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   2353篇
  免费   121篇
  国内免费   16篇
耳鼻咽喉   10篇
儿科学   94篇
妇产科学   63篇
基础医学   251篇
口腔科学   54篇
临床医学   189篇
内科学   486篇
皮肤病学   22篇
神经病学   205篇
特种医学   214篇
外科学   329篇
综合类   31篇
预防医学   130篇
眼科学   75篇
药学   127篇
中国医学   8篇
肿瘤学   202篇
  2023年   18篇
  2022年   35篇
  2021年   52篇
  2020年   26篇
  2019年   34篇
  2018年   45篇
  2017年   29篇
  2016年   42篇
  2015年   44篇
  2014年   56篇
  2013年   79篇
  2012年   103篇
  2011年   115篇
  2010年   86篇
  2009年   99篇
  2008年   105篇
  2007年   109篇
  2006年   110篇
  2005年   108篇
  2004年   89篇
  2003年   86篇
  2002年   67篇
  2001年   58篇
  2000年   65篇
  1999年   66篇
  1998年   41篇
  1997年   49篇
  1996年   58篇
  1995年   44篇
  1994年   36篇
  1993年   41篇
  1992年   34篇
  1991年   36篇
  1990年   42篇
  1989年   43篇
  1988年   41篇
  1987年   42篇
  1986年   37篇
  1985年   31篇
  1984年   26篇
  1983年   16篇
  1982年   23篇
  1981年   10篇
  1980年   18篇
  1979年   14篇
  1977年   12篇
  1976年   9篇
  1975年   10篇
  1973年   10篇
  1971年   6篇
排序方式: 共有2490条查询结果,搜索用时 0 毫秒
1.
Cidofovir is an acyclic nucleoside phosphonate with broad-spectrum activity against DNA viruses, including human papilloma virus (HPV). However, data on the efficacy of cidofovir in an immunosuppressive setting remain contradictory. We report for the first time on the promotion of the healing of recalcitrant warts in a patient with myelodysplastic syndrome with intravenous cidofovir treatment.  相似文献   
2.
Systemic effects of intraocular epinephrine during cataract surgery   总被引:2,自引:0,他引:2  
This paper examines the effects of intraocular epinephrine on systemic blood pressure and heart rate during cataract surgery. Sixty-two patients were studied, all of whom received an intraocular infusion of approximately 200 to 300 mL of balanced salt solution with 0.5 mL of epinephrine 1:1000. There was no statistically significant change in blood pressure or heart rate during the time of epinephrine administration. Electrocardiogram monitoring during surgery showed no changes. We believe that dilute concentrations of epinephrine administered during extracapsular cataract extraction pose little threat of systemic toxicity.  相似文献   
3.
4.
Schistosoma mansoni infection, both in humans and in animal models, is known to induce granulomas in the liver and intestine. It has also been reported that in humans the eggs of this parasite can reach the brain, causing psychiatric and neuropathological disorders. Whether this also occurs in rodents is unknown. To answer this question, mice were infected with this parasite and the central nervous system (CNS) examined at various time intervals. The results show that schistosomiasis induced granulomas in several regions of the CNS and increased nerve growth factor (NGF) levels in the cortex, hypothalamus and brain stem, but not in the hippocampus. The infection also caused paw hyperalgesia, as determined by the hot-plate test, and a local increase in NGF, but not in substance P. These findings indicate that the murine model of infection can be used for studying mechanisms leading to human neuroschistosomiasis and suggest that the neuropathological disorders and the sensory deficits observed in human schistosomiasis are associated with impaired levels of NGF in the peripheral and central nervous system. Received: 18 January 1996 / Revised, accepted: 16 April 1996  相似文献   
5.
6.
Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.  相似文献   
7.
8.
9.
10.
Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.  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