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   25652篇
  免费   1992篇
  国内免费   70篇
耳鼻咽喉   212篇
儿科学   832篇
妇产科学   648篇
基础医学   3630篇
口腔科学   493篇
临床医学   2670篇
内科学   5549篇
皮肤病学   505篇
神经病学   2677篇
特种医学   546篇
外国民族医学   4篇
外科学   2920篇
综合类   135篇
一般理论   20篇
预防医学   3300篇
眼科学   366篇
药学   1432篇
中国医学   67篇
肿瘤学   1708篇
  2024年   42篇
  2023年   388篇
  2022年   680篇
  2021年   1432篇
  2020年   850篇
  2019年   1213篇
  2018年   1347篇
  2017年   878篇
  2016年   911篇
  2015年   957篇
  2014年   1241篇
  2013年   1581篇
  2012年   2234篇
  2011年   2281篇
  2010年   1116篇
  2009年   921篇
  2008年   1475篇
  2007年   1334篇
  2006年   1217篇
  2005年   969篇
  2004年   824篇
  2003年   753篇
  2002年   621篇
  2001年   283篇
  2000年   307篇
  1999年   270篇
  1998年   112篇
  1997年   76篇
  1996年   60篇
  1995年   61篇
  1994年   50篇
  1993年   47篇
  1992年   134篇
  1991年   131篇
  1990年   118篇
  1989年   78篇
  1988年   75篇
  1987年   55篇
  1986年   67篇
  1985年   72篇
  1984年   52篇
  1983年   37篇
  1982年   28篇
  1979年   23篇
  1978年   23篇
  1973年   26篇
  1972年   24篇
  1971年   24篇
  1970年   27篇
  1967年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Many recent efforts in the field of community psychology have been dedicated to moving from values to action in incorporating diversity into our work. An essential aspect of this goal is designing research that provides opportunities for underrepresented perspectives to be heard. The voices of refugee women, in particular, are not typically incorporated in research, planning for service provision, and policy design. This article explores methodological challenges involved in conducting research with refugee women who are marginalized both within broader U.S. contexts and within their own communities. Six guiding principles are presented: 1) develop strategies for involving marginalized refugee women; 2) consider the advantages and limitations of quantitative and qualitative methodologies and be innovative about combining them; 3) prepare for extensive time and effort for quantitative measure construction; 4) consider gendered decision‐making structures in the lives of refugee women and their potential impact on the research process; 5) plan for refugee women's common triple burden of working outside of the home, managing their households, and adjusting to life in a new country; and 6) attend to refugee women's cultural norms about and unfamiliarity with the interview process. © 2004 Wiley Periodicals, Inc. J Comm Psychol 32: 721–739, 2004.  相似文献   
4.
5.
6.
Background  Surgical procedures enhance production of pro- and anti-inflammatory cytokines and angiogenic factors that play a pivotal role in the immunological response to surgical trauma and take part in the pathogenesis of tumor growth and adhesions formation. The purpose of the study was to access the influence of low-pressure CO2 pneumoperitoneum on the inflammatory and angiogenic responses during the postoperative period after laparoscopy. Methods  The study group consisted of 40 patients, operated on due to cholelithiasis using standard-pressure (n = 20) and low-pressure (n = 20) CO2 pneumoperitoneum. Serum concentration of interleukin (IL)-6, IL-8, IL-10, vascular endothelial growth factor (VEGF)-A, and endostatin were measured before and at 6, 24, and 48 h after surgery with commercially available enzyme-linked immunosorbent assay (ELISA). Results  Concentrations of IL-6 increased significantly after the operations in both groups. No differences were observed between the groups in regards to IL-6, IL-8, and IL-10 levels. Concentrations of VEGF-A measured at 6 and 48 h were significantly lower in patients who underwent laparoscopies performed with low-pressure pneumoperitoneum. No significant variations were observed in endostatin serum concentration. Concentrations of the studied parameters were not influenced by duration of surgery or by age, gender, or body mass index (BMI) of the patients. Conclusions  The results obtained in our study do not show any significant differences between studied operative procedures with regards to systemic inflammatory response. Changes in the concentrations of VEGF-A and endostatin observed in the studied population may suggest this technique is more favorable with regards to angiogenesis process intensity, along with all its consequences and implications.  相似文献   
7.
8.
BACKGROUND: The dopamine transporter (DAT) is known to be a key regulator of dopamine, and recent studies of genetics, treatment, and imaging have highlighted the role of DAT in attention-deficit/hyperactivity disorder (ADHD). The findings of in vivo neuroimaging of DAT in ADHD have been somewhat discrepant, however. METHOD: Dopamine transporter binding was measured using a highly selective ligand (C-11 altropane) and positron emission tomography (PET). The sample consisted of 47 well-characterized, treatment-na?ve, nonsmoking, non-comorbid adults with and without ADHD. Additionally, control subjects had few symptoms of ADHD. RESULTS: Results showed significantly increased DAT binding in the right caudate in adults with ADHD compared with matched control subjects without this disorder. CONCLUSIONS: These results confirm abnormal DAT binding in the striatum of adults with ADHD and provide further support that dysregulation of DAT may be an important component of the pathophysiology of ADHD.  相似文献   
9.
OBJECTIVE: The aim of this study was to determine whether EEG slowing is more pronounced in older than younger OSAS patients and to verify whether this cortical slowing is correlated to daytime performance, respiratory perturbation and sleep fragmentation. METHODS: Twelve young OSAS patients (mean age 38.2+/-2.0 y) and 13 older OSAS patients (mean age 62.2+/-1.9 y) along with 13 young controls (mean age 35.8+/-2.0 y) and 14 older controls (mean age 60.2+/-2.0 y) underwent a polysomnographic evaluation followed by a waking EEG recording. As a global index of cortical slowing, a ratio of slow-to-fast frequencies was calculated in all cortical regions. Daytime performance was assessed using the four choice reaction time test. RESULTS: Differences in waking EEG and in daytime performance were analyzed by ANOVAs with Group and Age as factors. Waking EEG did not yield a Group by Age interaction. OSAS patients had higher ratios across all regions than controls. Similarly, daytime performance revealed no Group by Age interaction. However, OSAS patients showed more lapses than controls and older subjects were slower than younger subjects. CONCLUSIONS: Our results indicate that age does not interact with OSAS to worsen the severity of cortical slowing, but age can add to the OSAS effect to worsen daytime performance deficits in OSAS patients. SIGNIFICANCE: The daytime performance deficits observed particularly in elderly OSAS patients warrant a careful clinical assessment of these patients to prevent accidents and injuries.  相似文献   
10.

Background  

There are few effective strategies reported for the primary prevention of low back pain (LBP). Core stabilization exercises targeting the deep abdominal and trunk musculature and psychosocial education programs addressing patient beliefs and coping styles represent the current best evidence for secondary prevention of low back pain. However, these programs have not been widely tested to determine if they are effective at preventing the primary onset and/or severity of LBP. The purpose of this cluster randomized clinical trial is to determine if a combined core stabilization exercise and education program is effective in preventing the onset and/or severity of LBP. The effect of the combined program will be compared to three other standard programs.  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