全文获取类型
收费全文 | 582篇 |
免费 | 50篇 |
国内免费 | 58篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 13篇 |
2019年 | 17篇 |
2018年 | 14篇 |
2017年 | 15篇 |
2016年 | 24篇 |
2015年 | 33篇 |
2014年 | 27篇 |
2013年 | 40篇 |
2012年 | 47篇 |
2011年 | 35篇 |
2010年 | 34篇 |
2009年 | 21篇 |
2008年 | 29篇 |
2007年 | 25篇 |
2006年 | 15篇 |
2005年 | 22篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 27篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 11篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 8篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 7篇 |
1973年 | 3篇 |
1971年 | 8篇 |
1969年 | 5篇 |
1966年 | 4篇 |
排序方式: 共有690条查询结果,搜索用时 15 毫秒
681.
682.
683.
Total serum haemolytic complement (HC) activity has been determined in 130 young bulls of the Norwegian Red Cattle Breed (NRF). A highly significant sire effect (p < 0.01) on HC with a corresponding heritability of about 0.75 was estimated. Evidence of any simple mode of inheritance is not produced but the distribution patterns of HC indicate influences of relatively few genes. 相似文献
684.
685.
P.A.R. de Milliano J.G.P. Tijssen P.A. van Zwieten K.I. Lie 《Netherlands heart journal》2001,9(8):334-342
Treatment for heart failure may be directed at relieving symptoms and/or improving prognosis. One of the primary aims of research in heart failure is to alter the progressive decline in pump function and thereby improve prognosis.For many years, diuretics have been known as therapeutics in heart failure and they are very effective in symptom relief. Vasodilators and inotropes also have beneficial effects on symptom relief especially in the acute phase through changes in cardiac output, filling pressures and renal perfusion. However, although these treatments produce short-term relief, none have been shown to influence the disease process and thereby improve mortality. Indeed, many of these drugs may even lead to untoward long-term clinical outcomes as has been shown for example for milrinone and ibopamine.There is overwhelming evidence that drugs interfering with the neurohormonal activation in heart failure not only produce symptomatic relief but are also capable of attenuating disease progression with concomitant reductions in both morbidity and mortality. About a decade ago, convincing and large-scale evidence showed that ACE inhibitors produced favourable effects by antagonising the activated renin-angiotensin system. More recently, β-blockers, which antagonise the activated sympathetic system, were shown to be beneficial in the long term in moderate severe heart failure in terms of significant improvements in both morbidity and mortality. The RALES study further amplified the concept that drugs that interact in the neurohormonal system have beneficial effects. In this study, spironolactone, a weak, potassium-sparing diuretic counteracting aldosterone showed a reduction in mortality in more severe forms of heart failure. 相似文献
686.
Wei‐Guang Shan Zhao‐Ying Wu Wei‐Wei Pang Lie‐Feng Ma You‐Min Ying Zha‐Jun Zhan 《化学与生物多样性》2015,12(11):1718-1724
One new diketopiperazine alkaloid amauromine B ( 1 ), along with three known meroterpenoids, austalide B ( 2 ), austalides N and O ( 3 and 4 ), and two known steroids ( 5 and 6 ), was isolated and identified from the culture broth of the fungus Aspergillus terreus 3.05358. Their structures were elucidated by extensive spectroscopic techniques, including 2D‐NMR and MS analysis, the absolute configuration of 1 was unambiguously established by single crystal X‐ray diffraction analysis. All the isolates were evaluated for their inhibitory effects on α‐glucosidase. Amauromine B ( 1 ) and austalide N ( 3 ) exhibited more potent α‐glucosidase inhibitory activities than the positive control acarbose. 相似文献
687.
The fatty acids of the triacylglycerol fraction of the latex of the rubber plant consists of 97% of a C18 furanoid fatty acid, 10,13-epoxy-11-methyloctadeca-10,12-dienoic. The free fatty acid fraction is composed of a more equally distributed mixture of 16:0, 18:0, 18:1, 18:2 and the furanoid acid. A novel dioxo fatty acid, 10,13-dioxo-11-methyloctadecanoic, was also isolated and characterized. 相似文献
688.
689.
690.
褪黑素是新近引起人们广泛注意的天然抗肿瘤药物,对多种恶性或良性肿瘤具有明显抑制作用。其抗瘤机制复杂而广泛,主要包括调节雌激素作用通路,影响细胞周期,调节生长因子,干扰钙调素和微管蛋白功能,增加细胞间缝隙连接,对细胞代谢的影响以及抗氧化作用和免疫增强作用等。对于褪黑素作用机制的全面了解将有助于其进一步应用于临床。 相似文献