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   47237篇
  免费   8506篇
  国内免费   185篇
耳鼻咽喉   1033篇
儿科学   1550篇
妇产科学   1361篇
基础医学   4031篇
口腔科学   2973篇
临床医学   7384篇
内科学   10130篇
皮肤病学   866篇
神经病学   4189篇
特种医学   1664篇
外科学   6885篇
综合类   433篇
现状与发展   12篇
一般理论   32篇
预防医学   6200篇
眼科学   798篇
药学   2074篇
  1篇
中国医学   25篇
肿瘤学   4287篇
  2024年   173篇
  2023年   1399篇
  2022年   813篇
  2021年   1728篇
  2020年   1835篇
  2019年   1445篇
  2018年   2363篇
  2017年   2005篇
  2016年   2234篇
  2015年   2306篇
  2014年   2909篇
  2013年   3615篇
  2012年   2608篇
  2011年   2566篇
  2010年   2236篇
  2009年   2682篇
  2008年   2018篇
  2007年   1812篇
  2006年   1742篇
  2005年   1518篇
  2004年   1276篇
  2003年   1189篇
  2002年   1006篇
  2001年   879篇
  2000年   814篇
  1999年   846篇
  1998年   709篇
  1997年   678篇
  1996年   689篇
  1995年   558篇
  1994年   451篇
  1993年   396篇
  1992年   531篇
  1991年   498篇
  1990年   468篇
  1989年   474篇
  1988年   399篇
  1987年   400篇
  1986年   352篇
  1985年   357篇
  1984年   256篇
  1983年   247篇
  1982年   217篇
  1981年   171篇
  1980年   150篇
  1979年   240篇
  1978年   175篇
  1977年   149篇
  1976年   136篇
  1974年   136篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
To determine percent of patients without malignancy and ≤ 40 years of age with high cumulative radiation doses through recurrent CT exams and assess imaging appropriateness. From the cohort of patients who received cumulative effective dose (CED) of ≥ 100 mSv over a 5-year period, a sub-set was identified with non-malignant disease. The top 50 clinical indications leading to multiple CTs were determined. Clinical decision support (CDS) system scores were analyzed using a widely adopted standard of 1–3 (red) as “not usually appropriate,” 4–6 (yellow) “may or may not be appropriate,” and 7–9 (green) “usually appropriate.” Clinicians reviewed patient records to assess compliance with appropriate use criteria (AUC). 9.6% of patients in our series were with non-malignant conditions and 1.4% with age ≤ 40 years. CDS scores (rounded) were 2% red, 38% yellow, 27% green, and 33% unscored CTs. Clinical society guidelines for CT exams, wherever available, were followed in 87.5 to 100% of cases. AUCs were not available for several clinical indications as also referral guidelines for serial CT imaging. More than half of CT exams were unrelated to follow-up of a primary chronic disease. We are faced with a situation wherein patients in age ≤ 40 years require or are thought to require many CT exams over the course of a few years but the radiation risk creates concern. There is a fair number of conditions for which AUC are not available. Suggested solutions include development of CT scanners with lesser radiation dose and further development of appropriateness criteria.  相似文献   
3.
Neorickettsia helminthoeca (NH), the agent of salmon poisoning disease or canine neorickettiosis (CN), is a bacterial endosymbiont of the nematode Nanophyetus salmincola, and infections are spreading among specific fish‐eating mammalians. This article describes the pathologic and immunohistochemical findings associated with spontaneous NH‐induced infections in dogs from Southern Brazil. The principal pathologic findings were hypertrophy of Peyer patches and lymphadenopathy with lymphocytic proliferation, chronic interstitial pneumonia, and chronic enteritis associated with positive intralesional immunoreactivity to antigens of NH within macrophages and histiocytes. Positive immunoreactivity against canine parvovirus‐2 (CPV‐2) or/and canine distemper virus was not detected in the evaluated intestinal segments or in the samples from the cerebellum and lungs, respectively, from the dogs evaluated. These findings demonstrated that NH was involved in the enteric, pulmonary, and lymphoid lesions herein described, and provide additional information to confirm the occurrence of this bacterial endosymbiont within this geographical location. It is proposed that chronic pneumonia should be considered as a pathologic manifestation of NH‐induced infections. Additionally, our results show that the occurrences of CN seem to be underdiagnosed in Southern Brazil due to the confusion with the incidence of CPV‐2.  相似文献   
4.
5.
6.
7.
8.
9.
The association between asbestos exposure, mainly in occupational settings, and malignant mesothelioma has been well established; this has prompted several countries to establish mesothelioma epidemiologic surveillance programs often at the request of national agencies. This review compares currently existing mesothelioma registries worldwide to develop a concept model for a US real-time case capture mesothelioma registry. Five countries were identified with a mesothelioma specific registry, including Italy, France, UK, Australia, and South Korea. All, except the UK, used interviews to collect exposure data. Linkage with the national death index was available or was in future plans for all registries. The registries have limited information on treatment, quality of life, and other patient-centered outcomes such as symptoms and pain management. To thoroughly collect exposure data, “real-time” enrollment is preferable; to maximize the capture of mesothelioma cases, optimal coverage, and a simplified consent process are needed.  相似文献   
10.
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