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   2395313篇
  免费   200042篇
  国内免费   4333篇
耳鼻咽喉   34486篇
儿科学   73472篇
妇产科学   63409篇
基础医学   338056篇
口腔科学   68000篇
临床医学   217938篇
内科学   473423篇
皮肤病学   48399篇
神经病学   203437篇
特种医学   96694篇
外国民族医学   887篇
外科学   363885篇
综合类   56602篇
现状与发展   1篇
一般理论   1001篇
预防医学   192592篇
眼科学   55903篇
药学   179220篇
  5篇
中国医学   4390篇
肿瘤学   127888篇
  2018年   24742篇
  2017年   19206篇
  2016年   21024篇
  2015年   23833篇
  2014年   34293篇
  2013年   51959篇
  2012年   70356篇
  2011年   74029篇
  2010年   43505篇
  2009年   41831篇
  2008年   70264篇
  2007年   74784篇
  2006年   75652篇
  2005年   73794篇
  2004年   70864篇
  2003年   68545篇
  2002年   67639篇
  2001年   112688篇
  2000年   116700篇
  1999年   98585篇
  1998年   28161篇
  1997年   25758篇
  1996年   25665篇
  1995年   24787篇
  1994年   23332篇
  1993年   21744篇
  1992年   79550篇
  1991年   76526篇
  1990年   73697篇
  1989年   70956篇
  1988年   65954篇
  1987年   64886篇
  1986年   61411篇
  1985年   58525篇
  1984年   44384篇
  1983年   37800篇
  1982年   23063篇
  1981年   20519篇
  1980年   19200篇
  1979年   41399篇
  1978年   29086篇
  1977年   24449篇
  1976年   22926篇
  1975年   24012篇
  1974年   29713篇
  1973年   28095篇
  1972年   26279篇
  1971年   24204篇
  1970年   22783篇
  1969年   21124篇
排序方式: 共有10000条查询结果,搜索用时 646 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.
147.
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   
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