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   29861篇
  免费   2595篇
  国内免费   49篇
耳鼻咽喉   355篇
儿科学   1068篇
妇产科学   698篇
基础医学   3498篇
口腔科学   634篇
临床医学   3905篇
内科学   5618篇
皮肤病学   468篇
神经病学   2828篇
特种医学   1290篇
外科学   3696篇
综合类   665篇
一般理论   46篇
预防医学   3439篇
眼科学   513篇
药学   2147篇
  2篇
中国医学   33篇
肿瘤学   1602篇
  2021年   407篇
  2020年   272篇
  2019年   363篇
  2018年   467篇
  2017年   330篇
  2016年   400篇
  2015年   455篇
  2014年   705篇
  2013年   1039篇
  2012年   1202篇
  2011年   1368篇
  2010年   803篇
  2009年   624篇
  2008年   1202篇
  2007年   1345篇
  2006年   1313篇
  2005年   1222篇
  2004年   1218篇
  2003年   1037篇
  2002年   977篇
  2001年   985篇
  2000年   996篇
  1999年   798篇
  1998年   342篇
  1997年   351篇
  1996年   304篇
  1995年   288篇
  1994年   266篇
  1993年   240篇
  1992年   701篇
  1991年   715篇
  1990年   685篇
  1989年   642篇
  1988年   623篇
  1987年   583篇
  1986年   591篇
  1985年   570篇
  1984年   436篇
  1983年   429篇
  1982年   291篇
  1981年   280篇
  1980年   243篇
  1979年   430篇
  1978年   313篇
  1977年   279篇
  1976年   253篇
  1975年   239篇
  1974年   299篇
  1973年   261篇
  1972年   233篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.

Objectives

Injury severity scoring tools allow systematic comparison of outcomes in trauma research and quality improvement by indexing an expected mortality risk for certain injuries. This study investigated the predictive value of the empirically derived ICD9-derived Injury Severity Score (ICISS) compared to expert consensus-derived scoring systems for trauma mortality in a pediatric population.

Methods

1935 consecutive trauma patients aged <18 years from 1/2000 to 12/2012 were reviewed. Mechanism of injury (MOI), Injury Severity Score (ISS), Revised Trauma Score (RTS), Trauma Score ISS (TRISS), and ICISS were compared using univariate and multivariate logistic regression analysis and receiver operator characteristic analysis.

Results

The population was a median age of 11 ± 6 year, 70 % male, and 76 % blunt injury. Median ISS 13 ± 12 and overall mortality 3.5 %. Independent predictors of mortality were initial hematocrit [odds ratio (OR) 0.83 (0.73–0.95)], HCO3 [OR 0.82 (0.67–0.98)], Glasgow Coma Scale score [OR 0.75 (0.62–0.90)], and ISS [OR 1.10 (1.04–1.15)]. TRISS was superior to ICISS in predicting survival [area under receiver operator curve: 0.992 (0.982–1.000) vs 0.888 (0.838–0.938)].

Conclusions

ICISS was inferior to existing injury scoring tools at predicting mortality in pediatric trauma patients.
  相似文献   
994.
995.
Breast density notification laws, passed in 19 states as of October 2014, mandate that patients be informed of their breast density. The purpose of this study is to assess the impact of this legislation on radiology practices, including performance of breast cancer risk assessment and supplemental screening studies. A 20‐question anonymous web‐based survey was emailed to radiologists in the Society of Breast Imaging between August 2013 and March 2014. Statistical analysis was performed using Fisher's exact test. Around 121 radiologists from 110 facilities in 34 USA states and 1 Canadian site responded. About 50% (55/110) of facilities had breast density legislation, 36% of facilities (39/109) performed breast cancer risk assessment (one facility did not respond). Risk assessment was performed as a new task in response to density legislation in 40% (6/15) of facilities in states with notification laws. However, there was no significant difference in performing risk assessment between facilities in states with a law and those without (p < 0.831). In anticipation of breast density legislation, 33% (16/48), 6% (3/48), and 6% (3/48) of facilities in states with laws implemented handheld whole breast ultrasound (WBUS), automated WBUS, and tomosynthesis, respectively. The ratio of facilities offering handheld WBUS was significantly higher in states with a law than in states without (p < 0.001). In response to breast density legislation, more than 33% of facilities are offering supplemental screening with WBUS and tomosynthesis, and many are performing formal risk assessment for determining patient management.  相似文献   
996.
997.
998.
999.
Malignant catarrhal fever (MCF) is an often-fatal lymphoproliferative disease of a variety of ungulates that occurs worldwide. It is caused by either of the highly related but distinct gammaherpesviruses alcelaphine herpesvirus-1 (AlHV-1, wildebeest reservoir) or ovine herpesvirus-2 (OvHV-2, sheep reservoir). MCF in rabbits is an excellent model as it closely resembles the disease in susceptible ungulates that include cattle, deer and bison. In this study, newly available and previously characterized monoclonal antibodies specific for rabbit leucocyte differentiation molecules were used to perform a detailed immunohistochemical examination of both AlHV-1 MCF and OvHV-2 MCF in rabbits. Differences in the MCF caused by the two viruses included: less tissue necrosis and more lymphoid cell accumulations in AlHV-1 MCF compared with OvHV-2 MCF, and in particular marked tissue necrosis in the mesenteric lymph node, appendix and liver of OvHV-2-infected animals when compared with either other tissues in OvHV-2 MCF or AlHV-1 MCF lesions in any tissue. In both AlHV-1 MCF and OvHV-2 MCF, lymphoid cell accumulations in lymphoid and non-lymphoid tissues consisted mainly of T-cells with a corresponding absence of B-cells. CD8(+) T-cells accounted for a proportion of these in the non-lymphoid tissues, but there was evidence for the accumulation of an unidentified T-cell subset/subsets as well. This study extends our understanding of the mechanisms of immuno-pathogenesis of MCF.  相似文献   
1000.
Spirituality has been identified as one component of a culturally competent therapeutic intervention for African American women. The present study was designed to investigate the ability of factors, such as level of hopelessness and the use of positive religious coping strategies, to predict spiritual well-being over time. Seventy-four low-income African American women were administered self-report questionnaires measuring hopelessness, use of religious coping strategies, and two domains of spiritual well-being. Path analysis indicated that hopelessness, existential well-being, religious well-being, and positive religious coping are correlated with one another. Further, lower levels of hopelessness predict increases in existential well-being over time; higher levels of positive religious coping predict increases in religious well-being over time. Results were consistent with the study hypotheses and highlight the need to attend to predictors of spiritual well-being when implementing culturally relevant interventions with abused, suicidal African American women. Therapeutic strategies for reducing hopelessness and enhancing positive religious coping to improve spiritual and existential well-being are presented; such strategies will ensure the interventions are more culturally competent.  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