全文获取类型
收费全文 | 490篇 |
免费 | 14篇 |
国内免费 | 13篇 |
专业分类
系统科学 | 9篇 |
丛书文集 | 12篇 |
教育与普及 | 5篇 |
理论与方法论 | 1篇 |
现状及发展 | 115篇 |
综合类 | 368篇 |
自然研究 | 7篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 18篇 |
2014年 | 18篇 |
2013年 | 13篇 |
2012年 | 27篇 |
2011年 | 12篇 |
2010年 | 12篇 |
2009年 | 22篇 |
2008年 | 33篇 |
2007年 | 21篇 |
2006年 | 24篇 |
2005年 | 23篇 |
2004年 | 27篇 |
2003年 | 18篇 |
2002年 | 21篇 |
2001年 | 14篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 6篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 11篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 32篇 |
1984年 | 6篇 |
排序方式: 共有517条查询结果,搜索用时 15 毫秒
101.
Summary The effect of prolonged food deprivation on the triglyceride level in different types of skeletal muscle was studied in the rat. It has been found that fasting gradually reduces the triglyceride content in each muscle type. It is concluded that i.m. triglycerides play an important role as energy fuel during fasting. 相似文献
102.
The effect of exercise on protein turnover in isolated soleus and extensor digitorium longus muscles
Summary The rate of protein degradation was found to be increased in isolated soleus and extensor digitorum muscles of 60–80 g rats after exercise consisting of running for 120 min. These findings support the hypothesis that exercise causes an increase in skeletal muscle protein degradation, and that both red and white muscles are affected similarly. 相似文献
103.
J. E. Décombaz B. Reffet Y. Bloemhard 《Cellular and molecular life sciences : CMLS》1990,46(5):457-458
Summary To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise. 相似文献
104.
Exposure of voltage-clamped frog skeletal muscle fibres to silver caused a maintained inward current which could be carried by Ca2+, Mg2+ or Na+. Inorganic Ca2+ channel blockers and dithiothreitol (SH reducing agent) diminished this current, but a Na+ channel blocker did not. Thus, silver activates the Ca2+ channel by acting on SH groups in a Ca2+ channel protein. 相似文献
105.
O. Yu. Printseva A. I. Faerman A. V. Maksimenko A. G. Tonevitsky O. B. Ilynsky V. P. Torchilin 《Cellular and molecular life sciences : CMLS》1985,41(10):1342-1344
Summary Monoclonal antibodies to a surface antigen of the modulated smooth muscle cells originally isolated from the rat aorta media were conjugated with ricin A-chain via an oxidized dextran bridge. The interaction of cultured cells with the conjugates obtained and with control substances was monitored following incorporation of14C-leucine radioactivity. It was found that14C-leucine incorporation was suppressed by 80–90% at a conjugate concentration of 10–6–10–7 M. Antigen-negative cells (line IAR; rat hepatocytes) were insensitive to the conjugate at any concentration used. Control use of purified ricin A-chain, native or oxidized dextran, specific and nonspecific IgG did not affect normal14C-leucine incorporation. The data obtained may be useful for designing targeted drug transport systems and for selective screening of modulated smooth cells in vascular pathology models in vivo. 相似文献
106.
The distribution of satellite cells (sc) in long-sarcomere muscle fibers from the carpopod extensor muscle of the crayfish (Astacus fluviatilis) has been studied electron-microscopically. The sc are spindle-shaped and are oriented parallel to the long axis of a fiber. The mean lengths of sc nuclei (17.00 m) and that of myonuclei (18.35 m) differ non-significantly. In older animals, the mean ratio of the number of sc nuclei to the total number of nuclei (sc nuclei + myonrclei) is 0.0716, 0.0848, and 0.034 for the tendon, central and shell segments, respectively. The corresponding values for younger animals are 0.158, 0.166, and 0.081. The mean numbers of sc nuclei per mm of a fiber are 94, 117, and 47 (older animals), and 164, 117, and 94 (younger animals) for the tendon, central and shell segments, respectively. The high incidence of sc per unit fiber length in crayfish may be related to the fact that crayfish muscle fibers have a much larger diameter than vertebrate muscle cells. 相似文献
107.
Summary In the guinea pig taenia coli, when glycogen is depleted by repeating Ca-induced contracture in excess K solution containing no glucose, the tension cannot be maintained. The decrease in tension is accompanied by reduction of high energy phosphate compounds and oxygen consumption. When substrate is readmitted to the glycogendepleted preparation in the presence of 2.4 mM Ca and 20 mM K, the first response is hyperpolarization of the membrane and relaxation, and this is followed by depolarization and development of contracture. The latter response is blocked by verapamil, suggesting that energy supply increases the Ca conductance of the plasma membrane. The early response is considered to be due to activation of electrogenic Ca pump, since this is not affected by ouabain as well as removal of Na and K. ATP produced by substrate readmission is probably preferentially utilized for Ca pump activation to reduce the intracellular. Ca. The recovery of tension is likely to be brought about by ATP supply not only to the contractile machinery but also to the plasma membrane to remove inactivation of Ca conductance. It is postulated that as the energy source is depleted, energy consumption is automatically limited by suppressing Ca influx, as a selfdefence mechanism. Since HB is as effective as glucose in the recovery of these processes, and also in the activation of electrogenic Na pump, the matabolic pathway of oxidative phosphorylation alone can support these functions without a contribution of the glycolytic pathway. 相似文献
108.
《高技术通讯(英文版)》2016,(2):120-127
As the pneumatic artificial muscle(PAM) has flexibility properties similar to biological muscle which is widely used in robotics as one kind of actuators,the bionic mechanism driven by PAMs becomes a hot spot in robotics.In this paper,a kind of musculoskeletal leg mechanism driven by PAMs is presented,which has three joints driven by four PAMs.The jumping movement is divided into three phases.The forward and inverse kinematics of the leg mechanism in different jumping phases is derived.Considering the ground reaction force between feet and environment,the dynamic in different jumping phases is analyzed by Lagrange method,then the relationship between PAM driving force and the joints angular displacement,angular velocity,angular acceleration during one jumping cycle is obtained,which will lay a foundation for the jumping experiment of the musculoskeletal leg mechanism. 相似文献
109.
为了更加真实地模拟细胞内环境,在人肌肌酸激酶(HCK)的去折叠环境中同时加入了大分子拥挤试剂(葡聚糖)和小分子渗透剂(蔗糖),采用酶活性、荧光发射谱和溶液浊度检测等方法研究肌酸激酶在含有蔗糖和葡聚糖的混合拥挤环境中的稳定性,结果表明在肌酸激酶盐酸胍变性过程中,蔗糖不仅抑制肌酸激酶酶活性的丧失,还稳定肌酸激酶的构象,而葡聚糖对肌酸激酶保护能力相对较弱.对于热变性过程,相同质量浓度的蔗糖和葡聚糖能同等程度地减缓肌酸激酶活性的丧失,并抑制聚沉的产生.在葡聚糖和蔗糖同时存在的情况下,两者的保护作用可以累加,并共同维持肌酸激酶的稳定性. 相似文献
110.
Perfluorooctane sulfonate (PFOS) and other fluorochemicals in viscera and muscle of farmed pigs and chickens in Beijing,China 总被引:2,自引:0,他引:2
Eleven perfluorinated compounds (PFCs) were determined in tissue samples from farmed pigs and chickens (n=143) that were purchased in Beijing in March 2009. The total PFCs mean concentration was the highest in pig liver (3.438 ng g–1 wet weight (ww)), followed by pig kidney (0.508 ng g–1 (ww)), pig heart (0.167 ng g–1 (ww)), chicken liver (0.098 ng g–1 (ww)), chicken heart (0.050 ng g–1 (ww)), pork loin (0.018 ng g–1 (ww)), and chicken breast (0.012 ng g–1 (ww)). Among the PFCs analyzed, perfluorooctane sulfonate (PFOS) was the predominant compound in viscera and muscle of farmed pigs and chickens. In addition, a strong linear correlation (r = 0.932) was observed between the concentrations of PFOS and perfluoroundecanoic acid (PFUnDA) in pig liver. Our preliminary conclusion is that there is little potential risk of exposure to PFCs via the consumption of these products in Beijing. 相似文献