全文获取类型
收费全文 | 1305篇 |
免费 | 64篇 |
国内免费 | 96篇 |
专业分类
系统科学 | 31篇 |
丛书文集 | 23篇 |
教育与普及 | 14篇 |
理论与方法论 | 7篇 |
现状及发展 | 93篇 |
综合类 | 1295篇 |
自然研究 | 2篇 |
出版年
2024年 | 4篇 |
2023年 | 16篇 |
2022年 | 11篇 |
2021年 | 24篇 |
2020年 | 24篇 |
2019年 | 20篇 |
2018年 | 19篇 |
2017年 | 31篇 |
2016年 | 19篇 |
2015年 | 42篇 |
2014年 | 71篇 |
2013年 | 64篇 |
2012年 | 82篇 |
2011年 | 98篇 |
2010年 | 70篇 |
2009年 | 59篇 |
2008年 | 62篇 |
2007年 | 104篇 |
2006年 | 95篇 |
2005年 | 78篇 |
2004年 | 69篇 |
2003年 | 48篇 |
2002年 | 58篇 |
2001年 | 32篇 |
2000年 | 38篇 |
1999年 | 33篇 |
1998年 | 22篇 |
1997年 | 21篇 |
1996年 | 15篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 18篇 |
1992年 | 11篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 15篇 |
1984年 | 4篇 |
排序方式: 共有1465条查询结果,搜索用时 296 毫秒
121.
Summary I.v. administration of vasoactive intestinal polypeptide (VIP) to ring doves significantly elevated the plasma concentration of prolactin after 10 min in a dose-related manner. The plasma prolactin concentration of nonbreeding doves with low basal levels was increased by a similar amount as in brooding doves whose initially high concentration of plasma prolactin had been reduced by nest deprivation prior to treatment. 相似文献
122.
We investigated the effect of aging on glucose uptake, glucose-induced O2 consumption, glucose-induced45Ca movements, and calmodulin content to elucidate age-related impairment of glucose-induced insulin release in pancreatic islets of Wistar rats. Intact pancreatic islets from old (24-month-old) rats showed impaired glucose-induced insulin release; glucose uptake and O2 consumption were lower in old than in young (2-month-old) or adult (12-month-old) rats. Moreover,45Ca uptake and calmodulin content were decreased in pancreatic islets from older rats, which explained the impairment in glucose-induced insulin release in aging. No major differences between the 3 age groups in glucose-induced45Ca efflux in pancreatic islets were observed. 相似文献
123.
Summary Noradrenaline and taurine release from superfused rat cerebral cortex slices was stimulated by potassium ions, veratrine, ouabain and omission of sodium ions. Tetanus toxin enhanced only the ouabain-evoked calcium-dependent noradrenaline release and the ouabain-evoked calcium-independent taurine release. The uptake of both was marginally affected. 相似文献
124.
何农高 《西华师范大学学报(哲学社会科学版)》1991,12(4):333-335
抗药性是肿瘤化疗的最大障碍之一,具抗药性的肿瘤细胞药物外排功能很强,而钙阻断剂能抑制抗癌药物从抗药性肿癌细胞排出,导致细胞抗药性减弱,可用于肿囊化疗,有潜在的临床应用价值,但有副作用。故应寻求毒副作用小类似钙阻断剂的其他修饰物以促进肿癌化疗。 相似文献
125.
Summary Using an interdisciplinary approach, the current position in the dental amalgam controversy and the potential impact of amalgam mercury on human health are reviewed. Aspects of materials science, corrosion, mercury exposure, toxicology, neurology and immunology are included.New data on mercury exposure from corroded amalgam fillings in vivo are presented. The exposure can reach levels considerably over known threshold limit values. Also, measurements of mercury absorption from intraoral air are presented. The vital importance of avoiding a galvanic amalgam-gold coupling is emphasized. The symptomatology of a disabled patient, who recovered after amalgam removal, has been included.It is concluded that discussion of the dental amalgam issue has suffered from the lack of an interdisciplinary approach. It would be wise to learn from the lesson of acrodynia, and consider amalgam mercury among other possible factors in neurological and immunological diseases of unclear etiology. 相似文献
126.
《科学通报(英文版)》1996,41(15):1266-1266
127.
中华鳖常见致病菌对13种抗菌药物的敏感性测定 总被引:1,自引:0,他引:1
本研究检测了13种抗菌药物对7株中华鳖致病菌的最小抑菌浓度(MIC),结果表明,从河南郑州的患病中华鳖体内分离的菌株较湖北武汉、湖北咸宁的病鳖体内分离的菌株对各类药物的敏感性强,而从武汉和咸宁产地的病鳖体内分离的菌株其对各类药物的敏感性也有很大差异,结果显示供试菌株对抗菌药物产生了不同程度的耐药性,推测滥用药物和用药方法不当是导致病原菌产生耐药性的原因。 相似文献
128.
韩光盈 《山东科技大学学报(自然科学版)》1988,(1)
本文阐述小型低温强剖循环热水采暖系统中预防炉水汽化、循环水的热膨胀、水击以及排污、放气等安全装置的原理、结构和操作方法。 相似文献
129.
Dobner PR 《Cellular and molecular life sciences : CMLS》2005,62(17):1946-1963
The 13-amino acid peptide neurotensin (NT) was discovered over 30 years ago and has been implicated in a wide variety of neurotransmitter and endocrine functions. This review focuses on four areas where there has been substantial recent progress in understanding NT signaling and several functions of the endogenous peptide. The first area concerns the functional activation of the high-affinity NT receptor, NTR-1, including the delineation of the NT binding pocket and receptor domains involved in functional coupling to intracellular signaling pathways. The development of NT receptor antagonists and the application of genetic and molecular genetic approaches have accelerated progress in understanding NT function in several areas, including the involvement of NT in antipsychotic drug actions, psychostimulant sensitization and the modulation of pain, and these are reviewed in that order. There is now substantial evidence indicating that NT is required for certain antipsychotic drug actions and that the peptide plays a key role in stress-induced analgesia.Received 18 March 2005; received after revision 9 May 2005; accepted 23 May 2005 相似文献
130.
Jeon YH Heo YS Kim CM Hyun YL Lee TG Ro S Cho JM 《Cellular and molecular life sciences : CMLS》2005,62(11):1198-1220
Phosphodiesterases (PDEs) are essential regulators of cyclic nucleotide signaling with diverse physiological functions. Because of their great market potential and therapeutic importance, PDE inhibitors became recognized as important therapeutic agents in the treatment of various diseases. Currently, there are seven PDE inhibitors on the market, and the pharmacological and safety evaluations of many drug candidates are in progress. Three-dimensional (3D) structures of catalytic domains of PDE 1, -3, -4, -5 and -9 in the presence of their inhibitors are now available, and can be utilized for rational drug design. Recent advances in molecular pharmacology of PDE isoenzymes resulted in identification of new potential applications of PDE inhibitors in various therapeutic areas, including dementia, depression and schizophrenia. This review will describe the latest advances in PDE research on 3D structural studies, the potential of therapeutic applications and the development of drug candidates.Received 30 November 2004; received after revision 24 January 2005; accepted 5 February 2005 相似文献