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   623357篇
  免费   42783篇
  国内免费   3904篇
耳鼻咽喉   7885篇
儿科学   14581篇
妇产科学   14564篇
基础医学   85219篇
口腔科学   16280篇
临床医学   54854篇
内科学   130154篇
皮肤病学   11857篇
神经病学   51044篇
特种医学   22121篇
外国民族医学   93篇
外科学   98003篇
综合类   13360篇
现状与发展   1篇
一般理论   381篇
预防医学   38480篇
眼科学   15738篇
药学   47637篇
  6篇
中国医学   2547篇
肿瘤学   45239篇
  2021年   7862篇
  2020年   4811篇
  2019年   7875篇
  2018年   10293篇
  2017年   7796篇
  2016年   8332篇
  2015年   9712篇
  2014年   14032篇
  2013年   18896篇
  2012年   27532篇
  2011年   28642篇
  2010年   16521篇
  2009年   15021篇
  2008年   25668篇
  2007年   27361篇
  2006年   27147篇
  2005年   26204篇
  2004年   24663篇
  2003年   23245篇
  2002年   21948篇
  2001年   30326篇
  2000年   30329篇
  1999年   25912篇
  1998年   8162篇
  1997年   6755篇
  1996年   5977篇
  1995年   5534篇
  1994年   4816篇
  1993年   4375篇
  1992年   17267篇
  1991年   15924篇
  1990年   15120篇
  1989年   14911篇
  1988年   13523篇
  1987年   12979篇
  1986年   12034篇
  1985年   11253篇
  1984年   8108篇
  1983年   6703篇
  1982年   4060篇
  1981年   3520篇
  1980年   3159篇
  1979年   6169篇
  1978年   4076篇
  1977年   3599篇
  1975年   3103篇
  1974年   3532篇
  1973年   3262篇
  1972年   3168篇
  1971年   3042篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
81.
82.
83.
ObjectiveIdentify factors associated with healthcare providers' frequency of depot medroxyprogesterone acetate (DMPA) provision to adolescents.Study designWe analyzed data from surveys mailed to a nationally representative sample of public-sector providers and office-based physicians (n=1984). We estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of factors associated with frequent DMPA provision to adolescents in the past year.ResultsAlthough most providers (>95%) considered DMPA safe for adolescents, fewer reported frequent provision (89% of public-sector providers; 64% of office-based physicians). Among public-sector providers, factors associated with lower odds of frequent provision included working in settings without Title X funding (aOR 0.44, 95% CI 0.30–0.64), reporting primary care as their primary clinical focus versus reproductive or adolescent health (aOR 0.42, 95% CI 0.28–0.61), and providing fewer patients with family planning services. Among office-based physicians, factors associated with lower odds of frequent provision included specializing in obstetrics/gynecology (aOR 0.50, 95% CI 0.27–0.91) and family medicine (aOR 0.21, 95% CI 0.09–0.47) versus adolescent medicine, completing training ≥15 versus <5 years ago (aOR 0.27, 95% CI 0.09–0.83), and reporting that 0–24% of patients pay with Medicaid or other government healthcare assistance versus ≥50% (aOR 0.23, 95% CI 0.09–0.61). The reason most commonly reported by providers for infrequent DMPA provision was patient preference for another method.ConclusionsWhile most providers reported frequently providing DMPA to adolescents, training on evidence-based recommendations for contraception, focused on subgroups of providers with lower odds of frequent DMPA provision, may increase adolescents' access to contraception.ImplicationsAlthough >95% of providers considered depot medroxyprogesterone (DMPA) a safe contraceptive for adolescents, only 89% of public-sector providers and 64% of office-based physicians reported frequently providing DMPA to adolescents. Provider training on evidence-based recommendations for contraception counseling and provision may increase adolescents' access to DMPA and all methods of contraception.  相似文献   
84.
85.
BackgroundRural populations face many health disadvantages compared to urban areas. There is a critical need to better understand the current lung cancer screening landscape in these communities to identify targeted areas to improve the impact of this proven tool.MethodsData from the County Health Rankings of New Hampshire and Vermont was reviewed for population density, distribution of adult smokers, and level of education compared to the distribution of Lung Cancer Screening Facilities throughout these two states.ResultsScreening programs in southern counties of Vermont with lower levels of education have decreased access. In New Hampshire, there are no programs within 30 miles of the areas with the largest distribution of smokers, and decreased access in some areas with the lowest levels of education.ConclusionsImproving equitable access to high-quality screening services in rural regions and the creation of targeted interventions to address decreased access in areas of high tobacco use and low education is vital to decreasing the incidence of latestage presentations of lung cancer within these populations.  相似文献   
86.
Prevention Science - This study aimed to evaluate the effectiveness of the drug and violence resistance educational program (PROERD) on short-term secondary outcomes, such as intentions to use...  相似文献   
87.
88.
Magnetic resonance elastography aims to non-invasively and remotely characterize the mechanical properties of living tissues. To quantitatively and regionally map the shear viscoelastic moduli in vivo, the technique must achieve proper mechanical excitation throughout the targeted tissues. Although it is straightforward, ante manibus, in close organs such as the liver or the breast, which practitioners clinically palpate already, it is somewhat fortunately highly challenging to trick the natural protective barriers of remote organs such as the brain. So far, mechanical waves have been induced in the latter by shaking the surrounding cranial bones. Here, the skull was circumvented by guiding pressure waves inside the subject's buccal cavity so mechanical waves could propagate from within through the brainstem up to the brain. Repeatable, reproducible and robust displacement fields were recorded in phantoms and in vivo by magnetic resonance elastography with guided pressure waves such that quantitative mechanical outcomes were extracted in the human brain.  相似文献   
89.
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