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   2473556篇
  免费   203326篇
  国内免费   4331篇
耳鼻咽喉   36024篇
儿科学   76494篇
妇产科学   65598篇
基础医学   350191篇
口腔科学   71033篇
临床医学   224781篇
内科学   485992篇
皮肤病学   50939篇
神经病学   211161篇
特种医学   100155篇
外国民族医学   886篇
外科学   375524篇
综合类   56699篇
现状与发展   1篇
一般理论   1014篇
预防医学   196469篇
眼科学   57829篇
药学   184655篇
  4篇
中国医学   4524篇
肿瘤学   131240篇
  2018年   26481篇
  2017年   20740篇
  2016年   23052篇
  2015年   25421篇
  2014年   35887篇
  2013年   55165篇
  2012年   74061篇
  2011年   78250篇
  2010年   45950篇
  2009年   43380篇
  2008年   74744篇
  2007年   79402篇
  2006年   80076篇
  2005年   78058篇
  2004年   75028篇
  2003年   72700篇
  2002年   71806篇
  2001年   115705篇
  2000年   120657篇
  1999年   100726篇
  1998年   28942篇
  1997年   26401篇
  1996年   26120篇
  1995年   25195篇
  1994年   23758篇
  1993年   22102篇
  1992年   79904篇
  1991年   76842篇
  1990年   73984篇
  1989年   71278篇
  1988年   66232篇
  1987年   65244篇
  1986年   61705篇
  1985年   58942篇
  1984年   44761篇
  1983年   38099篇
  1982年   23366篇
  1981年   20763篇
  1980年   19462篇
  1979年   41690篇
  1978年   29346篇
  1977年   24744篇
  1976年   23155篇
  1975年   24312篇
  1974年   29947篇
  1973年   28307篇
  1972年   26444篇
  1971年   24381篇
  1970年   22955篇
  1969年   21280篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
201.
202.
Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. 18F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, 18F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to 18F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [18F]APPs.  相似文献   
203.
204.
205.
We report a case of disseminated Trichosporon asahii in a patient on systemic antifungal therapy who presented with multiple cutaneous nodules suggestive of fungal infection. Histologic features resembled neutrophilic eccrine hidradenitis but staining with periodic acid‐Schiff and Gomori methenamine silver confirmed the clinical diagnosis. This case highlights the importance of maintaining suspicion for trichosporonosis and contextualizing histologic findings within the underlying clinical picture.  相似文献   
206.
207.
Rheological behaviour of pharmaceutical semisolid preparations significantly affects manufacturing process, administration, stability, homogeneity of incorporated drug, accuracy of dosing, adhesion in the place of application, drug release, and resulting therapeutic effect of the product. We performed test of consistency by penetrometry, rotational, oscillation and creep tests, and squeeze and tack tests of model samples to introduce methods suitable for characterization and comparison of semisolids in practice. Penetrometry is a simple method allowing sorting the semisolids to low and high stress-resistant materials but deficient for rheological characterization of semisolids. Value of yield stress, generally considered to be appropriate feature of semisolids, is significantly influenced by the method of testing and the way of evaluation. The hysteresis loops of model semisolids revealed incomplete thixotropy, therefore, three-step thixotropy test was employed. Semisolids showed nonlinear response in the creep phase of tests and partial recovery of structure by storing energy in the recovery phase. Squeeze and tack tests seem to be convenient ways for comparison of semisolids. Our study can contribute to a better understanding of different flow behaviour of semisolids given by different physicochemical properties of excipients and can bring useful approaches to evaluation and comparison of semisolids in practice.  相似文献   
208.
209.
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   
210.
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