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   1822218篇
  免费   131578篇
  国内免费   4074篇
耳鼻咽喉   23672篇
儿科学   59104篇
妇产科学   49210篇
基础医学   260040篇
口腔科学   53350篇
临床医学   158722篇
内科学   361519篇
皮肤病学   41944篇
神经病学   141798篇
特种医学   67103篇
外国民族医学   243篇
外科学   271662篇
综合类   39651篇
现状与发展   4篇
一般理论   573篇
预防医学   140441篇
眼科学   43750篇
药学   133881篇
  7篇
中国医学   4969篇
肿瘤学   106227篇
  2021年   14741篇
  2019年   15743篇
  2018年   23739篇
  2017年   17648篇
  2016年   19059篇
  2015年   21667篇
  2014年   29224篇
  2013年   42598篇
  2012年   60794篇
  2011年   64003篇
  2010年   36959篇
  2009年   33771篇
  2008年   58442篇
  2007年   62206篇
  2006年   62394篇
  2005年   59291篇
  2004年   57035篇
  2003年   53996篇
  2002年   51971篇
  2001年   95148篇
  2000年   97467篇
  1999年   79889篇
  1998年   20286篇
  1997年   17621篇
  1996年   17737篇
  1995年   17054篇
  1994年   15562篇
  1993年   14286篇
  1992年   59099篇
  1991年   56826篇
  1990年   54517篇
  1989年   52105篇
  1988年   47440篇
  1987年   46184篇
  1986年   43506篇
  1985年   41204篇
  1984年   30194篇
  1983年   25669篇
  1982年   14301篇
  1979年   26587篇
  1978年   18277篇
  1977年   15580篇
  1976年   14512篇
  1975年   15340篇
  1974年   18636篇
  1973年   17952篇
  1972年   16646篇
  1971年   15411篇
  1970年   14322篇
  1969年   13465篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
142.
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   
143.
144.
145.
146.
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   
147.
148.
149.
150.
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