全文获取类型
| 收费全文 | 23191篇 |
| 免费 | 1112篇 |
| 国内免费 | 65篇 |
专业分类
| 耳鼻咽喉 | 364篇 |
| 儿科学 | 702篇 |
| 妇产科学 | 402篇 |
| 基础医学 | 2734篇 |
| 口腔科学 | 314篇 |
| 临床医学 | 2160篇 |
| 内科学 | 4932篇 |
| 皮肤病学 | 570篇 |
| 神经病学 | 1932篇 |
| 特种医学 | 797篇 |
| 外科学 | 3230篇 |
| 综合类 | 427篇 |
| 现状与发展 | 1篇 |
| 一般理论 | 20篇 |
| 预防医学 | 1992篇 |
| 眼科学 | 574篇 |
| 药学 | 1550篇 |
| 2篇 | |
| 中国医学 | 41篇 |
| 肿瘤学 | 1624篇 |
出版年
| 2024年 | 102篇 |
| 2023年 | 136篇 |
| 2022年 | 264篇 |
| 2021年 | 572篇 |
| 2020年 | 350篇 |
| 2019年 | 488篇 |
| 2018年 | 613篇 |
| 2017年 | 419篇 |
| 2016年 | 506篇 |
| 2015年 | 545篇 |
| 2014年 | 797篇 |
| 2013年 | 1110篇 |
| 2012年 | 1600篇 |
| 2011年 | 1682篇 |
| 2010年 | 952篇 |
| 2009年 | 868篇 |
| 2008年 | 1414篇 |
| 2007年 | 1501篇 |
| 2006年 | 1455篇 |
| 2005年 | 1381篇 |
| 2004年 | 1400篇 |
| 2003年 | 1221篇 |
| 2002年 | 1098篇 |
| 2001年 | 285篇 |
| 2000年 | 228篇 |
| 1999年 | 262篇 |
| 1998年 | 265篇 |
| 1997年 | 185篇 |
| 1996年 | 155篇 |
| 1995年 | 168篇 |
| 1994年 | 144篇 |
| 1993年 | 131篇 |
| 1992年 | 142篇 |
| 1991年 | 127篇 |
| 1990年 | 95篇 |
| 1989年 | 101篇 |
| 1988年 | 97篇 |
| 1987年 | 94篇 |
| 1986年 | 88篇 |
| 1985年 | 94篇 |
| 1984年 | 109篇 |
| 1983年 | 84篇 |
| 1982年 | 93篇 |
| 1981年 | 109篇 |
| 1980年 | 86篇 |
| 1979年 | 85篇 |
| 1978年 | 65篇 |
| 1977年 | 79篇 |
| 1976年 | 58篇 |
| 1975年 | 50篇 |
排序方式： 共有10000条查询结果，搜索用时 15 毫秒
941.
Keith R. Spencer Zachariah W. Foster Nazifa Abdul Rauf Latease Guilderson Derek Collins James G. Averill Sean E. Walker Ian Robey Jonathan D. Cherry Victor E. Alvarez Bertrand R. Huber Ann C. McKee Neil W. Kowall Christopher B. Brady Thor D. Stein 《Brain pathology (Zurich, Switzerland)》2020,30(6):1028
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting both the upper and lower motor neurons. Although ALS typically leads to death within 3 to 5 years after initial symptom onset, approximately 10% of patients with ALS live more than 10 years after symptom onset. We set out to determine similarities and differences in clinical presentation and neuropathology in persons with ALS with long vs. those with standard duration. Participants were United States military Veterans with a pathologically confirmed diagnosis of ALS (n = 179), dichotomized into standard duration (<10 years) and long‐duration (≥10 years). The ALS Functional Rating Scale‐Revised (ALSFRS‐R) was administered at study entry and semi‐annually thereafter until death. Microglial density was determined in a subset of participants. long‐duration ALS occurred in 76 participants (42%) with a mean disease duration of 16.3 years (min/max = 10.1/42.2). Participants with long‐duration ALS were younger at disease onset (P = 0.002), had a slower initial ALS symptom progression on the ALSFRS‐R (P < 0.001) and took longer to diagnose (P < 0.002) than standard duration ALS. Pathologically, long‐duration ALS was associated with less frequent TDP‐43 pathology (P < 0.001). Upper motor neuron degeneration was similar; however, long‐duration ALS participants had less severe lower motor neuron degeneration at death (P < 0.001). In addition, the density of microglia was decreased in the corticospinal tract (P = 0.017) and spinal cord anterior horn (P = 0.009) in long‐duration ALS. Notably, many neuropathological markers of ALS were similar between the standard and long‐duration groups and there was no difference in the frequency of known ALS genetic mutations. These findings suggest that the lower motor neuron system is relatively spared in long‐duration ALS and that pathological progression is likely slowed by as yet unknown genetic and environmental modifiers. 相似文献
942.
943.
944.
Karolina Pytka Neil Dawson Kyoko Tossell Mark A. Ungless Robin Plevin Ros R. Brett Trevor J. Bushell 《The European journal of neuroscience》2020,52(2):2838-2852
Mitogen‐activated protein kinases (MAPKs) regulate normal brain functioning, and their dysfunction is implicated in a number of brain disorders. Thus, there is great interest in understanding the signalling systems that control MAPK functioning. One family of proteins that contribute to this process, the mitogen‐activated protein kinase phosphatases (MKPs), directly inactivate MAPKs through dephosphorylation. Recent studies have identified novel functions of MKPs in foetal development, the immune system, cancer and synaptic plasticity and memory. In the present study, we performed an unbiased investigation using MKP‐2?/? mice to assess whether MKP‐2 plays a global role in modulating brain function. Local cerebral glucose utilization is significantly increased in the ventral tegmental area (VTA) of MKP‐2?/? mice, with connectivity analysis revealing alterations in VTA functional connectivity, including a significant reduction in connectivity to the nucleus accumbens and hippocampus. In addition, spontaneous excitatory postsynaptic current frequency, but not amplitude, onto putative dopamine neurons in the VTA is increased in MKP‐2?/? mice, which indicates that increased excitatory drive may account for the increased VTA glucose utilization. Consistent with modified VTA function and connectivity, in behavioural tests MKP‐2?/? mice exhibited increased sucrose preference and impaired amphetamine‐induced hyperlocomotion. Overall, these data reveal that MKP‐2 plays a role in modulating VTA function and that its dysfunction may contribute to brain disorders in which altered reward processing is present. 相似文献
945.
Anusha Mohan Neil Bhamoo Juan S. Riquelme Samantha Long Arnaud Norena Sven Vanneste 《Human brain mapping》2020,41(7):1819-1832
Several studies have demonstrated the neural correlates of chronic tinnitus. However, we still do not understand what happens in the acute phase. Past studies have established Zwicker tone (ZT) illusions as a good human model for acute tinnitus. ZT illusions are perceived following the presentation of a notched noise stimulus, that is, broadband noise with a narrow band‐stop filter (notch). In the current study, we compared the neural correlates of the reliable perception of a ZT illusion to that which is not. We observed changes in evoked and total theta power in wide‐spread regions of the brain particularly in the temporal‐parietal junction, pregenual anterior cingulate cortex/ventromedial prefrontal cortex (pgACC/vmPFC), parahippocampus during perception of the ZT illusion. Furthermore, we observe that increased theta power significantly predicts a gradual positive change in the intensity of the ZT illusion. Such changes may suggest a malfunction of the sensory gating system that enables habituation to redundant stimuli and suppresses hyperactivity. It could also suggest a successful retrieval of the memory of the missing frequencies, resulting in their conscious perception indicating the role of higher‐order processing in the mechanism of action of ZT illusions. To establish a more concrete relationship between ZT illusion and chronic tinnitus, future longitudinal studies following up a much larger sample of participants who reliably perceive a ZT illusion to see if they develop tinnitus at a later stage is essential. This could inform us if the ZT illusion may be a precursor to chronic tinnitus. 相似文献
946.
Jesse Mez MD MS Daniel H. Daneshvar MD PhD Bobak Abdolmohammadi BA Alicia S. Chua MS Michael L. Alosco PhD Patrick T. Kiernan BA Laney Evers BA Laura Marshall BA Brett M. Martin MS Joseph N. Palmisano MS Christopher J. Nowinski PhD Ian Mahar PhD Jonathan D. Cherry PhD Victor E. Alvarez MD Brigid Dwyer MD Bertrand R. Huber MD PhD Thor D. Stein MD PhD Lee E. Goldstein MD PhD Douglas I. Katz MD Robert C. Cantu MD Rhoda Au PhD Neil W. Kowall MD Robert A. Stern PhD Michael D. McClean MS ScD Jennifer Weuve MPH ScD Yorghos Tripodis PhD Ann C. McKee MD 《Annals of neurology》2020,87(1):116-131
947.
948.
Pamela R. Hirschberg Pallabi Sarkar Suraj B. Teegala Vanessa H. Routh 《Journal of neuroendocrinology》2020,32(1)
The ventromedial hypothalamus (VMH) plays a complex role in glucose and energy homeostasis. The VMH is necessary for the counter‐regulatory response to hypoglycaemia (CRR) that increases hepatic gluconeogenesis to restore euglycaemia. On the other hand, the VMH also restrains hepatic glucose production during euglycaemia and stimulates peripheral glucose uptake. The VMH is also important for the ability of oestrogen to increase energy expenditure. This latter function is mediated by VMH modulation of the lateral/perifornical hypothalamic area (lateral/perifornical hypothalamus) orexin neurones. Activation of VMH AMP‐activated protein kinase (AMPK) is necessary for the CRR. By contrast, VMH AMPK inhibition favours decreased basal glucose levels and is required for oestrogen to increase energy expenditure. Specialised VMH glucose‐sensing neurones confer the ability to sense and respond to changes in blood glucose levels. Glucose‐excited (GE) neurones increase and glucose‐inhibited (GI) neurones decrease their activity as glucose levels rise. VMH GI neurones, in particular, appear to be important in the CRR, although a role for GE neurones cannot be discounted. AMPK mediates glucose sensing in VMH GI neurones suggesting that, although activation of these neurones is important for the CRR, it is necessary to silence them to lower basal glucose levels and enable oestrogen to increase energy expenditure. In support of this, we found that oestrogen reduces activation of VMH GI neurones in low glucose by inhibiting AMPK. In this review, we present the evidence underlying the role of the VMH in glucose and energy homeostasis. We then discuss the role of VMH glucose‐sensing neurones in mediating these effects, with a strong emphasis on oestrogenic regulation of glucose sensing and how this may affect glucose and energy homeostasis. 相似文献
949.
950.