全文获取类型
收费全文 | 2076篇 |
免费 | 251篇 |
国内免费 | 229篇 |
专业分类
化学 | 1277篇 |
晶体学 | 33篇 |
力学 | 92篇 |
综合类 | 43篇 |
数学 | 207篇 |
物理学 | 904篇 |
出版年
2024年 | 8篇 |
2023年 | 38篇 |
2022年 | 71篇 |
2021年 | 66篇 |
2020年 | 63篇 |
2019年 | 86篇 |
2018年 | 75篇 |
2017年 | 49篇 |
2016年 | 79篇 |
2015年 | 68篇 |
2014年 | 80篇 |
2013年 | 115篇 |
2012年 | 157篇 |
2011年 | 153篇 |
2010年 | 106篇 |
2009年 | 121篇 |
2008年 | 111篇 |
2007年 | 94篇 |
2006年 | 95篇 |
2005年 | 110篇 |
2004年 | 95篇 |
2003年 | 73篇 |
2002年 | 64篇 |
2001年 | 94篇 |
2000年 | 48篇 |
1999年 | 53篇 |
1998年 | 53篇 |
1997年 | 44篇 |
1996年 | 34篇 |
1995年 | 38篇 |
1994年 | 25篇 |
1993年 | 25篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 33篇 |
1989年 | 20篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 21篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
排序方式: 共有2556条查询结果,搜索用时 15 毫秒
992.
Let f : M → M be an Anosov diffeomorphism on a nilmanifold. We consider Birkhoff sums for a Holder continuous observation along periodic orbits. We show that if there are two Birkhoff sums distributed at both sides of zero, then the set of Birkhoff sums of all the periodic points is dense in R. 相似文献
993.
Gan Chenquan Feng Qingdong Zhu Qingyi Zhang Zufan Zhang Yushu Xiang Yong 《Nonlinear dynamics》2020,100(2):1725-1740
Nonlinear Dynamics - This paper mainly aims to explore the propagation behaviors of computer virus over complex networks under the combined effects of network topology and removable storage media.... 相似文献
994.
Ziyu Gan Chaofeng Huang Yanfei Shen Qing Zhou Dan Han Jin Ma Songqin Liu Yuanjian Zhang 《中国化学快报》2020,31(2):513-516
As an emerging 2D conjugated material,graphitic carbon nitride(CN) has attracted great research attention as important catalytic medium for transforming solar energy.Nanostructure modulation of CN is an effective way to improve catalytic activities and has been extensively investigated,but remains challenging due to complex processes,time consuming or low yield.Here,taking advantage of recent discovered good solvents for CN,a nanoprecipitation approach using poor solvents is proposed for preparation of CN nanoparticles(CN NPs).With simple processes of CN dissolution and precipitation,we can quickly synthesize CN NPs(^40 nm) with a yield of up to 50%,the highest one to the best of our knowledge.As an example of potential applications,the as-prepared CN NPs were applied to photocatalytic degradation of dyes with an evident boosted performance up to 2.5 times.This work would open a new way for batch preparation of nanostructured CN and pave its large-scale industrial applications. 相似文献
995.
Gan Ting Ming Tingzhen Fang Weijie Liu Yang Miao Lei Ren Kun Ahmadi Mohammad Hossein 《Journal of Thermal Analysis and Calorimetry》2020,141(1):45-56
Journal of Thermal Analysis and Calorimetry - With the rapid increasing heat fluxes released from micro electronic devices, thermal management of electric components faces huge challenge. High... 相似文献
996.
Di Xiao Xiaojiang Duan Qianqian Gan Xuran Zhang Junbo Zhang 《Molecules (Basel, Switzerland)》2020,25(23)
Prostate-specific membrane antigen (PSMA) is a well-established biological target that is overexpressed on the surface of prostate cancer lesions. Radionuclide-labeled small-molecule PSMA inhibitors have been shown to be promising PSMA-specific agents for the diagnosis and therapy of prostate cancer. In this study, a glutamate-urea-based PSMA-targeted ligand containing an isonitrile (CNGU) was synthesized and labeled with 99mTc to prepare [99mTc]Tc-CNGU with a high radiochemical purity (RCP). The CNGU ligand showed a high affinity toward PSMA (Ki value is 8.79 nM) in LNCaP cells. The [99mTc]Tc-CNGU exhibited a good stability in vitro and hydrophilicity (log P = −1.97 ± 0.03). In biodistribution studies, BALB/c nude mice bearing LNCaP xenografts showed that the complex had a high tumor uptake with 4.86 ± 1.19% ID/g, which decreased to 1.74 ± 0.90% ID/g after a pre-injection of the selective PSMA inhibitor ZJ-43, suggesting that it was a PSMA-specific agent. Micro-SPECT imaging demonstrated that the [99mTc]Tc-CNGU had a tumor uptake and that the uptake was reduced in the image after blocking with ZJ-43, further confirming its PSMA specificity. All of the results in this work indicated that [99mTc]Tc-CNGU is a promising PSMA-specific tracer for the imaging of prostate cancer. 相似文献
997.
Xia Yang Li Jiaojiao Wang Hongjie Ye Zhangjun Zhou Xiaozheng Huang Hui Gan Yongping Liang Chu Zhang Jun Zhang Wenkui 《Journal of Solid State Electrochemistry》2019,23(2):519-527
Journal of Solid State Electrochemistry - In this work, a series of rationally designed hybrid membranes composed of poly(vinylidene fluoride) (PVDF) as polymer matrix and silica nanoparticles... 相似文献
998.
999.
Dan Zhou Fan Chen Prof. Dr. Stephan Handschuh-Wang Dr. Tiansheng Gan Prof. Dr. Xiaohu Zhou Prof. Dr. Xuechang Zhou 《Chemphyschem》2019,20(17):2139-2154
Recently, temperature-resistant hydrogels, hydrogels which are freezing- and dehydration-resistant, have garnered considerable attention in the scientific community as they extend the rage of application of hydrogels to arid and/or cold environments. Besides, these hydrogels exhibit tunable conductivity and mechanical performance while offering excellent biocompatibility and flexibility, making them interesting candidates for flexible and wearable electronics and (bio)sensors. Several biomimetic strategies were developed to fabricate anti-freezing and anti-dehydration hydrogels with a diversity of merits, such as high strain resistance and conductivity, even at sub-zero temperatures, and employed as (bio)sensors, electrodes, and energy-storage devices. This review summarizes the recent advances in the preparation and application of temperature-resistant hydrogels, indicates issues of the state-of-the-art hydrogels, and offers potential future research directions. 相似文献
1000.
In this work, the substituent effects on hydrogen bonding in one kind of hydrazone-based switch are revealed. The E/Z isomerization ratios of these hydrazones and their intramolecular hydrogen bond strengths in the Z form were evaluated using NMR technique. Linear correlations between these parameters and Hammett empirical values for substituent effects are explored as well. 相似文献