首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1999篇
  免费   28篇
  国内免费   12篇
耳鼻咽喉   2篇
儿科学   11篇
妇产科学   6篇
基础医学   475篇
口腔科学   1篇
临床医学   35篇
内科学   140篇
皮肤病学   1篇
神经病学   870篇
特种医学   22篇
外科学   29篇
综合类   80篇
预防医学   42篇
药学   253篇
中国医学   68篇
肿瘤学   4篇
  2021年   13篇
  2020年   10篇
  2019年   14篇
  2018年   11篇
  2016年   14篇
  2015年   25篇
  2014年   47篇
  2013年   49篇
  2012年   47篇
  2011年   70篇
  2010年   57篇
  2009年   78篇
  2008年   84篇
  2007年   58篇
  2006年   60篇
  2005年   48篇
  2004年   42篇
  2003年   81篇
  2002年   50篇
  2001年   62篇
  2000年   61篇
  1999年   49篇
  1998年   62篇
  1997年   49篇
  1996年   43篇
  1995年   44篇
  1994年   51篇
  1993年   55篇
  1992年   42篇
  1991年   45篇
  1990年   34篇
  1989年   32篇
  1988年   46篇
  1987年   38篇
  1986年   34篇
  1985年   42篇
  1984年   37篇
  1983年   21篇
  1982年   42篇
  1981年   25篇
  1980年   35篇
  1979年   26篇
  1978年   27篇
  1977年   27篇
  1976年   31篇
  1975年   16篇
  1974年   20篇
  1973年   29篇
  1972年   12篇
  1970年   9篇
排序方式: 共有2039条查询结果,搜索用时 31 毫秒
71.
背景 随着对抑郁症了解的深入,人们发现其不仅是一种神经退行性疾病,同时还与下丘脑-垂体-甲状腺轴(HPT轴)密切相关,而抑郁症的神经营养因子假说则认为脑源性神经营养因子前体(proBDNF)在抑郁症的发病过程中发挥着一定作用,但抑郁症、HPT轴和proBDNF三者间的关系却鲜有研究。目的 探索甲状腺激素、proBDNF水平与抑郁症之间的关系。方法 选取2017年10月-2018年6月在云南省精神病医院住院及门诊治疗的抑郁症患者43例为病例组。同期选取本院健康体检者31例为对照组。测定并比较两组一般资料及甲状腺激素〔三碘甲状腺原氨酸(T3)、甲状腺素(T4)、游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺激素(TSH)〕、proBDNF水平;分析病例组甲状腺激素、proBDNF水平与汉密尔顿抑郁量表24项(HAMD-24)总分及其各因子评分之间的相关性,甲状腺激素与proBDNF水平的相关性。结果 两组T3、FT4水平比较,差异无统计学意义(P>0.05);病例组T4、FT3、TSH水平低于对照组(P<0.05)。病例组FT3水平与HAMD-24总分及认知障碍评分呈正相关(P<0.05)。两组proBDNF水平比较,差异无统计学意义(P>0.05)。病例组proBDNF水平与HAMD-24总分及其各因子评分均无相关性(P>0.05)。病例组甲状腺激素水平与proBDNF水平无相关性(P>0.05)。结论 抑郁症患者更容易出现焦虑、自杀、偏执、强迫、绝望感及睡眠障碍等问题,且有并发甲状腺功能减退的可能。  相似文献   
72.
Comorbidity of major depressive disorder (MDD) and cardiovascular disease (CVD) represents the fourth leading cause of morbidity and mortality worldwide, and women have a two times greater risk than men. Thus understanding the pathophysiology has widespread implications for attenuation and prevention of disease burden. We suggest that sex-dependent MDD–CVD comorbidity may result from alterations in fetal programming consequent to the prenatal maternal environments that produce excess glucocorticoids, which then drive sex-dependent developmental alterations of the fetal hypothalamic–pituitary–adrenal (HPA) axis circuitry impacting mood, stress regulation, autonomic nervous system (ANS), and the vasculature in adulthood. Evidence is consistent with the hypothesis that disruptions of pathways associated with gamma aminobutyric acid (GABA) in neuronal and vascular development and growth factors have critical roles in key developmental periods and adult responses to injury in heart and brain. Understanding the potential fetal origins of these sex differences will contribute to development of novel sex-dependent therapeutics.  相似文献   
73.
74.
下丘脑是神经内分泌中枢,也是食欲调节中枢.胰高血糖素样肽-1(GLP-1)是一种胃肠道激素,能够在下丘脑表达并对食欲中枢有调节作用.GLP-1作为一种厌食信号肽,通过促肾上腺皮质激素释放激素(CRH)通路、组胺神经元通路、神经肽和刺鼠相关蛋白(NPY/AgRP)以及前阿片黑皮质素原和可卡因-苯丙胺调节转录肽(POMC/CART)通路及AMP活化蛋白激酶(AMPK)介导的摄食负反馈信号通路参与调节摄食活动.针对GLP-1调节摄食作用机制的研究对肥胖、胰岛素抵抗和2型糖尿病的防治有重要的理论意义.  相似文献   
75.
76.
Background: Cockayne syndrome (CS) is a genetic disorder caused by deficient nucleotide excision repair. Patients with CS exhibit progeroid features, developmental delay, and various neurological disorders; they are also known to suffer from sleep problems, which have never been investigated in detail. Objective: The aim of this study is to investigate the pathogenesis of sleep disorders in patients with CS. Methods: We performed a questionnaire survey of the families of patients with CS, enzyme-linked immunosorbent analyses of the melatonin metabolite, 6-sulphatoxymelatonin (6-SM), in the patients’ urine, and immunohistochemistry in the hypothalamus, the basal nucleus of Meynert (NbM), and the pedunculopontine tegmental nucleus (PPN) in four autopsy cases. Results: Sleep–wakefulness rhythms were disturbed in patients with CS, and these disturbances seemed to be related to a reduced urinary excretion of 6-SM. In addition, although the hypothalamic nuclei were comparatively preserved, acetylcholine neurons (AchNs) were severely decreased in the NbM and PPN. Conclusions: AchNs modulate both arousal and rapid eye movement sleep, and selective lesions of AchNs in the PPN and/or NbM in combination with disturbed melatonin metabolism might be involved in the sleep disorders in CS.  相似文献   
77.
78.
Obesity is a world problem that requires a better understanding of its physiological and genetic basis, as well as the mechanisms by which the hypothalamus controls feeding behavior. The volcano mouse Neotomodon alstoni develops obesity in captivity when fed with regular chow diet, providing a novel model for the study of obesity. Females develop obesity more often than males; therefore, in this study, we analysed in females, in proestrous lean and obese, the differences in hypothalamus expression of receptors for leptin, ghrelin (growth hormone secretagogue receptor GHS-R), and VPAC, and correlates for plasma levels of total ghrelin. The main comparisons are between mice fed ad libitum and mice after 24 hours of fasting. Mice above 65 g body weight were considered obese, based on behavioral and physiological parameters such as food intake, plasma free fatty acids, and glucose tolerance. Hypothalamic tissue from obese and lean mice was analysed by western blot. Our results indicate that after ad libitum food access, obese mice show no significant differences in hypothalamic leptin receptors, but a significant increase of 60% in the GHS-R, and a nearly 62% decrease in VPAC2 was noted. After a 24-hour fast, plasma ghrelin increased nearly two fold in both lean and obese mice; increases of hypothalamic leptin receptors and GHS-R were also noted, while VPAC2 did not change significantly; levels of plasma free fatty acids were 50% less after fasting in obese than in lean animals. Our results indicate that in obese N. alstoni mice, the levels of orexigenic receptors in the hypothalamus correlate with overfeeding, and the fact that lean and obese females respond in different ways to a metabolic demand such as a 24-hour fast.  相似文献   
79.
80.
Introduction and objectivesThis study evaluates the pathological and magnetic resonance imaging evidence to define the precise topographical relationships of craniopharyngiomas and to classify these lesions according to the risks of hypothalamic injury associated with their removal.Material and methodsAn extensive, systematic analysis of the topographical classification models used in the surgical series of craniopharyngiomas reported in the literature (n = 145 series, 4,588 craniopharyngiomas) was performed. Topographical relationships of well-described operated craniopharyngiomas (n = 224 cases) and of non-operated cases reported in autopsies (n = 201 cases) were also analysed. Finally, preoperative and postoperative magnetic resonance imaging studies displayed in craniopharyngiomas reports (n = 130) were compared to develop a triple-axis model for the topographical classification of these lesions with qualitative information regarding the associated risk of hypothalamic injury.ResultsThe 2 major variables with prognostic value to define the topography of a craniopharyngioma are its position relative to the sellar diaphragm and its degree of invasion of the third ventricle floor. A multivariate diagnostic model including 5 variables –patient age, presence of hydrocephalus and/or psychiatric symptoms, the relative position of the hypothalamus and the mammillary body angle– makes it possible to differentiate suprasellar craniopharyngiomas displacing the third ventricle upwards (pseudointraventricular craniopharyngiomas) from either strictly intraventricular craniopharyngiomas or lesions developing primarily within the third ventricle floor (infundibulo-tuberal or not strictly intraventricular craniopharyngiomas).ConclusionsA triple-axis topographical model for craniopharyngiomas that includes the degree of hypothalamus invasion is useful in planning the surgical approach and degree of resection. Infundibulo-tuberal craniopharyngiomas represent 42% of all cases. These lesions typically show tight, circumferential adhesion to the third ventricle floor, with their removal being associated with a 50% risk of hypothalamic injury. The endoscopically-assisted extended transsphenoidal approach provides a proper view to assess the degree and extension of craniopharyngioma adherence to the hypothalamus.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号