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   11627篇
  免费   873篇
  国内免费   85篇
耳鼻咽喉   101篇
儿科学   173篇
妇产科学   146篇
基础医学   1785篇
口腔科学   205篇
临床医学   1080篇
内科学   2672篇
皮肤病学   179篇
神经病学   1242篇
特种医学   471篇
外科学   1710篇
综合类   132篇
现状与发展   1篇
一般理论   5篇
预防医学   657篇
眼科学   316篇
药学   896篇
中国医学   28篇
肿瘤学   786篇
  2023年   84篇
  2022年   175篇
  2021年   460篇
  2020年   237篇
  2019年   265篇
  2018年   369篇
  2017年   242篇
  2016年   289篇
  2015年   371篇
  2014年   456篇
  2013年   587篇
  2012年   847篇
  2011年   991篇
  2010年   513篇
  2009年   470篇
  2008年   769篇
  2007年   745篇
  2006年   698篇
  2005年   687篇
  2004年   608篇
  2003年   568篇
  2002年   521篇
  2001年   110篇
  2000年   83篇
  1999年   89篇
  1998年   108篇
  1997年   94篇
  1996年   62篇
  1995年   54篇
  1994年   62篇
  1993年   49篇
  1992年   37篇
  1991年   40篇
  1990年   40篇
  1989年   35篇
  1988年   37篇
  1987年   29篇
  1986年   28篇
  1985年   28篇
  1984年   36篇
  1983年   38篇
  1982年   49篇
  1981年   44篇
  1980年   50篇
  1979年   36篇
  1978年   34篇
  1977年   36篇
  1976年   31篇
  1975年   28篇
  1974年   27篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Interleukin (IL)-2 and IL-4 are considered as important regulators of growth and differentiation of lymphocytes. We report that in mice made deficient for both IL-2 and IL-4 by gene targeting all major T cell subsets and B cells were normal, indicating that IL-2 and IL-4 are not essential for development of the immune system. Paradoxically, proliferation of T cells was increased in both IL-2- and IL-4-deficient homozygous mice.  相似文献   
43.
44.
Objective: To review a single institution experience with tracheal stenosis treatment and to define a role of endotracheal stenting in tracheal reconstruction surgery. Patients and methods: In the period between January 1991 and January 2003, 163 patients underwent tracheal reconstruction. There were 114 males and 49 females in age range from 0.5 to 79 years (mean 43.2 years). Indications for reconstruction were: posttracheostomic (PostTS) and postintubation (PostINT) stenoses in 111 cases, tumor-stenosis in 24 cases, tracheo-esophageal fistulas (T-Efist) in 17 cases, traumatic laesions in six and functional stenosis in five cases. For these indications, the following procedures were performed: segmental tracheal resection in 87 cases, stenting in 68 cases (by our own modification of Montgomery T-tube in 65 cases and by other traditional endo-stents in three cases). Primary suture of traumatic tracheal wall was performed in five cases. Three cases involved laser intervention and tumor resections, respectively. Results: Segmental tracheal resection (n=87) was successful in almost all the cases (96%). T-tube was applied in 65 cases; the indications included: PostTS and PostINT stenoses in 38 cases, tumors in 17 cases, T-E fistulas in seven cases and functional stenosis in three cases. Twenty-seven patients (41.6%) were successfully treated by this modality. In 19 patients (29.2%), the stenting is still continuing, but they are candidates for extraction of the T-tube in near future. In 19 patients (29.2%) with malignant stenoses, the T-tube was applied only as a palliation. All these patients died due to their underlying malignant disease; the follow-up ranged from 2 to 18 months. Conclusion: Tracheal stenosis is a serious, life-threatening disease with increasing incidence. In our study, the best results were achieved by segmental tracheal resection. However, the endotracheal stenting is the method of choice, when the segmental resection cannot be performed. The management of tracheal stenosis reconstruction by our own modification of Montgomery T-tube is being presented.  相似文献   
45.
46.
The first case of total bladder and urethral replacement by cecoappendiceal unit was achieved in a five-year-old boy born with bladder exstrophy. Residual vesical and prostatic tissue was utilized to provide continence successfully.  相似文献   
47.
Summary: Purpose: A prospective series of 643 persons with epilepsy attending a reference neurologic center in Medellin, Colombia, was examined by computed tomography (CT scan) or serology or both with the enzyme-linked immunoelectrotransfer blot assay (EITB) to assess the prevalence of Taenia solium cysticercosis. Methods: All presenting patients were consecutively enrolled in the study. Five hundred forty-six persons underwent cerebral CT scans; 376 of them also had serum EITB performed. Results: Prevalence of neurocys@ercosis by CT scan was 13.92%. Overall prevalence of T. solium antibodies with EITB was 9.82%, but for those with late-onset epilepsy (onset after age 30 years), prevalence increased to 17.5% and 19% for those who originated from outside urban Medellin. Seroprevalence in individuals with mixed lesions (cysts and calcifications) was 88.2% and 64.10% in those with live cysts. Conversely, only 2.72% of persons with CT findings not related to neurocysticercosis had positive EITB tests. Conclusions: Our study shows that an important proportion of individuals with epilepsy have radiologic or serologic evidence of T. solium infection, suggesting that neurocysticercosis is an important etiology for epilepsy in Colombia.  相似文献   
48.
The basal forebrain cholinergic neurons are implicated in the pathogenesis ofneurodegenerative diseases including Alzheimerfn2s disease (AD). The nicotinic acetylcholine receptors (nAChRs) have been found to besignificantly afflicted in AD. To study the underlying mechanisms for dysfunction of the basalforebrain cholinergic neurons development of suitable animal models is warranted. In this studywe investigated the effects of bilateral lesions of the nucleus basalis magnocellularis on nAChRs inthe rat brain using the cholinergic system selective immunotoxin 192-IgG saporin andnon-selective excitotoxin ibotenic acid. Changes in nAChRs were measured by 3H-cytisineand 3H-epibatidine, two ligands with different selectivity for nAChRs subtypes. Inthe parietal cortex of ibotenic acid lesioned rates, the choline acetyltransferase activity (ChAT)was decreased by 24% while no changes were detected in the frontal cortex or hippocampus.Similarly, a 40% decrease was observed in the number of nAChRs labelled by 3H-cytisine,but not by 3H-epibatidine, in the parietal cortex, while no changes were found in thefrontal cortex or hippocampus. Although the 192-IgG saporin induced lesions reduced the ChATactivity in the frontal cortex, parietal cortex and hippocampus by 77, 50 and 21%, respectively, nochanges were observed in the number of nAChRs as studied by 3H-cytisine or 3H-epibatidine. The results indicate a difference in vulnerability of the cortical nAChRsubtypes to experimental lesions of the nucleus basalis magnocellularis. The findings in this studysuggest that a major portion of the nAChRs might be located on non-cholinergic neurons in thebrain.  相似文献   
49.
Follicular lymphomas (FLs) are a heterogeneous group of tumors, but prognostic factors are evaluated insufficiently in this common hematologic neoplasm. While bcl-6 and CD10 are expressed characteristically in FLs, their significance for biologic behavior of FL has not been studied previously. Samples from 73 patients with FL and clinical follow-up from 7 to 231 months were evaluated by immunohistochemical analysis. Patients with high levels of bcl-6 expression had favorable overall survival (OS) (P = .003), disease-specific survival (DSS) (P = .033), and time to treatment failure (P = .003) compared with patients with low levels of bcl-6 expression. Multivariate analysis showed that the results for OS, DSS, and time to treatment failure were independent of the international prognostic index. Patients with CD10+ FLs also had longer OS (P = .001), DSS (P = .007), and time to treatment failure (P = .004), and grade 1 FL was associated with better OS (P = .01) and a statistical trend for longer DSS (P = .05) and time to treatment failure (P = .05), but these results were not independent of bcl-6 expression or the international prognostic index in multivariate analysis.  相似文献   
50.
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