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   956032篇
  免费   75606篇
  国内免费   2064篇
耳鼻咽喉   14288篇
儿科学   27665篇
妇产科学   27532篇
基础医学   137176篇
口腔科学   27968篇
临床医学   80981篇
内科学   185999篇
皮肤病学   19759篇
神经病学   77642篇
特种医学   37212篇
外国民族医学   173篇
外科学   148014篇
综合类   25056篇
现状与发展   2篇
一般理论   289篇
预防医学   77675篇
眼科学   22709篇
药学   72075篇
中国医学   1908篇
肿瘤学   49579篇
  2018年   10643篇
  2016年   8488篇
  2015年   9946篇
  2014年   13494篇
  2013年   20610篇
  2012年   29189篇
  2011年   30407篇
  2010年   17217篇
  2009年   15494篇
  2008年   27916篇
  2007年   30276篇
  2006年   29997篇
  2005年   29649篇
  2004年   28718篇
  2003年   27509篇
  2002年   26362篇
  2001年   38797篇
  2000年   39652篇
  1999年   33422篇
  1998年   9665篇
  1997年   8818篇
  1996年   8785篇
  1995年   8170篇
  1994年   7849篇
  1992年   27810篇
  1991年   27183篇
  1990年   26617篇
  1989年   25544篇
  1988年   24034篇
  1987年   23693篇
  1986年   22491篇
  1985年   21833篇
  1984年   16899篇
  1983年   14384篇
  1982年   9029篇
  1981年   8358篇
  1979年   17219篇
  1978年   12394篇
  1977年   10400篇
  1976年   9585篇
  1975年   10423篇
  1974年   13100篇
  1973年   12571篇
  1972年   11928篇
  1971年   11034篇
  1970年   10631篇
  1969年   10286篇
  1968年   9270篇
  1967年   8551篇
  1966年   7927篇
排序方式: 共有10000条查询结果,搜索用时 283 毫秒
71.
72.
73.
74.
75.
76.
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   
77.
78.
79.
80.
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   
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