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   1826篇
  免费   89篇
  国内免费   20篇
耳鼻咽喉   39篇
儿科学   78篇
妇产科学   106篇
基础医学   288篇
口腔科学   21篇
临床医学   104篇
内科学   457篇
皮肤病学   23篇
神经病学   219篇
特种医学   43篇
外科学   105篇
综合类   8篇
一般理论   1篇
预防医学   121篇
眼科学   26篇
药学   193篇
中国医学   5篇
肿瘤学   98篇
  2023年   16篇
  2022年   93篇
  2021年   126篇
  2020年   49篇
  2019年   70篇
  2018年   64篇
  2017年   47篇
  2016年   64篇
  2015年   65篇
  2014年   70篇
  2013年   101篇
  2012年   154篇
  2011年   127篇
  2010年   81篇
  2009年   66篇
  2008年   114篇
  2007年   109篇
  2006年   87篇
  2005年   77篇
  2004年   86篇
  2003年   73篇
  2002年   62篇
  2001年   7篇
  2000年   12篇
  1999年   12篇
  1998年   5篇
  1997年   7篇
  1996年   7篇
  1995年   1篇
  1994年   5篇
  1993年   4篇
  1992年   14篇
  1991年   9篇
  1990年   5篇
  1989年   5篇
  1988年   6篇
  1987年   9篇
  1986年   5篇
  1985年   1篇
  1984年   4篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1976年   2篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1972年   2篇
  1967年   3篇
排序方式: 共有1935条查询结果,搜索用时 0 毫秒
991.
Recent preclinical data indicated the antidepressant-like activity of zinc in different tests and models of depression. The present study investigates the involvement of the serotonergic system in zinc activity in the forced swim test (FST) in mice and rats. The combined treatment of sub-effective doses of zinc (hydroaspartate, 2.5 mg Zn/kg) and citalopram (15 mg/kg), fluoxetine (5 mg/kg) but not with reboxetine (2.5 mg/kg) significantly reduces the immobility time in the FST in mice. These treatments had no influence on the spontaneous locomotor activity. Moreover, while the antidepressant-like effect of zinc (5 mg/kg) in the FST was significantly blocked by pretreatment with inhibitor of serotonin synthesis, p-chlorophenylalanine (pCPA, 3 × 200 mg/kg), 5HT-2A/C receptor antagonist, ritanserin (4 mg/kg) or 5HT-1A receptor antagonist, WAY 1006335 (0.1 mg/kg), the zinc-induced reduction in the locomotor activity was not affected by these serotonin modulator agents. These results indicate the specific involvement of the serotonergic system in antidepressant but not the motion behavior of zinc in mice. Also, an increase in the swimming but not climbing parameter of the rat FST observed following zinc administration (2.5 and 5 mg Zn/kg) indicates the serotonin pathway participation. This present data indicates that the antidepressant-like activity of zinc observed in the FST involves interaction with the serotonergic system.  相似文献   
992.
993.
Estrogen receptor α (ERα) is over-expressed in reactive glia under conditions of neuronal damage. To elucidate the functional significance of ERα overexpression, an in vitro model of reactive astrocytes with enhanced expression of ERα was obtained by growth in G5 culture supplement. Exposure of cortical neurons to β-amyloid in the presence of either conditioned medium from reactive astrocytes previously treated with 17β-estradiol (17βE2) or transferring of 17βE2-pretreated astrocytes, caused a greater neuroprotective effect compared to the respective control conditions, although reactive glia resulted being per se neuroprotective. Blockade of ERα overexpression by the ER antagonist ICI182,780 was not successful as ICI182,780 behaved as an agonist. However, complete prevention of 17βE2 effect by ICI182,780 produced an increased sensitivity of neurons to β-amyloid toxicity. A similar effect was observed when ERα knock-down was induced by siRNA. It is suggested that increased ERα expression in reactive glia may have a role in limiting neuronal damage.  相似文献   
994.
Introduction: Resistance training promotes recovery from muscle atrophy, but optimum training programs have not been established. We aimed to determine the optimum training intensity for muscle atrophy. Methods: Mice recovering from atrophied muscles after 2 weeks of tail suspension underwent repeated isometric training with varying joint torques 50 times per day. Results: Muscle recovery assessed by maximal isometric contraction and myofiber cross‐sectional areas (CSAs) were facilitated at 40% and 60% maximum contraction strength (MC), but at not at 10% and 90% MC. At 60% and 90% MC, damaged and contained smaller diameter fibers were observed. Activation of myogenic satellite cells and a marked increase in myonuclei were observed at 40%, 60%, and 90% MC. Conclusions: The increases in myofiber CSAs were likely caused by increased myonuclei formed through fusion of resistance‐induced myofibers with myogenic satellite cells. These data indicate that resistance training without muscle damage facilitates efficient recovery from atrophy. Muscle Nerve 55 : 243–253, 2017  相似文献   
995.
The proliferative responses of peripheral blood mononuclear cells (PBMCs) to ovalbumin or bovine serum albumin in children with atopic dermatitis (AD) who are sensitive to hen's egg or cow's milk were significantly higher than responses of PBMCs of healthy children and hen's egg- or cow's milk-sensitive children with immediate symptoms. However, the percentages of positive RAST for hen's egg or cow's milk in the patients with AD were lower than percentages in the patients with immediate symptoms. In the patients with AD, there were no significant correlations between the proliferative responses of PBMCs and the RAST values. There were no significant differences of RAST scores among groups of patients having different degrees of severity of AD. The proliferative responses of PBMCs to ovalbumin or bovine serum albumin in patients with severe AD or moderate AD who were sensitive to hen's egg or cow's milk tended to be higher than responses of patients with mild AD, respectively, but there were no significant differences in those results. Taken together, the combination of RAST and the detection of proliferative responses of PBMCs to each food antigen is very useful in the diagnosis of hypersensitivity in children with AD who are sensitive to food allergens.  相似文献   
996.
Magnetic resonance imaging is gold standard for noninvasive evaluation of articular cartilage damage and has been also used for monitoring cartilage repair. The aim of this study was to find correlation between histological microscopy and microscopic MR in evaluation of the repair of osteochondral defects in articular cartilage. Study was based animal model (rabbit). The cartilage repair process was evaluated histology and micro MR. Most of the defects were filled with fibrocartilage and fibrous tissue formed. Both methods were equally efficient to show repair tissue thickness, subchondral bone reconstruction and disintegration. Result of observation by both histological and MR microscopy and showed good correlation. Micro MR is promising evaluation tool for cartilage repair monitoring. Results of micro MR correlate well with standard microscopy.  相似文献   
997.
There is a growing body of evidence showing that the intensity of rejection is weaker in older kidney allograft recipients while chronic complications, but not rejection, are the main causes of graft loss. To investigate whether the age of the recipient is a factor affecting the expressions of the CD28, CTLA-4, and CD40L costimulatory molecules on CD4+ T cells. Their expression levels were determined in 78 kidney transplant recipients aged 17-68 years. The expression was assessed on unstimulated and anti-CD3 antibody + IL-2-stimulated CD4+ T cells. Median time after transplantation was 20 months and median serum creatinine was 1.5 mg/dl. Significant correlations between age and CD28 expression (r = -0.4, P = 0.0004) on CD4+ T cells and between age and CTLA-4 expression after stimulation (r = 0.34, P = 0.008) were found. CD40L expression on CD4+ T cells was not affected by recipient age. The decreased expression of CD28 and enhanced expression of CTLA-4 (after stimulation) associated with age may be helpful in transplant acceptance.  相似文献   
998.
Cerebellum seems to have a role both in feeding behavior and emotion regulation; therefore, it is a region that warrants further neuroimaging studies in eating disorders, severe conditions that determine a significant impairment in the physical and psychological domain. The aim of this study was to examine the cerebellum intrinsic connectivity during functional magnetic resonance imaging resting state in anorexia nervosa (AN), bulimia nervosa (BN), and healthy controls (CN). Resting state brain activity was decomposed into intrinsic connectivity networks (ICNs) using group spatial independent component analysis on the resting blood oxygenation level dependent time courses of 12 AN, 12 BN, and 10 CN. We extracted the cerebellar ICN and compared it between groups. Intrinsic connectivity within the cerebellar network showed some common alterations in eating disordered compared to healthy subjects (e.g., a greater connectivity with insulae, vermis, and paravermis and a lesser connectivity with parietal lobe); AN and BN patients were characterized by some peculiar alterations in connectivity patterns (e.g., greater connectivity with the insulae in AN compared to BN, greater connectivity with anterior cingulate cortex in BN compared to AN). Our data are consistent with the presence of different alterations in the cerebellar network in AN and BN patients that could be related to psychopathologic dimensions of eating disorders.  相似文献   
999.
1000.
An epidemic of meningococcal disease occurred in Nairobi, Kenya, during 1989, outside the "meningitis belt" of sub-Saharan Africa. About 3800 cases occurred between April and November (250/100,000 population). The case-fatality rate was 9.4% among hospitalized patients. Areas that included Nairobi's largest slums had particularly high attack rates. The epidemic displayed an unusual age distribution, with high attack rates among those 20-29 years old. A vaccination campaign was conducted. By early January, the weekly case count had fallen to 25 from a high of 272 (in September). A case-control study estimated the vaccine efficacy to be 87% (95% confidence interval, 67%-95%). A model estimated that the vaccination campaign reduced the number of cases by at least 20%. Multilocus enzyme electrophoretic typing demonstrated that the strain responsible for this large epidemic is closely related to strains that caused other recent epidemics, documenting further spread of what may be a particularly virulent clonal complex of group A Neisseria meningitidis.  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