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   1470377篇
  免费   103908篇
  国内免费   2338篇
耳鼻咽喉   20747篇
儿科学   48301篇
妇产科学   41754篇
基础医学   215156篇
口腔科学   40069篇
临床医学   123774篇
内科学   293966篇
皮肤病学   31761篇
神经病学   116998篇
特种医学   55842篇
外国民族医学   457篇
外科学   221720篇
综合类   27324篇
现状与发展   1篇
一般理论   358篇
预防医学   110540篇
眼科学   33019篇
药学   111502篇
  1篇
中国医学   3087篇
肿瘤学   80246篇
  2019年   11434篇
  2018年   18315篇
  2017年   13187篇
  2016年   14316篇
  2015年   16352篇
  2014年   20938篇
  2013年   32328篇
  2012年   47551篇
  2011年   49881篇
  2010年   28129篇
  2009年   25157篇
  2008年   46909篇
  2007年   50711篇
  2006年   50173篇
  2005年   49333篇
  2004年   47099篇
  2003年   45171篇
  2002年   44137篇
  2001年   62597篇
  2000年   64149篇
  1999年   54731篇
  1998年   14985篇
  1997年   13449篇
  1996年   13647篇
  1995年   12881篇
  1994年   12233篇
  1992年   43349篇
  1991年   42472篇
  1990年   41923篇
  1989年   40540篇
  1988年   37824篇
  1987年   36910篇
  1986年   35188篇
  1985年   33505篇
  1984年   24927篇
  1983年   21684篇
  1982年   12906篇
  1981年   11353篇
  1979年   23539篇
  1978年   16494篇
  1977年   14294篇
  1976年   13463篇
  1975年   14809篇
  1974年   17415篇
  1973年   16841篇
  1972年   16009篇
  1971年   14926篇
  1970年   13877篇
  1969年   13421篇
  1968年   12567篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
101.
102.
103.
104.
Pulmonary hypertension of the newborn (PHN) constitutes a critical condition with severe cardiovascular and neurological consequences. One of its main causes is hypoxia during gestation, and thus, it is a public health concern in populations living above 2500 m. Although some mechanisms are recognized, the pathophysiological facts that lead to PHN are not fully understood, which explains the lack of an effective treatment. Oxidative stress is one of the proposed mechanisms inducing pulmonary vascular dysfunction and PHN. Therefore, we assessed whether melatonin, a potent antioxidant, improves pulmonary vascular function. Twelve newborn sheep were gestated, born, and raised at 3600 meters. At 3 days old, lambs were catheterized and daily cardiovascular measurements were recorded. Lambs were divided into two groups, one received daily vehicle as control and another received daily melatonin (1 mg/kg/d), for 8 days. At 11 days old, lung tissue and small pulmonary arteries (SPA) were collected. Melatonin decreased pulmonary pressure and resistance for the first 3 days of treatment. Further, melatonin significantly improved the vasodilator function of SPA, enhancing the endothelial‐ and muscular‐dependent pathways. This was associated with an enhanced nitric oxide‐dependent and nitric oxide independent vasodilator components and with increased nitric oxide bioavailability in lung tissue. Further, melatonin reduced the pulmonary oxidative stress markers and increased enzymatic and nonenzymatic antioxidant capacity. Finally, these effects were associated with an increase of lumen diameter and a mild decrease in the wall of the pulmonary arteries. These outcomes support the use of melatonin as an adjuvant in the treatment for PHN.  相似文献   
105.
106.
107.
108.
PurposeOur purpose was to determine the effect of chemoradiotherapy (CRT) on patient-reported quality of life (QOL) for patients with intact pancreas cancer.Methods and MaterialsWe reviewed a prospective QOL registry for patients with intact, clinically localized pancreatic ductal adenocarcinoma treated with CRT between June 2015 and November 2018. QOL was assessed pre-CRT (immediately before CRT, after neoadjuvant chemotherapy) and at the completion of CRT with the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) and its component parts: FACT-General (FACT-G) and hepatobiliary cancer subscore (HCS). A minimally important difference from pre-CRT was defined as ≥ 6, 5, and 8 points for FACT-G, HCS, and FACT-Hep, respectively.ResultsOf 157 patients who underwent CRT, 100 completed both pre- and post-CRT surveys and were included in the primary analysis. Median age at diagnosis was 65 years (range, 23-90). National Comprehensive Cancer Network resectability status was resectable (3%), borderline resectable (40%), or locally advanced (57%). Folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) (75%) or gemcitabine and nab-paclitaxel (42%) were given for a median of 6 cycles (range, 0-42) before CRT. Radiation therapy techniques included 3-dimensional conformal (22%), intensity modulated photon (55%), and intensity modulated proton (23%) radiation therapy to a median dose of 50 Gy (range, 36-62.5). Concurrent chemotherapy was most commonly capecitabine (82%). Sixty-three patients (63%) had surgery after CRT. The mean decline in FACT-G, HCS subscale, and FACT-Hep from pre- to post-CRT was 3.5 (standard deviation [SD], 13.7), 1.7 (SD 7.8), and 5.2 (SD 19.4), respectively. Each of these changes were statistically significant, but did not meet the minimally important difference threshold. Pancreatic head tumor location was associated with decline in FACT-Hep. Nausea was the toxicity with the greatest increase from pre- to post-CRT by both physician-assessment and patient-reported QOL.ConclusionsFor patients with intact pancreatic adenocarcinoma, modern CRT is well tolerated with minimal decline in QOL during treatment.  相似文献   
109.
110.
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