全文获取类型
收费全文 | 20163篇 |
免费 | 1971篇 |
国内免费 | 2080篇 |
出版年
2024年 | 14篇 |
2023年 | 263篇 |
2022年 | 360篇 |
2021年 | 1022篇 |
2020年 | 844篇 |
2019年 | 974篇 |
2018年 | 895篇 |
2017年 | 659篇 |
2016年 | 854篇 |
2015年 | 1318篇 |
2014年 | 1502篇 |
2013年 | 1593篇 |
2012年 | 1978篇 |
2011年 | 1689篇 |
2010年 | 1053篇 |
2009年 | 998篇 |
2008年 | 1063篇 |
2007年 | 966篇 |
2006年 | 842篇 |
2005年 | 744篇 |
2004年 | 565篇 |
2003年 | 559篇 |
2002年 | 515篇 |
2001年 | 344篇 |
2000年 | 285篇 |
1999年 | 296篇 |
1998年 | 176篇 |
1997年 | 196篇 |
1996年 | 186篇 |
1995年 | 167篇 |
1994年 | 159篇 |
1993年 | 128篇 |
1992年 | 137篇 |
1991年 | 96篇 |
1990年 | 109篇 |
1989年 | 98篇 |
1988年 | 82篇 |
1987年 | 58篇 |
1986年 | 74篇 |
1985年 | 64篇 |
1984年 | 42篇 |
1983年 | 34篇 |
1982年 | 30篇 |
1981年 | 20篇 |
1980年 | 23篇 |
1979年 | 28篇 |
1977年 | 18篇 |
1976年 | 14篇 |
1973年 | 12篇 |
1971年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Fluid-structural coupling occurs when microcantilever sensors vibrate in a fluid. Due to the complexity of the mechanical characteristics of microcantilevers and lack of high-precision microscopic mechanical testing instruments, effective methods for studying the fluid-structural coupling of microcantilevers are lacking, especially for non-rectangular microcantilevers. Here, we report fluid-structure interactions (FSI) of the cable-membrane structure via a macroscopic study. The simplified aeroelastic model was introduced into the microscopic field to establish a fluid-structure coupling vibration model for microcantilever sensors. We used the finite element method to solve the coupled FSI system. Based on the simplified aeroelastic model, simulation analysis of the effects of the air environment on the vibration of the commonly used rectangular microcantilever was also performed. The obtained results are consistent with the literature. The proposed model can also be applied to the auxiliary design of rectangular and non-rectangular sensors used in fluid environments. 相似文献
2.
Feng Xue Zhoushan Wu Jinrong Tong Jialun Zheng 《Bioscience, biotechnology, and biochemistry》2017,81(10):1891-1898
This study investigated the effects of high-intensity ultrasound and glycosylation on the structural and interfacial properties of the Maillard reaction conjugates of buckwheat protein isolate (BPI). The covalent attachment of dextran to BPI was confirmed by examination of the Fourier-transform infrared spectra. Emulsifying properties of the conjugates obtained by ultrasound treatment were improved as compared to those obtained by classical heating. Structural feature analyses suggested that conjugates obtained by ultrasound treatment had less α-helix and more random coil, higher surface hydrophobicity and less compact tertiary structure as compared to those obtained by classical heating. The surface activity measurement revealed that the BPI–dextran conjugates obtained by ultrasound treatment were closely packed and that each molecule occupied a small area of the interface. Combination of ultrasonic treatment and glycosylation was proved to be an efficient way to develop new stabilizers and thickening agents for food in this study. 相似文献
3.
Bayesian nonparametric inference for panel count data with an informative observation process 下载免费PDF全文
In this paper, the panel count data analysis for recurrent events is considered. Such analysis is useful for studying tumor or infection recurrences in both clinical trial and observational studies. A bivariate Gaussian Cox process model is proposed to jointly model the observation process and the recurrent event process. Bayesian nonparametric inference is proposed for simultaneously estimating regression parameters, bivariate frailty effects, and baseline intensity functions. Inference is done through Markov chain Monte Carlo, with fully developed computational techniques. Predictive inference is also discussed under the Bayesian setting. The proposed method is shown to be efficient via simulation studies. A clinical trial dataset on skin cancer patients is analyzed to illustrate the proposed approach. 相似文献
4.
5.
6.
7.
8.
9.
Liu Minliang Liang Liang Liu Haofei Zhang Ming Martin Caitlin Sun Wei 《Biomechanics and modeling in mechanobiology》2019,18(2):387-398
Biomechanics and Modeling in Mechanobiology - It is well known that residual deformations/stresses alter the mechanical behavior of arteries, e.g., the pressure–diameter curves. In an effort... 相似文献
10.
Jiaming Liang Thibault Mesplède Maureen Oliveira Kaitlin Anstett Mark A. Wainberg 《Journal of virology》2015,89(22):11269-11274