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   108383篇
  免费   6476篇
  国内免费   2017篇
耳鼻咽喉   567篇
儿科学   2051篇
妇产科学   1203篇
基础医学   9999篇
口腔科学   1886篇
临床医学   11694篇
内科学   11977篇
皮肤病学   740篇
神经病学   10249篇
特种医学   2511篇
外国民族医学   2篇
外科学   6674篇
综合类   14859篇
现状与发展   8篇
一般理论   9篇
预防医学   26246篇
眼科学   895篇
药学   9443篇
  115篇
中国医学   2789篇
肿瘤学   2959篇
  2023年   1743篇
  2022年   2751篇
  2021年   4592篇
  2020年   4442篇
  2019年   4705篇
  2018年   4345篇
  2017年   3485篇
  2016年   3160篇
  2015年   3352篇
  2014年   7360篇
  2013年   7540篇
  2012年   6808篇
  2011年   7433篇
  2010年   5802篇
  2009年   5430篇
  2008年   5458篇
  2007年   5176篇
  2006年   4404篇
  2005年   3483篇
  2004年   2874篇
  2003年   2451篇
  2002年   1962篇
  2001年   1711篇
  2000年   1423篇
  1999年   1217篇
  1998年   1140篇
  1997年   1042篇
  1996年   728篇
  1995年   786篇
  1994年   744篇
  1993年   657篇
  1992年   614篇
  1991年   571篇
  1990年   469篇
  1989年   413篇
  1988年   428篇
  1987年   396篇
  1986年   363篇
  1985年   717篇
  1984年   761篇
  1983年   540篇
  1982年   571篇
  1981年   540篇
  1980年   468篇
  1979年   374篇
  1978年   338篇
  1977年   270篇
  1976年   223篇
  1975年   154篇
  1974年   147篇
排序方式: 共有10000条查询结果,搜索用时 187 毫秒
1.

Objective

The aim of the study was to estimate the effect of the state-based reinsurance programs through the section 1332 State Innovation Waivers on health insurance marketplace premiums and insurer participation.

Data Source

2015 to 2022 Robert Wood Johnson Foundation Health Insurance Exchange Compare Datasets.

Study Design

An event study difference-in-differences (DD) model separately for each year of implementation and a synthetic control method (SCM) are used to estimate year-by-year effects following program implementation.

Data Collection/Extraction Methods

Not applicable.

Principal Findings

Reinsurance programs were associated with a decline in premiums in the first year of implementation by 10%–13%, 5%–19%, and 11%–17% for bronze, silver, and gold plans (p < 0.05). There is a trend of sustained declines especially for states that implemented their programs in 2019 and 2020. The SCM analyses suggest some effect heterogeneity across states but also premium declines across most states. There is no evidence that reinsurance programs affected insurer participation.

Conclusion

State-based reinsurance programs have the potential to improve the affordability of health insurance coverage. However, reinsurance programs do not appear to have had an effect on insurer participation, highlighting the need for policy makers to consider complementary strategies to encourage insurer participation.  相似文献   
2.
3.
4.
A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system.  相似文献   
5.
Whose values matter when considering which environment is healthier for a child whose guardianship is contested? The biological mother from a remote Australian Aboriginal community, who voluntarily relinquished her but has now requested her return? The foster mother who has cared for her in a metropolitan centre in another State of Australia, thousands of kilometres away? The welfare professionals who also live in that city? Or the child herself, who left her birth home and community five years earlier at the age of two? Drawing on a case study of a seven-year old Aboriginal girl, the authors argue that non-Indigenous values trumped Indigenous values without the realisation of key players who were empowered to make such determinations. The article uses Manuel DeLanda's neo-assemblage theory to consider the range of processes that exert themselves to shape place-values and social identity in colonised nations. It will also draw on Erik Erikson's and Lev Vygotsky's theories of psychosocial development to consider competing sets of values that raised feelings of dissonance within the child. Beliefs about what makes a place health-giving are revealed to be complex in colonised nations. Despite policy and legislative changes to better support Aboriginal people and their right to difference, non-Indigenous professionals can continue to be driven by an unrecognised systemic racism. While place-values are not, of course, the only (or perhaps even the most significant) consideration in guardianship determinations, this article will argue they can play a significant and covert role.  相似文献   
6.
BackgroundThe goal of this study was to characterize contemporary performance benchmarks and risk factors associated with negative appendectomy (NA) in children with suspected appendicitis.MethodsA multicenter retrospective cohort analysis of children undergoing appendectomy for suspected appendicitis was performed using data from the 2016–2021 NSQIP-Pediatric Appendectomy Targeted Public Use Files. Multivariable regression was used to evaluate the influence of year, age, sex, and WBC count on NA rate, and to generate rate estimates for NA based on different combinations of demographic characteristics and WBC profiles.Results100,322 patients were included from 140 hospitals. The overall NA rate was 2.4%, and rates decreased significantly during the study period (2016: 3.1% vs. 2021: 2.3%, p < 0.001). In adjusted analyses, the highest risk for NA was associated with a normal WBC (<9000/mm3; OR 5.31 [95% CI: 4.87–5.80]), followed by female sex (OR 1.55 [95% CI: 1.42–1.68]) and age <5 years (OR 1.64 [95% CI 1.39, 1.94]). Model-estimated risk for NA varied significantly across demographic and WBC strata, with a 14.4-fold range in rates between subgroups with the lowest and highest predicted risk (males 13–17 years with elevated WBC [1.1%] vs. females 3–4 years with normal WBC [15.8%]).ConclusionsContemporary NA rates have decreased over time, however NA risk remains high in children without a leukocytosis, particularly for girls and children <5 years of age. These data provide contemporary performance benchmarks for NA in children with suspected appendicitis and identify high-risk populations where further efforts to mitigate NA risk should be targeted.Level of EvidenceIII.  相似文献   
7.
ObjectivesOsteopathy is regulated as an independent healthcare profession in Portugal. The Osteopathic Practitioners Estimates and RAtes (OPERA) project was developed as a survey to profile the osteopathic profession. This study aimed to describe the characteristics of Portuguese osteopathic practitioners.MethodsA voluntary online-based survey was distributed across Portugal between February and June 2020. The survey, composed of 52 questions and seven sections, was formally translated from English to Portuguese and adapted from the original version. Two pilot tests evaluated cultural adaptation and reproducibility. Adult, self-defined osteopaths working in Portugal were eligible. Recruitment of participants was performed through social media and an e-based campaign.ResultsA total of 222 osteopaths participated in the study, 143 were male (64%), aging between 30 and 39 years (42%), mainly working in Lisbon (30%). Most respondents had preliminary healthcare training (68%), mainly as massage therapists. The majority of respondents were self-employed (83%), owner of a clinic (55%) and working alone (59%). The median number of consultations per week was 21–25 and respondents scheduled 46–60 min for each consultation. The majority of patients seek care for lumbar (52%), cervical (38%) and upper spine (38%) complaints. Although most respondents experience a strong osteopathic identity, they do not advertise themselves exclusively as osteopaths.ConclusionsThis study represents the first nationwide document to determine osteopaths' characteristics in Portugal. The study results provide a basis for future surveys that will include cohorts with higher levels of education, as well as findings from other European countries.  相似文献   
8.
The circadian rhythm in humans is determined by the central clock located in the hypothalamus’s suprachiasmatic nucleus, and it synchronizes the peripheral clocks in other tissues. Circadian clock genes and clock-controlled genes exist in almost all cell types. They have an essential role in many physiological processes, including lipid metabolism in the liver, regulation of the immune system, and the severity of infections. In addition, circadian rhythm genes can stimulate the immune response of host cells to virus infection. Hepatitis B virus (HBV) infection is the leading cause of liver disease and liver cancer globally. HBV infection depends on the host cell, and hepatocyte circadian rhythm genes are associated with HBV replication, survival, and spread. The core circadian rhythm proteins, REV-ERB and brain and muscle ARNTL-like protein 1, have a crucial role in HBV replication in hepatocytes. In addition to influencing the virus’s life cycle, the circadian rhythm also affects the pharmacokinetics and efficacy of antiviral vaccines. Therefore, it is vital to apply antiviral therapy at the appropriate time of day to reduce toxicity and improve the effectiveness of antiviral treatment. For these reasons, understanding the role of the circadian rhythm in the regulation of HBV infection and host responses to the virus provides us with a new perspective of the interplay of the circadian rhythm and anti-HBV therapy. Therefore, this review emphasizes the importance of the circadian rhythm in HBV infection and the optimization of antiviral treatment based on the circadian rhythm-dependent immune response.  相似文献   
9.
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