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   3310篇
  免费   287篇
  国内免费   80篇
耳鼻咽喉   20篇
儿科学   79篇
妇产科学   80篇
基础医学   374篇
口腔科学   203篇
临床医学   322篇
内科学   585篇
皮肤病学   92篇
神经病学   345篇
特种医学   154篇
外科学   421篇
综合类   143篇
预防医学   352篇
眼科学   99篇
药学   283篇
中国医学   2篇
肿瘤学   123篇
  2021年   47篇
  2019年   44篇
  2018年   59篇
  2017年   48篇
  2016年   36篇
  2015年   42篇
  2014年   55篇
  2013年   84篇
  2012年   116篇
  2011年   156篇
  2010年   84篇
  2009年   85篇
  2008年   102篇
  2007年   174篇
  2006年   142篇
  2005年   136篇
  2004年   125篇
  2003年   111篇
  2002年   108篇
  2001年   80篇
  2000年   96篇
  1999年   90篇
  1998年   59篇
  1997年   48篇
  1996年   50篇
  1995年   51篇
  1994年   36篇
  1993年   38篇
  1992年   76篇
  1991年   52篇
  1990年   56篇
  1989年   74篇
  1988年   54篇
  1987年   74篇
  1986年   74篇
  1985年   79篇
  1984年   54篇
  1983年   59篇
  1982年   37篇
  1981年   40篇
  1979年   53篇
  1978年   48篇
  1977年   41篇
  1976年   43篇
  1975年   29篇
  1974年   35篇
  1973年   38篇
  1971年   28篇
  1970年   31篇
  1969年   39篇
排序方式: 共有3677条查询结果,搜索用时 15 毫秒
91.
The optimal form of rehabilitation after rotator cuff repair has yet to be determined. A randomised clinical trial was undertaken to compare outcomes for two forms of rehabilitation for this condition: individualised supervised physiotherapy treatment, and a standardised unsupervised home exercise regime. Fifty-eight volunteers with all sizes of operatively repaired rotator cuff tears were allocated randomly to one of the two treatment groups. All subjects received a standardised home exercise regime. Subjects who were randomised to the physiotherapy group received additional individualised treatment. Independent, blinded assessments of range of motion, muscle force and functional outcome measures were performed pre-operatively, and at six, 12 and 24 weeks postoperation. At six, 12 and 24 weeks post-operation, comparable outcomes were demonstrated for both rehabilitation groups. By 24 weeks post-operation, most subjects demonstrated outcomes that were consistent with a favourable recovery, regardless of rehabilitation mode. On the basis of these results, outcomes for subjects allocated to individualised physiotherapy treatment after rotator cuff repair are no better than for subjects allocated to a standardised home exercise regime.  相似文献   
92.
Experimental studies with a balloon phantom, and clinical studies were performed to evaluate first-pass radionuclide angiocardiography using a gamma camera in the assessment of regional wall motion. The phantom studies showed that choice of isocount contour was not critical in edge detection. Adequate count densities could be achieved, but only at the expense of temporal resolution. The clinical studies disclosed a good correlation with radiography in normal subjects and those with diffuse ventricular disease but a poor correlation in subjects with localised abnormalities of wall motion.  相似文献   
93.
Use of a radioimmunoassay to quantify thrombospondin   总被引:8,自引:0,他引:8  
Saglio  SD; Slayter  HS 《Blood》1982,59(1):162-166
Results of radioimmunoassay procedures applied to samples containing thrombospondin indicated that reliable values are obtained either in saline or in plasma. Plasma levels in apparently normal individuals ranged from approximately 20 to 300 ng/ml. The mean for 20 individuals was 175 ng/ml. Plasma specimens stored either refrigerated at 4 degrees C or frozen at -80 degrees C showed significantly diminished thrombospondin levels over a period of 90 days. Serum levels of thrombospondin were found to range from 10,000 to 30,000 ng/ml.  相似文献   
94.
To assess the potential efficacy of trimethoprim-sulfamethoxazole (TMP-SMX) against serious enterococcal infections, we used a rat enterococcal endocarditis model comparing TMP-SMX therapy (500 mg of TMP plus 2,500 mg of SMX per kg of body weight per day given every 8 h by intragastric gavage) with intravenous ampicillin therapy (1,000 mg/kg per day). Despite concentrations of active drug in serum well in excess of the MIC and MBC, the mean residual vegetation bacterial titer in TMP-SMX-treated rats was similar to that in untreated controls (8.4 +/- 1.1 versus 8.6 +/- 1.3 log10 CFU/g) and significantly higher than that in the ampicillin-treated group (3.6 +/- 1.5 log10 CFU/g; P less than or equal to 0.001). This demonstrates discordance between in vitro activity and in vivo efficacy of TMP-SMX in serious enterococcal infection.  相似文献   
95.
目的:制备大鼠在体缺血再灌注模型,观察缺血预处理程序中心肌环磷酸腺苷含量及环磷酸腺苷依赖蛋白激酶活性的变化。方法:实验于2005-03/2006-10在解放军沈阳军区总医院医学实验动物中心和全军心血管研究所实验室完成。实验分组:选用健康雌性SD大鼠36只,根据预适应程序分为第1,2,3次缺血,第1,2,3次再灌注,每一时间点6只大鼠。实验过程:用手术套管法造成左冠状动脉主干缺血及再灌注。所有实验动物在实验程序结束后,取出心脏迅速置液氮保存备用。实验评估:用放射免疫法测环磷酸腺苷水平,生化法测环磷酸腺苷依赖蛋白激酶活性变化。结果:36只大鼠均进入结果分析。①环磷酸腺苷含量:第1次再灌注组低于第1次缺血组[(0.325±0.015),(0.395±0.024)pmol/g,t=6.06,P<0.001],第2次再灌注组低于第2次缺血组[(0.523±0.017),(0.708±0.067)pmol/g,t=6.56,P<0.001],第3次再灌注组低于第3次缺血组[(0.567±0.031),(0.712±0.038)pmol/g,t=7.24,P<0.001]。②环磷酸腺苷依赖蛋白激酶活性:第1次再灌注组低于第1次缺血组[(10.115±1.000),(16.351±0.849)pkat/g,t=11.12,P<0.001],第2次再灌注组低于第2次缺血组[(11.877±2.213),(14.869±0.619)pkat/g,t=3.31,P<0.01],第3次再灌注组低于第3次缺血组[(11.745±0.987),(14.766±0.329)pkat/g,t=7.09,P<0.001]。③缺血预处理程序中心肌环磷酸腺苷含量及环磷酸腺苷依赖蛋白激酶活性随缺血及再灌注呈周期性波动。在5min缺血预处理时表现为明显增高,而在间隔的再灌注程序中恰呈相反改变,有明显下降的趋势。结论:环磷酸腺苷及环磷酸腺苷依赖蛋白激酶的周期性波动变化可能是激发心肌缺血预处理的机制之一,环磷酸腺苷可能在预处理保护作用中起一些作用。  相似文献   
96.
The objective of this research was to examine the contribution of a moderately high fat (MHF) diet to the development of salt-sensitive hypertension in obese Zucker rats. Lean and obese Zucker rats were fed either a MHF diet or a diet of standard rat chow (control diet) for 10 weeks. From week 4 through week 10, the drinking water was supplemented with 1% NaCl. Blood pressure was measured weekly, and urinary excretion of nitric oxide metabolites (NO(x)) was determined at weeks 4 and 10. At week 10, renal nitric oxide synthase (NOS) activity was assessed in kidney homogenates. Blood pressures of obese, but not lean, rats on the MHF fat diet were significantly increased by salt-supplementation, whereas blood pressures of rats on the control diet were not appreciably affected. NO(x) excretion was increased in response to salt-supplementation in rats on the control diet, with the effect being particularly dramatic in obese rats. After salt-supplementation, NO(x) excretion by rats on the MHF diet was lower than rats on the control diet. In obese rats on the MHF diet, this decrease in NO production was accompanied by a reduction in renal NOS activity. These results indicate that obese rats are more inclined than lean rats to develop diet-induced hypertension in response to a moderately high fat, salt-supplemented diet. Furthermore, they suggest that MHF diet-induced defects in NO production may promote the salt-sensitivity of blood pressure in obese Zucker rats, which appear to require more NO to maintain blood pressure during a salt challenge.  相似文献   
97.
It has long been believed that the superior colliculus (SC) is involved in the production of saccades but plays no role in the generation of vergence eye movements. However, results from several recent studies suggest that it may be worthwhile to examine the role of the SC in saccade-vergence interactions. Specifically, the available literature suggests two questions: do saccade-related neurons in SC have three-dimensional movement fields and is the slowing of saccades by vergence attributable, in part, to changes in the level of activity in SC? Single-unit data were recorded from 51 saccade-related neurons in rhesus monkey SC during saccades without vergence, saccades accompanied by convergence, and saccades accompanied by divergence. Most cells (78% for convergence, 86% for divergence) showed a significant reduction in peak spike density when the saccade was accompanied by vergence. A minority of cells (16% for convergence, 2% for divergence) increased their firing rate for saccades accompanied by vergence. Three cells were found that discharged in association with saccades, vergence, and the combination of the two. There were no cells that exhibited the pattern of discharge that would be expected of a cell tuned for saccades with divergence. Thus the present results do not support the hypothesis that saccade-related SC neurons are, as a rule, tuned in three dimensions. Small, but significant, differences in firing rate were often found for saccades without vergence at near and far distances. Approximately half of the cells showed a significant relationship between spike activity and saccade velocity, but the correlations tended to be very weak. This suggests that the decreased neuronal activity of SC neurons has only a limited effect on saccade velocity. For some cells, the movement field shifted for saccades with vergence. These shifts were highly variable from one cell to another.  相似文献   
98.
99.
Asthma is responsible for approximately 25,000 deaths annually in Europe despite available medicines that maintain asthma control and reduce asthma exacerbations. Better treatments are urgently needed for the control of chronic asthma and reduction in asthma exacerbations, the major cause of asthma mortality. Much research spanning >20 years shows a strong association between microorganisms including pathogens in asthma onset, severity and exacerbation, yet with the exception of antibiotics, few treatments are available that specifically target the offending pathogens. Recent insights into the microbiome suggest that modulating commensal organisms within the gut or lung may also be a possible way to treat/prevent asthma. The European Academy of Allergy & Clinical Immunology Task Force on Anti‐infectives in Asthma was initiated to investigate the potential of anti‐infectives and immunomodulators in asthma. This review provides a concise summary of the current literature and aimed to identify and address key questions that concern the use of anti‐infectives and both microbe‐ and host‐based immunomodulators and their feasibility for use in asthma.  相似文献   
100.
Cancer diagnosed during pregnancy is a rare occurrence with an incidence of 0.1% of all pregnancies. However, its management can be challenging at times as one balances maternal benefit to fetal risk. Various treatment modalities are used in this context including surgical intervention, chemotherapy, and radiologic therapy. This review seeks to address the impact of pregnancy on disease as well as the effect of malignancy and its treatment on both mother and fetus. Attention is focused on the more common malignancies associated with pregnancy: cervix, breast, melanoma, and hematologic malignancies. In addition, special emphasis is placed on timing of delivery and how that affects neonatal outcomes.  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