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   110827篇
  免费   10804篇
  国内免费   2630篇
耳鼻咽喉   1102篇
儿科学   3913篇
妇产科学   1020篇
基础医学   9043篇
口腔科学   1263篇
临床医学   15198篇
内科学   15610篇
皮肤病学   790篇
神经病学   19332篇
特种医学   3395篇
外国民族医学   4篇
外科学   9748篇
综合类   16678篇
现状与发展   6篇
一般理论   1篇
预防医学   8110篇
眼科学   1167篇
药学   10110篇
  132篇
中国医学   5658篇
肿瘤学   1981篇
  2024年   305篇
  2023年   2154篇
  2022年   3320篇
  2021年   5721篇
  2020年   5551篇
  2019年   4714篇
  2018年   4328篇
  2017年   4830篇
  2016年   4874篇
  2015年   4235篇
  2014年   7675篇
  2013年   8652篇
  2012年   6176篇
  2011年   6785篇
  2010年   5466篇
  2009年   5148篇
  2008年   5279篇
  2007年   5308篇
  2006年   4630篇
  2005年   3920篇
  2004年   3193篇
  2003年   2826篇
  2002年   2442篇
  2001年   2136篇
  2000年   1724篇
  1999年   1479篇
  1998年   1323篇
  1997年   1210篇
  1996年   1014篇
  1995年   999篇
  1994年   855篇
  1993年   710篇
  1992年   754篇
  1991年   607篇
  1990年   521篇
  1989年   452篇
  1988年   442篇
  1987年   386篇
  1986年   287篇
  1985年   335篇
  1984年   302篇
  1983年   185篇
  1982年   236篇
  1981年   150篇
  1980年   120篇
  1979年   122篇
  1978年   119篇
  1977年   65篇
  1976年   67篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Marginal rate-based analyses are widely used for the analysis of recurrent events in clinical trials. In many areas of application, the events are not instantaneous but rather signal the onset of a symptomatic episode representing a recurrent infection, respiratory exacerbation, or bout of acute depression. In rate-based analyses, it is unclear how to best handle the time during which individuals are experiencing symptoms and hence are not at risk. We derive the limiting value of the Nelson-Aalen estimator and estimators of the regression coefficients under a semiparametric rate-based model in terms of an underlying two-state process. We investigate the impact of the distribution of the episode durations, heterogeneity, and dependence on the asymptotic and finite sample properties of standard estimators. We also consider the impact of these features on power in trials designed to test intervention effects on rate functions. An application to a trial of individuals with herpes simplex virus is given for illustration.  相似文献   
82.
Deep brain stimulation (DBS) in psychiatric illnesses has been clinically tested over the past 20 years. The clinical application of DBS to the superolateral branch of the medial forebrain bundle in treatment‐resistant depressed patients—one of several targets under investigation—has shown to be promising in a number of uncontrolled open label trials. However, there are remain numerous questions that need to be investigated to understand and optimize the clinical use of DBS in depression, including, for example, the relationship between the symptoms, the biological substrates/projections and the stimulation itself. In the context of precision and customized medicine, the current paper focuses on clinical and experimental research of medial forebrain bundle DBS in depression or in animal models of depression, demonstrating how clinical and scientific progress can work in tandem to test the therapeutic value and investigate the mechanisms of this experimental treatment. As one of the hypotheses is that depression engenders changes in the reward and motivational networks, the review looks at how stimulation of the medial forebrain bundle impacts the dopaminergic system.  相似文献   
83.
84.
85.
86.
87.
88.
89.
 目的 探讨甲状腺功能减退与子宫内膜癌(EC)的关系及EC患者癌组织分化程度和雌激素受体(ER)、孕激素受体(PR)的表达与甲状腺功能之间的关系。方法 选取2015年1月—2018年7月我院收治的EC患者113例,同时随机选取年龄与EC组相匹配的此段时间内我院健康体检的妇女156例作为对照组,检测血清促甲状腺激素(TSH)、甲状腺激素(FT4)。比较两组间甲状腺功能减退的患病率,并利用免疫组织化学法测定EC患者手术切除标本的癌组织中ER、PR的表达,分析EC患者癌组织分化程度及癌组织中ER、PR的表达与甲状腺功能之间的相关性。结果 EC组甲状腺功能减退的患病率较对照组高(P<0.000)。低分化EC患者的TSH高于中分化EC患者(P=0.025)。EC手术切除标本的癌组织中ER、PR阳性与阴性患者的TSH、FT4差异无统计学意义(P>0.05)。结论 甲状腺功能减退与EC具有相关性。  相似文献   
90.

Background

In a pooled analysis of the phase 3 Controlled Myelofibrosis Study With Oral JAK Inhibitor Treatment I (COMFORT-I) and COMFORT-II clinical trials, adult patients with intermediate-2 or high-risk myelofibrosis who received oral ruxolitinib at randomization or after crossover from placebo or best available therapy (BAT) had improved overall survival (OS).

Methods

This post hoc analysis of pooled COMFORT data examined relevant disease outcomes based on the disease duration (≤12 or >12 months from diagnosis) before ruxolitinib initiation.

Results

The analysis included 525 patients (ruxolitinib: ≤12 months, n = 84; >12 months, n = 216; placebo/BAT: ≤12 months, n = 66; >12 months, n = 159); the median age was 65.0–70.0 years. Fewer thrombocytopenia and anemia events were observed among patients who initiated ruxolitinib treatment earlier. At Weeks 24 and 48, the spleen volume response (SVR) was higher for patients who initiated ruxolitinib earlier (47.6% vs. 32.9% at Week 24, p = .0610; 44.0% vs. 26.9% at Week 48, p = .0149). In a multivariable analysis of factors associated with spleen volume reduction, a logistic regression model that controlled for confounding factors found that a significantly greater binary reduction was observed among patients with shorter versus longer disease duration (p = .022). At Week 240, OS was significantly improved among patients who initiated ruxolitinib earlier (63% [95% CI, 51%‒73%] vs. 57% [95% CI, 49%‒64%]; hazard ratio, 1.53; 95% CI, 1.01‒2.31; p = .0430). Regardless of disease duration, a longer OS was observed for patients who received ruxolitinib versus those who received placebo/BAT.

Conclusions

These findings suggest that earlier ruxolitinib initiation for adult patients with intermediate-2 and high-risk myelofibrosis may improve clinical outcomes, including fewer cytopenia events, durable SVR, and prolonged OS.

Plain Language Summary

  • Patients with myelofibrosis, a bone marrow cancer, often do not live as long as the general population. These patients may also have an enlarged spleen and difficult symptoms such as fatigue.
  • Two large clinical trials showed that patients treated with the drug ruxolitinib lived longer and had improved symptoms compared to those treated with placebo or other standard treatments.
  • Here it was examined whether starting treatment with ruxolitinib earlier (i.e., within a year of diagnosis) provided benefits versus delaying treatment.
  • Patients who received ruxolitinib within a year of diagnosis lived longer and experienced fewer disease symptoms than those whose treatment was delayed.
  相似文献   
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