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   2270921篇
  免费   174809篇
  国内免费   4089篇
耳鼻咽喉   31748篇
儿科学   74970篇
妇产科学   64732篇
基础医学   322034篇
口腔科学   65705篇
临床医学   197584篇
内科学   445725篇
皮肤病学   48533篇
神经病学   183230篇
特种医学   90953篇
外国民族医学   767篇
外科学   348435篇
综合类   54450篇
现状与发展   3篇
一般理论   768篇
预防医学   173198篇
眼科学   52593篇
药学   168834篇
  3篇
中国医学   4290篇
肿瘤学   121264篇
  2018年   21554篇
  2016年   18691篇
  2015年   21536篇
  2014年   30016篇
  2013年   46159篇
  2012年   62185篇
  2011年   65720篇
  2010年   39084篇
  2009年   37427篇
  2008年   62936篇
  2007年   66578篇
  2006年   67463篇
  2005年   65685篇
  2004年   64332篇
  2003年   61667篇
  2002年   60556篇
  2001年   104145篇
  2000年   107715篇
  1999年   91538篇
  1998年   25222篇
  1997年   23048篇
  1996年   22861篇
  1995年   22039篇
  1994年   20756篇
  1993年   19677篇
  1992年   74842篇
  1991年   72463篇
  1990年   70842篇
  1989年   68624篇
  1988年   63753篇
  1987年   62872篇
  1986年   60064篇
  1985年   57728篇
  1984年   43342篇
  1983年   37103篇
  1982年   21999篇
  1981年   19514篇
  1980年   18443篇
  1979年   40875篇
  1978年   28530篇
  1977年   24006篇
  1976年   22665篇
  1975年   24303篇
  1974年   29541篇
  1973年   28404篇
  1972年   26275篇
  1971年   24609篇
  1970年   22954篇
  1969年   21522篇
  1968年   20000篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Several cases of relapsing attacks during which the ear becomes red and patients experience a burning sensation have been reported in the literature. This combination of symptoms has been described as ‘red ear syndrome’ (RES). We report on a 7‐year‐old boy who had episodes of reddening, swelling and a burning sensation in one ear with local hyperthermia persisting for 3 years. The differential diagnosis included RES and erythromelalgia, as isolated auricular variants of erythromelalgia have been described and the symptoms are difficult to distinguish from RES. In this report, we discuss the similarities and differences between RES and erythromelalgia.  相似文献   
993.
994.
995.
996.
Abstract:  Long-term prophylaxis against cytomegalovirus (CMV) started immediately after transplantation in (D+/R−) poses a higher risk of late-onset CMV disease. Delayed CMV prophylaxis could allow a transitory exposure of the immune system to CMV, which would let the immune system mount an adequate CMV-specific cytotoxic response in (D+/R−) patients and confer protection against CMV disease. We included all (D+/R−) solid organ transplant recipients (SOT) performed at our institution (January 3/October 6) who received CMV prophylaxis (mainly with oral valganciclovir) during 100 d. In the first period (until December 4), prophylaxis was initiated immediately after transplantation (conventional prophylaxis: CP). Since January 5, it was initiated after 14 d (delayed prophylaxis: DP). Incidence and severity of CMV disease was compared between both groups. A total of 44 SOT recipients were included (CP: 26 and DP: 18). CMV disease was diagnosed in eight patients (18%), seven of 26 (27%) in the CP group, and one of 18 (5.5%) in the DP group (p = 0.07). CMV colitis was reported in five of 26 patients in the CP group (19%), whereas there were no cases of visceral CMV disease in the DP group (p = 0.048). A 14-d delay in the beginning of long-term prophylaxis against CMV in (D+/R−) is safe and could prevent the onset of late-CMV disease.  相似文献   
997.
998.
Pain control is one of the most challenging aspects in the management of chronic pancreatitis. Total pancreatectomy can successfully relieve the intractable abdominal pain in these patients but will inevitably result in insulin-dependent diabetes. Islet autotransplantation aims to preserve, as far as possible, the insulin secretory function of the islet cell mass thereby reducing (or even removing) the requirement for exogenous insulin administration after a total pancreactomy. Despite the relatively small number of centres able to perform these procedures, there are important technical variations in the details of their approaches. The aim of this review is to provide details of the current surgical practice for total pancreatectomy combined with islet autotransplantation, and outline the potential advantages and disadvantages of the variations adopted in each centre.  相似文献   
999.
Abstract: As the most prevalent pathogen among transplant patients, cytomegalovirus (CMV) affects up to three-quarters of all solid organ transplant recipients. While we have made great strides in preventing CMV infection and disease in the early post-transplant period, late CMV infection and indirect effects due to viral immunomodulation remain problematic. Changing immunosuppression practices, including the increasing use of T-cell depleting induction antibodies, have the potential to affect the risk for CMV infection and disease, even in the face of good prophylactic and preemptive therapy. The purpose of this review article is to discuss the impact of CMV infection on long-term allograft outcomes and to re-evaluate the risks and management strategies for prevention of CMV in the framework of evolving modern immunosuppressive strategies.  相似文献   
1000.

Objectives

For individuals not on antiretroviral therapy, the risk of heterosexual transmission of HIV appears negligible when blood plasma (BP) viral loads are <1500 HIV‐1 RNA copies/mL. It is not clear whether this observation can be extrapolated to individuals on highly active antiretroviral therapy (HAART). Because of differential tissue penetration, antiretroviral drug concentrations may be sufficient to maintain an undetectable viral load in the BP yet not achieve adequate levels to suppress HIV in the genital tract. Therefore, we wanted to correlate HIV viral loads and drug concentrations in semen plasma (SP) and BP.

Methods

Thirty‐three men were included. All were on combination antiretroviral therapy with an undetectable BP viral load for at least 1 year. Blood and semen samples were collected within 2 h of each other and tested for HIV RNA by the NucliSens QT (bioMerieux, St Laurent, QC, Canada) method; drug concentrations were determined by liquid chromatography tandem mass spectrometry.

Results

Two of the 33 patients (6.1%) with BP viral loads below detection had time‐matched HIV viral loads in SP ≥700 copies/mL. Both patients were on efavirenz, the SP concentrations of which were ≤10% of the levels in BP and well below the minimal therapeutic drug monitoring target concentration required to suppress HIV.

Conclusions

Because, at least in part, of poor drug penetration into the genital tract, an undetectable HIV viral load in the BP does not guarantee an undetectable viral load in semen. In view of this, caution should be taken in concluding that patients on HAART with suppressed viraemia are sexually non‐infectious.  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