power,and even by using different materials of dielectric tubes.In addition,the emission spectrum,the plume temperature,and other plasma parameters are measured,which shows that the proposed pulsed microwave plasma jets can be adjusted for plasma biomedical applications. 相似文献
94.
Click‐Tag and Amine‐Tag: Chemical Tag Approaches for Efficient Protein Labeling In Vitro and on Live Cells using the Naturally Split Npu DnaE Intein 下载免费PDF全文
Dr. Vivien Schütz Prof. Dr. Henning D. Mootz 《Angewandte Chemie (International ed. in English)》2014,53(16):4113-4117
Protein labeling with synthetic moieties remains in many cases a technically challenging or unresolved task. Two new and simple concepts are presented. In both approaches, a very short tag of only a few amino acids is prepared with the desired chemical modification and, in a second step, it is transferred to the protein of interest by protein trans‐splicing. For the amine‐tag, a recombinant intein fragment free of lysine residues was generated such that the amine group of the N terminus could be selectively modified with regular amine‐reactive reagents. Thus, standard bioconjugation procedures without any chemical synthesis could be applied without modification of lysines in the protein of interest. For the click‐tag, protein trans‐splicing was combined with unnatural amino acid mutagenesis and subsequent bioorthogonal side chain modification, as demonstrated for click chemistry using p‐azidophenylalanine. By the two‐step strategy, exposure of the protein of interest to the copper catalyst was avoided. 相似文献
95.
Salt,Shake, Fuse—Giant Hybrid Polymer/Lipid Vesicles through Mechanically Activated Fusion 下载免费PDF全文
Ian M. Henderson Walter F. Paxton 《Angewandte Chemie (International ed. in English)》2014,53(13):3372-3376
Large (200 nm) poly(ethylene oxide)‐b‐poly(butadiene) polymer vesicles fuse into giant (>1 μm) vesicles with mild agitation in dilute aqueous NaCl solutions. This unusual effect is attributed to the salt‐induced contraction of the poly(ethylene oxide) corona, reducing steric resistance between vesicles and, with agitation, increasing the probability of contact between the hydrophobic cores of adjacent membranes. In addition, NaCl and agitation facilitated the creation of giant hybrid vesicles from much smaller homogeneous polymersomes and liposomes. Whereas lipid vesicles do not readily fuse with each other under the same circumstances, they did fuse with polymersomes to produce hybrid polymer/lipid vesicles. 相似文献
96.
TiO2 decorated with partially crystallized Pd nanoparticles (Pd/TiO2-P) was successfully prepared by atmospheric-pressure dielectric barrier discharge cold plasma. The XRD and XPS analyses proved that Pd ions were reduced to partially crystallized metallic Pd nanoparticles in Pd/TiO2-P. The XPS spectra also indicated that an enhanced metal-support interaction was formed due to the existence of partially crystallized Pd nanoparticles with lower coordination number in Pd/TiO2-P. Photocatalytic activity of Pd/TiO2-P was much higher than that of TiO2 samples decorated with well crystallized Pd nanoparticles. 相似文献
97.
Dr. Archishman Ghosh Prof. Huan-Xiang Zhou 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(47):21023-21026
Biomolecular droplets formed through phase separation have a tendency to fuse. The speed with which fusion occurs is a direct indicator of condensate liquidity, which is key to both cellular functions and diseases. Using a dual-trap optical tweezers setup, we found the fusion speeds of four types of droplets to differ by two orders of magnitude. The order of fusion speed correlates with the fluorescence of thioflavin T, which in turn reflects the macromolecular packing density inside droplets. Unstructured protein or polymer chains pack loosely and readily rearrange, leading to fast fusion. In contrast, structured protein domains pack more closely and have to break extensive contacts before rearrangement, corresponding to slower fusion. This molecular interpretation for disparate fusion speeds provides mechanistic insight into the assembly and aging of biomolecular droplets. 相似文献
98.
基于常压质谱的直接、快速、无需样品预处理检测的优势,该文拓展了其在药物质检领域的应用。采用自行搭建的解析电喷雾(DESI)装置,对常用感冒药对乙酰氨基酚片进行快速质谱检测,无需样品预处理,直接获得药片中有效成分的分子结构信息。为克服基质差异对定量分析的影响,以淀粉为基质构建对乙酰氨基酚模拟药片,在优化的基础上进行定量实验。针对实际药片中高浓度对乙酰氨基酚检测的需要,研究了其在较高浓度范围的定量关系,结果显示,方法对0.35~4.52 mg/mm^2范围内的对乙酰氨基酚具有较好的线性关系(r^2=0.9982),定量下限为1.903 ng/mm^2,检出限为0.237 ng/mm^2,加标回收率为102%~114%。对3种市售的对乙酰氨基酚片进行直接检测,与厂家提供的标准数据相比,相对标准偏差(RSD)为7.2%~12%,表明方法具有较好准确度。该工作很好地证明了DESI-MS在药品快检中的优势,从而为药品质检提供了潜在的高效、可靠的检测手段。 相似文献
99.
Shota Ooi B. Adinarayana Daiki Shimizu Takayuki Tanaka Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2020,59(24):9423-9427
While oxidation of 5,5′,15,15′‐tetramesityl‐10‐10′‐linked 3NH‐corrole dimer with DDQ gave the corresponding triply linked 2NH‐corrole tape, the use of an equimolar amount of p‐chloranil as a milder oxidant resulted in the formation of a 10‐10′‐linked neutral 2NH‐corrole radical dimer as a stable product. The stability of this peculiar product is ascribed largely to strong antiferromagnetic interaction of the two spins. Further oxidation of this diradical produced corrole tape, suggesting its involvement as a reaction intermediate to the corrole tape. Oxidation of 10‐10′‐linked bis‐pyridine‐coordinated CoIII corrole dimer with DDQ produced a cobalt corrole radical dimer and a doubly linked corrole dimer both as stable compounds bearing pyridine and cyanide axial ligands. This type of oxidative transformation involving neutral diradical intermediates is a unique reaction mechanism specific for corrole dimers. 相似文献
100.