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   1143篇
  免费   79篇
  国内免费   6篇
耳鼻咽喉   33篇
儿科学   21篇
妇产科学   52篇
基础医学   154篇
口腔科学   47篇
临床医学   109篇
内科学   352篇
皮肤病学   10篇
神经病学   148篇
特种医学   24篇
外科学   144篇
综合类   2篇
一般理论   1篇
预防医学   24篇
眼科学   5篇
药学   52篇
肿瘤学   50篇
  2023年   2篇
  2022年   12篇
  2021年   32篇
  2020年   22篇
  2019年   30篇
  2018年   46篇
  2017年   30篇
  2016年   43篇
  2015年   29篇
  2014年   45篇
  2013年   52篇
  2012年   83篇
  2011年   76篇
  2010年   44篇
  2009年   44篇
  2008年   87篇
  2007年   80篇
  2006年   77篇
  2005年   64篇
  2004年   75篇
  2003年   71篇
  2002年   50篇
  2001年   6篇
  2000年   9篇
  1999年   10篇
  1998年   11篇
  1997年   5篇
  1996年   9篇
  1995年   6篇
  1994年   2篇
  1993年   6篇
  1992年   5篇
  1991年   11篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1987年   6篇
  1986年   6篇
  1984年   4篇
  1982年   4篇
  1977年   2篇
  1976年   2篇
  1975年   2篇
  1974年   2篇
  1973年   5篇
  1972年   1篇
  1970年   1篇
  1969年   1篇
  1968年   3篇
  1966年   1篇
排序方式: 共有1228条查询结果,搜索用时 15 毫秒
61.
62.
The serotonin (5-HT) neurotransmitter system, which has a widespread distribution in the central nervous system, has been implicated in regulating mood and many human behaviors. There is evidence from postmortem human studies and limited information from prior in vivo studies to support a decline in 5-HT2A receptor density with aging. We examined nine elderly (ages 61–76) and nine young (ages 18–29) healthy individuals with positron emission tomography (PET) and [ ]altanserin, a ligand with high affinity for the 5-HT2A binding site. The PET data were corrected for differences in brain tissue volume between the young and elderly subjects using a magnetic resonance (MR) imaging-based partial volume correction method. Highly significant and widespread cortical reductions in 5-HT2A specific binding were demonstrated in the elderly group relative to young controls. Regional losses averaged 61% before and 57% following correction for effects of cerebral atrophy. This finding, which is consistent with prior postmortem and in vivo studies, has both etiological and potential therapeutic implications for behavioral changes commonly observed in the elderly, including geriatric depression.  相似文献   
63.
64.
The severe acute respiratory syndrome (SARS) epidemic brought into the spotlight the need for rapid development of effective anti-viral drugs against newly emerging viruses. Researchers have leveraged the 20-year battle against AIDS into a variety of possible treatments for SARS. Most prominently, based solely on viral genome information, silencers of viral genes, viral-enzyme blockers and viral-entry inhibitors were suggested as potential therapeutic agents for SARS. In particular, inhibitors of viral entry, comprising therapeutic peptides, were based on the recently launched anti-HIV drug enfuvirtide. This could represent one of the most direct routes from genome sequencing to the discovery of antiviral drugs.  相似文献   
65.
Erythropoietin in heart failure   总被引:3,自引:0,他引:3  
The incidence of both congestive heart failure (CHF) and end-stage renal disease both are increasing. Anemia is common in both conditions and is associated with a marked increase in mortality and morbidity in both CHF and chronic kidney insufficiency (CKI). Each of these 3 conditions can cause or worsen the other 2. In other words, a vicious circle frequently is present in which CHF can cause or worsen both anemia and CKI, in which CKI can cause or worsen both anemia and CHF, and in which anemia can cause or worsen both CHF and CKI. We have called this vicious circle the cardio renal anemia syndrome. Optimal treatment of CHF with all the recommended CHF medications at their recommended doses will, in our experience, frequently fail to improve the CHF and CKI if anemia is present and is not corrected. On the other hand, correction of the anemia with subcutaneous erythropoietin and intravenous iron has caused a great improvement in the CHF including a marked improvement in patient and cardiac function and a marked reduction in the need for hospitalization and for high-dose diuretics. It also frequently has caused renal function to improve or at least stabilize. In addition, patients' quality of life and exercise capacity also have improved with the correction of the anemia. In CKI patients, anemia also may play an important role in increasing the risk for death, coronary heart disease, stroke, and progression to end-stage renal disease. Erythropoietin may have a direct positive effect on the heart and brain unrelated to correction of the anemia by reducing cell apoptosis and by increasing neovascularization, both of which could prevent tissue damage. This could have profound therapeutic implications not only in CHF but in the future treatment of myocardial infarction, coronary heart disease, strokes, and renal failure.  相似文献   
66.
We report improved ability to name pictures at 2 and 8 months after repetitive transcranial magnetic stimulation (rTMS) treatments to the pars triangularis portion of right Broca's homologue in a 57 year-old woman with severe nonfluent/global aphasia (6.5 years post left basal ganglia bleed, subcortical lesion). TMS was applied at 1 Hz, 20 minutes a day, 10 days, over a two-week period. She received no speech therapy during the study. One year after her TMS treatments, she entered speech therapy with continued improvement. TMS may have modulated activity in the remaining left and right hemisphere neural network for naming.  相似文献   
67.
Recurrences of cervical intraepithelial neoplasia (CIN) as well as invasive cervical carcinoma have been reported to arise following ablative or excisional treatment for cervical intraepithelial neoplasia. This review utilizes MEDLINE and National Library of Medicine's PubMed review of the various screening tools used in follow-up protocols for women treated by loop excision for CIN. Cervical cytology, colposcopy, endocervical curettage and HPV typing have been advocated for use as tools for follow up. Involvement of the surgical margins and the presence of HPV-DNA are associated with higher risks of recurrence and should be taken into consideration. The psychological impact of undergoing colposcopy may affect compliance with follow-up visits and should be dealt with appropriately. LEARNING OBJECTIVES: After completion of this article, the reader should be able to list the various tools that can be used for the surveillance of patients after treatment for CIN, to compare the advantages and disadvantages of each surveillance method, and summarize methods to improve compliance with follow-up.  相似文献   
68.
Several representative oxazaborolidines have been synthesized and evaluated against S. mutans for antibacterial activity. This is the first reported antibacterial activity of this class of compounds. The minimal inhibitory concentration values ranged from 0.53 to 6.75 mM.  相似文献   
69.
70.
The relationships between acute life events and type of depression were evaluated among inpatient adolescents with schizophrenia. Forty-two adolescent inpatients were assessed, 25 with schizophrenia and 17 with personality disorder. Acute life events and other psychosocial situations were identified with the ICD-10 Axis V semistructured interviews. The Depression Equivalent Questionnaire for Adolescents (DEQ-A) and the Positive and Negative Symptom Scale (PANSS) were used to measure quality and severity of depression. In the patients with schizophrenia, psychosocial situations were related to the anaclitic type of depression, whereas in the subjects with personality disorder, they were highly correlated with introjective depression. In the schizophrenic group, the psychosocial situations related to depression were of a more intrapersonal nature and, in the personality-disordered group, they were more interpersonal. Environmental factors play an important role in the course of schizophrenia in adolescents and should remain a focus of study. Object relations theory may be of heuristic value in the investigation of these factors.  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