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   1841篇
  免费   93篇
  国内免费   20篇
耳鼻咽喉   39篇
儿科学   81篇
妇产科学   106篇
基础医学   294篇
口腔科学   21篇
临床医学   106篇
内科学   465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   71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   111篇
  2006年   87篇
  2005年   79篇
  2004年   87篇
  2003年   75篇
  2002年   62篇
  2001年   8篇
  2000年   13篇
  1999年   12篇
  1998年   6篇
  1997年   7篇
  1996年   10篇
  1995年   3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   10篇
  1986年   5篇
  1985年   2篇
  1984年   4篇
  1983年   1篇
  1982年   2篇
  1981年   2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1954条查询结果,搜索用时 15 毫秒
81.
Widespread cortical-subcortical networks are involved in the recognition and discrimination of emotional contents of facial and vocal expression, whereby the cerebellum and basal ganglia are two subcortical regions implicated in these networks with limited evidence to their specific contributions. To investigate this we compared patients with circumscribed cerebellar lesions and patients with Parkinson’s disease (PD) on an approved test battery. We studied two groups with subcortical disease, focal cerebellar infarction (n = 22) and PD (n = 22), and a neurological control group with focal supratentorial ischemia (SI) (n = 16) were. Assessments were according to inpatient protocols for neuropsychological routine evaluation, including tests of memory, executive function and attention. Participants completed the Tuebingen Affect Battery, a recognized measure of recognition and discrimination of facial and vocal expression of emotion. As a result, cerebellar lesions were associated with greater impairment than PD and SI in recognition and discrimination of cues of both facial and vocal expressions of differing basic emotions. No confounding effect of other cognitive domains, particularly executive function and attention, was found. Taken together, our findings suggest a specific contribution of the cerebellum to cerebral networks that process facial and vocal emotion expression, related to rapid decisions regulating appropriate behavioral responses in social environments.  相似文献   
82.
83.
In the present study, we used in situ hybridization to examine the influence of acute or repeated cocaine administrations and withdrawal from repeated cocaine treatment on the level of brain-derived neurotrophic factor (BDNF) and its receptor trkB mRNAs in rat brain. Cocaine (10 mg/kg i.p.) injected acutely produced locomotor hyperactivation, while repeated (single injection for 5 days) administrations of cocaine (10 mg/kg) induced a two-fold increases in the locomotor activity in rats in response to a challenge cocaine dose (10 mg/kg) on day 10, as compared to the saline-treated animals (sensitization). Cocaine treatments induced a brain-region-specific decrease in the levels of trkB mRNA. On the other hand, BDNF mRNA in the rat hippocampus was increased only in the group of rats subjected to cocaine withdrawal. Animals under cocaine withdrawal demonstrated a significant increase in the immobility time measured by the use of modified forced swimming test. Therefore, the increases in the levels of BDNF mRNA in the rat hippocampus seem to be correlated with "depressive-like" behavioral effects during withdrawal from repeated cocaine treatment. In the shell (but not in the core) of the nucleus accumbens, the levels of BDNF mRNA were significantly increased following acute and repeated cocaine treatment as well as during cocaine withdrawal, which indicates that the alterations in the neurotrophin level in the brain region important for the expression of cocaine-induced sensitization involve other mechanisms.  相似文献   
84.
85.
Introduction  Both smooth and rough Proteus sp. strains can be found. The latter are characterized by their lack of an O-polysaccharide chain in the lipopolysaccharide (LPS) molecule, which makes them suitable for obtaining anti-core sera. Using this kind of material enables identifying fragments of the Proteus LPS core region that might be involved in cross-reactions. To date only a few similar epitopes have been established for the genus Proteus. Materials and Methods  Polyclonal rabbit antisera directed against three rough strains of Proteus sp. were tested by enzyme-linked immunosorbent assay (ELISA) with a set of LPSs. The reactivity of the selected cross-reactive and homologous systems was checked by the Western blot technique and by a passive immunohemolysis assay preceded by the absorption of each antiserum with appropriate cross-reactive and homologous alkalized LPSs. Results  On the basis of the ELISA results, 19 cross-reactive antigens were selected among which both smooth and rough LPS forms were found. All the observed reactions involved the core region of the LPS. Using the antisera absorbed with the appropriate LPSs allowed identification of four groups of antigens with serologically identical core regions. Conclusions  Comparing the results of the serological studies with the known chemical structures of the core regions of the LPSs used enabled the identification of a few core oligosaccharide fragments probably involved in the observed cross-reactions. All were located in the most distal part of LPS core region, which made them more easily recognized by specific antibodies.  相似文献   
86.
Results of the research on the lowering of allergenicity of wheat flour fermented using homo- and heterofermentative lactic acid bacteria and mixed cultures with yeast were discussed. The gliadins’ immunoreactivity was measured using the indirect non-competitive enzyme-linked immunosorbent assay method. The biggest decrease of the immunoreactivity of gliadin fraction was observed in the case of fermentation performed with the use of mixed cultures of lactic acid bacteria and yeast. This way of wheat flour modification seems to be promising, because fermentation is a natural process causing not only lowering of the allergenicity, but also improving organoleptic and nutritional values of obtained products.  相似文献   
87.
Neurotoxicity Research - Cocaine was previously shown to act at the Sigma1R which is a target for counteracting cocaine actions. It therefore becomes of interest to test if the monoamine stabilizer...  相似文献   
88.
It has been established that serotonergic pathways project to cerebral areas involved in learning and memory and that serotonin (5-HT) receptor agonists and antagonists modify these processes. Indeed, most of the 5-HT receptors characterized so far, i.e., 5-HT(1) through 5-HT(7), show a regional distribution in brain areas involved in learning and memory, such as hippocampal formation (HF), amygdala and cortex. Although 5-HT(7) receptor biological functions are still to be clarified, it was recently suggested that it may play a role in the control of learning and memory processes. The aim of our study was to assess the role of 5-HT(7) receptors antagonist SB-269970 on working and reference memory in a radial arm maze task, utilizing a two-phase procedure, comprising an acquisition and test phase, conducted to evaluate working and reference memory, respectively. Our results showed that 5-HT(7) receptors antagonist SB-269970 improved memory, decreasing the number of errors in test phase and, thus, affecting reference memory, while no effects were observed in working memory. These results could be explained taking into consideration the specific localization of 5-HT(7) receptors in the CNS. In fact, high concentrations of 5-HT(7) receptors were found in the HF, which exerts an important role on reference memory, while relatively low concentrations were present in the prefrontal cortex, involved in working memory. Thus, 5-HT(7) receptor blockade had procognitive effect, when the learning task implicated a high degree of difficulty. This conclusion has a major implication in the context that 5-HT receptors play an important role under amnesia states (e.g., Alzheimer's disease) or when the learning is complex.  相似文献   
89.
Despite advances in diagnostics, the cause of epilepsy has still not been unequivocally determined in 60-65% of patients. In this group of patients, genetic factors probably play the main role. It is thought that genetic predisposition is responsible for the occurrence of so-called "idiopathic" forms of epilepsy in about 40% of patients. The genetic basis of epilepsy has been substantiated by numerous examples of familial forms of epileptic syndromes. Among these, autosomal dominant nocturnal frontal lobe epilepsy and juvenile myoclonic epilepsy can be mentioned. Mutations in the neuronal nicotinic acetylcholine receptor subunit genes are responsible for both these epilepsies. Recent advances in molecular genetics have provided the means for better understanding of human epileptogenesis at a molecular level, which facilitates clinical diagnosis and provides a more rational basis for therapy and prevention of this form of epilepsy.  相似文献   
90.
Circulating T cells and monocytes expressing T-bet, pSTAT1 and pSTAT3 increase in relapsing-remitting multiple sclerosis (RRMS) during relapse. Natalizumab (NZB) is an effective drug in RRMS, but exacerbation of the disease after its discontinuation has been described in some patients. The aim of this research was to study the effect of NZB treatment on circulating lymphomonocyte subpopulations expressing T-bet, pSTAT1, pSTAT3 and CD4+CD25+Foxp3+ regulatory T cells. Flow cytometry was used to evaluate the percentages of circulating CD4+ and CD8+ T cells, CD14+ monocytes and B cells expressing T-bet, pSTAT1, and pSTAT3, and CD4+CD25+Foxp3+ regulatory T cells from RRMS patients before and after 6-12 NZB infusions. In NZB-treated RRMS patients, the percentages of CD4+pSTAT1+ and CD8+pSTAT1+ T cells, CD14+pSTAT1+ monocytes, CD4+T-bet+, CD8+T-bet+ and CD4+pSTAT3+ T cells and CD14+pSTAT3+ monocytes increased after 12 drug infusions and were similar to those observed in untreated relapsing RRMS patients. Otherwise in vitro NZB exposure of peripheral blood mononuclear cells from untreated RRMS patients and controls had no effect. It was concluded that NZB treatment determines an accumulation of CD4+pSTAT1+, CD8+pSTAT1+, CD4+T-bet+, CD8+T-bet+ and CD4+STAT3+ T cells in peripheral blood that may account for the exacerbation of the disease observed in some patients after the discontinuation of the drug.  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