全文获取类型
收费全文 | 179970篇 |
免费 | 1146篇 |
国内免费 | 34篇 |
学科分类
医药卫生 | 181150篇 |
出版年
2023年 | 34篇 |
2021年 | 89篇 |
2020年 | 63篇 |
2019年 | 103篇 |
2018年 | 22011篇 |
2017年 | 17445篇 |
2016年 | 19604篇 |
2015年 | 1004篇 |
2014年 | 954篇 |
2013年 | 906篇 |
2012年 | 7189篇 |
2011年 | 21261篇 |
2010年 | 18946篇 |
2009年 | 11613篇 |
2008年 | 19694篇 |
2007年 | 21893篇 |
2006年 | 722篇 |
2005年 | 2360篇 |
2004年 | 3541篇 |
2003年 | 4567篇 |
2002年 | 2707篇 |
2001年 | 408篇 |
2000年 | 560篇 |
1999年 | 336篇 |
1998年 | 262篇 |
1997年 | 252篇 |
1996年 | 131篇 |
1995年 | 151篇 |
1994年 | 129篇 |
1993年 | 82篇 |
1992年 | 144篇 |
1991年 | 176篇 |
1990年 | 229篇 |
1989年 | 165篇 |
1988年 | 135篇 |
1987年 | 116篇 |
1986年 | 100篇 |
1985年 | 97篇 |
1984年 | 77篇 |
1983年 | 75篇 |
1982年 | 46篇 |
1980年 | 61篇 |
1978年 | 31篇 |
1974年 | 31篇 |
1970年 | 38篇 |
1969年 | 40篇 |
1938年 | 60篇 |
1934年 | 30篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Makiko Kawaguchi Koji Yamamoto Hiroaki Kataoka Aya Izumi Fumiki Yamashita Takumi Kiwaki Takahiro Nishida Eric Camerer Tsuyoshi Fukushima 《Cancer science》2020,111(4):1193-1202
Hepatocyte growth factor activator inhibitor‐1 (HAI‐1), encoded by the SPINT1 gene, is a membrane‐bound protease inhibitor expressed on the surface of epithelial cells. Hepatocyte growth factor activator inhibitor‐1 regulates type II transmembrane serine proteases that activate protease‐activated receptor‐2 (PAR‐2). We previously reported that deletion of Spint1 in ApcMin/+ mice resulted in accelerated formation of intestinal tumors, possibly through enhanced nuclear factor‐κB signaling. In this study, we examined the role of PAR‐2 in accelerating tumor formation in the ApcMin/+ model in the presence or absence of Spint1. We observed that knockout of the F2rl1 gene, encoding PAR‐2, not only eliminated the enhanced formation of intestinal tumors caused by Spint1 deletion, but also reduced tumor formation in the presence of Spint1. Exacerbation of anemia and weight loss associated with HAI‐1 deficiency was also normalized by compound deficiency of PAR‐2. Mechanistically, signaling triggered by deregulated protease activities increased nuclear translocation of RelA/p65, vascular endothelial growth factor expression, and vascular density in ApcMin/+‐induced intestinal tumors. These results suggest that serine proteases promote intestinal carcinogenesis through activation of PAR‐2, and that HAI‐1 plays a critical tumor suppressor role as an inhibitor of matriptase, kallikreins, and other PAR‐2 activating proteases. 相似文献
2.
Yoshida Akihito Motomura Kazuya Natsume Atsushi Chalise Lushun Iijima Kentaro Hara Daisuke Kadono Izumi Wakai Kenji Wakabayashi Toshihiko 《Journal of neuro-oncology》2020,146(1):195-205
Journal of Neuro-Oncology - This study aimed to investigate the preoperative predictive factors affecting return to work in patients with gliomas in the left cerebral hemisphere undergoing awake... 相似文献
3.
Huinan Zhang Jingru Meng Shimeng Zhou Yunhan Liu Di Qu Ling Wang Xubo Li Ning Wang Xiaoxing Luo Xue Ma 《The AAPS journal》2016,18(2):385-394
Exendin-4 is now considered as a promising drug for the treatment of cerebral ischemia. To determine the neuroprotective effects of intranasal exendin-4, C57BL/6J mice were intranasally administered with exendin-4 daily for 7 days before middle cerebral artery occlusion (MCAO) surgery. Intranasally administered exendin-4 produced higher brain concentrations and lower plasma concentrations when compared to identical doses administered interperitoneally. Neurological deficits and volume of infarcted lesions were analyzed 24 h after ischemia. Intranasal administration of exendin-4 exhibited significant neuroprotection in C57BL/6 mice subjected to MCAO by reducing neurological deficit scores and infarct volume. The neuroprotective effects of exendin-4 were blocked by the knockdown of GLP-1R with shRNA. However, exendin-4 has no impact on glucose and insulin levels which indicated that the neuroprotective effect was mediated by the activation of GLP-1R in the brain. Exendin-4 intranasal administration restored the balance between pro- and anti-apoptotic proteins and decreased the expression of Caspase-3. The anti-apoptotic effect was mediated by the cAMP/PKA and PI3K/Akt pathway. These findings provided evidence that exendin-4 intranasal administration exerted a neuroprotective effect mediated by an anti-apoptotic mechanism in MCAO mice and protected neurons against ischemic injury through the GLP-1R pathway in the brain. Intranasal delivery of exendin-4 might be a promising strategy for the treatment of ischemic stroke. 相似文献
4.
5.
Khushbu K. Modi Suresh B. Rangasamy Sridevi Dasarathi Avik Roy Kalipada Pahan 《Journal of neuroimmune pharmacology》2016,11(4):693-707
This study underlines the importance of cinnamon, a commonly used natural spice and flavoring material, and its metabolite sodium benzoate (NaB) in converting poor learning mice to good learning ones. NaB, but not sodium formate, was found to upregulate plasticity-related molecules, stimulate NMDA- and AMPA-sensitive calcium influx and increase of spine density in cultured hippocampal neurons. NaB induced the activation of CREB in hippocampal neurons via protein kinase A (PKA), which was responsible for the upregulation of plasticity-related molecules. Finally, spatial memory consolidation-induced activation of CREB and expression of different plasticity-related molecules were less in the hippocampus of poor learning mice as compared to good learning ones. However, oral treatment of cinnamon and NaB increased spatial memory consolidation-induced activation of CREB and expression of plasticity-related molecules in the hippocampus of poor-learning mice and converted poor learners into good learners. These results describe a novel property of cinnamon in switching poor learners to good learners via stimulating hippocampal plasticity. 相似文献
6.
Savleen Kaur Sonam Yangzes Swati Singh Nishant Sachdev 《International ophthalmology》2016,36(3):335-340
To evaluate the efficacy and safety of treatment of diabetic macular edema (persistent type) with difluprednate ophthalmic emulsion 0.05 % (off label use). 20 patients with persistent diabetic macular edema were enrolled. In all subjects, more than 4 months had passed since prior treatment. All patients were treated with difluprednate ophthalmic emulsion 0.05 % three times daily for 3 months. At the end of 3 months the visual acuity had increased by two lines to a mean value of 0.61 ± 0.18 on logMAR from a baseline value of 0.885 ± 0.20 and the central retinal thickness had decreased from 423 ± 72.04 microns to 345 ± 68.7 microns. Hence, there was a total of 18.4 % decrease in retinal thickness on difluprednate. Major side effects included raised intraocular pressure in 20 %. Difluprednate is a potent and strong steroid which causes a rapid decrease in persistent diabetic macular edema. However, the potential side effect of raised intraocular pressure limits its use as an adjuvant therapy in non-steroid responders. 相似文献
7.
8.
Tobacco use is common among homeless adults, yet few homeless shelters offer tobacco dependence treatment. Using a pre-intervention and post-intervention study design, we pilot tested the feasibility of a capacity building intervention that consisted of a 3.5-h training for shelter staff to provide cessation counseling. Staff (n = 12) and homeless clients (n = 46) completed questionnaires at pre-intervention, post-intervention (6 weeks), and at 12-weeks follow-up. Staff completed a questionnaire on tobacco-related knowledge, attitudes toward and practices around treating tobacco dependence, and self-efficacy in providing cessation counseling (score range 1–5). Clients completed a questionnaire on tobacco-related knowledge, attitudes toward tobacco dependence, and receipt of tobacco-related services from the program (score range 1–5). We used repeated measures linear regression analysis to examine change in scores over time. From pre-intervention to post-intervention, staff knowledge (β coefficient 0.4, 95 % CI 0.1–0.8) and efficacy (β coefficient 0.4, 95 % CI 0.2–0.7) in treating tobacco dependence increased. Client receipt of tobacco-related program services increased significantly from post-intervention to follow-up (β coefficient 0.3, 95 % CI 0.1–0.5). A brief capacity building intervention has the potential to increase tobacco-related interventions among clients in homeless shelters. 相似文献
9.
Continuous processing in pharmaceutical manufacturing is a relatively new approach that has generated significant attention. While it has been used for decades in other industries, showing significant advantages, the pharmaceutical industry has been slow in its adoption of continuous processing, primarily due to regulatory uncertainty. This paper aims to help address these concerns by introducing methods for batch definition, raw material traceability, and sensor frequency determination. All of the methods are based on established engineering and mathematical principles, especially the residence time distribution (RTD). This paper introduces a risk-based approach to address content uniformity challenges of continuous manufacturing. All of the detailed methods are discussed using a direct compaction manufacturing line as the main example, but the techniques can easily be applied to other continuous manufacturing methods such as wet and dry granulation, hot melt extrusion, capsule filling, etc. 相似文献
10.