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   3261篇
  免费   291篇
  国内免费   37篇
耳鼻咽喉   16篇
儿科学   146篇
妇产科学   55篇
基础医学   338篇
口腔科学   40篇
临床医学   247篇
内科学   717篇
皮肤病学   116篇
神经病学   293篇
特种医学   219篇
外国民族医学   1篇
外科学   556篇
综合类   184篇
一般理论   2篇
预防医学   218篇
眼科学   73篇
药学   171篇
  1篇
中国医学   13篇
肿瘤学   183篇
  2023年   24篇
  2022年   40篇
  2021年   88篇
  2020年   42篇
  2019年   68篇
  2018年   95篇
  2017年   75篇
  2016年   74篇
  2015年   69篇
  2014年   103篇
  2013年   144篇
  2012年   219篇
  2011年   192篇
  2010年   109篇
  2009年   141篇
  2008年   165篇
  2007年   192篇
  2006年   149篇
  2005年   142篇
  2004年   129篇
  2003年   97篇
  2002年   88篇
  2001年   91篇
  2000年   93篇
  1999年   80篇
  1998年   67篇
  1997年   74篇
  1996年   63篇
  1995年   42篇
  1994年   51篇
  1993年   44篇
  1992年   51篇
  1991年   32篇
  1990年   48篇
  1989年   59篇
  1988年   48篇
  1987年   33篇
  1986年   40篇
  1985年   34篇
  1984年   21篇
  1983年   12篇
  1982年   24篇
  1981年   17篇
  1980年   20篇
  1979年   12篇
  1978年   9篇
  1977年   17篇
  1976年   17篇
  1975年   8篇
  1973年   6篇
排序方式: 共有3589条查询结果,搜索用时 15 毫秒
11.
12.
Qureshi  Bashir 《JAMA》1998,279(22):1838-1839
  相似文献   
13.
14.
15.
Rhodopseudomonas (Rhodobacter) sphaeroides diphosphoryl lipid A is a relatively inert species of lipid A but has been shown to antagonize the effects of toxic lipopolysaccharide (LPS) both in vivo and in vitro. The antagonist and its monophosphoryl derivative were examined for the ability to block tumor necrosis factor synthesis and reverse tolerance induction in vitro in macrophage cultures stimulated with bioactive preparations of smooth LPS, rough LPS, diphosphoryl lipid A, and monophosphoryl lipid A. Inhibition of agonist activity and reversal of tolerance by these novel penta-acylated lipid A antagonists provides new insight into macrophage-LPS interactions.  相似文献   
16.
This report describes a low-grade B-cell lymphoma of mucosa associated lymphoid tissue (MALT) involving the thymus of a 63-year-old woman with features suggestive of a connective tissue disease. Sections of the thymic lesion and of a lung biopsy performed at the same operation were examined histologically and by immunohistochemistry using the monoclonal antibodies CD45, CD20, CD79a, CD3, CD45RO, and AE1/AE3. Polymerase chain reaction (PCR) for immunoglobulin heavy chain gene rearrangement was also performed. The dense infiltrate of small lymphoid cells intimately admixed with ramifying epithelial elements, some of which had undergone cystic change, closely resembled a thymoma. The lymphoid infiltrate comprised centrocyte-like cells, small lymphocytes, plasma cells, and blasts. Most of the lymphoid cells were immunoreactive with the B-cell markers CD20 and CD79a, and PCR showed clonal immunoglobulin heavy chain gene rearrangement. The lung biopsy showed dense infiltration by small lymphoid cells, morphologically suggestive of lymphoid interstitial pneumonia. However, PCR showed a weak band in the amplification for immunoglobulin heavy chain gene rearrangement, identical to that within the thymus and suggesting either recirculation of cells to accumulated MALT or subhistological lymphoma. MALT lymphoma may rarely involve the thymus, and pathologists should be aware of this to avoid misdiagnosis as a thymoma. Immunohistochemical and/or molecular studies are of value in this regard. MALT lymphomas of the thymus, common with those arising in other organs, may develop in the setting of a connective tissue disease.  相似文献   
17.
Microarray-based comparative genomic hybridization (CGH) provides a powerful tool for whole genome analyses and the rapid detection of genomic variation that underlies virulence and disease. In the field of Plasmodium research, many of the parasite genomes that one might wish to study in a high throughput manner are not laboratory clones, but clinical isolates. One of the key limitations to the use of clinical samples in CGH, however, is the miniscule amounts of genomic DNA available. Here we describe the successful application of multiple displacement amplification (MDA), a non-PCR-based amplification method that exhibits clear advantages over all other currently available methods. Using MDA, CGH was performed on a panel of NF54 and IT/FCR3 clones, identifying previously published deletions on chromosomes 2 and 9 as well as polymorphism in genes associated with disease pathology.  相似文献   
18.
This study tested whether concordance could be achieved for abnormal inflammation in the basal decidua of placental specimens among 6 pathologists experienced in placental pathology. Thirty microscope slides were evaluated by the pathologists for chronic deciduitis. They also scored the severity and extent of inflammation and the presence of plasma cells. No definition of chronic deciduitis was provided. Concordance (5/6 or 6/6 agreement) was achieved in 23 cases (76%). Spearman's rank correlation showed that the diagnosis of chronic deciduitis was almost identical to the assessment of the severity of the inflammation. A regression analysis showed that the perception of severity (and hence chronic deciduitis) was influenced by the other 2 variables, extent and plasma cells. The results were shared with the pathologists, and 25 cases (excluding those with previous 6/6 consensus) were reevaluated. Concordance was now achieved in the 83% of those remaining cases. Using a threshold based on the severity and the extent of lymphocytes, and the presence of plasma cells, pathologists are able to diagnose chronic deciduitis with sufficient concordance to be of value in clinical correlation studies.  相似文献   
19.
Interventions from randomised controlled trials can only be replicated if they are reported in sufficient detail. The results of trials can only be confidently interpreted if the delivery of the intervention was systematic and the protocol adhered to. We systematically reviewed trials of anaesthetic interventions published in 12 journals from January 2016 to September 2019. We assessed the detail with which interventions were reported, using the Consolidated Standards of Reporting Trials statement for non-pharmacological treatments. We analysed 162 interventions reported by 78 trials in 18,675 participants. Detail sufficiently precise to replicate the intervention was reported for 111 (69%) interventions. Intervention standardisation was reported for 135 (83%) out of the 162 interventions, and protocol adherence was reported for 20 (12%) interventions. Sixty (77%) out of the 78 trials reported the administrative context in which interventions were delivered and 36 (46%) trials detailed the expertise of the practitioners. We conclude that bespoke reporting tools should be developed for anaesthetic interventions and interventions in other areas such as critical care.  相似文献   
20.
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