全文获取类型
收费全文 | 2318篇 |
免费 | 194篇 |
国内免费 | 3篇 |
出版年
2021年 | 31篇 |
2020年 | 17篇 |
2019年 | 30篇 |
2018年 | 19篇 |
2017年 | 28篇 |
2016年 | 42篇 |
2015年 | 64篇 |
2014年 | 69篇 |
2013年 | 102篇 |
2012年 | 119篇 |
2011年 | 129篇 |
2010年 | 75篇 |
2009年 | 64篇 |
2008年 | 90篇 |
2007年 | 108篇 |
2006年 | 85篇 |
2005年 | 92篇 |
2004年 | 105篇 |
2003年 | 90篇 |
2002年 | 98篇 |
2001年 | 25篇 |
2000年 | 25篇 |
1999年 | 41篇 |
1998年 | 46篇 |
1997年 | 27篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 22篇 |
1993年 | 25篇 |
1992年 | 30篇 |
1991年 | 26篇 |
1990年 | 20篇 |
1989年 | 27篇 |
1988年 | 23篇 |
1987年 | 16篇 |
1985年 | 21篇 |
1984年 | 26篇 |
1982年 | 35篇 |
1981年 | 27篇 |
1980年 | 31篇 |
1979年 | 16篇 |
1978年 | 27篇 |
1977年 | 20篇 |
1976年 | 26篇 |
1974年 | 24篇 |
1973年 | 21篇 |
1972年 | 17篇 |
1961年 | 17篇 |
1959年 | 15篇 |
1957年 | 16篇 |
排序方式: 共有2515条查询结果,搜索用时 31 毫秒
91.
92.
Maurice Jay Bernard Voirin Aurangzeb Hasan Jean-François Gonnet Marie-Rose Viricel 《Biochemical Systematics and Ecology》1980,8(2):127-132
A survey of the leaves and flowers of 62 representatives of the tribe Loteae (Leguminosae) showed the presence of several classes of flavonoids: flavonol 7-methyl ethers (rhamnocitrin, rhamnetin), 8-O-substituted flavonols (gossypetin, limocitrin, sexangularetin, corniculatusin), 3′,4′,5′-tri-O-substituted flavonols (myricetin, mearnsetin, syringetin, laricitrin), proanthocyanidins and flavone-C-glycosides. The trisubstitution of the B-ring and the 8-O-substitution of the A-ring allow the definition of a major group including the genera Dorycnium, Bonjeania, Lotus and Tetragonolobus. The presence of proanthocyanidins and 7-O-methylation determine a second group consisting of the genus Anthyllis. Finally, Securigera, on the basis of its flavonoid chemistry, appears to be rather remote from other members of the tribe. 相似文献
93.
Maurice Ellis 《BMJ (Clinical research ed.)》1959,1(5117):299-300
94.
95.
96.
On the Mechanism of Integration of Transforming Deoxyribonucleate 总被引:12,自引:0,他引:12
Maurice S. Fox 《The Journal of general physiology》1966,49(6):183-196
The characteristics of the intermediates in the reaction, between DNA and pneumococcus, that results in genetic transformation are described in so far as they have been characterized. Transformation with DNA isolated from bacteria carrying in addition to genetic markers 32P as a radioactive label and 2H and 15N as density labels has permitted the characterization of the product of recombination between the newly introduced DNA and the DNA of a recipient bacterium. The evidence for a single strand displacement mechanism producing a hybrid structure in the DNA of the recipient bacteria is presented. Progeny of single transformants have been examined. The results of these segregation studies permit the further characterization of this hybrid product of transformation as a genetically heterozygous structure. 相似文献
97.
98.
Maurice Campbell 《BMJ (Clinical research ed.)》1950,1(4663):1188-1190
99.
Lin Chung-Ying Cheng Andy S. K. Imani Vida Saffari Mohsen Ohayon Maurice M. Pakpour Amir H. 《Sleep and biological rhythms》2020,18(4):343-349
Sleep and Biological Rhythms - To examine the psychometric properties of the Sleep Condition Indicator (SCI) using different psychometric approaches [including classical test theory, Rasch models,... 相似文献
100.
Richard W. Clayton Ewan A. Langan David M. Ansell Ivo J. H. M. de Vos Klaus Gbel Marlon R. Schneider Mauro Picardo Xinhong Lim Maurice A. M. van Steensel Ralf Paus 《Biological reviews of the Cambridge Philosophical Society》2020,95(3):592-624
The nervous system communicates with peripheral tissues through nerve fibres and the systemic release of hypothalamic and pituitary neurohormones. Communication between the nervous system and the largest human organ, skin, has traditionally received little attention. In particular, the neuro‐regulation of sebaceous glands (SGs), a major skin appendage, is rarely considered. Yet, it is clear that the SG is under stringent pituitary control, and forms a fascinating, clinically relevant peripheral target organ in which to study the neuroendocrine and neural regulation of epithelia. Sebum, the major secretory product of the SG, is composed of a complex mixture of lipids resulting from the holocrine secretion of specialised epithelial cells (sebocytes). It is indicative of a role of the neuroendocrine system in SG function that excess circulating levels of growth hormone, thyroxine or prolactin result in increased sebum production (seborrhoea). Conversely, growth hormone deficiency, hypothyroidism, and adrenal insufficiency result in reduced sebum production and dry skin. Furthermore, the androgen sensitivity of SGs appears to be under neuroendocrine control, as hypophysectomy (removal of the pituitary) renders SGs largely insensitive to stimulation by testosterone, which is crucial for maintaining SG homeostasis. However, several neurohormones, such as adrenocorticotropic hormone and α‐melanocyte‐stimulating hormone, can stimulate sebum production independently of either the testes or the adrenal glands, further underscoring the importance of neuroendocrine control in SG biology. Moreover, sebocytes synthesise several neurohormones and express their receptors, suggestive of the presence of neuro‐autocrine mechanisms of sebocyte modulation. Aside from the neuroendocrine system, it is conceivable that secretion of neuropeptides and neurotransmitters from cutaneous nerve endings may also act on sebocytes or their progenitors, given that the skin is richly innervated. However, to date, the neural controls of SG development and function remain poorly investigated and incompletely understood. Botulinum toxin‐mediated or facial paresis‐associated reduction of human sebum secretion suggests that cutaneous nerve‐derived substances modulate lipid and inflammatory cytokine synthesis by sebocytes, possibly implicating the nervous system in acne pathogenesis. Additionally, evidence suggests that cutaneous denervation in mice alters the expression of key regulators of SG homeostasis. In this review, we examine the current evidence regarding neuroendocrine and neurobiological regulation of human SG function in physiology and pathology. We further call attention to this line of research as an instructive model for probing and therapeutically manipulating the mechanistic links between the nervous system and mammalian skin. 相似文献