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   7558篇
  免费   389篇
  国内免费   20篇
耳鼻咽喉   67篇
儿科学   377篇
妇产科学   118篇
基础医学   897篇
口腔科学   200篇
临床医学   563篇
内科学   1327篇
皮肤病学   110篇
神经病学   481篇
特种医学   235篇
外科学   963篇
综合类   110篇
一般理论   5篇
预防医学   354篇
眼科学   326篇
药学   937篇
  1篇
中国医学   113篇
肿瘤学   783篇
  2023年   38篇
  2022年   126篇
  2021年   268篇
  2020年   131篇
  2019年   165篇
  2018年   221篇
  2017年   143篇
  2016年   195篇
  2015年   249篇
  2014年   327篇
  2013年   432篇
  2012年   644篇
  2011年   605篇
  2010年   341篇
  2009年   320篇
  2008年   462篇
  2007年   474篇
  2006年   435篇
  2005年   437篇
  2004年   399篇
  2003年   334篇
  2002年   271篇
  2001年   102篇
  2000年   92篇
  1999年   74篇
  1998年   52篇
  1997年   30篇
  1996年   42篇
  1995年   44篇
  1994年   36篇
  1993年   35篇
  1992年   48篇
  1991年   43篇
  1990年   34篇
  1989年   35篇
  1988年   23篇
  1987年   23篇
  1986年   21篇
  1985年   31篇
  1984年   23篇
  1983年   20篇
  1982年   13篇
  1981年   20篇
  1980年   17篇
  1979年   20篇
  1978年   12篇
  1976年   5篇
  1974年   5篇
  1971年   6篇
  1965年   5篇
排序方式: 共有7967条查询结果,搜索用时 31 毫秒
61.
This paper constructs a unified framework to survey most of the work done to date on decision
  • 1 decision horizon replaces the term planning horizon used in the literature in the context of this paper. This is done because of an alternate and more popular use of the term planning horizon as simply the given length of the horizon in a finite horizon problem.
  • and forecast horizons in a stochastic environment. The paper is divided into sections by type of model. For each model type, the issues of existence of these horizons and of derivation of sufficient conditions for their determination are studied. Appropriate examples are presented.  相似文献   
    62.
    BackgroundAlthough recent studies have shown an association between obesity and adverse coronavirus disease 2019 (COVID-19) patient outcomes, there is a paucity in large studies focusing on hospitalized patients. We aimed to analyze outcomes associated with obesity in a large cohort of hospitalized COVID-19 patients.MethodsWe performed a retrospective study at a tertiary care health system of adult patients with COVID-19 who were admitted between March 1 and April 30, 2020. Patients were stratified by body mass index (BMI) into obese (BMI ≥ 30 kg/m 2) and non-obese (BMI < 30 kg/m 2) cohorts. Primary outcomes were mortality, intensive care unit (ICU) admission, intubation, and 30-day readmission.ResultsA total of 1983 patients were included of whom 1031 (51.9%) had obesity and 952 (48.9%) did not have obesity. Patients with obesity were younger (P < 0.001), more likely to be female (P < 0.001) and African American (P < 0.001) compared to patients without obesity. Multivariable logistic models adjusting for differences in age, sex, race, medical comorbidities, and treatment modalities revealed no difference in 60-day mortality and 30-day readmission between obese and non-obese groups. In these models, patients with obesity had increased odds of ICU admission (adjusted OR, 1.37; 95% CI, 1.07?1.76; P = 0.012) and intubation (adjusted OR, 1.37; 95% CI, 1.04?1.80; P = 0.026).ConclusionsObesity in patients with COVID-19 is independently associated with increased risk for ICU admission and intubation. Recognizing that obesity impacts morbidity in this manner is crucial for appropriate management of COVID-19 patients.  相似文献   
    63.
    Health Care Management Science - An important challenge confronting healthcare is the effective management of access to primary care. Appointment scheduling policies/templates can help strike an...  相似文献   
    64.
    65.
    Legg-Calvé-Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis, which produces chronic hip synovitis, permanent femoral head deformity, and premature osteoarthritis. Currently, there is no medical therapy for LCPD. Interleukin-6 (IL-6) is significantly elevated in the synovial fluid of patients with LCPD. We hypothesize that IL-6 elevation promotes chronic hip synovitis and impairs bone healing after ischemic osteonecrosis. We set out to test if anti-IL-6 therapy using tocilizumab can decrease hip synovitis and improve bone healing in the piglet model of LCPD. Fourteen piglets were surgically induced with ischemic osteonecrosis and assigned to two groups: the no treatment group (n = 7) and the tocilizumab group (15 to 20 mg/kg, biweekly intravenous injection, n = 7). All animals were euthanized 8 weeks after the induction of osteonecrosis. Hip synovium and femoral heads were assessed for hip synovitis and bone healing using histology, micro-CT, and histomorphometry. The mean hip synovitis score and the number of synovial macrophages and vessels were significantly lower in the tocilizumab group compared with the no treatment group (p < .0001, p = .01, and p < .01, respectively). Micro-CT analysis of the femoral heads showed a significantly higher bone volume in the tocilizumab group compared with the no treatment group (p = .02). The histologic assessment revealed a significantly lower number of osteoclasts per bone surface (p < .001) in the tocilizumab group compared with the no treatment group. Moreover, fluorochrome labeling showed a significantly higher percent of mineralizing bone surface (p < .01), bone formation rate per bone surface (p < .01), and mineral apposition rate (p = .04) in the tocilizumab group. Taken together, tocilizumab therapy decreased hip synovitis and osteoclastic bone resorption and increased new bone formation after ischemic osteonecrosis. This study provides preclinical evidence that tocilizumab decreases synovitis and improves bone healing in a large animal model of LCPD. © 2020 American Society for Bone and Mineral Research (ASBMR).  相似文献   
    66.
    67.
    68.
    Journal of Public Health - In this study, we conduct a systematic review of literature to understand the effectiveness of interventions on continuum of maternal and child healthcare services, the...  相似文献   
    69.
    We describe the clinical and demographic characteristics, virological follow-up, and management of five confirmed monkeypox cases from New Delhi, India without any international travel history. The viral load kinetics and viral clearance were estimated in oropharyngeal swabs (OPS), nasopharyngeal swabs (NPS), EDTA blood, serum, urine, and various lesion specimens on every fourth day of follow-up ranging from 5 to 24 post onset day (POD) of illness. All five cases presented with mild to moderate-grade intermittent fever, myalgia, and lesions on the genitals, groins, lower limb, trunk, and upper limb. Four cases had non-tender firm lymphadenopathy. No secondary complications or sexually transmitted infections were recorded in these cases except for the presence of viral hepatitis B infection marker hepatitis B virus surface antigen (HBsAg) in one case. All the cases were mild and had a good recovery. A higher viral load was detected in lesion fluid (POD 9), followed by lesion roof (POD 9), urine (POD 5), lesion base (POD 5), and OPS/NPS (POD 5). The monkeypox virus (MPXV) DNA was detected in clinical samples from 5th to 24th POD. These monkeypox cases without international travel history suggest the underdiagnosed monkeypox infection in the community. This emphasizes the need for active surveillance of MPXV in the high-risk population such as men having sex with men and female sex workers.  相似文献   
    70.
    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