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   131765篇
  免费   9265篇
  国内免费   840篇
耳鼻咽喉   1708篇
儿科学   3398篇
妇产科学   2182篇
基础医学   16910篇
口腔科学   2469篇
临床医学   13513篇
内科学   27443篇
皮肤病学   1978篇
神经病学   12375篇
特种医学   4535篇
外国民族医学   5篇
外科学   18721篇
综合类   2850篇
现状与发展   5篇
一般理论   168篇
预防医学   11535篇
眼科学   3313篇
药学   9659篇
  8篇
中国医学   554篇
肿瘤学   8541篇
  2023年   590篇
  2022年   566篇
  2021年   2437篇
  2020年   1524篇
  2019年   2271篇
  2018年   2566篇
  2017年   2024篇
  2016年   2178篇
  2015年   2797篇
  2014年   3835篇
  2013年   5746篇
  2012年   8332篇
  2011年   8883篇
  2010年   5079篇
  2009年   4752篇
  2008年   8382篇
  2007年   8868篇
  2006年   8731篇
  2005年   9012篇
  2004年   8464篇
  2003年   8262篇
  2002年   7819篇
  2001年   1414篇
  2000年   1142篇
  1999年   1457篇
  1998年   1797篇
  1997年   1524篇
  1996年   1259篇
  1995年   1252篇
  1994年   1001篇
  1993年   1020篇
  1992年   870篇
  1991年   807篇
  1990年   759篇
  1989年   723篇
  1988年   626篇
  1987年   595篇
  1986年   586篇
  1985年   699篇
  1984年   855篇
  1983年   836篇
  1982年   1158篇
  1981年   1062篇
  1980年   961篇
  1979年   479篇
  1978年   584篇
  1977年   546篇
  1976年   435篇
  1975年   405篇
  1974年   370篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
31.
32.
Ovarian cancer is the fourth most common cause of cancer-related death in women in the developed world, and one of the most heritable cancers. One of the most significant risk factors for epithelial ovarian cancer (EOC) is a family history of breast and/or ovarian cancer. Combined risk factors can be used in models to stratify risk of EOC, and aid in decisions regarding risk-reduction strategies. Germline pathogenic variants in EOC susceptibility genes including those involved in homologous recombination and mismatch repair pathways are present in approximately 22% to 25% of EOC. These genes are associated with an estimated lifetime risk of EOC of 13% to 60% for BRCA1 variants and 10% to 25% for BRCA2 variants, with lower risks associated with remaining genes. Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) thought to explain an additional 6.4% of the familial risk of ovarian cancer, with 34 susceptibility loci identified to date. However, an unknown proportion of the genetic component of EOC risk remains unexplained. This review comprises an overview of individual genes and SNPs suspected to contribute to risk of EOC, and discusses use of a polygenic risk score to predict individual cancer risk more accurately.  相似文献   
33.
34.
PurposeTwitter is an increasingly popular social media platform within the health care community. The objective of this analysis is to characterize the profile of radiation oncology–related tweets and Twitter users over the past 6 years.Methods and MaterialsUsing the web-based social media analytics platform Symplur Signals, we filtered tweets containing at least 1 of the following hashtags or key words: #radonc, #radiationoncology, "rad onc," or "radiation oncology." We evaluated radiation oncology–related Twitter activity between October 2014 and March 2020 for tweet frequency, tweet content, and individuals or groups posting tweets. We identified the most influential Twitter users contributing to radiation oncology–related tweets.ResultsFrom 2014 to 2020, the quarterly volume of radiation oncology–related tweets increased from 5027 to 29,763. Physicians contributed the largest growth in tweet volume. Academic radiation oncologists comprise 60% of the most influential Twitter accounts responsible for radiation oncology–related content. The number of radiation-oncology resident physicians on Twitter increased from 25 to 328 over the past 6 years, and 20% of radiation-oncology residency programs have a Twitter account. Seventy-one percent of radiation oncology–related tweets generated direct communication via mentions, and 59% of tweets contain links to external sources, including scientific articles.ConclusionsThe number of physicians contributing radiation oncology–related Twitter content has increased significantly in recent years. Academic radiation oncologists are the primary influencers of radiation oncology–related Twitter activity. Twitter is used by radiation oncologists to both professionally network and discuss findings related to the field. There remains the opportunity for radiation oncologists to broaden their audience on Twitter to encompass a more diverse community, including patients.  相似文献   
35.
36.
BackgroundDiffuse midline glioma, formerly DIPG (diffuse intrinsic pontine glioma), is the deadliest pediatric brainstem tumor with median survival of less than one year. Here, we investigated (i) whether direct delivery of adenovirus-expressing cluster of differentiation (CD)40 ligand (Ad-CD40L) to brainstem tumors would induce immune-mediated tumor clearance and (ii) if so, whether therapy would be associated with a manageable toxicity due to immune-mediated inflammation in the brainstem.MethodsSyngeneic gliomas in the brainstems of immunocompetent mice were treated with Ad-CD40L and survival, toxicity, and immune profiles determined. A clinically translatable vector, whose replication would be tightly restricted to tumor cells, rAd-Δ24-CD40L, was tested in human patient–derived diffuse midline gliomas and immunocompetent models.ResultsExpression of Ad-CD40L restricted to brainstem gliomas by pre-infection induced complete rejection, associated with immune cell infiltration, of which CD4+ T cells were critical for therapy. Direct intratumoral injection of Ad-CD40L into established brainstem tumors improved survival and induced some complete cures but with some acute toxicity. RNA-sequencing analysis showed that Ad-CD40L therapy induced neuroinflammatory immune responses associated with interleukin (IL)-6, IL-1β, and tumor necrosis factor α. Therefore, to generate a vector whose replication, and transgene expression, would be tightly restricted to tumor cells, we constructed rAd-Δ24-CD40L, the backbone of which has already entered clinical trials for diffuse midline gliomas. Direct intratumoral injection of rAd-Δ24-CD40L, with systemic blockade of IL-6 and IL-1β, generated significant numbers of cures with readily manageable toxicity.ConclusionsVirus-mediated delivery of CD40L has the potential to be effective in treating diffuse midline gliomas without obligatory neuroinflammation-associated toxicity.  相似文献   
37.

Negative implications of exposure to violence on health and well-being of youth have been observed and studied worldwide and especially in Israel. Youth in the Western Negev of the country have been exposed to missile and terror attacks for more than a decade. However, implications of such prolonged exposure have not been fully studied. This study is aimed at the implications of exposure to such conditions on youth in the town of Ofakim in the Negev. A focus group was conducted with youth following the Israeli Defense Forces’ “Protective Edge” response to continued attacks from Gaza (July–August 2014). Focus group participants reported high stress levels during the operation that resulted in an increase of substance use including alcohol, tobacco, cannabis, and synthetic cannabis-like substances (e.g., “Nice Guy,” “Spice,” and “Black Mamba”) and changes in eating and sleeping behavior. The Ofakim resilience center served as a shelter for participants providing for them with physical and emotional comfort. Staying in the “shelter” used for protection against missile attack promoted youth resilience. Exposure to violence has a significant impact on the health and well-being of young people and others. A secure receptive facility that provides trust and support can serve as an important moderator of the negative impact of emergency conditions. From the results reported in this article, further research is needed to fully assess the long-term effects of stress conditions including the use of cannabis and synthetic cannabis-like substances among youth and other residents in the Western Negev.

  相似文献   
38.
39.
Nickel is the leading cause of allergic contact dermatitis (ACD) from early childhood through adolescence. Studies have shown that skin piercings and other nickel‐laden exposures can trigger the onset of nickel ACD in those who are susceptible. Nickel ACD causes a vast amount of cutaneous disease in children. Cases of nickel ACD in children have been reported in peer‐reviewed literature from 28 states. Common items that contain inciting nickel include jewelry, coins, zippers, belts, tools, toys, chair studs, cases for cell phones and tablets, and dental appliances. The diagnosis of nickel ACD has been routinely confirmed by patch testing in children older than 6 months suspected of ACD from nickel. Unlike in Europe, there are no mandatory restrictions legislated for nickel exposure in the United States. Denmark has demonstrated that regulation of the nickel content in metals can lower the risk of ACD and the associated health care–related costs that arise from excess nickel exposure. To further awareness, this article reviews the prominent role of nickel in pediatric skin disease in the United States. It discusses the need for a campaign by caretakers to reduce nickel‐related morbidity. Lastly, it promotes the model of European legislation as a successful intervention in the prevention of nickel ACD.  相似文献   
40.
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