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   1295篇
  免费   91篇
  国内免费   22篇
耳鼻咽喉   4篇
儿科学   48篇
妇产科学   17篇
基础医学   83篇
口腔科学   19篇
临床医学   153篇
内科学   384篇
皮肤病学   228篇
神经病学   39篇
特种医学   101篇
外科学   97篇
综合类   15篇
预防医学   137篇
药学   56篇
肿瘤学   27篇
  2018年   8篇
  2017年   12篇
  2016年   30篇
  2015年   35篇
  2014年   35篇
  2013年   64篇
  2012年   12篇
  2011年   17篇
  2010年   34篇
  2009年   53篇
  2008年   15篇
  2007年   18篇
  2006年   25篇
  2005年   11篇
  2004年   12篇
  2003年   12篇
  2002年   14篇
  2001年   10篇
  2000年   22篇
  1999年   39篇
  1998年   68篇
  1997年   55篇
  1996年   60篇
  1995年   51篇
  1994年   56篇
  1993年   38篇
  1992年   57篇
  1991年   15篇
  1990年   42篇
  1989年   43篇
  1988年   55篇
  1987年   35篇
  1986年   28篇
  1985年   13篇
  1984年   35篇
  1983年   17篇
  1982年   20篇
  1981年   22篇
  1980年   17篇
  1978年   11篇
  1977年   8篇
  1976年   13篇
  1975年   8篇
  1973年   9篇
  1972年   7篇
  1971年   9篇
  1966年   9篇
  1964年   14篇
  1960年   6篇
  1941年   6篇
排序方式: 共有1408条查询结果,搜索用时 15 毫秒
41.
42.
The molecular characterization of the mutations in hemophilia A patients is hampered by the large size of the factor VIII gene and the great heterogeneity of mutations. In this study, we have performed a protocol involving multiplex polymerase chain reaction in which 19 exons were amplified in four different combinations followed by nonradioactive single-strand conformational polymorphism (SSCP) to screen for mutations. Southern blotting was used to detect inversion of the factor VIII gene resulting from recombination between copies of the gene A (F8A) located in intron 22 of the factor VIII gene and two copies close telomeric region of X chromosome. Forty-two hemophilia A patients (21 with severe and 21 with mild-to-moderate disease) were studied. The inversion of factor VIII occurred in 13 of 21 patients affected by severe hemophilia A. One patient showed a large extra band in addition to the three bands observed after Southern blotting with the F8A probe. An abnormal electrophoretic pattern of SSCP was detected in 85% and 50% of the patients affected by mild-to-moderate and severe disease, respectively. Sixteen different mutations were identified. Eleven mutations were novel and comprised 9 point mutations and 2 small deletions. This study shows that the methodology used is safe and rapid and has potential for detecting almost all of the genetic defects of the studied hemophilia A patients.  相似文献   
43.
44.
45.
Online forums for chronic health conditions emerged as early as 30 yr ago and interest in their study has blossomed. Type 1 diabetes (T1D) forums have grown exponentially since 2005. Therefore, a comprehensive evaluation of these forums is needed. This study assesses the demographics and motivations of parents who use type 1 diabetes forums and the potential impact that forum membership (FM) has on parenting stress and hypoglycemic fear. One hundred and two parents were recruited through online T1D forums and asked to complete qualitative and quantitative measures of their experience with the T1D forums. Results of this study suggest that parents who use T1D forums mirror those who participate in clinic‐based research protocols and are primarily motivated to participate in forums to increase their diabetes knowledge and gain social support. Indeed, parents who use T1D forums report high levels of trust, social support, and perceived knowledge gained. However, FM was positively related to increased self‐reported parenting stress frequency and hypoglycemic fear behaviors. Taken together, the relationships formed within these communities may have a significant impact on the experience of these caregivers. The need for future research and potential implications for physicians, including parent debriefing, are discussed.  相似文献   
46.
Care for patients who experience out-of-hospital cardiac arrest (OHCA) has rapidly evolved in the past decade. Increased sophistication of care in the community, emergency medical services (EMS) and hospital setting is associated with improved patient-centred outcomes. Notably, Utstein survival doubled from 11.6% to 23.1% between 2011 and 2016. These achievements involved collaboration between policymakers, clinicians and researchers, and were made possible by a strategic interplay of policy, research and implementation. We review the development and current state of OHCA in Singapore using primary population-based data from the Pan-Asian Resuscitation Outcomes Study and an unstructured search of research databases. We discuss the roles of important milestones in policy, community, dispatch, EMS and hospital interventions. Finally, we relate these interventions to relevant processes and outcomes, such as the relationship between the strategic implementation of bystander cardiopulmonary resuscitation and placement of automated external defibrillator with return of spontaneous circulation, survival to discharge and survival with favourable neurological outcomes.  相似文献   
47.
Background. Pericapillary fibrin cuffs (PFC) are a recognized part of the pathology of venous stasis ulcers. A hydrocolloid dressing capable of lysing wound surface fibrin was tested in venous ulcers for its capacity to lyse pericapillary fibrin below the wound surface. Methods. Tissue biopsies from the rims of 19 venous ulcers were evaluated for thickness of shallow and deep dermal PFCS before and after treatment with DuoDERM covered by Unna's boot and a compression bandage (DD+UB; n=9) versus the same treatment without the hydrocolloid dressing (UB; n=10). Frozen sections of all biopsies were stained with an immunofluorescent antibody to fibrin for rating of PFC thickness. Separate sections were stained with hematoxylin and eosin to assess capillary frequency, histopathology, and inflammation. All ratings and pathology assessments were performed blinded to treatment conditions. Results. Both deep and shallow PFCS were reduced in 89% of ulcers treated with DD+UB versus 40% of ulcers treated with UB (α < 0.04). No other significant differences in inflammation, histopathology, or capillary frequency were observed. Conclusions. Treatment with DD+UB reduced PFCS in twice the number of ulcers than UB alone in 1 week. This is the first scientific documentation that a topical wound dressing could reduce the pathophysiology associated with venous ulcers, beyond the known beneficial effect of graduated compression. Not all hydrocolloid dressings are fibrinolytic, so this effect may not generalize to other dressings.  相似文献   
48.
49.
50.
Albunex Does Not Increase the Sensitivity of the Lung to Pulsed Ultrasound   总被引:1,自引:0,他引:1  
If cavitation in the vasculature of the lung is the physical mechanism responsible for lung hemorrhage, then addition of cavitation nuclei to the blood should enhance the bioeffect. To test the cavitation hypothesis, the extent of lung hemorrhage in mice injected with the echocontrast agent, Albunex®, was compared to lung hemorrhage in animals injected with saline. Animals were exposed for 5 minutes to 1.1-MHz pulsed ultrasound (10 μs pulse length, 100-Hz pulse repetition frequency) at a peak positive pressure at the surface of the animal of 2 MPa. This exposure is approximately twice the threshold pressure amplitude for lung hemorrhage. Lesion areas did not differ significantly in the two groups of animals and were approximately equal to the lesion area in uninjected mice from an earlier study where acoustic exposures were the same. Neither this study nor a related study of hemolysis in vivo suggests that use of Albunex in echocardiographic procedures increases the risk of bioeffects.  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