全文获取类型
收费全文 | 3930篇 |
免费 | 370篇 |
国内免费 | 243篇 |
专业分类
化学 | 1322篇 |
晶体学 | 6篇 |
力学 | 107篇 |
综合类 | 18篇 |
数学 | 1031篇 |
物理学 | 683篇 |
无线电 | 1376篇 |
出版年
2024年 | 5篇 |
2023年 | 44篇 |
2022年 | 77篇 |
2021年 | 95篇 |
2020年 | 104篇 |
2019年 | 94篇 |
2018年 | 71篇 |
2017年 | 123篇 |
2016年 | 135篇 |
2015年 | 146篇 |
2014年 | 178篇 |
2013年 | 362篇 |
2012年 | 237篇 |
2011年 | 230篇 |
2010年 | 217篇 |
2009年 | 212篇 |
2008年 | 195篇 |
2007年 | 279篇 |
2006年 | 210篇 |
2005年 | 179篇 |
2004年 | 184篇 |
2003年 | 156篇 |
2002年 | 122篇 |
2001年 | 112篇 |
2000年 | 103篇 |
1999年 | 111篇 |
1998年 | 85篇 |
1997年 | 56篇 |
1996年 | 57篇 |
1995年 | 62篇 |
1994年 | 54篇 |
1993年 | 43篇 |
1992年 | 21篇 |
1991年 | 28篇 |
1990年 | 12篇 |
1989年 | 17篇 |
1988年 | 17篇 |
1987年 | 13篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1969年 | 1篇 |
排序方式: 共有4543条查询结果,搜索用时 452 毫秒
1.
Elise Laszlo Gregory De Crescenzo Alfonso Nieto-Argüello Xavier Banquy Davide Brambilla 《Advanced functional materials》2021,31(46):2106061
The noninvasive sampling of dermal interstitial fluid (ISF) for the monitoring of clinical biomarkers is a greatly appealing area of research. The identification of molecular biomarkers in biological fluids has been accelerated with -omics analyses but remains limited in ISF because of its time-consuming and complex extraction process. Here, the generation of microneedle (MN) patches made of superabsorbent acrylate-based hydrogels for the rapid sampling of dermal ISF is described to explore its proteome. In depth, iterative optimization allows the identification of novel acrylate-based compositions with the required chemical, mechanical, and biocompatibility properties allowing proteomic analysis of the extracted ISF for the first time after sampling with swelling MNs. The generated MN arrays show no cytotoxic effect, successfully cross the stratum corneum, and can collect up to 6 µL of dermal ISF in 10 min in vivo. Proteomics lead to the detection of 176 clinically relevant biomarkers in the collected samples validating the use of ISF as a relevant bodily fluid for disease monitoring and diagnostic. Importantly, it is discovered that extraction fingerprint is strongly dependent on the MNs chemistry, and thus specific biomarkers could be selectively extracted by tuning the composition of the patch, making the system versatile and specific. 相似文献
2.
Mariusz Marć Marek Tobiszewski Bożena Zabiegała Miguel de la Guardia Jacek Namieśnik 《Analytica chimica acta》2015
This review summarizes the different tools and concepts that are commonly applied in air quality monitoring. The monitoring of atmosphere is extremely important as the air quality is an important problem for large communities. Main requirements for analytical devices used for monitoring include a long period of autonomic operation and portability. These instruments, however, are often characterized by poor analytical performance. Monitoring networks are the most common tools used for monitoring, so large-scale monitoring programmes are summarized here. Biomonitoring, as a cheap and convenient alternative to traditional sample collection, is becoming more and more popular, although its main drawback is the lack of standard procedures. Telemonitoring is another approach to air monitoring, which offers some interesting opportunities, such as ease of coverage of large or remote areas, constituting a complementary approach to traditional strategies; however, it requires huge costs. 相似文献
3.
4.
在数据采集中采用带通采样,可大大降低采样率,但系统中的抗混叠滤波器会造成相位的非线性。采用对滤波后的信号进行带通采样,然后再用FRR滤波器校正相位的非线性,从而不失真地还原原信号,最后在Matlab中进行仿真,验证了该方法的有效性。 相似文献
5.
6.
We consider a system of multicolour disordered lattice gas, following closely the (monocolour) introduced by Faggionato and Martinelli(3,4). We study the projection on the monocolour system and we derive an estimate of the closeness between grand canonical and canonical Gibbs measures.
AMS Classification: Primary: 60K35, 82C20, 82C22 相似文献
7.
可变抽样区间的非参数控制图 总被引:1,自引:1,他引:0
最近几年一些学者研究了可变抽样区间的质量控制图。Amin等提出了可变抽样区间(VSI)的非参数控制图———符号 (Sign)统计量图〔1〕。本文在此基础上研究位置VSI符号控制图的制定方法 ,并设计离散VSI符号控制图。符号控制图的优点是对非正态总体亦可应用 ,并且不需要过程方差的信息。本文将所设计的VSI符号控制图同固定抽样区间 (FSI)的常规图作比较 ,并举实例说明符号控制图的应用 相似文献
8.
9.
We study the induced measure obtained from a 1-step Markov measure, supported by a topological Markov chain, after the mapping of the original alphabet onto another one. We give sufficient conditions for the induced measure to be a Gibbs measure (in the sense of Bowen) when the factor system is again a topological Markov chain. This amounts to constructing, when it does exist, the induced potential and proving its Hölder continuity. This is achieved through a matrix method. We provide examples and counterexamples to illustrate our results. 相似文献
10.
Let {Xk}k?1 be a strictly stationary time series. For a strictly increasing sampling function g:?→? define Yk=Xg(k) as the deterministic sub‐sampled time series. In this paper, the extreme value theory of {Yk} is studied when Xk has representation as a moving average driven by heavy‐tailed innovations. Under mild conditions, convergence results for a sequence of point processes based on {Yk} are proved and extremal properties of the deterministic sub‐sampled time series are derived. In particular, we obtain the limiting distribution of the maximum and the corresponding extremal index. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献