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   4318篇
  免费   308篇
  国内免费   47篇
耳鼻咽喉   46篇
儿科学   185篇
妇产科学   76篇
基础医学   406篇
口腔科学   92篇
临床医学   409篇
内科学   717篇
皮肤病学   56篇
神经病学   253篇
特种医学   337篇
外科学   627篇
综合类   316篇
一般理论   1篇
预防医学   303篇
眼科学   60篇
药学   225篇
中国医学   82篇
肿瘤学   482篇
  2023年   20篇
  2022年   26篇
  2021年   96篇
  2020年   59篇
  2019年   60篇
  2018年   93篇
  2017年   75篇
  2016年   63篇
  2015年   82篇
  2014年   157篇
  2013年   162篇
  2012年   243篇
  2011年   256篇
  2010年   165篇
  2009年   182篇
  2008年   248篇
  2007年   234篇
  2006年   200篇
  2005年   185篇
  2004年   172篇
  2003年   183篇
  2002年   179篇
  2001年   150篇
  2000年   110篇
  1999年   95篇
  1998年   49篇
  1997年   49篇
  1996年   58篇
  1995年   40篇
  1994年   31篇
  1993年   25篇
  1992年   65篇
  1991年   58篇
  1990年   63篇
  1989年   74篇
  1988年   70篇
  1987年   60篇
  1986年   67篇
  1985年   64篇
  1984年   35篇
  1983年   33篇
  1982年   30篇
  1981年   31篇
  1980年   19篇
  1979年   37篇
  1978年   20篇
  1976年   20篇
  1975年   16篇
  1969年   18篇
  1968年   16篇
排序方式: 共有4673条查询结果,搜索用时 15 毫秒
1.
Background: Dense deposit disease and atypical hemolytic uremic syndrome are often caused by Complement Factor H (CFH) mutations. This study describes the retinal abnormalities in dense deposit disease and, for the first time, atypical haemolytic uremic syndrome. It also reviews our understanding of drusen pathogenesis and their relevance for glomerular disease. Methods: Six individuals with dense deposit disease and one with atypical haemolytic uremic syndrome were studied from 2 to 40 years after presentation. Five had renal transplants. All four who had genetic testing had CFH mutations. Individuals underwent ophthalmological review and retinal photography, and in some cases, optical coherence tomography, and further tests of retinal function. Results: All subjects with dense deposit disease had impaired night vision and retinal drusen or whitish-yellow deposits. Retinal atrophy, pigmentation, and hemorrhage were common. In late disease, peripheral vision was restricted, central vision was distorted, and there were scotoma from sub-retinal choroidal neovascular membranes and atypical serous retinopathy. Drusen were present but less prominent in the young person with atypical uremic syndrome due to a heterozygous CFH mutation. Conclusions: Drusen are common in forms of C3 glomerulopathy caused by compound heterozygous or heterozygous CFH mutations. They are useful diagnostically but also impair vision. Drusen have an identical composition to glomerular deposits. They are also identical to the drusen of age-related macular degeneration, and may respond to the same treatments. Individuals with a C3 glomerulopathy should be assessed ophthalmologically at diagnosis, and monitored regularly for vision-threatening complications.  相似文献   
2.
3.
4.
Thin slices of teleost retina continue to grow in culture   总被引:2,自引:0,他引:2  
Thin slices of differentiated fish retinas were maintained up to 5 days in culture conditions where they exhibited properties essentially identical to those found in retinas of intact animals. Retinal slices were prepared by embedding eyecups from young fish in agarose and sectioning them on a vibratome. Phenotypic integrity of specific cell types was maintained, as demonstrated by specific antibody staining patterns. Stem cells in the retinal margin and presumptive rod progenitor cells in the outer nuclear layer continued to proliferate in vitro, just as they do in vivo. Some of these cells differentiated in vitro as demonstrated by labelling both cell division and cell phenotype. After several days in culture, some regeneration-like responses were observed, such as growth of neurites and swelling of cell bodies in the ganglion cell layer. This retinal slice preparation appears to offer a unique opportunity for studying the interactions among developing retinal cells.  相似文献   
5.
6.

Introduction  

Although ependymoma is the third most common pediatric brain tumor, we know little about the genetic/epigenetic basis of its initiation, maintenance, or progression. This is due in part to the heterogeneity of the disease, as well as the small sample size of the cohorts analyzed in most studies.  相似文献   
7.
Strahlentherapie und Onkologie - Several randomized trials have demonstrated that men with localized prostate cancer benefit from the use of short-term neoadjuvant androgen deprivation therapy...  相似文献   
8.
9.
In an open, randomized cross-over study in 124 patients, we compared the efficacy, safety and patient preference of oral and subcutaneous sum triptan in the acute treatment of migraine. Patients were treated for 3 attacks or 3 months and then crossed over. Primary clinical efficacy was defined as a reduction in headache severity on a four-point self-rating scale from severe (3) or moderate (2) to mild (1) or none (0), or mild (1) to none (0). Efficacy was evaluated 2 h after the administration of subcutaneous and 4h after the administration of oral sumatriptan. Subcutaneous sumatriptan was significantly more effective than oral sumatriptan in relieving headache (over all three attacks 78% vs 61% improvement), improving clinical disability (55% vs 41 % improvement) and relieving nausea (69% vs 53%), vomiting (72% vs 32%) and phono- or photophobia (67% vs 49%). Median time to recurrence was shorter after subcutaneous (12.5 h) than after oral sumatriptan (18 h); the number of patients experiencing a recurrence was similar Patients reported more adverse events after subcutaneous sumatriptan (1.32 per attack) than after the oral form (0.85 per attack), but all adverse events were mild to moderate in intensity and of short duration. Patient opinion was more often positive after subcutaneous sumatriptan. These results may be useful in counselling patients to choose between the available marketed formulations of sumatriptan.  相似文献   
10.
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