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   545篇
  免费   25篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   5篇
基础医学   48篇
口腔科学   26篇
临床医学   60篇
内科学   124篇
皮肤病学   3篇
神经病学   8篇
特种医学   74篇
外科学   61篇
综合类   18篇
预防医学   28篇
眼科学   1篇
药学   59篇
中国医学   1篇
肿瘤学   52篇
  2023年   4篇
  2022年   4篇
  2021年   5篇
  2020年   9篇
  2019年   6篇
  2018年   10篇
  2017年   6篇
  2016年   13篇
  2015年   7篇
  2014年   13篇
  2013年   17篇
  2012年   11篇
  2011年   11篇
  2010年   17篇
  2009年   28篇
  2008年   14篇
  2007年   26篇
  2006年   9篇
  2005年   9篇
  2004年   8篇
  2003年   13篇
  2002年   7篇
  2001年   11篇
  2000年   6篇
  1999年   9篇
  1998年   30篇
  1997年   33篇
  1996年   33篇
  1995年   28篇
  1994年   24篇
  1993年   20篇
  1992年   16篇
  1991年   10篇
  1990年   14篇
  1989年   19篇
  1988年   16篇
  1987年   18篇
  1986年   6篇
  1985年   6篇
  1983年   2篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1979年   2篇
  1977年   6篇
  1976年   4篇
  1975年   3篇
  1973年   2篇
  1972年   2篇
  1966年   2篇
排序方式: 共有582条查询结果,搜索用时 125 毫秒
11.
Use of a radioimmunoassay to quantify thrombospondin   总被引:8,自引:0,他引:8  
Saglio  SD; Slayter  HS 《Blood》1982,59(1):162-166
Results of radioimmunoassay procedures applied to samples containing thrombospondin indicated that reliable values are obtained either in saline or in plasma. Plasma levels in apparently normal individuals ranged from approximately 20 to 300 ng/ml. The mean for 20 individuals was 175 ng/ml. Plasma specimens stored either refrigerated at 4 degrees C or frozen at -80 degrees C showed significantly diminished thrombospondin levels over a period of 90 days. Serum levels of thrombospondin were found to range from 10,000 to 30,000 ng/ml.  相似文献   
12.
13.
Usher syndrome is recognized as the most frequent cause of hereditary deaf-blindness. Usher syndrome type I (USH1), the most severe form of the disease, is characterized by profound congenital sensorineural deafness, constant vestibular dysfunction, and retinitis pigmentosa of prepubertal onset. This form is genetically heterogeneous and five loci (USH1A-E) have been mapped thusfar. However, only the gene responsible for USH1 B (which accounts for approximately 75% of USH1 cases) has been characterized. It encodes a long-tailed unconventional myosin, myosin VIIA, with a predicted 2215 amino acid sequence. Primers covering the complete myosin VIIA coding sequence as well as the 3' non coding sequence were designed, allowing direct sequence analysis of each of the 48 coding exons and flanking splice sites in seven patients affected by USH1. Four novel mutations were thereby identified. The possibility should now be considered of a sequence-based prenatal diagnosis in some of the families affected by this very severe form of Usher syndrome.   相似文献   
14.
Evolutionary silencing of the human elastase I gene (ELA1)   总被引:6,自引:0,他引:6  
  相似文献   
15.
16.
PurposeWe aimed to assess the prognostic value of Neutrophil to Lymphocyte Ratio (NLR) on long-term outcomes and graft dysfunction after lung transplantation.MethodsWe retrospectively reviewed all patients receiving a lung transplant at our institution from 2011 to 2014. The primary exposure was elevated NLR at the time of transplant, defined by NLR>4. The primary outcomes were graft failure and three-year all-cause mortality. Multivariate logistic regression and Kaplan-Meier survival analysis were used to analyze outcomes.Results95 patients were included. 40 patients (42%) had an elevated NLR. Elevated NLR was associated with graft failure (OR: 4.7 [1.2–18.8], p = 0.02), and three-year mortality (OR: 5.4 [1.3–23.2], p = 0.03) on multivariate logistic regression. Patients with elevated NLR demonstrated significantly lower survival on Kaplan-Meier analysis (50% versus 74%, p = 0.02). The c-statistic for our multivariate model was 0.91.ConclusionElevated neutrophil to lymphocyte ratio is associated with poor long-term survival and graft failure after lung transplantation.  相似文献   
17.
Infant oral mutilation is the practice of removing developing tooth germs, commonly the mandibular canine, in infants up to the age of 1 year. Subsequent complications include missing, impacted or hypoplastic permanent anterior and canine teeth. We report on a case of bilaterally missing lower canines thought to be due to infant oral mutilation. It is important that general dental practitioners are aware of this practice and resulting complications when treating families from sub‐Saharan East Africa.  相似文献   
18.
Peripheral myelin protein 2 (PMP2) is a small protein located on the cytoplasmic side of compact myelin, involved in the lipids transport and in the myelination process. In the last years few families affected with demyelinating Charcot‐Marie‐Tooth neuropathy (CMT1), caused by PMP2 mutations, have been identified. In this study we describe the first case of a PMP2 in‐frame deletion. PMP2 was analyzed by direct sequencing after exclusion of the most frequent CMT‐associated genes by using a next generation sequencing (NGS) genes panel. Sanger sequencing was used for family's segregation analysis. Molecular modeling analysis was used to evaluate the mutation impact on the protein structure. A novel PMP2: p.I50del has been identified in a child with early onset CMT1 and in three affected family members. All family members show an early onset demyelinating neuropathy without other distinguish features. Molecular modeling analysis and in silico evaluations do not suggest a strong impact on the overall protein structure, but a most likely altered protein function. This study suggests the importance to add PMP2 in CMT NGS genes panels or, at most, to test it after major CMT1 genes exclusion, due to the lack of diagnostic‐addressing additional features.  相似文献   
19.
An increased HLA DR2 frequency is seen in aplastic anemia patients   总被引:4,自引:3,他引:4  
Nimer  SD; Ireland  P; Meshkinpour  A; Frane  M 《Blood》1994,84(3):923-927
The underlying etiology of aplastic anemia is unknown in the majority of patients, although medications, chemical exposure, or viral infections can be implicated in some. Genetic susceptibility to a variety of diseases has been shown and it has recently been suggested that aplastic anemia is more common in individuals who are HLA DR2+ than in the general population. To examine this question, we retrospectively analyzed the results of HLA-DR typing in 75 aplastic anemia patients who received antithymocyte globulin (ATG) therapy or an HLA-matched sibling bone marrow transplant at UCLA between 1978 and 1989. Thirty-one patients were DR2+, a 1.9-fold higher incidence than the expected number of 16.6 patients (P < .0005). Of the 37 patients who received ATG, 33 were evaluable for a response; 14 patients had either a complete (4 patients) or partial (10 patients) response, for an overall response rate of 42.4%. Of the 14 DR2+ patients who received ATG, 7 responded, for a 50% response rate, which is not significantly higher than the response rate for the DR2- patients (7 of 19 [36.8%]; P = .50). The median survival of patients who are DR2+ was slightly, but not significantly, longer than that of the DR2- patients in the ATG group (P = .19). Although the incidence of HLA DR2 was clearly increased in these patients with aplastic anemia, response rates to ATG were not significantly different in the DR2+ and DR2- patients.  相似文献   
20.
PURPOSE: Only limited information is available on the natural course of spermatogenesis in patients with testicular cancer who underwent unilateral orchiectomy and surveillance. We analyze long-term exocrine function of the remaining testicle in patients following surveillance policy. MATERIALS AND METHODS: Sperm counts and serum follicle-stimulating hormone (FSH) levels were available in 60 nonrelapsing cases approximately 3 weeks (baseline), 1 year and 2 years or greater after orchiectomy. Contralateral testicular cancer subsequently developed in 2 men. RESULTS: At baseline 36 patients were normospermic (10 or greater x 106/ml.), 7 were azoospermic and 17 were oligospermic. After 1 year 45 patients were normospermic. Mean sperm concentrations increased significantly from 26 to 39 x 106/ml. during year 1 after orchiectomy. Elevated serum FSH at baseline was associated with incomplete recovery of spermatogenesis, although sperm counts improved in 3 of 7 patients. Furthermore, in the 2 initially oligospermic patients with subsequent contralateral testicle cancer transient normospermia was observed after 1 year. After orchiectomy fatherhood was recorded in 28 men and was assisted by fertilization using fresh semen in 2. CONCLUSIONS: In nonrelapsing testicular cancer cases on surveillance, initially reduced spermatogenesis recovers during year 1 after orchiectomy especially if baseline serum FSH is normal. Transient recovery also occurs in patients in whom contralateral testicular cancer subsequently develops. In high risk patients and in initially oligospermic patients with plans for future fatherhood, the period of improved spermatogenesis may be used for multiple semen cryopreservations enabling subsequent assisted fertilization.  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