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   4169篇
  免费   343篇
  国内免费   25篇
耳鼻咽喉   36篇
儿科学   150篇
妇产科学   62篇
基础医学   762篇
口腔科学   33篇
临床医学   467篇
内科学   875篇
皮肤病学   76篇
神经病学   496篇
特种医学   75篇
外科学   459篇
综合类   14篇
一般理论   2篇
预防医学   369篇
眼科学   42篇
药学   300篇
中国医学   9篇
肿瘤学   310篇
  2024年   2篇
  2023年   40篇
  2022年   45篇
  2021年   104篇
  2020年   63篇
  2019年   106篇
  2018年   115篇
  2017年   73篇
  2016年   86篇
  2015年   116篇
  2014年   158篇
  2013年   210篇
  2012年   320篇
  2011年   354篇
  2010年   181篇
  2009年   177篇
  2008年   300篇
  2007年   294篇
  2006年   287篇
  2005年   282篇
  2004年   263篇
  2003年   286篇
  2002年   224篇
  2001年   37篇
  2000年   22篇
  1999年   34篇
  1998年   42篇
  1997年   51篇
  1996年   35篇
  1995年   24篇
  1994年   32篇
  1993年   34篇
  1992年   13篇
  1991年   20篇
  1990年   16篇
  1989年   11篇
  1988年   3篇
  1987年   5篇
  1986年   14篇
  1985年   3篇
  1984年   10篇
  1983年   5篇
  1982年   7篇
  1981年   7篇
  1980年   5篇
  1979年   4篇
  1978年   4篇
  1971年   2篇
  1966年   2篇
  1962年   1篇
排序方式: 共有4537条查询结果,搜索用时 203 毫秒
81.

We evaluated the long-term serological follow-up of patients with vascular risk factors for chronic Q fever that were previously Coxiella burnetii seropositive. C. burnetii phase I IgG titers were reevaluated in patients that gave informed consent or retrospectively collected in patients already deceased or lost to follow-up. Of 107 patients, 25 (23.4%) became seronegative, 77 (72.0%) retained a profile of past resolved Q fever infection, and five (4.7%) developed chronic Q fever. We urge clinicians to stay vigilant for chronic Q fever beyond two years after primary infection and perform serological testing based on clinical presentation.

  相似文献   
82.
Fanconi anemia (FA) is a rare genetic disorder characterized by congenital malformations, progressive bone marrow failure (BMF), and susceptibility to malignancies. FA is caused by biallelic or hemizygous mutations in one of 15 known FA genes, whose products are involved in the FA/BRCA DNA damage response pathway. Here, we report on a patient with previously unknown mutations of the most recently identified FA gene, SLX4/FANCP. Whole exome sequencing (WES) revealed a nonsense mutation and an unusual splice site mutation resulting in the partial replacement of exonic with intronic bases, thereby removing a nuclear localization signal. Immunoblotting detected no residual SLX4 protein, which was consistent with abrogated interactions with XPF/ERCC1 and MUS81/EME1. This cellular finding did not result in a more severe clinical phenotype than that of previously reported FA‐P patients. Our study additionally exemplifies the versatility of WES for the detection of mutations in heterogenic disorders such as FA.  相似文献   
83.
84.

Background

Although pain is frequently experienced by patients with cancer, it remains under-treated. The primary aim of this study was to estimate the prevalence of cancer-related neuropathic pain (CRNP) in patients with chronic pain who attended an outpatient clinic for standard care in Europe (irrespective of the reason or stage of the cancer). The secondary aims of this study were to characterise pain and cancer in patients with CRNP (including treatment) and to evaluate the usefulness of the painDETECT (PD-Q) screening tool to help physicians identify a potential neuropathic component of cancer-related pain.

Methods

An observational, non-interventional, cross-sectional, multi-centre study of adult patients with cancer using patient and physician case report forms (CRFs). Patients with CRNP were identified by physicians’ clinical assessments after examining the completed PD-Q.

Results

A total of 951 patients visiting outpatient clinics across Europe were enrolled in this study between August 2010 and July 2011. Of these, 310 patients (32.60%; 95% confidence interval 29.62, 35.58) were identified as having CRNP. Twenty-nine of 39 (74.4%) physicians who completed the CRF relating to the PD-Q considered it a useful tool to help detect CRNP in daily practice and 28 of 39 (71.8%) indicated that they would use this tool in the future for most or some of their patients. Data from physicians before and after review of the completed PD-Qs showed a shift in clinical opinion (either to positive CRNP diagnosis [yes] or negative CRNP diagnosis [no]) in respect of 142 patients; about half of which (74) were categorised with an initial diagnosis of unknown. Opinions also shifted from a no to a yes diagnosis in 10 patients and from a yes to a no diagnosis in 51 patients.

Conclusions

Approximately one-third of adults with cancer experiencing chronic pain attending outpatient clinics as part of routine care were considered to have CRNP in the opinion of the physicians after considering scores on the PD-Q. While physicians did not consider the PD-Q to be a useful tool for all patients, shifts in diagnosis before and after the use of this tool indicate that it may help physicians identify CRNP, especially where there is initial uncertainty.
  相似文献   
85.
86.
87.
A water-soluble extract of Nocardia markedly increased in vitro [(3)H]thymidine incorporation by mouse spleen lymphocytes. The blastogenic activity of the extract and lipopolysaccharide was studied comparatively on various mouse lymphocyte subpopulations. The data obtained by [(3)H]thymidine incorporation and by electron microscopy have demonstrated that this preparation stimulates selectively mouse bone-marrow-derived cortisone-sensitive lymphocytes. This stimulation is related neither to a natural infection of mice with Nocardia organisms nor to the presence in Nocardia water-soluble mitogen of a lipopolysaccharide contaminant or of a lipopolysaccharide-like material.  相似文献   
88.
Dendritic cells (DCs), the mononuclear cells that initiate immune response, and osteoclasts, the multinucleated bone-resorbing cells, are derived from monocyte/macrophage precursor cells. Granulocyte-macrophage colony-stimulating factor and macrophage colony-stimulating factor (M-CSF) reciprocally regulate the differentiation of both lineages in mice. Using human monocyte-derived DCs generated in vitro, we show that immature DCs transdifferentiate into functional osteoclasts (OCs) in the presence of M-CSF and receptor activator of nuclear factor-kappaB ligand (RANKL). Transdifferentiation operates through fusion of intermediate adherent bipolar fusiform mononuclear cells expressing CD14, CD1a, and RANKL and able to induce RANKL(+) T-cell proliferation. Surprisingly, DC fusion in vitro is faster and more efficient than monocyte fusion to form multinucleated giant cells. The transdifferentiation process reported here supports the existence of a high cellular plasticity within differentiated myeloid phagocytes. Importantly, this process is greatly enhanced by rheumatoid arthritis synovial fluid and involves proinflammatory cytokines such as interleukin 1 or tumor necrosis factor alpha, as well as components of the extracellular matrix such as hyaluronic acid. Our data therefore suggest that DC-derived OCs may be directly involved in the osteolytic lesions observed in human inflammatory bone diseases such as rheumatoid arthritis or in particular forms of Langerhans cell histiocytosis, characterized by accumulation of immature skin DCs and chronic lytic bone lesions.  相似文献   
89.
90.
Location of Ribosomal Protein Binding Sites on 16S Ribosomal RNA   总被引:13,自引:4,他引:13       下载免费PDF全文
The distribution of ribosomal protein binding sites on the 16S ribosomal RNA molecule has been analyzed by limited ribonuclease hydrolysis of RNA-protein complexes, as well as by the interaction of individual proteins with RNA fragments purified from partial enzymatic digests. Of the six 30S subunit proteins known to interact directly with 16S RNA, proteins S4, S8, S15, S20, and, probably, S13 bind within a fragment produced by T(1) RNase (12S RNA) that comprises some 900 nucleotides and covers almost the entire 5'-terminal half of the 16S molecule. A fragment of 500-600 nucleotides (8S RNA) that is contiguous with 12S RNA and arises from the 3'-terminal portion of the 16S molecule is believed to contain the binding site for protein S7. Protein S15 interacts specifically with a sequence of about 135 nucleotides (4S RNA) that derives from 12S RNA after more extensive hydrolysis. Protein S4, but none of the other ribosomal proteins, binds to a 500-nucleotide fragment (9S RNA), generated by pancreatic RNase, that lies at the 5'-terminus of 16S RNA and is completely overlapped by the 12S fragment. A preliminary map of the binding sites is presented.  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