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   19541篇
  免费   1278篇
  国内免费   531篇
耳鼻咽喉   16篇
儿科学   492篇
妇产科学   321篇
基础医学   1116篇
口腔科学   140篇
临床医学   1980篇
内科学   6252篇
皮肤病学   68篇
神经病学   991篇
特种医学   343篇
外科学   768篇
综合类   3250篇
现状与发展   2篇
预防医学   1768篇
眼科学   208篇
药学   2404篇
  15篇
中国医学   979篇
肿瘤学   237篇
  2024年   61篇
  2023年   294篇
  2022年   582篇
  2021年   885篇
  2020年   655篇
  2019年   547篇
  2018年   524篇
  2017年   548篇
  2016年   656篇
  2015年   703篇
  2014年   1302篇
  2013年   1402篇
  2012年   1297篇
  2011年   1360篇
  2010年   1099篇
  2009年   989篇
  2008年   992篇
  2007年   846篇
  2006年   721篇
  2005年   657篇
  2004年   535篇
  2003年   446篇
  2002年   336篇
  2001年   364篇
  2000年   274篇
  1999年   226篇
  1998年   187篇
  1997年   195篇
  1996年   166篇
  1995年   168篇
  1994年   169篇
  1993年   142篇
  1992年   121篇
  1991年   130篇
  1990年   130篇
  1989年   115篇
  1988年   118篇
  1987年   104篇
  1986年   102篇
  1985年   139篇
  1984年   129篇
  1983年   76篇
  1982年   110篇
  1981年   86篇
  1980年   109篇
  1979年   75篇
  1978年   66篇
  1977年   69篇
  1976年   59篇
  1973年   57篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
临床护理工作中发现,高张葡萄糖的使用,在某些情况下存在一定的危险性,使用不当则加重病情的发展,甚至危及病人的生命。因此要掌握好高张葡萄糖对某些疾病所产生的不良影响,做到预防在先,合理使用。  相似文献   
42.
Hereditary hypertriglyceridemic rats (hHTg) were developed as a new genetic model for the study of relationships between blood pressure (BP) and metabolic abnormalities. This strain has been produced by selective inbreeding from Wistar rats according to the rise of plasma triglycerides induced by a high-sucrose diet. Though hHTg rats display hypertriglyceridemia, impaired glucose tolerrance, hyperinsulinemia, insulin resistance and increased BP even without nutritional stimuli, high sucrose feeding further aggravates these symptoms. High plasma triglycerides levels in hHTg rats seem to be a consequence of their hyperproduction. Impaired insulin action is responsible for the defective glucoregulation in this strain. The loss of insulin responsiveness might be due to a reduction in the number of glucose transporters. Highly significant relationships among plasma triglycerides, ouabain-resistant Na+ transport and BP were demonstrated in the hHTg rats. Segregating populations (F2 hybrids) should be used for genetic analysis of the primary role of lipid and/or ion transport abnormalities in the pathogenesis of this form of genetic hypertension.  相似文献   
43.
The incretin glucagon-like peptide 1 (GLP-1) shows glucose-dependent insulinotropic activity and may exert anabolic effects. Whole-body protein metabolism was assessed by measuring [1-13C]-leucine kinetics in 13 healthy volunteers during hyperglycaemic clamping with or without pancreatic clamping (somatostatin infusion) in order to differentiate between insulin-mediated and direct GLP-1 effects. During intact pancreatic secretion leucine flux and leucine oxidation rate as parameters of whole-body protein breakdown decreased markedly after 180 min of synthetic GLP-1 infusion (GLP-1 vs. placebo: P  < 0.003). Indirect calorimetry showed an increase in energy expenditure and CO2 production during GLP-1 administration ( P  < 0.0005). Plasma insulin increased after 3 h of GLP-1 infusion to 1486 ± 145 pmol L−1 vs. 185 ± 12 pmol L−1 for saline ( P  < 0.0001). When plasma insulin levels were kept constant (GLP-1 vs. saline, NS) during pancreatic clamping, GLP-1 effects on both protein metabolism and energy expenditure were abolished. Thus, GLP-1 infusion in man exerts protein anticatabolic and thermic effects, which are mediated by GLP-1-induced stimulation of insulin secretion.  相似文献   
44.
1. The effects of graded doses of the α2-adrenoceptor agonists clonidine, tizanidine and BHT-920, and the α2-adrenoceptor antagonists yohimbine and idazoxan, on gastrointestinal transit were investigated in mice using the charcoal meal test. 2. The agonists produced significant and dose-dependent decreases in gastrointestinal transit, and the antagonists produced the opposite effect. In affecting the gastrointestinal transit, clonidine (1 mg/kg) was as effective as tizanidine (12 mg/kg) and BHT-920 (40 mg/kg), while yohimbine (2 mg/kg) was as effective as idazoxan (1 mg/kg). 3. Morphine (2, 4 and 8 mg/kg) significantly inhibited gastrointestinal transit. This effect was significantly reversed by the co-administration of yohimbine (2 mg/kg) and idazoxan (1 mg/kg). 4. The acute administration of glucose (5.04 g/kg, i.p.) potentiated the inhibition of gastrointestinal transit produced by clonidine (1 mg/kg) and BHT-920 (40 mg/kg). Glucose treatment, however, had no significant effect on the increase in gastrointestinal transit induced by yohimbine (2 mg/kg) or idazoxan (1 mg/kg). 5. Castor oil (0.25 mL/mouse, orally) induced diarrhoea in saline-treated animals within about 45 min. Clonidine (1 mg/kg), tizanidine (12 mg/kg) and BHT-920 (40 mg/kg) delayed the occurrence of diarrhoea to 2.1, 1.2 and 1.4 h, respectively.  相似文献   
45.
本文报道46例肝硬化患者口服葡萄糖胰岛素释放试验的结果,并与18名正常人和18名原发性糖尿病患者比较。肝硬化患者糖耐量减低者28例(60.9%),其中29例(43.5%)呈糖尿病型耐量曲线。胰岛素释放高峰值在服糖后2h;释放过多和分泌延迟者32例(69.6%),降低者4例(8.7%)。20例肝源性糖尿病患者的胰岛素释放指数明显高于原发性糖尿患者。笔者认为血浆胰岛素和胰岛素释放指数测定对鉴别这两种类型的糖尿病有很大价值。  相似文献   
46.
The purpose of our study was to test the hypothesis that the quotient between plasma glucose and whole body oxygen consumption (VO2) as a 'metabolic index' is a sensitive indicator of early graft function. Arterial levels of glucose and oxygen consumption were determined in 100 consecutive patients during orthotopic liver transplantation performed without anhepatic veno-venous bypass. Patients were divided into survivors with no obvious problems related to graft function and those with primary nonfunction of the graft. The neohepatic increase in VO2 was significantly higher in survivors (112 +/- 4 vs 88 +/- 11 ml.min-1.m-2; p < 0.05), whereas blood glucose levels after reperfusion were higher (352 +/- 18 vs. 287 +/- 36 mg dl-1) in those with primary non-function of the graft. The calculated metabolic index was also higher (4.02 +/- 0.93 vs 2.67 +/- 0.45, p < 0.05) in patients with primary nonfunction of the graft. Our principal conclusion was that 92% of normal functioning liver grafts could be classified correctly by the metabolic index immediately after reperfusion, whereas glucose levels and VO2 alone classified only 67% and 70% of normal functioning liver grafts correctly.  相似文献   
47.
ABSTRACT. The effects of procedures which stimulate sympathetic activity, viz. mental stress induced by a colour-word conflict test (CWT) for 20 min, and orthostasis (ORT) for 8 min were studied in 8 young (16-20 yr) insulin-dependent diabetes mellitus (IDDM) patients and 9 age and sex-matched healthy controls. The IDDM patients showed no signs of neuropathy or retinopathy and their mean HbA1c value was 8.4 ±0.6% (normal value < 5.0 %). Blood pressure and heart rate increased significantly during CWT and ORT in both groups. The changes in systolic blood pressure and heart rate were comparable in both groups during CWT; the IDDM group showed a higher ( p < 0.05) heart rate after 8 min of orthostasis, however. CWT and ORT elicited equivalent increases in noradrenaline in venous plasma in both groups ( p < 0.05), but the IDDM patients had 50% lower values ( p < 0.01) at rest, during CWT and at rest after CWT than controls. CWT and ORT evoked equivalent plasma adrenaline increases in both groups. The lipolysis marker, plasma glycerol, was about 40 % lower ( p < 0.05) in the IDDM group before and after CWT. Yet, mental stress evoked equivalent increases in glycerol levels ( p < 0.01) in both groups. These findings indicate that sympathetic activity in the young diabetic patients without signs of neuropathy may be blunted.  相似文献   
48.
The dynamics of125I distribution is studied in rats with induced tumors of the prostate and mammary gland for intravenous administration of125I-3D-G. It is found that 80% of the activity is eliminated in the first 24 hours. A relatively high level of125I accumulation is found in necrotically altered regions of the tumor. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, № 3, pp. 294–295, March, 1994.  相似文献   
49.
目的:观察第二、三代口服避孕药(COC)对育龄妇女体重指数、血压、血糖和血脂的影响。方法:将自愿服用COC避孕1年的妇女105例随机分为两组,其中54例给予第二代COC(EE/LNG组),51例给予第三代COC(EE/DG组)。并对研究前后所有病例的体重指数(BMI)、血压、血糖和血脂代谢指标进行比较分析。结果:EE/LNG组:BMI、收缩压、舒张压、甘油三酯(TG)、总胆固醇(TC)、低密度脂蛋白(LDL)和载脂蛋白B(ApoB)水平均升高,高密度脂蛋白(HDL)水平下降,血糖、载脂蛋白AI(ApoAI)水平无明显改变。EE/DG组收缩压、TG、HDL水平升高,BMI、舒张压、血糖、TC、LDL、ApoAI和ApoB均未发生显著变化。以上所有测量指标均未超出正常范围。结论:使用1年第二、三代COC对妇女BMI、血压和血脂代谢都有微弱的影响,对空腹血糖无明显影响。第三代COC对妇女BMI、收缩压、舒张压、TG、TC、LDL、HDL水平和ApoB的不利影响小于第二代,更加安全可靠。  相似文献   
50.
A. Green 《Diabetologia》1987,30(3):188-192
Summary To determine whether adenosine is involved in long-term regulation of glucose transport in adipose tissue, we have investigated effects of administration of an adenosine receptor antagonist (theophylline) on adipocyte glucose transport. Rats were injected with theophylline (30 mg/kg, dissolved in 0.9% NaCl) daily for 7 days. Controls were injected with saline. The rats were then killed, and epididymal adipocytes were isolated. Insulin-stimulated glucose transport rates were decreased by about 25%–30% in the cells from theophylline-treated rats at all insulin concentrations tested. The half-maximally effective concentration of insulin was not altered (6.5±0.5 and 6.7±0.5 mU/l in control and treated cells respectively), suggesting a post-insulin binding defect. This was confirmed by the finding that 125I-insulin binding to the cells was not altered. Adenosine receptor number and affinity (measured on detergent-solubilized adipocyte extracts using 125I-hydroxyphenylisopropyl adenosine) was also not changed by theophylline treatment. We conclude that theophylline administration causes decreased glucose transport rates in rat adipocytes at a post-insulin binding level. Thus, chronic adenosine receptor blockade impairs adipocyte glucose transport, suggesting that adenosine is involved in long-term regulation of glucose metabolism in adipose tissue.  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