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   3015篇
  免费   144篇
  国内免费   77篇
耳鼻咽喉   15篇
儿科学   200篇
妇产科学   93篇
基础医学   330篇
口腔科学   75篇
临床医学   368篇
内科学   721篇
皮肤病学   83篇
神经病学   176篇
特种医学   430篇
外科学   249篇
综合类   55篇
预防医学   128篇
眼科学   48篇
药学   128篇
  2篇
肿瘤学   135篇
  2022年   10篇
  2021年   22篇
  2020年   18篇
  2019年   24篇
  2018年   42篇
  2017年   32篇
  2016年   40篇
  2015年   53篇
  2014年   66篇
  2013年   87篇
  2012年   74篇
  2011年   83篇
  2010年   108篇
  2009年   103篇
  2008年   99篇
  2007年   149篇
  2006年   93篇
  2005年   99篇
  2004年   65篇
  2003年   60篇
  2002年   66篇
  2001年   61篇
  2000年   63篇
  1999年   47篇
  1998年   142篇
  1997年   165篇
  1996年   141篇
  1995年   114篇
  1994年   119篇
  1993年   105篇
  1992年   43篇
  1991年   55篇
  1990年   60篇
  1989年   76篇
  1988年   68篇
  1987年   70篇
  1986年   72篇
  1985年   66篇
  1984年   50篇
  1983年   31篇
  1982年   33篇
  1981年   42篇
  1980年   32篇
  1979年   17篇
  1978年   20篇
  1977年   28篇
  1976年   34篇
  1975年   18篇
  1971年   9篇
  1970年   7篇
排序方式: 共有3236条查询结果,搜索用时 26 毫秒
1.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
2.
In obstetrics and gynaecology, as well as in many other fields of medicine, ultrasound has become an indispensable diagnostic tool. Ultrasound training, however, still lacks proper quality assessment and control. In fact, in prenatal diagnostics most fetal anomalies requiring diagnosis during pregnancy are extremely rare. Therefore, effective training opportunities are limited to the very few medical centres which treat many such cases. Ultrasound simulator-based training, as performed with the Sonofit Sonotrainer, has been demonstrated to partly overcome this dilemma. In this article, the authors summarize their experience in using and evaluating various teaching concepts after the implementation of the ultrasound simulator under different conditions. Furthermore, an overview of the advantages of the Sonotrainer-based ultrasound training and its acceptance among trainees is provided. The authors also focus on aspects of quality assessment in gynaecological and prenatal ultrasound.  相似文献   
3.
A retrospective chart review of 43 patients who underwent technetium 99m (Tc-99m) sestamibi scans from June 1995 to January 1997 was performed. Only those who underwent subsequent parathyroid exploration with excision were included in the study. Twenty subjects (13 women and seven men) were included in the study. Ages ranged from 21 to 84 years (mean, 58 years). All patients had laboratory values and clinical findings consistent with primary hyperparathyroidism. Two patients had preoperative magnetic resonance imaging (MRI) scans (one patient with recurrent disease), and one had a preoperative computed tomography (CT) scan. The remaining patients had the sestamibi scan as the only preoperative localization study. There were 18 pathologic diagnoses of parathyroid adenoma and two of parathyroid hyperplasia. Sestamibi failed to correctly identify the location of the parathyroid lesion in two cases. In 18 cases the preoperative sestamibi scan correctly localized the lesion, a predictive value of 90%. We conclude that the Tc-99m sestamibi scan is an accurate preoperative tool that can be used as a single modality to localize parathyroid adenomas.  相似文献   
4.
5.
6.
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2, PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α.  相似文献   
7.
8.
Occurrence of the t(2;5)(p23;q35) in non-Hodgkin's lymphoma   总被引:9,自引:3,他引:6  
Primary CD30(Ki-1)-positive anaplastic large-cell lymphoma (ALCL) is considered by some to be a distinct clinicopathologic entity associated with the t(2;5) (p23;q35). However, the specificity of t(2;5) for ALCL has not been carefully studied. Therefore, we performed a detailed analysis of all cases of ALCL with abnormal cytogenetics results in the Nebraska Lymphoma Study Group registry, as well as all other cases of non-Hodgkin's lymphoma with t(2;5) in the registry. We found the t(2;5) in only five of 10 cases of ALCL, four of whom were young patients. However, we also found the t(2;5) in 11 other cases of nonanaplastic lymphoma, including eight children with typical peripheral T-cell lymphomas of various types. The t(2;5) was also found in three older adults with B-cell lymphomas of various types. Thus, the t(2;5) was not specific for CD30+ ALCL. However, t(2;5) may define a clinicopathologic entity in children and young adults characterized by variable morphologies with a T-cell or indeterminate phenotype, CD30-positivity, nodal disease with frequent extranodal involvement, advanced stage, and an excellent response to therapy, including bone marrow transplantation for relapsed disease. The clinical relevance of the t(2;5) in older patients requires further study.  相似文献   
9.
10.
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