全文获取类型
收费全文 | 4514篇 |
免费 | 265篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 194篇 |
妇产科学 | 82篇 |
基础医学 | 524篇 |
口腔科学 | 235篇 |
临床医学 | 337篇 |
内科学 | 1084篇 |
皮肤病学 | 96篇 |
神经病学 | 363篇 |
特种医学 | 88篇 |
外科学 | 753篇 |
综合类 | 35篇 |
一般理论 | 2篇 |
预防医学 | 436篇 |
眼科学 | 51篇 |
药学 | 254篇 |
中国医学 | 15篇 |
肿瘤学 | 163篇 |
出版年
2023年 | 27篇 |
2022年 | 31篇 |
2021年 | 58篇 |
2020年 | 39篇 |
2019年 | 79篇 |
2018年 | 122篇 |
2017年 | 83篇 |
2016年 | 65篇 |
2015年 | 130篇 |
2014年 | 112篇 |
2013年 | 192篇 |
2012年 | 288篇 |
2011年 | 296篇 |
2010年 | 169篇 |
2009年 | 129篇 |
2008年 | 271篇 |
2007年 | 242篇 |
2006年 | 205篇 |
2005年 | 187篇 |
2004年 | 170篇 |
2003年 | 142篇 |
2002年 | 173篇 |
2001年 | 145篇 |
2000年 | 141篇 |
1999年 | 125篇 |
1998年 | 36篇 |
1997年 | 39篇 |
1996年 | 36篇 |
1995年 | 28篇 |
1994年 | 28篇 |
1993年 | 32篇 |
1992年 | 80篇 |
1991年 | 76篇 |
1990年 | 72篇 |
1989年 | 74篇 |
1988年 | 82篇 |
1987年 | 54篇 |
1986年 | 42篇 |
1985年 | 61篇 |
1984年 | 26篇 |
1983年 | 27篇 |
1980年 | 19篇 |
1979年 | 41篇 |
1978年 | 19篇 |
1977年 | 19篇 |
1976年 | 19篇 |
1975年 | 26篇 |
1974年 | 25篇 |
1973年 | 20篇 |
1969年 | 24篇 |
排序方式: 共有4789条查询结果,搜索用时 15 毫秒
1.
2.
Aldo Cunha Medeiros Irami Araújo Filho Vítor Brasil Medeiros Laíza Araújo Mohana Pinheiro Flávio Henrique Miranda Araújo Freire Italo Medeiros Azevedo José Brand?o-Neto 《Journal of investigative surgery》2007,20(1):41-48
After total gastrectomy, the ileocecal graft may act as a reservoir and protect against reflux but give rise to transposition of the ileum and cause possible changes in bile acid metabolism and nutrition. This study compared the ileocecal graft and jejunal pouch. Male Wistar rats weighing 265 +/- 22 g were submitted to sham operation (S), ileocecal interposition graft (IIG), and jejunal pouch interposition graft (JP) after total gastrectomy. Eight weeks later, the esophagus was examined for evidence of esophagitis. Nutritional biochemistry and weight profile were documented preoperatively and 8 weeks after surgery. The oral glucose tolerance test was performed. Thirty-three rats were operated on and 30 survived for 8 weeks. Esophagitis occurred in seven JP rats. Body weight was significantly higher in IIG than in JP rats (p < .05). Normal glucose tolerance to intragastric glucose load was observed in sham and operated rats. JP rats had a significant decrease in serum albumin, glucose, transferrin, hemoglobin, iron, folate, and calcium, compared to sham (p < .05). Cobalamine was significantly lower in IIG rats than in JP rats (p < .05). In the IIG and JP groups, serum/hepatic total bile acid did not differ significantly from preoperative and sham values. In conclusion, the IIG interposition graft in rats prevented esophagitis, preserved nutrition, and did not interfere with enterohepatic total bile acid circulation. 相似文献
3.
Randall E Brand Henry T Lynch 《Endocrinology & Metabolism Clinics of North America》2006,35(2):405-15, xi
It is estimated that 5% to 10% of pancreatic cancer cases are attributable to hereditary factors. We believe that the number of cases that are genetic in etiology are even greater, however, based not on a classic autosomal dominant pattern of inheritance but rather when one takes into account low-penetrant inherited susceptibility factors. There is also a growing recognition that the development of pancreatic cancer in pancreatic cancer-prone families is dependent not only on genetic variables but on nongenetic factors. The aim of this article is to review the challenges in identifying pancreatic cancer-prone families and how environmental factors interact with genetic factors in these families. 相似文献
4.
5.
Robert D. Felner Stephen Brand Kay Erwin Mulhall Brian Counter Joyce B. Millman Judy Fried 《The journal of primary prevention》1994,15(2):123-146
A partnership between corporate worksites, a community-based prevention agency, and families in those worksites is described. Its primary goals were the reduction of family risk and enhancement of family protective factors that predispose children and youth to substance abuse and related social and emotional difficulties. A related goal of the program is to reduce family stress levels and attitudes that may influence the parents' levels of risk for substance abuse and related disorder. The program delivery strategy is conceived of as part of the necessart efforts of prevention programs to reach target populations in host settings in which they may naturally participate, thereby reducing obstacles and barriers to participation that often impede prevention efforts. Evaluation revealed that the program was generally better able to retain parents for a fairly lengthy period, and with high rates of attendance. Program attendance was also not affected by parental background characteristics that, in other delivery approaches, are often associated with poor attendance and high drop-out levels. Results also indicated that levels of program exposure (dosage) do make a significant difference in the efficacy of such efforts as those parents in the program who participated in higher percentages and numbers of sessions (i.e. more than 80% of sessions) showed both short-term and longer-term (i.e. across 18 month follow-ups) gains in their ratings of the target child's behavior problems and strengths, substance abuse resistance related knowledge and attitudes, reduced parental stress, depression and irritability, and increased utilization of social support. By contrast, parents who received a low program exposure exhibited a more restricted set of short-term gains. The findings are discussed in terms of their importance for consideration of program dosage for prevention programs, and the need to attend to the context in which programming is offered as it may facilitate or impede efforts to provide levels of dosage and fidelity to create enduring impacts 相似文献
6.
Randomised double blind placebo controlled trial of prednisolone in children admitted to hospital with respiratory syncytial virus bronchiolitis 总被引:10,自引:1,他引:9
下载免费PDF全文
![点击此处可从《Thorax》网站下载免费的PDF全文](/ch/ext_images/free.gif)
J. B. van Woensel T. F. Wolfs W. M. van Aalderen P. L. Brand J. L. Kimpen 《Thorax》1997,52(7):634-637
BACKGROUND: Experimental and clinical evidence suggests that respiratory syncytial virus (RSV) bronchiolitis is an immune mediated disease. Corticosteroids might therefore be effective in the treatment of RSV bronchiolitis. METHODS: A randomised double blind trial was conducted in children up to two years of age admitted to hospital with RSV bronchiolitis to compare prednisolone (1 mg/ kg/day orally for seven days) with placebo. Variables used for the efficacy analysis were a daily symptom score and the length of time in hospital in the non- ventilated patients, and the duration of mechanical ventilation and the length of time in hospital in the ventilated patients. RESULTS: Fifty four patients were included in the trial, 40 of whom were non- ventilated (20 in each group) and 14 were ventilated (seven in each group). During the first three days of treatment the symptom score decreased significantly faster in the prednisolone group than in the placebo group (mean (SE) decrease -1.2 (0.2) points/day versus -0.6 (0.2) points/day; mean (95% confidence interval (CI)) for difference = - 0.6 (-0.1 to -1.2); p = 0.02). The mean duration of hospital stay of all 40 non-ventilated patients was not significantly different between the two groups. In the ventilated patients the duration of mechanical ventilation was not significantly different, but the length of time in hospital was six days shorter in the prednisolone group than in the placebo group (mean (SE) 11.0 (0.7) versus 17.0 (2.0) days; mean (95% CI) difference = 7.0 (1.8 to 10.2) days; p < 0.01). CONCLUSIONS: These results suggest that prednisolone may be effective in accelerating the clinical recovery of children admitted to hospital with RSV bronchiolitis.
相似文献
相似文献
7.
8.
Aida Brand?o Sónia Magalh?es Adelino Correia 《Revista portuguesa de cardiologia》2004,23(7-8):993-999
Congenitally corrected transposition of the great arteries, L-TGA, is a rare abnormality accounting for less than 0.5% of clinically apparent congenital heart disease. Age at time of diagnosis and survival rate are variable and depend mostly on associated anomalies. The authors present a clinical case of a twenty-four-year-old woman in whom, in a routine echocardiogram, congenitally corrected transposition of the great arteries and aortic coarctation were diagnosed, an unusual association. They describe the results of complementary exams (echocardiography, chest X-ray, electrocardiogram and cardiac angiography) that they believe to be useful for the correct diagnosis of this clinical situation. Additionally, the authors make a brief review of the literature relevant to the case. 相似文献
9.
Burst-suppression EEG (BS-EEG) after cardiopulmonary resuscitation implies a bad prognosis, but little is known of the temporal dynamics of postanoxic BS-EEG. The authors studied 24 consecutive patients who developed BS-EEG within 24 hours after cardiopulmonary resuscitation, and followed 20 of these patients with serial EEGs. Except for one patient, BS-EEG was followed by another EEG pattern within 1 day, mainly areactive alpha EEG (n = 6), isoelectric EEG (n = 5), generalized continuous epileptiform discharges (n = 4), or theta; EEG (n = 3). The coexistence of different EEG patterns in the same recording was seen in 10 patients. Serial recordings disclosed a variety of EEG sequences with (often subtle) transitions between the different EEG patterns, including reappearance of BS-EEG. Postanoxic BS-EEG is followed by a variety of EEG sequences composed of different EEG patterns, each of which is recognized as an unfavorable sign in and of itself. The coexistence of different unfavorable EEG patterns in the same recording, and transitions between these EEG patterns in subsequent recordings, are common in patients with postanoxic BS-EEG. It seems reasonable to speculate that BS-EEG and subsequently evolving EEG patterns in anoxic encephalopathy reflect different forms of neocortical dysfunction, which occur at different stages of a dynamic process, leading ultimately to severe neuronal loss. 相似文献
10.
A survey on attitudes to water fluoridation in the South African population (N = 2,220) was undertaken in 1998. The purpose of this study was to evaluate responses to, and underlying reasons for pro- and anti-fluoridation attitudes. In response to a structured questionnaire, 61.9% of respondents were in favour of fluoride being added to drinking water and 9% were against it. Reasons supporting and opposing this measure were as follows. Of those who favoured the measure, 30% of respondents said it was because it would reduce tooth decay and 30% said it 'affects health', presumably positively. Other reasons include, 'it purifies water' (10.3%), 'more people will be reached' (9.8%), 'it strenghtens bones' (6%), 'it prevents plaque' (4.6%) and it 'improves the taste of water' (3.1%). There was a 1.3% 'don't know' response. Those opposed to the measure said, 'water should stay as it is' (26.1%), 'if it stays in the system it will create other problems' (15.6%), it 'affects health', presumably negatively (12.3%) and 'it will increase the cost of water' (8.8%). The 'don't know' response was 10.5%. When asked to give reasons for their 'don't know' response in the 'uncertain' category, 90% said they did not know. Given the contradictory and variable responses in both 'yes' and 'no' categories, the possible reasons for these findings could include: the differences between knowledge and beliefs, alternative health and lifestyle practices, levels of education, resistance to change and personality factors, among others. Understanding the assumption people make about fluoridation would help to structure education programmes to provide accurate and comprehensive information. 相似文献