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   583篇
  免费   54篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   39篇
妇产科学   2篇
基础医学   89篇
口腔科学   7篇
临床医学   58篇
内科学   103篇
皮肤病学   24篇
神经病学   58篇
特种医学   79篇
外科学   73篇
综合类   23篇
预防医学   27篇
眼科学   5篇
药学   44篇
中国医学   5篇
肿瘤学   6篇
  2020年   6篇
  2019年   4篇
  2015年   8篇
  2014年   11篇
  2013年   16篇
  2012年   14篇
  2011年   15篇
  2010年   21篇
  2009年   19篇
  2008年   17篇
  2007年   15篇
  2006年   20篇
  2005年   16篇
  2004年   21篇
  2003年   19篇
  2002年   17篇
  2001年   10篇
  2000年   12篇
  1999年   18篇
  1998年   15篇
  1997年   14篇
  1996年   26篇
  1995年   15篇
  1994年   13篇
  1993年   19篇
  1992年   18篇
  1991年   13篇
  1990年   15篇
  1989年   18篇
  1988年   18篇
  1987年   7篇
  1986年   12篇
  1985年   18篇
  1984年   10篇
  1983年   8篇
  1982年   12篇
  1981年   10篇
  1980年   8篇
  1979年   5篇
  1977年   6篇
  1976年   10篇
  1975年   4篇
  1972年   6篇
  1969年   5篇
  1966年   4篇
  1965年   6篇
  1943年   3篇
  1933年   3篇
  1919年   3篇
  1878年   3篇
排序方式: 共有644条查询结果,搜索用时 15 毫秒
51.
Background Gastric carcinoma is a significant cause of death in Ireland. Surgery offers the best option of cure, but the five-year survival following resection remains dismal at 10–15%. Experience from Japan and from some Western units suggest that an extended (D2) lymphadenectomy in association with gastrectomy increases the prospect of cure, but concern about the morbidity and mortality of this operation and lack of evidence from randomised studies has limited its acceptance. Aims This study reports the experience of a specialist upper gastrointestinal unit with D2 gastrectomy in a four-year audit. Methods Sixty-two resections were performed for gastric cancer. Results Nineteen patients were deemed unsuitable for the D2 procedure and underwent a more limited lymphadenectomy (DO or D1). Forty-three patients underwent D2 resection, 12 with an oesophagogastrectomy, 22 with total gastrectomy and nine with a sub-total distal resection. Eight patients undergoing D2 resection had extended resections, five with splenectomy and three with a distal pancreatectomy. Post-operative complications occurred in 31% of patients. Thirty-day and 90-day mortality were zero. Median survival was 822 days in the D2 group (range 120–1,320). Conclusions These results show that a D2 gastrectomy can be performed with a low morbidity and mortality and a median survival of greater than two years.  相似文献   
52.
Mature dorsal root ganglion cells respond to neurotrophins, and the intracellular signalling pathways activated by neurotrophins have been characterized in vitro. We have now used immunocytochemistry and Western blots to examine the expression and activation of extracellular signal-regulated protein kinase-1/2 (ERK) in rat dorsal root ganglion cells in vivo, using antisera to total (tERK) and phosphorylated (pERK) forms. This has revealed a number of novel findings. tERK immunoreactivity is present in most dorsal root ganglion cells but is expressed most strongly in small (nociceptive) cells and, surprisingly, is absent in a population of large cells that expressed trkB or trkC but mainly lack p75(NTR) immunoreactivity. In contrast pERK is prominent in a few trkA cells and in satellite glial cells, and is further increased by NGF treatment. tERK and pERK both undergo fast anterograde and retrograde axonal transport, indicated by accumulation at a sciatic nerve ligature, and NGF reduces the level of retrograde pERK transport.  相似文献   
53.
The type of trigeminal ganglion cells that express 5-HT1B receptors has not been well characterized, despite the fact that these receptors are important targets for anti-migraine drugs. We have therefore used combined in situ hybridization and immunofluorescence to examine the expression of 5-HT1B receptor messenger RNA in identified subpopulations of rat trigeminal ganglion cells. 5-HT1B-expressing cells accounted for 15% of all trigeminal ganglion cells, were medium sized, and showed immunoreactivity for either 200,000 mol. wt neurofilament, calcitonin gene-related peptide, or nerve growth factor receptor (trkA). In contrast few 5-HT1B cells showed immunoreactivity for substance P or binding of the lectin Griffonia simplicifolia IB4. Our results are consistent with 5-HT1B receptors acting to control the release of calcitonin gene-related peptide from trigeminal neurons with finely myelinated axons. 5-HT1B receptor agonists may reduce neurogenic vasodilation by activating such receptors. However many nociceptive trigeminal neurons, including the substance P and IB4-binding populations, do not express the 5-HT1B receptor.  相似文献   
54.
OBJECTIVE: To define the modes of presentation, incidence of major organ dysfunction, predictors of hospital mortality, and adverse outcomes in neonates with critical heart disease admitted to a tertiary care center. DESIGN: Retrospective chart review. SETTING: A tertiary care pediatric cardiac intensive care unit and neonatal intensive care unit. PATIENTS: The medical records for all neonates (< or = 30 days of age) with heart disease admitted to the cardiac intensive care unit or neonatal intensive care unit between October 1, 2002, and September 30, 2003, were reviewed. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A total of 190 neonates met inclusion criteria during this 1-yr period, of which 146 (77%) had at least one surgical procedure. Single ventricle heart disease was present in 42%. The most common mode of presentation was following a prenatal diagnosis (53%), followed by diagnosis in the newborn nursery (38%) and diagnosis after newborn hospital discharge (8%). The most common presenting findings in the newborn nursery were isolated murmur (38%) or cyanosis (32%), while circulatory collapse (38%) was the most common presentation after discharge. For the entire study cohort, 13% had a known genetic syndrome, 23% had a major noncardiac congenital anomaly, and 16% weighed < 2.5 kg. The hospital mortality for the entire cohort was 7.4%. Risk factors associated with an increased risk of hospital mortality included younger age at admission, higher number of cardiopulmonary bypass runs, and need for postoperative cardiopulmonary resuscitation. Total hospital length of stay was > 1 month in 17% of neonates. CONCLUSIONS: In patients with complex congenital heart disease, including nearly half with single ventricle heart disease, neonatal hospital mortality was 7%. These patients have a high frequency of multiple congenital anomalies, genetic syndromes, low birth weight, and prolonged length of stay.  相似文献   
55.
The clinical course of 4 patients who had reduced activities of 3-methylcrotonyl CoA carboxylase (also called 3-methylcrotonylglycinuria) is described. Two children presented with a metabolic acidosis, one in the neonatal period and the other with episodes of acidosis that started in the second year of life. In the other 2 children neurological symptoms were prominent, one having infantile spasms and the other developmental regression with a skin rash and alopecia. Three of the children responded well to oral biotin and dietary protein restriction but the fourth, despite a biochemical response to biotin, has a severe neurological handicap. The clinical presentation of inborn errors of 3-methylcrotonyl CoA carboxylase is variable. Metabolic acidosis may not be conspicuous and instead neurological features may predominate.  相似文献   
56.
57.
58.
59.
Aim:   A short vaccination protocol against hepatitis B was compared to the standard approach in patients under haemodialysis who were primarily non-responsive to the vaccine.
Methods:   This randomized, controlled open trial included 51 chronic haemodialysis subjects previously vaccinated against hepatitis B and with anti-HBs levels of less than 10 IU/mol/L. Twenty-six patients received 20 µg i.m. once a week for 8 weeks (short protocol) and 25 subjects three doses of 40 µg i.m. at months 0, 1 and 6 (standard protocol). Clinical and laboratory data were compared between responders and non-responders. A logistic regression model included selected parameters to assess risk factors for non-seroconversion.
Results:   Seroconversion rates to vaccine at 2 months were 80% and 78% in the short and standard protocol groups, respectively ( P  = 0.99). Median of anti-HBs levels were similar up to 6 months of follow up, but patients in the standard protocol showed a trend to higher anti-HBs in month 3 and a more steady decline in antibody titres. Non-responders were older, had longer duration of dialysis and a higher prevalence of a prior renal transplant and hepatitis C. In multivariate analysis, only advanced age and hepatitis C remained independently associated with non-responsiveness to vaccination.
Conclusion:   In haemodialysis patients, a short vaccination protocol against hepatitis B did not provide any benefit compared to the standard approach with respect to peak anti-HBs titres or a higher rate of seroprotection at the end of follow up. Other strategies to increase seroconversion rates should be explored, especially in the elderly and in patients with hepatitis C.  相似文献   
60.
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