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   713篇
  免费   47篇
  国内免费   3篇
耳鼻咽喉   21篇
儿科学   15篇
妇产科学   8篇
基础医学   67篇
口腔科学   21篇
临床医学   50篇
内科学   283篇
皮肤病学   2篇
神经病学   25篇
特种医学   31篇
外科学   95篇
综合类   2篇
预防医学   45篇
眼科学   14篇
药学   22篇
肿瘤学   62篇
  2024年   1篇
  2023年   4篇
  2022年   11篇
  2021年   23篇
  2020年   21篇
  2019年   15篇
  2018年   17篇
  2017年   13篇
  2016年   25篇
  2015年   10篇
  2014年   31篇
  2013年   32篇
  2012年   61篇
  2011年   67篇
  2010年   36篇
  2009年   41篇
  2008年   25篇
  2007年   47篇
  2006年   41篇
  2005年   27篇
  2004年   24篇
  2003年   34篇
  2002年   25篇
  2001年   16篇
  2000年   12篇
  1999年   9篇
  1998年   3篇
  1997年   8篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1993年   4篇
  1992年   5篇
  1991年   4篇
  1990年   9篇
  1989年   4篇
  1988年   6篇
  1987年   6篇
  1986年   8篇
  1985年   10篇
  1984年   8篇
  1983年   2篇
  1982年   3篇
  1980年   1篇
  1978年   1篇
  1977年   1篇
  1974年   3篇
  1973年   1篇
  1972年   2篇
排序方式: 共有763条查询结果,搜索用时 15 毫秒
51.
52.
BACKGROUND: Mucosal leishmaniasis (ML) is an important complication of new world cutaneous leishmaniasis (CL) caused by species of the Leishmania Viannia subgenus. Previous reports of ML among travellers to Latin America are few. AIMS: To determine the annual number of cases of CL due to L. Viannia species diagnosed at this institution and to correlate this with changing patterns of travel. Secondly, to document the clinical presentation, diagnosis, treatment and outcome of ML at this institution. DESIGN: Retrospective observational study. METHODS: Data were collected from a clinical database, laboratory records, patient case notes and an international passenger survey. RESULTS: Between 1995 and 2003, the annual number of cases of CL (total 79) steadily increased from 4 per year to 18 per year; the estimated number of travellers from the UK to Latin America increased 3.5-fold. Six cases of ML were diagnosed among British travellers in 1995 (1), 1997 (1) and 2002 (4). These infections were acquired in Bolivia (3), Colombia (2) and Belize (1). Nasopharyngeal symptoms developed 0-15 months after returning to the UK. Four patients had concurrent CL at diagnosis. Diagnosis of ML was delayed up to 6 months from the onset of symptoms. Mucosal biopsies from all 6 patients were PCR-positive for L. (Viannia) DNA; microscopy and culture were less sensitive. ML relapsed in one patient following treatment. DISCUSSION: Increasing travel to Latin America from the UK was associated with an increasing number of diagnoses of L. Viannia CL. ML is likely to emerge as a more frequently imported infection among such travellers. Familiarity with these diseases is important for prompt diagnosis and optimal management.  相似文献   
53.
Embryonal tumors are a group of malignant neoplasms that most commonly affect the pediatric population. Embryonal tumor with abundant neuropil and true rosettes is a recently recognized rare tumor. It is composed of neurocytes and undifferentiated neuroepithelial cells arranged in clusters, cords and several types of rosettes in a prominent neuropil‐rich background. We describe a new case of this tumor. The patient, a 24‐month‐old female infant, was referred to the Meyer Children's Hospital with a history of right brachio‐crural deficit associated with occasional episodes of headache and vomiting. Computed tomography scan and MRI revealed a large bihemispheric mass. The patient underwent two consecutive surgeries. The resultant surgical resection of the tumor was macroscopically complete. The postoperative period was uneventful. On light microscopy the tumor showed a composite morphology: embryonal tumor with abundant neuropil and true rosettes (specimen from the first surgery); medulloepithelioma with mesenchymal and epithelial areas (specimen from the second surgery). The immunohistochemistry evidenced the heterogeneous (neuronal, mesenchymal and epithelial) immunoprofile of tumoral cells. By real‐time polymerase chain reaction (RT‐PCR), the PTEN gene expression in the tumor was lower than in the five non‐neoplastic brain tissues used as control. Mutation analysis did not show any variation in INI‐1 and PTEN sequence while P53 analysis showed the presence of homozygote P72R variation. Fluorescent in situ hybridization analysis showed polysomy of chromosome 2 while amplification of N‐MYC was not detected. Owing to the rarity of embryonal tumor with abundant neuropil and true rosettes, each new case should be recorded to produce a better clinical, pathological and molecular characterization of this lesion.  相似文献   
54.
55.
56.
Santi R, Cetica V, Franchi A, Pepi M, Cesinaro A M, Miracco C, Paglierani M, De Giorgi V, Delfino C, Difonzo E M, Pimpinelli N, Bianchi S, Sardi I, Santucci M & Massi D
(2011) Histopathology 58 , 455–466
Tumour suppressor gene TP53 mutations in atypical vascular lesions of breast skin following radiotherapy Aims: Atypical vascular lesions (AVL) occurring at the site of radiotherapy represent an uncommon but well‐documented complication in the setting of breast‐conserving therapy for breast carcinoma. Although the biological behaviour of AVL has been regarded as benign, it has been suggested that AVL may represent a precursor of angiosarcoma. A better understanding of the biology of AVL is essential in order to assess appropriate patient management. The aim of the present study was to investigate alterations of tumour suppressor gene TP53 in a series of radiation‐induced AVL and angiosarcomas (AS). Methods and results: Direct sequencing analysis of the TP53 gene showed the presence of at least one variation in 10 of 12 (83.3%) AVL and in seven of eight (87.5%) AS. The most common alteration in both categories was the P72R polymorphism in exon 4. One angiosarcoma sample carried a pathogenetically relevant disruptive mutation c.592delG, a frameshift deletion in exon 6, causing a premature stop codon. Conclusions: The presence of TP53 alterations suggests that its mutational inactivation may be implicated in the pathogenesis of radiation‐associated vascular proliferations. The common mutational pathway suggested by our data supports the hypothesis that AVL and AS are biologically related entities, most probably representing the extremes of a morphological continuum.  相似文献   
57.
The presence of asymptomatic eosinophilia in HIV patients has been demonstrated to have a wide variety of causes. Untreated parasitic infections in immunocompromised individuals can have potentially serious consequences. The utility of screening for parasitic infections in immigrant HIV-positive Africans with eosinophilia was investigated in a UK-based HIV clinic. HIV-positive African patients with eosinophilia were matched with HIV-positive African controls without eosinophilia. More than half of African HIV patients with eosinophilia had positive parasitic serology, and were significantly more likely to have positive serology compared with African HIV patients without eosinophilia. This study shows that asymptomatic eosinophilia in HIV-1-infected Africans is strongly suggestive of underlying parasitic infection. Individuals with eosinophilia should thus be screened for parasitic infections according to the infections prevalent in the countries they have lived in or visited for substantial periods of time.  相似文献   
58.
59.
60.
We report a case of recurrent abdominal pain due to intermittent caecal volvulus arising in a patient with mesenterium commune. Colonic enema, abdominal CT scan and virtual colonography with three-dimensional colonic reconstruction were useful for detecting this rare abnormal intestinal fixation. Although right hemicolectomy was indicated, we performed a wide colonic resection from the terminal ileum to the distal sigmoid because the patient's short mesentery made it impossible to perform an ileum-transverse anastomosis. At six months follow-up, the patient was in good health and free of abdominal symptoms.  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