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   2285篇
  免费   123篇
  国内免费   58篇
耳鼻咽喉   10篇
儿科学   80篇
妇产科学   12篇
基础医学   211篇
口腔科学   27篇
临床医学   206篇
内科学   872篇
皮肤病学   136篇
神经病学   69篇
特种医学   336篇
外国民族医学   21篇
外科学   99篇
综合类   27篇
预防医学   116篇
眼科学   17篇
药学   131篇
中国医学   2篇
肿瘤学   94篇
  2023年   6篇
  2022年   6篇
  2021年   15篇
  2020年   13篇
  2019年   14篇
  2018年   28篇
  2017年   8篇
  2016年   10篇
  2015年   23篇
  2014年   23篇
  2013年   61篇
  2012年   73篇
  2011年   55篇
  2010年   64篇
  2009年   93篇
  2008年   80篇
  2007年   114篇
  2006年   102篇
  2005年   91篇
  2004年   69篇
  2003年   79篇
  2002年   86篇
  2001年   87篇
  2000年   97篇
  1999年   72篇
  1998年   87篇
  1997年   91篇
  1996年   111篇
  1995年   76篇
  1994年   67篇
  1993年   66篇
  1992年   42篇
  1991年   42篇
  1990年   45篇
  1989年   58篇
  1988年   50篇
  1987年   55篇
  1986年   64篇
  1985年   57篇
  1984年   15篇
  1983年   18篇
  1982年   17篇
  1981年   11篇
  1980年   14篇
  1979年   21篇
  1978年   16篇
  1977年   11篇
  1976年   16篇
  1975年   15篇
  1970年   6篇
排序方式: 共有2466条查询结果,搜索用时 15 毫秒
61.
62.
Out of 196 patients with Beh?et's disease, 12 (10 men and 2 women, mean age 34 +/- 7 years) had non-coronary arterial lesions. Beh?et's disease was complete in 4 patients. The arterial lesions had appeared 8.6 +/- 8 years on average (20 years at most) after the first sign of the disease. Three patients showed evidence of stenosis or occlusion involving one or several arteries. Eight patients had both stenotic and aneurysmal lesions. One patient had an arteriovenous fistula. Another developed a false aneurysm at the site of introduction of a femoral catheter. Yet another patient developed an anastomotic aneurysm one year after implantation of an abdominal aortic graft. In 2 cases histology showed fragmentation of the media associated with vasculitis of the vasa vasorum. Two patients with pulmonary aneurysm died of massive haemoptysis. In 2 patients combined corticosteroid and cyclophosphamide therapy failed to prevent the development of aneurysmal lesions. Phlebitis was associated with arterial involvement in 7 patients. Comparison between patients with or without arterial lesions showed no significant difference in time of onset of Beh?et's disease, sex, main clinical features and presence of HLA B5. Aneurysmal lesions respond poorly to medical treatment, and surgery is mandatory. Since recurrence at the site of anastomosis is possible, prolonged monitoring is required.  相似文献   
63.
Erythema infectiosum, fifth disease, is a usually benign macular or maculopapular exanthem of childhood caused by the human parvovirus B19. A 27-year-old woman with a serologically documented human parvovirus infection who presented with a hemorrhagic exanthem and enanthem with areas of pustules and pseudo-pustules is described. The histologic findings were unusual because they combined the histologic features of morbilliform and vesiculopustular viral lesions. This case serves to underscore the occurrence of human parvovirus infection in adults. Further, it demonstrates the need to include parvovirus infection in the differential diagnosis of virally induced vesiculopustular skin eruptions.  相似文献   
64.
65.
66.
A young man developed syncopal complete paroxysmal atrioventricular block (AVB) over a 36 hour period, on a background of 1st degree AVB which persisted for 6 weeks. During the 3rd week, electrophysiological studies showed an isolated prolonged AH interval. This episode followed skin and articular manifestations occurring one month after being bitten by a tick in Corsica. The clinical picture suggested Lyme's disease which was confirmed serologically. This condition transmitted bu Ixodes ricinus, a tick present in country districts, is due to spirochetal infection. It is characterized by a chronic migrating erythema, and may sometimes be complicated by severe AV conduction defects which are always regressive, as in our case.  相似文献   
67.
68.
Chen  CL; Fuscoe  JC; Liu  Q; Relling  MV 《Blood》1996,88(6):2210-2218
Etoposide is one of the most widely used antineoplastics. Unfortunately, the same treatment schedules associated with impressive efficacy are associated with an increased risk of secondary acute myeloid leukemia (AML), which has prompted its withdrawal from some treatment regimens, thereby potentially compromising efficacy against the original tumor. Because etoposide-associated AML is characterized by site-specific illegitimate DNA recombination, we studied whether etoposide could directly cause site-specific deletions of exons 2 and 3 in the hprt gene. Human lymphoid CCRF-CEM cells were treated with etoposide for 4 hours, and DNA was isolated after subculturing. The deletion of exons 2 and 3 from hprt was assayed by a quantitative polymerase chain reaction (PCR) method. In the absence of etoposide treatment, the frequency of deletions of exons 2 and 3 was very low (5.05 x 10(-8)). After exposure to 10 mumol/ L etoposide, the frequency of the exon 2 + 3 deletion was increased immediately after and at 24 hours after etoposide treatment (65 to 89 x 10(-8)) and increased to higher levels (128 to 173 x 10(-8)) after 2 and 6 days of subculture (P < .001 overall). The frequency of the exon 2 + 3 deletion assessed at 6 days of subculture after 4 hours of 0, 0.25, 1, 2.5, 5, and 10 mumol/L etoposide treatment increased with etoposide concentration, ie, 5.05 x 10(-8), 89.2 x 10(-8), 108 x 10(-8), 142 x 10(-8), 163 x 10(-8), and 173 x 10(-8), respectively (P < .0001). Sequencing of a subset of amplified products confirmed the presence of DNA sequences at the breakpoints consistent with V(D)J recombination. By contrast, exon 2 + 3 deletions after etoposide treatment in the myeloid cell lines KG-1A and K562 showed no evidence of V(D)J recombinase in their genesis. We conclude that etoposide can induce the illegitimate site-specific action of V(D)J recombinase on an unnatural DNA substrate after a single treatment in human lymphoid cells.  相似文献   
69.
70.
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