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   1317篇
  免费   106篇
  国内免费   14篇
耳鼻咽喉   21篇
儿科学   68篇
妇产科学   39篇
基础医学   133篇
口腔科学   30篇
临床医学   136篇
内科学   219篇
皮肤病学   20篇
神经病学   142篇
特种医学   145篇
外科学   177篇
综合类   25篇
预防医学   122篇
眼科学   10篇
药学   81篇
肿瘤学   69篇
  2022年   5篇
  2021年   26篇
  2020年   10篇
  2019年   18篇
  2018年   37篇
  2017年   20篇
  2016年   20篇
  2015年   25篇
  2014年   27篇
  2013年   56篇
  2012年   58篇
  2011年   65篇
  2010年   46篇
  2009年   49篇
  2008年   40篇
  2007年   69篇
  2006年   44篇
  2005年   46篇
  2004年   35篇
  2003年   37篇
  2002年   35篇
  2001年   40篇
  2000年   28篇
  1999年   30篇
  1998年   60篇
  1997年   53篇
  1996年   31篇
  1995年   29篇
  1994年   24篇
  1993年   19篇
  1992年   20篇
  1991年   17篇
  1990年   20篇
  1989年   24篇
  1988年   24篇
  1987年   26篇
  1986年   23篇
  1985年   22篇
  1984年   21篇
  1983年   21篇
  1982年   13篇
  1981年   12篇
  1980年   14篇
  1979年   10篇
  1978年   6篇
  1977年   6篇
  1976年   11篇
  1975年   9篇
  1974年   6篇
  1973年   7篇
排序方式: 共有1437条查询结果,搜索用时 15 毫秒
41.
OBJECTIVES: We investigated the acute and long-term hemodynamic and neurohumoral effects of the vasopeptidase inhibitor omapatrilat in human heart failure. BACKGROUND: Angiotensin-converting enzyme (ACE) inhibition constitutes a major advance in the treatment of chronic heart failure (CHF). Simultaneous inhibition of both neutral endopeptidase and ACE with omapatrilat may represent a new treatment strategy in CHF. METHODS: Three hundred and sixty-nine patients with symptomatic heart failure were randomized to double-blind treatment with omapatrilat (first 190 patients: 2.5 mg, 5 mg or 10 mg; last 179 patients: 2.5 mg, 20 mg or 40 mg once daily) for 12 weeks. RESULTS: Acutely, the 10 mg, 20 mg and 40 mg doses of omapatrilat produced greater reductions in pulmonary capillary wedge pressure (PCWP), systolic blood pressure (SBP) and systemic vascular resistance compared with 2.5 mg. Higher doses were associated with greater increases in vasodilator and natriuretic peptides, in addition to ACE inhibition. After 12 weeks, omapatrilat 20 mg and 40 mg showed greater falls from baseline in PCWP (40 mg: 0 h to 12 h average change -7.3 +/- 0.8 mm Hg) and SBP (40 mg: -11.7 +/- 1.7 mm Hg) than 2.5 mg (both p < 0.01 vs. 2.5 mg). The incidence of adverse experiences and patient withdrawal were similar in all groups. CONCLUSIONS: In CHF, the acute hemodynamic benefit seen with higher doses of omapatrilat was associated with increases in plasma vasodilator and natriuretic peptide levels in addition to ACE inhibition. After 12 weeks, the hemodynamic benefit was maintained. Omapatrilat may be a promising new agent in CHF.  相似文献   
42.
OBJECTIVE: The aim of this study was to test the effect of gut manipulation by either novel synbiotics or by metronidazole on either endotoxemia or the severity of liver damage in the course of acute pancreatitis from alcohol ingestion. METHODS: Sprague–Dawley rats were fed for 1 week through an intragastric tube a liquid diet with either: (i) 1 mL t.i.d. of a mixture of synbiotics (Lactobacillus acidophilus, Lactobacillus helveticus and Bifidobacterium in an enriched medium); (ii) 20 mg/kg t.i.d. metronidazole; or (iii) standard diet. Then, acute pancreatitis was induced by caerulein and when the disease was full‐blown, rats were fed an alcohol‐rich diet. Synbiotic and metronidazole treatment was given for a further 2 weeks. Transaminase and endotoxemia levels were measured before treatment, after 6 h, after 24 h and 2 weeks later, at the time the rats were killed. Liver samples were obtained for histological analysis. RESULTS: Synbiotics but not metronidazole improved the acute pancreatitis‐induced increase in endotoxemia and transaminase levels. The addition of alcohol worsened these variables to a limited extent in the synbiotic‐treated group, while metronidazole had a negative effect on liver damage. CONCLUSIONS: Gut flora pretreatment with synbiotics was able to effectively protect against endotoxin/bacterial translocation, as well as liver damage in the course of acute pancreatitis and concomitant heavy alcohol consumption. The beneficial effect of synbiotics on liver histology seems to be correlated with endotoxemia. Metronidazole did not produce such a beneficial effect; in fact, it further worsened liver damage when alcohol was added to the background of ongoing acute pancreatic inflammation.  相似文献   
43.
We report an experimental study of imitation of two types of meaningful gestures: (a) social-communicative gestures, and (b) pantomimed actions with objects (including counterfunctional object use) by children and adolescents with autism. Controls were (a) children with nonautistic developmental delays, matched for chronological age and receptive language age, and (b) typically developing children matched for receptive language. Children in both comparison groups imitated actions more accurately than did children with autism, who nonetheless demonstrated understanding of the meaning of the gestures. However, the autistic group tended to have difficulty naming gestures and also was less able than controls to produce actions on verbal request. Children with lower levels of language ability, including those with autism, had difficulty imitating unconventional use of objects, instead using the object for their conventional functions. The discussion addresses the implications of these results and our own previous related findings for representational and executive accounts of praxic deficits in autistic spectrum disorders.  相似文献   
44.
European Child & Adolescent Psychiatry - Physiological stress is thought to be one way that early adversity may impact children's health. How this occurs may be related to parental factors...  相似文献   
45.

Background

Chronic kidney disease (CKD) is highly prevalent in patients with diabetes or hypertension in primary care. A shared care model could improve quality of care in these patients

Aim

To assess the effect of a shared care model in managing patients with CKD who also have diabetes or hypertension.

Design and setting

A cluster randomised controlled trial in nine general practices in The Netherlands.

Method

Five practices were allocated to the shared care model and four practices to usual care for 1 year. Primary outcome was the achievement of blood pressure targets (130/80 mmHg) and lowering of blood pressure in patients with diabetes mellitus or hypertension and an estimated glomerular filtration rate (eGFR)<60ml/min/1.73m2.

Results

Data of 90 intervention and 74 control patients could be analysed. Blood pressure in the intervention group decreased with 8.1 (95% CI = 4.8 to 11.3)/1.1 (95% CI = −1.0 to 3.2) compared to −0.2 (95% CI = −3.8 to 3.3)/−0.5 (95% CI = −2.9 to 1.8) in the control group. Use of lipid-lowering drugs, angiotensin-system inhibitors and vitamin D was higher in the intervention group than in the control group (73% versus 51%, 81% versus 64%, and 15% versus 1%, respectively, [P = 0.004, P = 0.01, and P = 0.002]).

Conclusion

A shared care model between GP, nurse practitioner and nephrologist is beneficial in reducing systolic blood pressure in patients with CKD in primary care.  相似文献   
46.
47.
The range of cranial morphology seen in domestic dogs (Canis lupus familiaris) is a direct result of thousands of years of selective breeding. This article is the first to investigate how selection for reduced faces in brachycephalic dogs impacted the neuroanatomy of the canine brain through the analysis of endocasts. Previous research has demonstrated global effects on the shape of the bony cranium as the result of these breeding practices; however, these studies have largely focused on the bony structures of the skull and failed to consider the influence of facial reduction on the soft tissues of the brain. We generated endocasts from an existing set of clinically-obtained CT scans representing a variety of dogs with various cranial morphologies. These dogs represented four breeds as well as a comparative sample of dogs of unknown breed. We recorded three-dimensional coordinate data for 31 landmarks representing various gyri, sulci, and other neuroanatomical landmarks that allowed us to analyze differences in shape of the endocasts. Through geometric morphometric analyses, we determined that the endocast shape variance in this sample is correlated with cephalic index, and thus the selection for facial reduction has caused a perceivable effect on canine neuroanatomy. Additionally, we found the majority of the shape variance in the sample to be associated with olfactory anatomy; however, the rest of the morphology also correlates with cephalic index. The results of this article indicate that modern breeding practices and the selection for dogs with short faces have significantly influenced canine neuroanatomy.  相似文献   
48.
49.
50.
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