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   18532篇
  免费   979篇
  国内免费   137篇
耳鼻咽喉   243篇
儿科学   331篇
妇产科学   196篇
基础医学   2050篇
口腔科学   592篇
临床医学   1238篇
内科学   5230篇
皮肤病学   245篇
神经病学   1145篇
特种医学   617篇
外科学   3187篇
综合类   77篇
预防医学   445篇
眼科学   320篇
药学   1207篇
中国医学   64篇
肿瘤学   2461篇
  2023年   100篇
  2022年   73篇
  2021年   387篇
  2020年   241篇
  2019年   317篇
  2018年   426篇
  2017年   310篇
  2016年   434篇
  2015年   453篇
  2014年   538篇
  2013年   628篇
  2012年   1042篇
  2011年   1174篇
  2010年   685篇
  2009年   522篇
  2008年   1032篇
  2007年   1069篇
  2006年   1049篇
  2005年   1064篇
  2004年   1044篇
  2003年   1049篇
  2002年   1047篇
  2001年   414篇
  2000年   381篇
  1999年   402篇
  1998年   204篇
  1997年   174篇
  1996年   156篇
  1995年   166篇
  1994年   150篇
  1993年   161篇
  1992年   298篇
  1991年   267篇
  1990年   223篇
  1989年   200篇
  1988年   206篇
  1987年   184篇
  1986年   166篇
  1985年   165篇
  1984年   123篇
  1983年   106篇
  1982年   68篇
  1981年   73篇
  1980年   44篇
  1979年   65篇
  1978年   63篇
  1977年   49篇
  1975年   58篇
  1974年   55篇
  1969年   51篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.

Objective

This study assessed the association between the timing of first epinephrine administration (EA) and the neurological outcomes following out-of-hospital cardiac arrests (OHCAs) with both initial shockable and non-shockable rhythms.

Methods

This was a post-hoc analysis of a multicenter prospective cohort study (SOS-KANTO 2012), which registered OHCA patients in the Kanto region of Japan from January 2012 to March 2013. We included consecutive adult OHCA patients who received epinephrine. The primary result included 1-month favorable neurological outcomes defined as cerebral performance category (CPC) 1 or 2. Secondary results included 1-month survival and return of spontaneous circulation (ROSC) after arrival at the hospital. Multivariable logistic regression analysis determined the association between delay per minute of the time from call to first EA in both pre- or in-hospital settings and outcomes.

Results

Of the 16,452 patients, 9344 were eligible for our analyses. In univariable analysis, the delay in EA was associated with decreased favorable neurological outcomes only when the initial rhythm was a non-shockable rhythm. In multivariable analyses, delay in EA was associated with decreased ROSC (adjusted odds ratio [OR] for one minute delay, 0.97; 95% confidence interval [CI], 0.96–0.98) and 1-month survival (adjusted OR, 0.95; 95% CI, 0.92–0.97) when the initial rhythm was a non-shockable rhythm, whereas during a shockable rhythm, delay in EA was not associated with decreased ROSC and 1-month survival.

Conclusions

While assessing the effectiveness of epinephrine for OHCA, we should consider the time-limited effects of epinephrine. Additionally, consideration of early EA based on the pathophysiology is needed.  相似文献   
4.
5.
ObjectivesEosinophilic otitis media (EOM) is an intractable otitis media mostly associated with bronchial asthma. Dupilumab, an anti-interleukin (IL)-4 receptor (R)α, is effective and has been approved for use in patients with moderate to severe bronchial asthma, atopic dermatitis and chronic rhinosinusitis with nasal polyposis, whose diseases are not controlled by previous treatments including other molecular targeted drugs. We aimed to assess efficacy of dupilumab in three EOM patients with associated bronchial asthma, who were poor responders to previous topical and systemic corticosteroid therapy and molecular targeted therapies.Patients and methodsThree patients with severe, refractory EOM (two with a granulation type) associated with bronchial asthma received dupilumab as add-on therapy for at least 6 months. The efficacy of dupilumab therapy was evaluated using severity scores, symptom scores, hearing acuities, temporal bone computed tomography (CT) scores, and surrogate markers before and after therapy.ResultsSeverity scores in all patients were dramatically reduced to 2 points or less (full score: 16 points) after initiation of therapy. Air conduction hearing levels were improved in all patients. Temporal bone CT scores in two patients were reduced, and serum IgE levels in all three patients also decreased following therapy.ConclusionWe provide the first report that add-on dupilumab therapy was effective in patients with severe, refractory EOM who did not respond to the treatments including other molecular targeted therapy. Patients with severe middle ear mucosal change may benefit particularly from dupilumab therapy.  相似文献   
6.
In eusocial insect colonies, non-reproductive workers often perform different tasks. Tasks of an individual worker are shifted depending on various factors, e.g., age and colony demography. Although a vitellogenin (Vg) gene play regulatory roles in both reproductive and non-reproductive division of labours in a honeybee, it has been shown that the insect Vg underwent multiple gene duplications and sub-functionalisation, especially in apical ant lineages. The regulatory roles of duplicated Vgs were suggested to change evolutionarily among ants, whereas such roles in phylogenetically basal ants remain unclear. Here, we examined the expression patterns of conventional Vg (CVg), Vg-like A, Vg-like B and Vg-like C, as well as Vg receptor, during the task shift in an age-dependent manner and under experimental manipulation of colony demography in a primitive ant Diacamma sp. Expressions of CVg and Vg-like A in a brain were associated with a nursing task. It is suggested that associations of brain expressions of these Vgs with worker tasks were acquired in the basal ant lineage, and that such Vg functions could have sub-functionalised in the derived ant lineage.  相似文献   
7.
BackgroundMalnutrition measured by the geriatric nutritional risk index (GNRI) was reported to be associated with poor prognosis for patients with peripheral artery disease (PAD). However, the optimal cut-off value of preprocedural GNRI for critical limb ischemia (CLI) and intermittent claudication (IC) is unknown. We aimed to determine its optimal cut-off value for CLI or IC patients requiring endovascular revascularization.MethodsWe explored data of 2246 patients (CLI: n = 1061, IC: n = 1185) registered in the Tokyo-taMA peripheral vascular intervention research COmraDE (TOMA-CODE) registry, which prospectively enrolled consecutive PAD patients who underwent endovascular revascularization in 34 hospitals in Japan from August 2014 to August 2016. The optimal cut-off values of GNRI were assessed by the survival classification and regression tree (CART) analyses, and the survival curve analyses for major adverse cardiovascular and limb events (MACLEs) were performed for these cut-off values.ResultsIn addition to the first cut-off value of 96.2 in CLI and 85.6 in IC, the survival CART provided an additional cut-off value of 78.2 in CLI and 106.0 in IC for further risk stratification. The survival curve was significantly stratified by the GNRI-based malnutrition status in both CLI [high risk: 47.7% (51/107), moderate: 30.1% (118/392), and low: 10.2% (53/520), log–rank p < 0.001] and IC [high risk: 14.3% (7/49), moderate: 4.5% (29/646), and low: 0.5% (2/407), log–rank p < 0.001]. The multivariate Cox-proportional hazard analysis showed that a higher GNRI was significantly associated with a better outcome in both CLI [hazard ratio (HR) per 1-point increase: 0.97, 95% CI: 0.96–0.98, p < 0.001] and IC (HR: 0.94, 95% CI: 0.91–0.97, p < 0.001).ConclusionsPreprocedural nutritional status significantly stratified future events in patients with PAD. Given that the optimal cut-off value of GNRI in CLI was almost 10-points lower than that of IC, using a disease-specific cut-off value is important for risk stratification.  相似文献   
8.
9.
BackgroundWhether coronary plaque characteristics assessed in coronary computed tomography angiography (CCTA) in association with the coronary artery calcium score (CACS) have predictive value for coronary events is unclear. We aimed to examine the predictive value of the CACS and plaque characteristics for the occurrence of coronary events.MethodsAmong 2802 patients who were analyzed in the PREDICT registry, 2083 with suspected coronary artery disease (CAD) were studied using post hoc analysis. High-risk plaques were defined as having ≥2 adverse characteristics, such as low computed tomographic attenuation, positive remodeling, spotty calcification, and napkin-ring sign. An adjudicative composite of coronary events (cardiac death, nonfatal acute coronary syndrome, and coronary revascularization ≥3 months after indexed CCTA) were analyzed.ResultsSeventy-three (3.5%) patients had coronary events and 313 (15.0%) had high-risk plaques. Multivariate Cox proportional hazard analysis showed that high-risk plaques remained an independent predictor of coronary events (adjusted hazard ratio [HR] 1.95, 95% confidence interval [CI] 1.13–3.34, P ?= ?0.0154), as well as the log-transformed CACS (adjusted HR 1.24, 95% CI 1.11–1.39, P ?= ?0.0002) and the presence of obstructive stenosis (adjusted HR 5.63, 95% CI 3.22–10.12, P 0.0001). In subgroup analyses, high-risk plaques were independently predictive only in the low CACS class (<100).ConclusionThis study shows that assessment of adverse features by coronary plaque imaging independently predicts coronary events in patients with suspected CAD and a low CACS. Our findings suggest that the clinical value of high-risk plaques to CACS and stenosis assessment appears marginal.  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