全文获取类型
收费全文 | 251745篇 |
免费 | 11685篇 |
国内免费 | 6447篇 |
专业分类
化学 | 146782篇 |
晶体学 | 2441篇 |
力学 | 12083篇 |
综合类 | 435篇 |
数学 | 26062篇 |
物理学 | 82074篇 |
出版年
2021年 | 2651篇 |
2020年 | 3503篇 |
2019年 | 3435篇 |
2018年 | 3297篇 |
2017年 | 2982篇 |
2016年 | 4934篇 |
2015年 | 4434篇 |
2014年 | 5755篇 |
2013年 | 12323篇 |
2012年 | 10717篇 |
2011年 | 12282篇 |
2010年 | 8285篇 |
2009年 | 8029篇 |
2008年 | 9769篇 |
2007年 | 9497篇 |
2006年 | 9107篇 |
2005年 | 8144篇 |
2004年 | 7097篇 |
2003年 | 6041篇 |
2002年 | 5303篇 |
2001年 | 6724篇 |
2000年 | 5254篇 |
1999年 | 4564篇 |
1998年 | 3566篇 |
1997年 | 3584篇 |
1996年 | 3537篇 |
1995年 | 3390篇 |
1994年 | 3224篇 |
1993年 | 2982篇 |
1992年 | 3370篇 |
1991年 | 3147篇 |
1990年 | 3010篇 |
1989年 | 2955篇 |
1988年 | 2768篇 |
1987年 | 2725篇 |
1986年 | 2521篇 |
1985年 | 3404篇 |
1984年 | 3347篇 |
1983年 | 2739篇 |
1982年 | 2927篇 |
1981年 | 2848篇 |
1980年 | 2701篇 |
1979年 | 2859篇 |
1978年 | 3126篇 |
1977年 | 2935篇 |
1976年 | 2887篇 |
1975年 | 2745篇 |
1974年 | 2679篇 |
1973年 | 2718篇 |
1967年 | 2132篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Pomogaev V. A. Lee H. J. Goh E. Tchaikovskaya O. N. Kononov A. I. Avramov P. V. 《Russian Physics Journal》2022,64(11):2076-2081
Russian Physics Journal - Theoretical calculations of excited states in the complexes of gold and silver three-atom nanoclusters with carbon quantum nanodots are performed using the M062X... 相似文献
2.
Circularly polarized luminescence (CPL) has attracted attention as a next-generation light signal because of its carrying more information compared with normal and linearly polarized lights as well as its potential wide application in information fields. Recently, much attention has been paid to small organic molecules-based CPL emitters because of easy synthesis, fine structural modification at molecular level, and tunable wide range emission wavelength. This review highlights the development of small organic molecules-based CPL emitters in the past 5 years (2017–2021). The progress suggests that small organic molecules-based CPL emitters provide a simple and efficient way to generate CPL. 相似文献
3.
Utamima Amalia Reiners Torsten Ansaripoor Amir H. 《Annals of Operations Research》2022,316(2):955-977
Annals of Operations Research - In recent years, operations research in agriculture has improved the harvested yield, reduced the cost and time required for field operations, and maintained... 相似文献
4.
Nonlinear Dynamics - The perovskite solar cell (PSC) is one of the most promising photovoltaic candidates along with the highly increasing demand for green electricity. One of the main concerns... 相似文献
5.
Science China Chemistry - Human health is always under global spotlight, but now it suffers from severe environmental issue and various diseases. Developing highly selective and effective... 相似文献
6.
Sørbye Sigrunn H. Nicolau Pedro G. Rue Håvard 《Statistical Inference for Stochastic Processes》2022,25(3):577-598
Statistical Inference for Stochastic Processes - The class of autoregressive (AR) processes is extensively used to model temporal dependence in observed time series. Such models are easily... 相似文献
7.
Xin Liu Lili Chen Yanfeng Zhao Xianhua Song 《Mathematical Methods in the Applied Sciences》2022,45(1):77-92
In this paper, the problem of the uniform stability for a class of fuzzy fractional-order genetic regulatory networks with random discrete delays, distributed delays, and parameter uncertainties is studied. Although there is a portion of literature on using fixed point theorems to study the stability of fractional neural networks, most of them required the fractional order to be in . However, the case of the fractional-order belonging to has not been discussed. To solve it, this work proposes a novel idea of using fixed point theory to study the stability of fuzzy (0,1) order neural networks, the problem of the uniqueness of the solution of the considered genetic regulatory networks is resolved, and a novel sufficient condition to guarantee the uniform stability of above genetic regulatory networks is also derived. Eventually, an example is given to demonstrate that the obtained result is effective. 相似文献
8.
9.
Atopic dermatitis is characterized by leukocyte migration into the skin dermis and typically driven by excessive chemokine production at the site of inflammation. Conventional topical formulations such as gels, creams, and ointments are insufficient for this treatment because of low penetration of drug molecules into the targeted skin tissues. Herein, using a simple, green, sustainable strategy, we have developed novel primary zein nanoparticles embedded in curcumin (Cur) and coated with silk sericin (ZHSCs) for the topical delivery of Cur to penetrate into the dermis and exercise anti-dermatitis effects on the lesion with minimal side-effects. Transdermal delivery experiments and porcine skin fluorescence imaging indicated that ZHSCs facilitate the penetration of Cur across the epidermis layer of skin to reach deep-seated sites. Notably, ZHSCs = 1:0.25 (zein-to-silk sericin mass ratios of 1:0.25) markedly elevated the skin permeability and cumulative turnover of Cur transferred, which were provided a greater than a 3.8-fold increase relative to free Cur. The special nanoparticles of ZHS = 1:0.25 possessed the deepest localization depth and experience a transition of the particle structure and core-shell separation after penetrating into the dermis of skin. In a cell model of dermatitis induced by tumor necrosis factor α/interferon γ co-stimulation, compared with free Cur, Cur-loaded ZHS nanoparticles down-regulated the generation of inflammatory cytokines and chemokines in keratinocytes through suppression of the nuclear translocation of NF-κBp65 and hence exerted an anti-dermatitis effect. This strategy may provide new avenues and direction for the demanding issues of valid topical delivery systems. 相似文献
10.
Majorana fermions induced fast-and slow-light in a hybrid semiconducting nanowire/superconductor device 下载免费PDF全文
We investigate theoretically Rabi-like splitting and Fano resonance in absorption spectra of quantum dots(QDs)based on a hybrid QD-semiconducting nanowire/superconductor(SNW/SC)device mediated by Majorana fermions(MFs).Under the condition of pump on-resonance and off-resonance,the absorption spectrum experiences the conversion from Fano resonance to Rabi-like splitting in different parametric regimes.In addition,the Fano resonances are accompanied by the rapid normal phase dispersion,which will indicate the coherent optical propagation.The results indicate that the group velocity index is tunable with controlling the interaction between the QD and MFs,which can reach the conversion between the fast-and slow-light.Fano resonance will be another method to detect MFs and our research may indicate prospective applications in quantum information processing based on the hybrid QD-SNW/SC devices. 相似文献