全文获取类型
收费全文 | 54741篇 |
免费 | 5332篇 |
国内免费 | 221篇 |
专业分类
耳鼻咽喉 | 535篇 |
儿科学 | 1912篇 |
妇产科学 | 1242篇 |
基础医学 | 7699篇 |
口腔科学 | 777篇 |
临床医学 | 7180篇 |
内科学 | 11827篇 |
皮肤病学 | 1273篇 |
神经病学 | 5767篇 |
特种医学 | 1540篇 |
外国民族医学 | 5篇 |
外科学 | 6870篇 |
综合类 | 443篇 |
一般理论 | 34篇 |
预防医学 | 5096篇 |
眼科学 | 666篇 |
药学 | 3365篇 |
中国医学 | 84篇 |
肿瘤学 | 3979篇 |
出版年
2023年 | 352篇 |
2022年 | 595篇 |
2021年 | 1291篇 |
2020年 | 1045篇 |
2019年 | 1704篇 |
2018年 | 1893篇 |
2017年 | 1517篇 |
2016年 | 1583篇 |
2015年 | 1794篇 |
2014年 | 2205篇 |
2013年 | 3058篇 |
2012年 | 3760篇 |
2011年 | 3868篇 |
2010年 | 2449篇 |
2009年 | 2227篇 |
2008年 | 3319篇 |
2007年 | 3399篇 |
2006年 | 3241篇 |
2005年 | 3225篇 |
2004年 | 3068篇 |
2003年 | 2946篇 |
2002年 | 2906篇 |
2001年 | 520篇 |
2000年 | 444篇 |
1999年 | 531篇 |
1998年 | 621篇 |
1997年 | 546篇 |
1996年 | 425篇 |
1995年 | 469篇 |
1994年 | 389篇 |
1993年 | 357篇 |
1992年 | 260篇 |
1991年 | 279篇 |
1990年 | 249篇 |
1989年 | 212篇 |
1988年 | 217篇 |
1987年 | 202篇 |
1986年 | 207篇 |
1985年 | 192篇 |
1984年 | 212篇 |
1983年 | 177篇 |
1982年 | 240篇 |
1981年 | 237篇 |
1980年 | 191篇 |
1979年 | 122篇 |
1978年 | 135篇 |
1977年 | 134篇 |
1976年 | 124篇 |
1975年 | 100篇 |
1974年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Mathieu Beaulieu David Williamson Gilbert Pichette Jean Lachaine 《Infection control and hospital epidemiology》2007,28(11):1305-1307
Our study was conducted to determine whether use of gastric acid-suppressive agents increased the risk of Clostridium difficile-associated disease (CDAD) in a medical intensive care unit of one of the first hospitals to be threatened by the current CDAD epidemic in Quebec, Canada. Our findings suggest that efforts to determine risk factors for CDAD should focus on other areas, such as older age and antibiotic use. 相似文献
93.
94.
Emilie Balasse Gregory Gatouillat Dominique Patigny Marie Christine Andry Claudie Madoulet 《Vaccine》2009
Malignant melanoma causes significant health problems. The identification of tumour-associated antigens has led to novel approaches to increase T cell mediated anti-tumour immune response. Melan-A/MART-1 has been use as target antigen for several T cell based immunotherapeutic treatments. More recently, the critical role of CD4+ T cells in inducing and maintaining anti-tumour immunity has been increasingly recognized. In order to optimize tumour immunotherapy, greater efforts have been concentrated on the identification of tumour antigens presented by MHC class II molecules to CD4+ T cells. In a publication, Tiwari et al. (2004) [1] have identified by a computational approach the 15-mer amino-acid sequence 101–115 (PPAYEKLSAEQSPPP) of the Melan-A/MART-1 as a good target for a vigorous and safe immunotherapy. Therefore, we have investigated the in vivo anti-tumour activity of this peptide in a murine melanoma model. For the prophylactic treatment, 20 μg or 50 μg peptide was subcutaneously injected in mice once a week during 3 weeks before tumour induction. Treatment with 50 μg peptide significantly affected tumour development. Thus, our preliminary data demonstrate potential in vivo prophylactic activity of the 101–115 peptide-based vaccine to control melanoma growth. 相似文献
95.
96.
Presence of specific 11C-meta-Hydroxyephedrine retention in heart, lung, pancreas, and brown adipose tissue. 总被引:1,自引:0,他引:1
(11)C-meta-Hydroxyephedrine (HED) is used in cardiac PET as an index of norepinephrine (NE) reuptake transporter (NET) density and synaptic NE levels. Whereas cardiac uptake is well documented, tracer retention in other tissues with rich noradrenergic innervation is unclear. Dysfunctional sympathetic nervous system (SNS) function in extracardiac metabolic storage tissues (i.e., adipose tissue and skeletal muscle) and endocrine organs contributes to several disorders. The aim of this study was to determine the potential of HED as an index of NE function in brown adipose tissue, lung, pancreas, skeletal muscle, and kidney by identifying NET-specific retention and determining the presence of radiolabeled metabolites. METHODS: Male Sprague-Dawley rats were administered HED and sacrificed at 30 min after tracer injection. Tissues were rapidly excised and counted for radioactivity, and relative tracer retention was quantified. Pretreatment with NET inhibitors established specific HED accumulation. The effect of elevated NE was tested by subcutaneous minipump NE infusion or inhibition of monoamine oxidase. Column-switch high-performance liquid chromatography (HPLC) was used to analyze the presence of radiolabeled metabolites in heart, brown adipose tissue, pancreas, and plasma. RESULTS: NET-specific retention was observed in heart, brown adipose tissue, lung, and pancreas but not in liver, skeletal muscle, or kidney. A dose-dependent response of HED accumulation to treatments elevating NE levels was established in tissues exhibiting specific uptake. At 30 min after tracer administration, HPLC analysis revealed 93%-95% of total radioactivity signal derived from unchanged HED in heart, pancreas, and brown adipose tissue compared with 61% +/- 8% unchanged HED in plasma. CONCLUSION: In addition to the heart, lung, pancreas, and brown adipose tissue exhibit specific and NE-responsive uptake of HED, supporting the potential for novel PET studies of SNS integrity in these tissues. 相似文献
97.
98.
Prospective, Double-Blind, Randomized, Parallel-Group, Dose-Ranging Study of Botulinum Toxin Type A in Men with Glabellar Rhytids 总被引:3,自引:0,他引:3
BACKGROUND: The effective dose for treating glabellar lines with botulinum toxin type A in men has not been studied adequately. OBJECTIVE: To compare the safety, efficacy, and duration of response of four doses of botulinum toxin type A on glabellar rhytids in men. METHODS: Eighty men were randomized to receive a total dose of either 20, 40, 60, or 80 U of botulinum toxin type A (BOTOX, BOTOX Cosmetic, or Vistabel, Allergan, Inc., Irvine, CA, USA) in the glabellar area. Glabellar lines were assessed at rest and maximum frown by a trained observer at baseline, 2 and 4 weeks, and monthly thereafter. Patients provided self-evaluations at the same visits. Adverse events were monitored throughout. RESULTS: The 40, 60, and 80 U doses of botulinum toxin type A were consistently more effective in reducing glabellar lines than the 20 U dose (duration, peak response rate, improvement from baseline). There was a dose-dependent increase in both the response rate at maximum frown and the duration of effect assessed by the trained observer. In addition, the participants reported a dose-dependent reduction in the ability to frown, improvement in their global assessment, and increased feelings of attractiveness, self-confidence, and satisfaction. The incidence of adverse events was not increased with higher doses. CONCLUSION: Male participants with glabellar rhytids benefit from starting doses of at least 40 U of botulinum toxin type A. 相似文献
99.
Ramón Rodrigo Hernán Prat Walter Passalacqua Julia Araya Cristián Guichard Jean P B?chler 《Hypertension research》2007,30(12):1159-1167
This study investigated the association of blood pressure with blood oxidative stress-related parameters in normotensive and hypertensive subjects. A cross-sectional design was applied to 31 hypertensive patients and 35 healthy normotensive subjects. All subjects were men between the ages of 35 and 60 years. Exclusion criteria were obesity, dyslipidemia, diabetes mellitus, smoking and current use of any medication. All patients underwent 24-h ambulatory blood pressure monitoring and sampling of blood and urine. Antioxidant enzymes activity, reduced/oxidized glutathione ratio (GSH/GSSG), and lipid peroxidation (malondialdehyde) were determined in erythrocytes. Parameters measured in the plasma of test subjects were plasma antioxidant status, lipid peroxidation (8-isoprostane), plasma vitamin C and E, and the blood pressure modulators renin, aldosterone, endothelin-1 and homocysteine. Daytime systolic and diastolic blood pressures of hypertensives were negatively correlated with plasma antioxidant capacity (r=-0.46, p<0.009 and r=-0.48, p<0.007), plasma vitamin C levels (r=-0.53, p<0.003 and r=-0.44, p<0.02), erythrocyte activity of antioxidant enzymes, and erythrocyte GSH/GSSG ratio, with hypertensives showing higher levels of oxidative stress. Blood pressures showed a positive correlation with both plasma and urine 8-isoprostane. Neither plasma vitamin E nor the assessed blood pressure modulator levels showed significant differences between the groups or correlation with blood pressures. These findings demonstrate a strong association between blood pressure and some oxidative stress-related parameters and suggest a possible role of oxidative stress in the pathophysiology of essential hypertension. 相似文献
100.