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   24891篇
  免费   1822篇
  国内免费   82篇
耳鼻咽喉   318篇
儿科学   564篇
妇产科学   511篇
基础医学   3417篇
口腔科学   745篇
临床医学   2836篇
内科学   5030篇
皮肤病学   219篇
神经病学   2651篇
特种医学   958篇
外国民族医学   2篇
外科学   3066篇
综合类   349篇
一般理论   24篇
预防医学   1970篇
眼科学   489篇
药学   2055篇
中国医学   21篇
肿瘤学   1570篇
  2023年   90篇
  2021年   357篇
  2020年   247篇
  2019年   343篇
  2018年   386篇
  2017年   358篇
  2016年   415篇
  2015年   513篇
  2014年   716篇
  2013年   1076篇
  2012年   1638篇
  2011年   1779篇
  2010年   1040篇
  2009年   899篇
  2008年   1715篇
  2007年   1651篇
  2006年   1648篇
  2005年   1737篇
  2004年   1603篇
  2003年   1555篇
  2002年   1462篇
  2001年   316篇
  2000年   251篇
  1999年   318篇
  1998年   332篇
  1997年   247篇
  1996年   219篇
  1995年   254篇
  1994年   213篇
  1993年   189篇
  1992年   195篇
  1991年   165篇
  1990年   152篇
  1989年   148篇
  1988年   139篇
  1987年   138篇
  1986年   143篇
  1985年   147篇
  1984年   160篇
  1983年   156篇
  1982年   202篇
  1981年   164篇
  1980年   181篇
  1979年   101篇
  1978年   121篇
  1977年   114篇
  1976年   87篇
  1975年   87篇
  1974年   75篇
  1972年   60篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Tumor metastasis is a singularly important determinant of survival in most cancers. Historically, radiation therapy (RT) directed at a primary tumor mass was associated infrequently with remission of metastasis outside the field of irradiation. This away-from-target or “abscopal effect” received fringe attention because of its rarity. With the advent of immunotherapy, there are now increasing reports of abscopal effects upon RT in combination with immune checkpoint inhibition. This sparked investigation into underlying mechanisms and clinical trials aimed at enhancement of this effect. While these studies clearly attribute the abscopal effect to an antitumor immune response, the initial molecular triggers for its onset and specificity remain enigmatic. Here, we propose that DNA damage–induced inflammation coupled with neoantigen generation is essential during this intriguing phenomenon of systemic tumor regression and discuss the implications of this model for treatment aimed at triggering the abscopal effect in metastatic cancer.  相似文献   
3.
4.
Objectives: To identify all studies of gymnastics injuries and assess injury rates, types, locations, and causes.

Methods: Seven electronic and two grey literature databases were searched. Two reviewers independently assessed titles/abstracts, abstracted data, and calculated average rates weighted by study size.

Results: One study (n = 963) of three Olympic games (2008,2012,2016) provided injury rates for females of 86.4/1000gymnasts and males 79.9. For 29 databases one study of males (n = 64) provided a rate of 8.8 injuries/1000hours/AE (AE = athletic-exposure) and three of females varied rates (8.5, 9.4, and 91). Three studies for males (n = 153) provided a weighted average rate of 1.4 injuries/1000hours/training, and for females six studies (n = 476) 1.5 injuries. Four studies of males (n = 286) provided a weighted average of 678 injuries/1000gymnasts per year and eight studies of females (n = 1,764) a rate of 306. Of 19 surveys, eight provided rates for females (n = 1,463) of 596 injuries/gymnast per year and two for males (n = 40) a rate of 1,036. In the Olympics injuries were preponderately lower limb (63%) then trunk (23%) and upper limb (14%); injury type was sprains (35%) followed by tendinopathy/arthritis/impingements (17%), contusions (10%), and fractures (7%). Five database studies provided injury location data for 274 males: averages weighted by study size were upper extremity 42.8%, lower extremity 33.6%, torso/spine 11.8%, and head/neck 4.9% and 12 studies with 843 females provided average rates for lower extremity 51%, upper extremity 30.8%, torso/spine 13% and head/neck 0.8%. Official gymnastics organizations’ websites provide no readily available data about injury rates or methods of prevention.

Conclusions: Studies need to collect comprehensive data for injury rates by training/competitions, gender, age, injury location/type/cause. Studies could assess whether trainers and physiotherapists monitoring gymnasts closely for injury risk would reduce injuries. Studies including randomized controlled trials (RCTs) of interventions in training, videotaping and performance feedback to reduce injury rates would be helpful.  相似文献   

5.
Methadone has several unique characteristics that make it an attractive option for pain relief in serious illness, but the safety of methadone has been called into question after reports of a disproportionate increase in opioid-induced deaths in recent years. The American Pain Society, College on Problems of Drug Dependence, and the Heart Rhythm Society collaborated to issue guidelines on best practices to maximize methadone safety and efficacy, but guidelines for the end-of-life scenario have not yet been developed. A panel of 15 interprofessional hospice and palliative care experts from the U.S. and Canada convened in February 2015 to evaluate the American Pain Society methadone recommendations for applicability in the hospice and palliative care setting. The goal was to develop guidelines for safe and effective management of methadone therapy in hospice and palliative care. This article represents the consensus opinion of the hospice and palliative care experts for methadone use at end of life, including guidance on appropriate candidates for methadone, detail in dosing, titration, and monitoring of patients' response to methadone therapy.  相似文献   
6.
7.
8.
9.
Background: The field of addiction studies (AS) has grown in the last several decades. However, little is known about the structure and conditions of current academic programs. Only two studies have examined AS programs in the U.S., and both were conducted almost 15 years ago. The current study was designed to identify AS programs existing in the U.S. universities.

Methods: We conducted an Internet search to identify university-based programs according to defined key words. The university program websites were then subjected to content analysis.

Results: A total of 333 U.S. universities were identified that offered 392 different academic programs in AS of which 302 were degree programs. Out of these, 161 (53%) programs were offered at the associate degree level, 48 (15,9%) at the bachelor’s level, 55 (18.2%) at the master’s level, and 5 (1.6%) at the doctorate level. The largest number of programs was in California. Two states in the U.S. had no identifiable programs. Only one university located in the state of New York offered comprehensive academic programs across the educational spectrum. Many of the academic programs offered certificates. The most common phrases used in program titles were “substance abuse”, “addiction studies/counseling”, and “chemical dependency”.

Conclusions: There is a wide range of academic AS programs in the U.S., although their focus is mostly on clinical training rather than on research or drug policy. Future surveys such as this one would benefit from greater attention to issues related to certification, licensing, and academic curricula.  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