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   36165篇
  免费   3113篇
  国内免费   65篇
耳鼻咽喉   413篇
儿科学   1160篇
妇产科学   891篇
基础医学   4686篇
口腔科学   543篇
临床医学   4596篇
内科学   6851篇
皮肤病学   525篇
神经病学   3304篇
特种医学   1206篇
外国民族医学   8篇
外科学   4358篇
综合类   604篇
一般理论   23篇
预防医学   4208篇
眼科学   863篇
药学   2664篇
中国医学   26篇
肿瘤学   2414篇
  2023年   335篇
  2022年   560篇
  2021年   1142篇
  2020年   648篇
  2019年   1077篇
  2018年   1179篇
  2017年   805篇
  2016年   930篇
  2015年   994篇
  2014年   1333篇
  2013年   1641篇
  2012年   2462篇
  2011年   2516篇
  2010年   1292篇
  2009年   1094篇
  2008年   1866篇
  2007年   1940篇
  2006年   1852篇
  2005年   1711篇
  2004年   1621篇
  2003年   1361篇
  2002年   1255篇
  2001年   629篇
  2000年   660篇
  1999年   584篇
  1998年   341篇
  1997年   276篇
  1996年   255篇
  1995年   237篇
  1994年   212篇
  1993年   189篇
  1992年   432篇
  1991年   433篇
  1990年   389篇
  1989年   410篇
  1988年   361篇
  1987年   340篇
  1986年   338篇
  1985年   323篇
  1984年   271篇
  1983年   232篇
  1982年   158篇
  1981年   126篇
  1979年   195篇
  1978年   172篇
  1977年   146篇
  1976年   141篇
  1974年   162篇
  1973年   147篇
  1972年   132篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
82.
PURPOSE: The U.S. Department of Veterans Affairs (VA) supports 8,700 resident positions nationally to enhance quality of care for veterans and to educate physicians. This study sought to establish a yearly quality indicator to identify and follow strengths and opportunities for improvement in VA clinical training programs. METHOD: In March 2001, the VA Learners' Perceptions Survey, a validated 57-item questionnaire, was mailed to 3,338 residents registered at 130 VA facilities. They were asked to rate their overall satisfaction with the VA clinical training experience and their satisfaction in four domains: faculty/preceptor, learning, working, and physical environments using a five-point Likert scale. Questionnaires were received from 1,775 residents (53.2%). A full analysis was conducted using 1,436 of these questionnaires, whose respondents were categorized in four training programs: medicine (n = 706), surgery (n = 291), subspecialty (n = 266), and psychiatry (n = 173). RESULTS: On a scale of 0 to 100, residents gave their clinical training experience an average score of 79. Eighty-four percent would have recommended VA training to peers, and 81% would have chosen VA training again. Overall, 87% were satisfied with their faculty/preceptors, 78% with the learning environment, and 67% with the working and physical environments. The survey was sensitive to differences in satisfaction among the trainee groups, with residents in internal medicine (IM) the least satisfied. CONCLUSION: The VA Learners' Perceptions Survey is the first validated survey to address comprehensive satisfaction issues in clinical training. The survey highlights strengths and opportunities for improvement in VA clinical training and is the first step toward improving education.  相似文献   
83.
Study Objective . To determine if one commercial extended-release formulation of nifedipine (Adalat CC) is as effective as another (Procardia XL) in controlling blood pressure over 24 hours. Design . Open-label, randomized, crossover study. Setting . University-affiliated family medicine clinic. Patients . Fifteen patients with stage 1–4 primary hypertension. Interventions . Procardia XL or Adalat CC once/day was titrated to achieve blood pressure control. The effective dose was continued for 4 weeks, washed out for 1 week, and reinstituted with other study drug. Measurements and Main Results . Twenty-four-hour ambulatory blood pressure was recorded the conclusion of each treatment phase. Treatment phases were compared for mean 24-hour blood pressure, mean daytime (6:00 a.m.–10:00 p.m.) and mean nighttime blood pressure, and mean blood pressure load (percentage of blood pressure measurements < 140/90 mm Hg daytime and > 120/80 mm Hg nighttime). Thirteen patients completed the study. No statistically significant difference was seen in mean 24-hour blood pressure (138/86 mm Hg for Procardia XL vs 137/85 mm Hg for Adalat CC), daytime or nighttime blood pressure, or blood pressure load. Two patients experienced clinically significant adverse effects while taking Adalat CC. Conclusions . In these patients with primary hypertension, Adalat CC was as effective as Procardia XL at controlling blood pressure for 24 hours. Blood pressure, heart rate, and adverse effects should be monitored 2–4 weeks after any exchange of Adalat CC for Procardia XL.  相似文献   
84.
85.
To investigate the in vivo role of NMDA receptor stimulation in HIV-1-related CNS neurotoxicity, we evaluated the neuroprotective potential of the NMDA receptor antagonist memantine in transgenic mice which have gp120-induced CNS damage. Brains of mice treated chronically with memantine and of untreated controls were analysed for structural damage by laser scanning confocal microscopy of sections immunolabeled for microtubule-associated protein-2 (MAP-2) and synaptophysin. Qualitative and quantitative analysis of confocal images revealed that memantine treatment substantially decreased neuropathology in gp120 transgenic mice; this included statistically significant improvements in both dendritic and presynaptic terminal density. These results provide in vivo evidence that gp120 can activate neurotoxic pathways that can ultimately result in aberrant NMDA receptor stimulation and neuronal damage in the CNS. They also suggest that clinically tolerated NMDA receptor antagonists may be useful in the prevention of neuronal damage in HIV-1-infected patients.  相似文献   
86.
We determined whether epitope-specific monoclonal antibodies to the galactose-inhibitable adherence protein (GIAP) of Entamoeba histolytica could be used in an enzyme-linked immunosorbent assay (ELISA) to detect antigen in serum and feces and differentiate between nonpathogenic zymodemes and the potentially invasive pathogenic organisms that require treatment. Overall, 57% of subjects from Cairo, Egypt, with symptomatic intestinal amebiasis and 42% with asymptomatic infection possessed GIAP antigen in their sera, whereas 4% of uninfected controls or subjects with other parasitic infections possessed GIAP antigen in their sera (P < 0.001). In subjects from Durban, South Africa, only 6% of uninfected controls or those with nonpathogenic E. histolytica infection were positive for GIAP in serum, whereas 3 of 4 with asymptomatic pathogenic intestinal infection and 75% with amebic liver abscess were positive for GIAP in serum. Fifteen stool samples from patients with intestinal amebiasis were available for study; all had a positive ELISA result for fecal GIAP antigen. Epitope-specific monoclonal antibodies identified 8 of 15 subjects with fecal antigen from pathogenic strains. Seven of those eight subjects had adherence protein antigen in their sera, whereas none of seven with apparent nonpathogenic E. histolytica infection had adherence protein antigen in their sera. In summary, we were able to detect E. histolytica adherence protein antigen directly in serum and fecal samples by ELISA. The presence of amebic antigen in serum demonstrated 94% specificity for pathogenic E. histolytica infection, and amebic antigen is present during asymptomatic intestinal infection. In conjunction with antibody detection, this method should be very useful in the diagnosis and management of intestinal amebiasis.  相似文献   
87.
88.
Designing behavior change programs and evaluating their effects on patient care has been a persistent challenge in research on continuing medical education. The challenge becomes even more complex when we aim to change behaviors that are interactive and highly influenced by the formal and informal institutional context. The authors describe an interdisciplinary continuing education program in bioethics that is designed to effect just such behaviors. The program aims to help hospital and long-term care facilities improve their ability to resolve the ethical dilemmas inherent in terminal care decisions. Targeted to interdisciplinary groups of physicians, nurses, social workers, pastoral counselors, and administrators, Decisions Near the End of Life will provide strategies and tools for examining institutional policies and team practices as well as more traditional information, education, and skill building. The authors describe the program's rationale and design, and raise questions about the potential for developing interdisciplinary, action-oriented CME on other topics.  相似文献   
89.
External cephalic version has been used periodically for centuries to manage breech presentations. As cesarean section rates have escalated in the last two decades, ways to curb this rise have been evaluated. By reducing the number of infants that arrive in labor in a representation, it is possible to impact the overall cesarean section rate. External cephalic version is a safe, effective method when used in appropriate cases of breech presentation. A forward or backward roll can be accomplished in women at term with singleton gestations, adequate amniotic fluid, and reactive nonstress tests. Parity, fetal and placental position, and descent of the presenting part may all influence the success rate of the version.  相似文献   
90.
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