全文获取类型
收费全文 | 14007篇 |
免费 | 1611篇 |
国内免费 | 1650篇 |
出版年
2024年 | 16篇 |
2023年 | 211篇 |
2022年 | 298篇 |
2021年 | 767篇 |
2020年 | 643篇 |
2019年 | 729篇 |
2018年 | 652篇 |
2017年 | 502篇 |
2016年 | 651篇 |
2015年 | 983篇 |
2014年 | 1140篇 |
2013年 | 1182篇 |
2012年 | 1357篇 |
2011年 | 1162篇 |
2010年 | 746篇 |
2009年 | 674篇 |
2008年 | 779篇 |
2007年 | 640篇 |
2006年 | 596篇 |
2005年 | 482篇 |
2004年 | 458篇 |
2003年 | 401篇 |
2002年 | 412篇 |
2001年 | 285篇 |
2000年 | 225篇 |
1999年 | 200篇 |
1998年 | 160篇 |
1997年 | 134篇 |
1996年 | 117篇 |
1995年 | 102篇 |
1994年 | 90篇 |
1993年 | 74篇 |
1992年 | 83篇 |
1991年 | 55篇 |
1990年 | 51篇 |
1989年 | 31篇 |
1988年 | 39篇 |
1987年 | 26篇 |
1986年 | 16篇 |
1985年 | 19篇 |
1984年 | 32篇 |
1983年 | 13篇 |
1982年 | 14篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1969年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
1.
Honghong Yang Yuanyuan Zhang Zhihai Wang Shixun Zhong Guohua Hu Wenqi Zuo 《Bioelectromagnetics》2020,41(3):219-229
To investigate the possible mechanisms for biological effects of 1,800 MHz mobile radiofrequency radiation (RFR), the radiation-specific absorption rate was applied at 2 and 4 W/kg, and the exposure mode was 5 min on and 10 min off (conversation mode). Exposure time was 24 h short-term exposure. Following exposure, to detect cell DNA damage, cell apoptosis, and reactive oxygen species (ROS) generation, the Comet assay test, flow cytometry, DAPI (4′,6-diamidino-2-phenylindole dihydrochloride) staining, and a fluorescent probe were used, respectively. Our experiments revealed that mobile phone RFR did not cause DNA damage in marginal cells, and the rate of cell apoptosis did not increase (P > 0.05). However, the production of ROS in the 4 W/kg exposure group was greater than that in the control group (P < 0.05). In conclusion, these results suggest that mobile phone energy was insufficient to cause cell DNA damage and cell apoptosis following short-term exposure, but the cumulative effect of mobile phone radiation still requires further confirmation. Activation of the ROS system plays a significant role in the biological effects of RFR. Bioelectromagnetics. © 2020 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc. 相似文献
2.
Xun Qi Yonghui Yuan Ke Xu Hongshan Zhong Zhen Zhang Huan Zhai Gefei Guan Guibo Yu 《PloS one》2015,10(5)
BackgroundPeripheral artery disease (PAD), which is caused by atherosclerosis, results in progressive narrowing and occlusion of the peripheral arteries and inhibits blood flow to the lower extremities. Therapeutic angiogenesis is a promising strategy for treating ischemia caused by PAD. Nitric oxide (NO) has been shown to be a key mediator of angiogenesis. It has been demonstrated that β-cyclodextrincan stimulate vessel growth in rabbit corneas. In this study, we assessed the mechanism of action and therapeutic potential of a new angiogenic molecule, (2-hydroxypropyl)-β-cyclodextrin (2HP-β-CD).ConclusionsTherapeutic angiogenesis by 2HP-β-CD may be beneficial to patients with PAD. 相似文献
3.
4.
Yan Xue Liu Jia Wu Ke-Xin Yang Nan Pan Li-Ben Song Ying Liu Yang Tang Zhong-Hua 《Journal of Plant Growth Regulation》2022,41(6):2421-2434
Journal of Plant Growth Regulation - Early-spring plants are a special type of plant that complete their life cycle promptly in cold, early spring. Very little effort has been made into researching... 相似文献
5.
6.
7.
In order to investigate polymeric flavonoids, the polycondensate of catechin with glyoxylic acid (PCG) was prepared and its chemically antioxidant, cellular antioxidant (CAA) and α-glucosidase inhibitory activities were evaluated. The DPPH and ABTS radical scavenging activities and antiproliferative effect of PCG were lower than those of catechin, while PCG had higher CAA activity than catechin. In addition, PCG had very high α-glucosidase inhibitory activities (IC50 value, 2.59 μg/mL) in comparison to catechin (IC50 value, 239.27 μg/mL). Inhibition kinetics suggested that both PCG and catechin demonstrated a mixture of noncompetitive and anticompetitive inhibition. The enhanced CAA and α-glucosidase inhibitor activities of PCG could be due to catechin polymerization enhancing the binding capacity to the cellular membrane and enzymes. 相似文献
8.
Agar Diffusion Method for Negative Staining of Microbial Suspensions in Salt Solutions 总被引:5,自引:3,他引:2 下载免费PDF全文
Microbial suspensions in a saline medium can be prepared for negative staining by a simple agar diffusion method that achieves a high degree of particle concentration. 相似文献
9.
Li Zhang Shan Lei Hui Xie Qianqian Li Shuo Liu Qiang Liu Weijin Huang Xinyue Xiao Youchun Wang 《中国病毒学》2020,35(2):235-239
正Dear Editor,Marburg virus(MARV) belongs to the Filoviridae family,along with the related Ebola virus(EBOV). Although MARV is less renowned than EBOV, it causes an equally devastating disease, with clinical symptoms similar to EBOV infection and a remarkably high mortality rate. To 相似文献