全文获取类型
收费全文 | 2609篇 |
免费 | 8篇 |
国内免费 | 25篇 |
专业分类
系统科学 | 45篇 |
丛书文集 | 2篇 |
教育与普及 | 11篇 |
理论与方法论 | 41篇 |
现状及发展 | 293篇 |
研究方法 | 366篇 |
综合类 | 1785篇 |
自然研究 | 99篇 |
出版年
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 25篇 |
2017年 | 16篇 |
2016年 | 30篇 |
2015年 | 22篇 |
2014年 | 22篇 |
2013年 | 44篇 |
2012年 | 203篇 |
2011年 | 351篇 |
2010年 | 72篇 |
2009年 | 10篇 |
2008年 | 223篇 |
2007年 | 232篇 |
2006年 | 223篇 |
2005年 | 250篇 |
2004年 | 253篇 |
2003年 | 187篇 |
2002年 | 243篇 |
2001年 | 5篇 |
2000年 | 17篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 9篇 |
1982年 | 10篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1971年 | 6篇 |
1970年 | 6篇 |
1967年 | 5篇 |
排序方式: 共有2642条查询结果,搜索用时 265 毫秒
31.
32.
Salamah M. Alwahsh Hassan Rashidi David C. Hay 《Cellular and molecular life sciences : CMLS》2018,75(8):1307-1324
The prevalence of liver diseases is increasing globally. Orthotopic liver transplantation is widely used to treat liver disease upon organ failure. The complexity of this procedure and finite numbers of healthy organ donors have prompted research into alternative therapeutic options to treat liver disease. This includes the transplantation of liver cells to promote regeneration. While successful, the routine supply of good quality human liver cells is limited. Therefore, renewable and scalable sources of these cells are sought. Liver progenitor and pluripotent stem cells offer potential cell sources that could be used clinically. This review discusses recent approaches in liver cell transplantation and requirements to improve the process, with the ultimate goal being efficient organ regeneration. We also discuss the potential off-target effects of cell-based therapies, and the advantages and drawbacks of current pre-clinical animal models used to study organ senescence, repopulation and regeneration. 相似文献
33.
34.
35.
The purpose of the paper is to present a framework that enables action researchers to create quality action research projects within the organization development (OD) domain using the broad criteria of being rigorous, reflective and relevant and so contribute to the realm of practical knowing. What constitutes good quality action research within OD is a difficult question, given the broad range of approaches that operates in a wide variety of settings and with great diversity. It advances specific dimensions by which action researchers can create, review and assess quality in action research work. This integrative framework and criteria are practical tools to enable action researchers to create quality action research in OD. 相似文献
36.
37.
Milne JC Lambert PD Schenk S Carney DP Smith JJ Gagne DJ Jin L Boss O Perni RB Vu CB Bemis JE Xie R Disch JS Ng PY Nunes JJ Lynch AV Yang H Galonek H Israelian K Choy W Iffland A Lavu S Medvedik O Sinclair DA Olefsky JM Jirousek MR Elliott PJ Westphal CH 《Nature》2007,450(7170):712-716
Calorie restriction extends lifespan and produces a metabolic profile desirable for treating diseases of ageing such as type 2 diabetes. SIRT1, an NAD+-dependent deacetylase, is a principal modulator of pathways downstream of calorie restriction that produce beneficial effects on glucose homeostasis and insulin sensitivity. Resveratrol, a polyphenolic SIRT1 activator, mimics the anti-ageing effects of calorie restriction in lower organisms and in mice fed a high-fat diet ameliorates insulin resistance, increases mitochondrial content, and prolongs survival. Here we describe the identification and characterization of small molecule activators of SIRT1 that are structurally unrelated to, and 1,000-fold more potent than, resveratrol. These compounds bind to the SIRT1 enzyme-peptide substrate complex at an allosteric site amino-terminal to the catalytic domain and lower the Michaelis constant for acetylated substrates. In diet-induced obese and genetically obese mice, these compounds improve insulin sensitivity, lower plasma glucose, and increase mitochondrial capacity. In Zucker fa/fa rats, hyperinsulinaemic-euglycaemic clamp studies demonstrate that SIRT1 activators improve whole-body glucose homeostasis and insulin sensitivity in adipose tissue, skeletal muscle and liver. Thus, SIRT1 activation is a promising new therapeutic approach for treating diseases of ageing such as type 2 diabetes. 相似文献
38.
Cdk1 is sufficient to drive the mammalian cell cycle 总被引:1,自引:0,他引:1
Santamaría D Barrière C Cerqueira A Hunt S Tardy C Newton K Cáceres JF Dubus P Malumbres M Barbacid M 《Nature》2007,448(7155):811-815
39.
40.