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   5701篇
  免费   357篇
  国内免费   31篇
耳鼻咽喉   26篇
儿科学   139篇
妇产科学   95篇
基础医学   832篇
口腔科学   236篇
临床医学   512篇
内科学   1269篇
皮肤病学   113篇
神经病学   671篇
特种医学   153篇
外科学   574篇
综合类   23篇
预防医学   509篇
眼科学   69篇
药学   433篇
中国医学   6篇
肿瘤学   429篇
  2024年   16篇
  2023年   79篇
  2022年   135篇
  2021年   256篇
  2020年   168篇
  2019年   192篇
  2018年   238篇
  2017年   149篇
  2016年   180篇
  2015年   221篇
  2014年   272篇
  2013年   342篇
  2012年   499篇
  2011年   470篇
  2010年   267篇
  2009年   203篇
  2008年   331篇
  2007年   370篇
  2006年   295篇
  2005年   304篇
  2004年   277篇
  2003年   197篇
  2002年   177篇
  2001年   41篇
  2000年   35篇
  1999年   50篇
  1998年   27篇
  1997年   24篇
  1996年   23篇
  1995年   12篇
  1994年   24篇
  1993年   11篇
  1992年   29篇
  1991年   21篇
  1990年   22篇
  1989年   15篇
  1988年   22篇
  1987年   17篇
  1986年   17篇
  1985年   15篇
  1984年   8篇
  1983年   7篇
  1980年   3篇
  1979年   6篇
  1978年   4篇
  1977年   2篇
  1973年   2篇
  1972年   4篇
  1971年   2篇
  1970年   2篇
排序方式: 共有6089条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
BACKGROUND: To obtain the best surgical results in orthognathic surgery, treatment planning and the evaluation of results should be performed on measurable three-dimensional reproductions of the face of the patients, and compared to reference subjects. METHODS: Seven women aged 18-35 years, all with a skeletal Class III and mandibular asymmetry, were assessed both before (on average, 2 months) and after (on average, 10.7 months) surgical intervention (mandibular reduction by sagittal split osteotomy and LeFort I maxillary advancement). The three-dimensional coordinates of 50 soft tissue facial landmarks (face, eyes, nose, mouth and lips, ears) were collected with a noninvasive, electromagnetic digitizer; facial volumes were estimated, and compared to reference values collected in 87 healthy women of the same age and ethnic group. Inter-individual modifications in facial shape were also assessed. RESULTS: Before surgery the patients had smaller faces than the reference women, with larger lower lips and noses. A large within-group variability was found. Surgical treatment significantly reduced total facial volume and mandibular volume, increased total and upper lip volumes (Student's t test, p<0.05), and made all values more homogenous within the group. Shape differences were significantly larger before than after surgery. On average, right side gonion was the landmark that moved the most, closely followed by menton, while the tragi and ala nasi moved the least. The three-dimensional approach used in this study enabled quantitative evaluation of the final soft tissue results of surgery, without submitting the patients to invasive procedures.  相似文献   
5.
Taurolidine (TRD) has antimicrobial and anti-inflammatory properties. However, the anti-inflammatory effects of TRD in inflammatory bowel diseases (IBD) have not been investigated. Here, we have analyzed the toxicity of TRD after oral long-term application in mice and examined the impact of oral TRD in a dextran sulfate sodium (DSS) model of experimental colitis. Female C57/BL6 mice received TRD in various concentrations (0.1% to 0.4%) for 60 days. Toxicity was evaluated by use of a disease activity index (DAI) and histological examination of major metabolic organs. Furthermore, the impact of 0.2% TRD on a chronic DSS colitis was examined by daily DAI, histological crypt damage score (CDS), bacterial translocation into mesenteric lymph nodes (MLN), and colonic expression of tumor necrosis factor (TNF) alpha, transforming growth factor (TGF) beta, interleukin (IL)-1beta, IL-6, cytochrome oxidase (COX)-2, and monocyte chemotactic protein (MCP)-1 by real-time polymerase chain reaction (PCR). Oral TRD administration for 60 days was well tolerated by the animals and did not show any toxic effects in terms of DAI and histological changes. TRD treatment of DSS colitis led to increased survival of 100%, compared to 33% in the untreated colitis group (p < or = .005). Clinical amelioration was mirrored by significantly reduced DAI and CDS in the TRD treated colitis. Colonic cytokine expression and bacterial translocation into MLN showed no differences between both groups. We thus report for the first time that oral application of TRD results in amelioration of an experimental IBD model. We hypothesize direct intraluminal antimicrobial effects of TRD as well as anti-inflammatory effects during the acute phase of DSS colitis.  相似文献   
6.
Lesion of the anteroventral portion of the third cerebral ventricle causes hypernatremia, adipsia, and attenuation of the pressor response to intravenous administration of angiotensin II and norepinephrine. In addition, these lesions prevent the development of several experimental models of hypertension. In this study, a lesion of the third cerebral ventricle region was made in 14 dogs. In seven dogs in which hypernatremia developed the lesions included the organum vasculosum of the lamina terminalis; seven animals in which the circumventricular organ was spared by the lesion remained normonatremic. Vascular responsiveness of isolated right carotid artery rings to angiotensin II and phenylephrine was assessed 3 days after lesioning the anteroventral portion of the third cerebral ventricle. In endothelium-denuded ring vessels, vasoconstrictor responses to phenylephrine were significantly decreased in animals both with and without inclusion of the organum vasculosum of the lamina terminalis. A similar effect was observed in intact vessels of dogs in which the circumventricular organ was spared but not in those with lesions that included this area. In contrast, angiotensin II-induced vasoconstriction was significantly decreased in the arteries with intact endothelium of both groups of lesioned animals. These data show that lesion of the anteroventral third ventricle area alters alpha 1-adrenergic and angiotensin II vascular responsiveness in isolated carotid artery rings with the possible participation of the endothelium.  相似文献   
7.
Evidence for an intrinsic angiotensin system in the canine pancreas.   总被引:10,自引:0,他引:10  
Increasing evidence suggests an association between hypertension and abnormalities of glucose metabolism. Since components of the renin-angiotensin system exist in a variety of tissues consistent with paracrine actions of the peptide, we sought to determine whether the pancreas contains a local angiotensin system. We report the presence of angiotensinogen messenger (m) RNA, angiotensinogen protein, angiotensin II and high-affinity binding sites for angiotensin II in the canine pancreas. These novel findings establish a foundation for future studies to evaluate whether angiotensin acts as a paracrine regulator of endocrine and/or exocrine functions of the pancreas.  相似文献   
8.
Aim of our study was to assess if the 2D-Echo transverse diameter of the left hepatic vein (LHV) obtained from the subcostal approach is correlated with invasive mean right atrial pressure (RAP). Thirty-two consecutive patients with acute myocardial infarction were studied by simultaneous 2D-Echo and right heart catheterization. LHV could be adequately imaged in 90% of patients. Mean RAP values at catheterization ranged from 0 to 15mmHg (mean 6±3.5 mmHg). A correlation was found between mean RAP and LHV diameter calculated after inspiration (r=0.81, SEE=1.54 mm, slope=0.71,p< 0.001) as well as after expiration (r=0.82, SEE=1.32mm, slope=0.62,p< 0.001) or during post-expiratory apnoea (r=0.85, SEE=1.3 mm, slope=0.71,p< 0.001). Moreover, percent increments of LHV diameter correlated well with percent changes of mean RAP during rapid infusion of 250–500 cc of saline in 4 patients (r=0.98,p< 0.001). Thus, the 2D-Echo LHV diameter is a feasible measurement that seems to correlate well with invasive mean RAP over a wide range of mean RAP values in patients with myocardial infarction; the changes in LHV diameter correlate well with the percent increase in central venous pressure obtained with saline infusion. Underestimation of invasive RAP occurs when mean RAP value exceeds 12 mmHg and can be explained by limited venous compliance. However these preliminary results suggest that this method may represent a valid alternative to obtain a non invasive estimate of mean RAP with 2D-Echocardiography.  相似文献   
9.
Meningeal involvement in leptospiral infection is quite common, usually mild and often overlooked. In contrast, cases of isolated involvement of the central nervous system, including aseptic meningitis, have been reported only rarely. A case of a patient with acute aseptic meningitis caused byLeptospira australis serovarbratislava is reported. This is believed to be the first report of aseptic meningitis due toLeptospira australis. This case indicates the need to consider human leptospirosis in the differential diagnosis of aseptic meningitis.  相似文献   
10.
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