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   75359篇
  免费   5183篇
  国内免费   156篇
耳鼻咽喉   527篇
儿科学   2875篇
妇产科学   2601篇
基础医学   8879篇
口腔科学   926篇
临床医学   12789篇
内科学   13830篇
皮肤病学   1195篇
神经病学   6981篇
特种医学   1264篇
外国民族医学   33篇
外科学   6510篇
综合类   943篇
一般理论   106篇
预防医学   10633篇
眼科学   910篇
药学   4400篇
  1篇
中国医学   154篇
肿瘤学   5141篇
  2023年   476篇
  2022年   670篇
  2021年   1402篇
  2020年   1003篇
  2019年   1627篇
  2018年   1853篇
  2017年   1350篇
  2016年   1502篇
  2015年   1646篇
  2014年   2271篇
  2013年   3728篇
  2012年   5345篇
  2011年   5544篇
  2010年   3006篇
  2009年   2839篇
  2008年   4855篇
  2007年   5428篇
  2006年   5187篇
  2005年   5142篇
  2004年   4925篇
  2003年   4611篇
  2002年   4396篇
  2001年   639篇
  2000年   477篇
  1999年   606篇
  1998年   936篇
  1997年   731篇
  1996年   641篇
  1995年   571篇
  1994年   548篇
  1993年   519篇
  1992年   391篇
  1991年   353篇
  1990年   358篇
  1989年   292篇
  1988年   269篇
  1987年   269篇
  1986年   247篇
  1985年   287篇
  1984年   313篇
  1983年   289篇
  1982年   357篇
  1981年   324篇
  1980年   264篇
  1979年   187篇
  1978年   166篇
  1977年   175篇
  1976年   134篇
  1975年   135篇
  1973年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Twoin vitro models of immune surveillance were used to examine the immune status of the gut-associated lymphoid tissue, mesenteric lymph nodes, and spleen during the early stages of 1,2-dimethylhydrazine (DMN)-induced colon tumorigenesis. DMH-and vehicletreated Fischer rats were sacrificed at one of three time points; one week, two months, or five months after cessation of treatment. Colonic, lymph node, and splenic natural killer cell cytolytic activity toward YAC-1 tumor targets and T-cell response to autologous la-induced balstogenesis were measured at each time point. We found little change in natural killer cell activity or T-cell proliferation induced by autologous Ia gene products at these time periods.This investigation was supported in part by grant CA26917 from the National Cancer Institute, Department of Health and Human Services.  相似文献   
62.
63.
64.
65.
66.
BACKGROUND: Perfusion functional magnetic resonance imaging (fMRI) was used to investigate the effect of genetic variation of the human serotonin transporter (5-HTT) gene (5-HTTLPR, SLC6A4) on resting brain function of healthy individuals. METHODS: Twenty-six healthy subjects, half homozygous for the 5-HTTLPR short allele (s/s group) and half homozygous for the long allele (l/l group), underwent perfusion functional and structural magnetic resonance imaging during a resting state. The two genotype groups had no psychiatric illness and were similar in age, gender, and personality scores. RESULTS: Compared with the l/l group, the s/s group showed significantly increased resting cerebral blood flow (CBF) in the amygdala and decreased CBF in the ventromedial prefrontal cortex. The effect of functional modulation in these regions by 5-HTTLPR genotype cannot be accounted for by variations in brain anatomy, personality, or self-reported mood. CONCLUSIONS: The 5-HTTLPR genotype alters resting brain function in emotion-related regions in healthy individuals, including the amygdala and ventromedial prefrontal cortex. Such alterations suggest a broad role of the 5-HTT gene in brain function that may be associated with the genetic susceptibility for mood disorders such as depression.  相似文献   
67.
68.
Esophageal perforation is associated with a significant risk of morbidity and mortality. We report herein a case of lye-induced esophageal perforation managed successfully by employing endoscopic T-tube placement with a successful outcome.  相似文献   
69.
This article reports the results of semi-structured interviews with substance abuse treatment (SAT) program directors (PDs) regarding the ways SAT is being influenced by managed care (MC), plans for future SAT, and strategies for decreasing costs of care. It compares findings to an earlier survey of 50 SAT PDs.

Interviews were conducted in 20 SAT programs to gather information about treatment delivery since the advent of MC, including PD responsibilities, funding source, treatment intensity, location, duration, and methods of treatment. Open-ended responses were used to gather information about current and future plans in providing SAT, and awareness of new types of treatment being planned by organizations impacted by MC.

PDs reported changes in SAT secondary to MC such as decreased treatment length, limiting of inpatient and outpatient services, and delayed treatment secondary to benefit determination. Political and economic constraints were seen as barriers to providing adequate and effective services. SAT being subsumed by mental health was viewed as problematic along with an emerging split between alcohol abuse and drug treatment. A positive emerging treatment trend was the development of targeted programs for special need groups.

PDs revealed a variety of strategies that have promoted necessary adaptations to economic and political influences within the structure of managed behavioral care. Strategies such as varying treatment length, modality, and subspecialty care reflected necessary adaptations to diverse market needs.

Managed care continues to have a tremendous impact on the delivery of SAT services. While MC has helped to contain costs, negative outcomes are decreased availability of appropriate care and overtaxing of units that have survived MC cut backs. However, special need programs have allowed SAT programs to specialize, expand, and even flourish in today's competitive SAT market. Interviews with PDs reinforced the need for maintaining quality and diversified SAT services in today's MC environment.  相似文献   
70.
Background contextLumbar discectomy is the most common type of back surgery performed in the United States. Outcomes after this procedure can be variable and it appears that Workers' Compensation patients might be at increased risk for poor outcomes.PurposeTo examine long-term multidimensional outcomes of lumbar discectomy within a cohort of Workers' Compensation patients from Utah and identify presurgical biopsychosocial factors related to poor outcomes.Study design/settingA retrospective cohort study consisting of a review of presurgical medical records and assessment of patient outcomes via a telephone survey. Outcomes were assessed at least 2 years postsurgery.Patient sampleA consecutive sample of 271 workers from Utah who underwent lumbar discectomy from 1994 to 1999. A total of 134 patients were surveyed at the time of follow-up.Outcome measuresPatient satisfaction, Roland-Morris Disability Questionnaire, SF-36v2, and Stauffer-Coventry Index.MethodsA retrospective review of presurgical biopsychosocial variables and outcome assessment via telephone survey was conducted.ResultsWork disability rate for the cohort was 12.7% (17/134). Analysis of patient satisfaction, back pain-related dysfunction, and the Short-Form Health Survey-36 subscales indicated approximately 25% of patients experienced poor outcomes. Older age, number of comorbid health conditions, assigned case manager, litigation, and time delay from injury to surgery were consistently statistically significant predictors (p<.05) of poor outcomes.ConclusionsResults of this study suggest that compensated back surgery patients are at greater risk for poor lumbar discectomy outcomes than noncompensation patients. Presurgery correlates of poor outcomes may be useful in identifying high-risk compensation patients.  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