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   28370篇
  免费   3474篇
  国内免费   521篇
耳鼻咽喉   318篇
儿科学   361篇
妇产科学   358篇
基础医学   1928篇
口腔科学   9601篇
临床医学   2195篇
内科学   2486篇
皮肤病学   513篇
神经病学   748篇
特种医学   479篇
外国民族医学   2篇
外科学   1529篇
综合类   2555篇
现状与发展   4篇
一般理论   1篇
预防医学   2170篇
眼科学   153篇
药学   3943篇
  31篇
中国医学   1418篇
肿瘤学   1572篇
  2024年   102篇
  2023年   793篇
  2022年   1048篇
  2021年   1522篇
  2020年   1619篇
  2019年   1519篇
  2018年   1307篇
  2017年   1195篇
  2016年   1220篇
  2015年   1201篇
  2014年   1683篇
  2013年   2209篇
  2012年   1551篇
  2011年   1629篇
  2010年   1219篇
  2009年   1140篇
  2008年   1167篇
  2007年   1110篇
  2006年   970篇
  2005年   920篇
  2004年   768篇
  2003年   710篇
  2002年   653篇
  2001年   581篇
  2000年   464篇
  1999年   392篇
  1998年   367篇
  1997年   402篇
  1996年   312篇
  1995年   262篇
  1994年   256篇
  1993年   202篇
  1992年   219篇
  1991年   174篇
  1990年   159篇
  1989年   181篇
  1988年   135篇
  1987年   124篇
  1986年   113篇
  1985年   97篇
  1984年   94篇
  1983年   67篇
  1982年   86篇
  1981年   75篇
  1980年   58篇
  1979年   43篇
  1978年   37篇
  1977年   65篇
  1976年   44篇
  1975年   34篇
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
131.
BACKGROUND: Making diagnoses in oral pathology are often difficult and confusing in dental practice, especially for the less-experienced dental student. One of the most promising areas in bioinformatics is computer-aided diagnosis, where a computer system is capable of imitating human reasoning ability and provides diagnoses with an accuracy approaching that of expert professionals. This type of system could be an alternative tool for assisting dental students to overcome the difficulties of the oral pathology learning process. This could allow students to define variables and information, important to improving the decision-making performance. However, no current open data management system has been integrated with an artificial intelligence system in a user-friendly environment. Such a system could also be used as an education tool to help students perform diagnoses. The aim of the present study was to develop and test an open case-based decision-support system. METHODS: An open decision-support system based on Bayes' theorem connected to a relational database was developed using the C++ programming language. The software was tested in the computerisation of a surgical pathology service and in simulating the diagnosis of 43 known cases of oral bone disease. The simulation was performed after the system was initially filled with data from 401 cases of oral bone disease. RESULTS: The system allowed the authors to construct and to manage a pathology database, and to simulate diagnoses using the variables from the database. CONCLUSION: Combining a relational database and an open decision-support system in the same user-friendly environment proved effective in simulating diagnoses based on information from an updated database.  相似文献   
132.
P-glycoprotein, a membrane-associated transport protein, has recently been recognised as an important element of the intestinal epithelium. This paper summarises thein vivodata on the pharmacological role of intestinal P-glycoprotein. These data show that P-glycoprotein contributes to the elimination of many drugs by mediating their direct secretion from the blood into the intestinal lumen. In addition, there is also evidence that this protein can limit oral drug absorption. Hence, inhibition of intestinal P-glycoprotein, e.g. by a reversal agent like cyclosporin A, may be a promising strategy for improving the oral bioavailability of P-glycoprotein substrate drugs. Indeed, several preclinical and clinical studies have shown that coadministration of drugs with a reversal agent can substantially increase oral drug absorption.  相似文献   
133.
OBJECTIVE: To examine the effect of short-term improvements in glycaemic control on brachial artery endothelial function as a marker of cardiovascular health. METHODS: Persons with Type 2 diabetes who were poorly controlled on oral therapy were randomly assigned to monotherapy with repaglinide or combination therapy with repaglinide plus metformin. Brachial artery flow-mediated vasodilation was assessed by ultrasonography at randomization and following 16 weeks of therapy. The primary outcome was change in brachial artery endothelial function from baseline. Comparison of randomized groups was a secondary aim. RESULTS: Eighty-six participants were randomized, and 83 were followed to study completion. Post occlusion brachial artery vasodilation was 3.74% at baseline and 3.82% following 16 weeks of therapy (P = 0.77). The treatment effect was 0.08% (95% CI: -0.48%, 0.64%). No difference was seen between treatment groups (P = 0.69). Overall, A1C was reduced from 8.3% to 7.0%, with a greater reduction in the combination therapy group (from 8.4% to 6.7%) than in the monotherapy group (from 8.3% to 7.3%, p for difference between groups = 0.01). Statistically significant reductions were observed in fasting glucose, and plasminogen activator inhibitor-1. Statistically significant increases were observed for fasting insulin, uric acid, weight and BMI. CONCLUSIONS: Brachial artery endothelial function was not influenced by short-term improvements in glycaemic control. The CONTROL DM group was successful in lowering A1C. Future research should explore more intensive and longer-lasting improvements in glycaemic control on endothelial function. Some data previously published in abstract form (Diabetes 2001; 50 (Suppl. 2): A217).  相似文献   
134.
目的:评价太极通天液治疗血管性痴呆的临床疗效。方法:随机将148例血管性痴呆分为太极通天液治疗组和丹参口服液对照组,另接应用韦氏成人智力量表评分,将血管性痴呆组分为3个亚组:即80-89分组,70-79分组和70分以下组,观察期为3个月。结果:太极通天液治疗前后WAIS-RC评分与对照组比较,80-89分组和70-79分组均有统计学差异(P<0.05),而70分以下组无统计学差异(P>0.05),结论:太极通天液对血管性痴呆有较好的治疗效果,且与痴呆病情程度有关。  相似文献   
135.
AIMS: To estimate the prevalence of diabetes mellitus with three diagnostic criteria (WHO-1985 and 1999 and ADA-1997), evaluate their concordance and analyse the sensitivity and specificity of the different screening strategies for diabetes. METHODS: A cross-sectional population study with two-step sampling. One thousand and 34 people were selected randomly. A 75-g oral glucose tolerance test (OGTT) was performed and venous blood samples were obtained fasting and at 2 h. RESULTS: The prevalence of known Type 2 diabetes mellitus (DM-2) is 4%[95% confidence interval (CI) 2.8, 5.1]. By WHO-1985 criteria the prevalence of unknown DM-2 is 5.9% (4.5, 7.4); by ADA-1997 criteria 3.5% (2.5, 4.6) and by WHO-1999 criteria 7.3% (5.8, 8.8). Diagnostic overlap and statistical concordance (coefficient K) are WHO-1985/ADA-1997 29.3%, K=0.42; WHO-1985/WHO-1999 80%, K=0.88; ADA-1997/WHO-1999 48%, K=0.63. If only fasting glucose was used (following ADA-1997), 36.3% of those with diabetes (2-h glucose > or =11.1 mmol/l) would be diagnosed. If OGTT was performed (i) in those with a fasting glucose between 6.1 mmol/l and 6.9 mmol/l (9.8% of the population) we would diagnose 66.6%, and (ii) in all those between 5.7 mmol/l and 6.9 mmol/l (18.9% of the population) 81.8% would be diagnosed. CONCLUSIONS: The ADA criteria decrease the prevalence of DM in the adult population of Asturias by 2.4% and concordance with the classical criteria (WHO-1985) was only 29.3%. Using fasting glucose only (ADA-1997) diagnoses 36.3% of those with diabetes. The recent recommendations of the WHO-1999 increases this to 66.6%. To improve the diagnostic strategy for diabetes and detect up to 81.8% of patients, we propose the use of OGTT for all those with a fasting glucose between 5.7 mmol/l and 6.9 mmol/l.  相似文献   
136.
吸毒人群口腔黏膜疾病的调查   总被引:2,自引:0,他引:2  
目的 了解吸毒人群口腔卫生习惯、个人嗜好,以及口腔黏膜病的患病情况,以期对此类人群进行早期口腔黏膜病的防治。方法 1999~2000年对厦门戒毒所200名吸毒人员进行口腔健康调查,通过询问及口腔检查了解此类人群口腔黏膜患病情况及与不良嗜好的关系。结果 200人中有125人患有9种口腔黏膜病,患病率最高为尼古丁口炎(27.5%),其次为口干症(26.6%),白色水肿(22.5%)。有口腔梅毒病史4例。200人均有吸烟嗜好,饮酒者190人,嗜酒者32人,占16%。结论 吸毒人群是不良嗜好的高发人群,是口腔黏膜病的高发人群,是性病高发人群。  相似文献   
137.
138.
We reported a case of photoleukomelanodermatitis (Kobori) type drug eruption due to afloqualone (Arofuto®). The patient was given afloqualone and imipramine hydrochloride (Chrytemin®) for cervical spondylosis from November of 1990. Edematous erythema with slight itching appeared on the sun-exposed areas in December of 1990. As drug eruption was suspected, drugs were ceased, and the cutaneous lesions almost disappeared but pigmentations and depigmentations developed in spots in sun-exposed areas in March of 1991. Photopatch and oral challenge tests were positive.  相似文献   
139.
An evaluation of the residual activity of quick-drying agents (alcoholic solutions) used for hygienic hand disinfection is described. We looked for residual efficacy following hand disinfection with soap and water alone or followed by one of two alcoholic handrub lotions supplied from an automatic hand washing machine. The bacterial counts on the hands obtained before and within 2 successive hours after disinfection showed that alcoholic chlorhexidine was the most effective for 10 minutes after contamination of the hands. WELPAS® (alcoholic chlorbenzarconium) followed this in its immediate effect and was better than soap and water alone. There were no significant differences after 30‘ or 120‘ between the three disinfecting methods.  相似文献   
140.
The experiment investigated the effects in healthy volunteers of a single dose of temazepam (30 mg, oral) on effortful and automatic processing, by measuring memory for information and its context. Effortful processing was impaired, as shown by significant impairments in free recall of an 18-item list, but automatic processing was spared, as evidenced by no impairments in recall of the frequency of presentation, the colour, size or form of the items. In a second task, temazepam significantly impaired both recognition and recency memory of 30 items, although these scores were not correlated. Temazepam caused significant sedation, measured by an objective test and by subjective ratings, but this did not correlate with the memory impairments. The pattern of results is discussed with reference to the hypothesis that the memory impairments resulting from benzodiazepines are due to a reduction in information processing resources and thus affect effortful processing more than automatic processing.  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