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   2798篇
  免费   179篇
  国内免费   75篇
耳鼻咽喉   4篇
儿科学   198篇
妇产科学   27篇
基础医学   276篇
口腔科学   71篇
临床医学   332篇
内科学   657篇
皮肤病学   78篇
神经病学   154篇
特种医学   456篇
外科学   275篇
综合类   74篇
预防医学   155篇
眼科学   22篇
药学   141篇
  2篇
中国医学   2篇
肿瘤学   128篇
  2023年   11篇
  2022年   12篇
  2021年   21篇
  2020年   27篇
  2019年   26篇
  2018年   50篇
  2017年   32篇
  2016年   40篇
  2015年   52篇
  2014年   72篇
  2013年   82篇
  2012年   80篇
  2011年   70篇
  2010年   124篇
  2009年   113篇
  2008年   103篇
  2007年   135篇
  2006年   101篇
  2005年   99篇
  2004年   54篇
  2003年   45篇
  2002年   55篇
  2001年   71篇
  2000年   63篇
  1999年   51篇
  1998年   141篇
  1997年   162篇
  1996年   138篇
  1995年   121篇
  1994年   115篇
  1993年   102篇
  1992年   50篇
  1991年   49篇
  1990年   49篇
  1989年   69篇
  1988年   52篇
  1987年   51篇
  1986年   56篇
  1985年   51篇
  1984年   34篇
  1983年   19篇
  1982年   26篇
  1981年   33篇
  1980年   26篇
  1979年   7篇
  1978年   12篇
  1977年   20篇
  1976年   29篇
  1975年   14篇
  1968年   6篇
排序方式: 共有3052条查询结果,搜索用时 31 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.
3.
4.
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   
5.
6.
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   
7.
8.
9.
Background Out of area placements for people with challenging behaviour represent an expensive and often ineffective strategy for meeting the needs of this service user group. Methods More than 800 agencies and service settings in a large area of South Wales were screened to identify children and adults with challenging behaviour against a number of defined operational criteria. Detailed data on identified individuals and the services they received were collected by interviewing key informants. Univariate and multivariate statistics were employed to identify predictors of out of area placement. Results In total, 1458 people were identified. Full data were available for 901 participants, 97 of whom were placed out of area. Predictors of out of area placement included behaviours resulting in physical injury and exclusion from service settings, a history of formal detention under the mental health act, the presence of mental health problems, a diagnosis of autism and higher total score on the Adaptive Behaviour Scale. Out of area placements were typically of high cost, and associated with only limited evidence of improved service quality. Conclusions Identifying predictors for out of area placement can be used to highlight deficiencies in local services and individuals at increased risk of exclusion from local services.  相似文献   
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