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   1417篇
  免费   69篇
  国内免费   46篇
耳鼻咽喉   1篇
儿科学   55篇
妇产科学   14篇
基础医学   84篇
口腔科学   11篇
临床医学   150篇
内科学   372篇
皮肤病学   6篇
神经病学   39篇
特种医学   35篇
外科学   53篇
综合类   193篇
预防医学   177篇
眼科学   5篇
药学   206篇
中国医学   116篇
肿瘤学   15篇
  2023年   26篇
  2022年   46篇
  2021年   63篇
  2020年   56篇
  2019年   53篇
  2018年   49篇
  2017年   62篇
  2016年   33篇
  2015年   25篇
  2014年   103篇
  2013年   116篇
  2012年   88篇
  2011年   84篇
  2010年   50篇
  2009年   48篇
  2008年   71篇
  2007年   57篇
  2006年   51篇
  2005年   20篇
  2004年   41篇
  2003年   40篇
  2002年   31篇
  2001年   22篇
  2000年   26篇
  1999年   21篇
  1998年   17篇
  1997年   17篇
  1996年   15篇
  1995年   6篇
  1994年   12篇
  1993年   18篇
  1992年   9篇
  1991年   17篇
  1990年   8篇
  1989年   6篇
  1988年   10篇
  1987年   5篇
  1986年   7篇
  1985年   8篇
  1984年   6篇
  1983年   7篇
  1982年   10篇
  1981年   7篇
  1980年   7篇
  1979年   12篇
  1978年   8篇
  1976年   6篇
  1975年   5篇
  1974年   10篇
  1972年   5篇
排序方式: 共有1532条查询结果,搜索用时 15 毫秒
1.
孕妇血清与初乳中分泌型IgA含量的关系   总被引:1,自引:0,他引:1  
目的探讨孕妇营养与初乳中分泌型免疫球蛋白A(SIgA)含量的关系。方法对101例孕妇作了膳食营养评价,并对其血液营养学指标与产后第3d初乳SIgA含量进行相关分析。结果孕妇血清IgA与初乳SIgA呈明显的正相关(r=0.498P<0.01);血清甘油三酯与初乳SIgA呈明显的负相关(r=-0.338P<0.005);血清叶酸与初乳SIgA呈明显正相关(孕中期r=0.737P<0.001,孕晚期r=0.362P<0.01)相关呈高度显著性。结论初乳SIgA与孕妇个体免疫状态以及孕期代谢状态有关。  相似文献   
2.
Data on 232 members of a single pedigree, descended from two pairs of original parents, were made available to the participants of Genetic Analysis Workshop 8 (GAW8). In addition to information concerning age and sex, measurements for 10 quantitative traits and genotypes at 22 polymorphic marker loci were also provided for a subset of 193 of these family members. © 1993 Wiley-Liss, Inc.  相似文献   
3.
It has been demonstrated that total parenteral nutrition (TPN) modulates the function of the hepatic reticuloendothelial system (RES). The objective of this study was to evaluate the impact of two different TPN lipid emulsions on the recovery of allograft RES function after orthotopic liver transplantation (OLTx). In a prospective, double-blind study, OLTx patients were randomly assigned to two treatment groups. Group I ( n=13) received a TPN regimen that included long-chain triglycerides (LCT). Group II ( n=9) received a TPN regimen that included a fat emulsion consisting of both medium-chain triglycerides (MCT) and LCT. At baseline, i.e., on days 2 or 3 after OLTx ( t1), before lipids for TPN were started, hepatic RES function was determined using the human serum albumin millimicrosphere technique (K-value, 1/min). A second measurement ( t2) was obtained after 7 days of TPN, including one of the study's two fat emulsions. The mean (+/- SD) K-value (1/min) was 0.48+/-0.16 in the LCT group and 0.55+/-0.28 in the MCT/LCT group at t1, and it improved to 0.62+/-0.21 in the LCT group and to 0.86+/-0.32 in the MCT/LCT group at t2. RES function recovery was significantly better in the MCT/LCT group ( P< or = 0.05). MCT/LCT emulsion appears to be the TPN fat emulsion of choice after OLTx as it seems to have less impact on hepatic RES recovery.  相似文献   
4.
Test meals with 10.9 g dietary fibre from sugar beet and corresponding control meals were given to eight healthy subjects, aged 67 ± 9 years. The postprandial glucose, triglyceride, hormone and glycerol responses were monitored during 3 hours. After the beet fibre meal the insulin and C-peptide areas were reduced by 28 ( P < 0.01) and 22% ( P > 0.025), respectively, and the somatostatin levels increased by approximately 30% ( P > 0.05). Further, the maximum relative postprandial reduction of plasma glycerol levels was less evident after the fibre-rich meal than after the control meal (36 ± 4% v. 46 ± 4%, P < 0.05). There was no apparent difference in the overall glycaemic response between the meals. The triglyceride levels were similar after both test meals.
Suspension of beet fibre bread given to rats by oro-gastric intubation induced lower blood glucose response than a control bread at 15 and 30 min ( P < 0.001), respectively, but a similar insulin response.
The results suggest an effect of beet fibre on the rate of carbohydrate absorption, expressed as a lower insulin response in the healthy volunteers and a reduced glucose response in the rat.
The mechanism behind this effect in healthy subjects could possibly be mediated by an increased somatostatin response.  相似文献   
5.
The aim of this study was to examine the effects of dietary fenofibrate (0.05% in the diet) on ketone body production and lipid secretion in isolated perfused rat liver. Feeding with fenofibrate for 7–9 days caused an increased liver weight. Ketone body production was significantly greater in the livers perfused with oleic acid than in those perfused without fatty acid, with the elevation of the ratio ofβ-hydroxybutyrate:acetoacetate indicating an increased redox potential in mitochondrial compartments by exogenous fatty acid. On the other hand, fenofibrate feeding caused a further stimulation of ketone body production from both endogenous and exogenous fatty acid substrates, respectively, with a decreased ratio ofβ-hydroxybutyrate:acetoacetate as compared to respective control livers, indicating a decreased redox potential. Hepatic secretion of triglyceride, but not of cholesterol, was decreased markedly in the fenofibrate-fed rats, especially when oleate was provided, suggesting an inverse relationship between rates of ketogenesis and triglyceride secretion. These results suggest that the altered hepatic metabolism of long-chain fatty acids between oxidation and esterification caused by fenofibrate may thus be a factor responsible for the decreased secretion of triglyceride, hence leading to hypotriglyceridaemiain vivo.  相似文献   
6.
高果糖诱导IR大鼠模型血清脂质代谢的改变及意义   总被引:4,自引:0,他引:4  
目的: 评估高果糖膳食对机体胰岛素敏感性及血清脂质代谢的影响及意义.方法:以高果糖膳食(果糖占总热量34.5%)诱导并经钳夹技术证实建立胰岛素抵抗(IR)大鼠模型,生化比色法测定血清游离脂肪酸(FFA),生化酶法测定血清甘油三酯(TG)及总胆固醇(TC).结果:高果糖膳食喂养4周后,实验组大鼠葡萄糖输注率由(11.5±0.6)mg/kg·min-1下降至(6.6±0.4)mg/kg·min-1(P<0.01);血清FFA由(0.45±0.09)mmol/L增至(0.78±0.19)mmol/L(P<0.01);TG由(0.54±0.10)mmol/L增至(0.96±0.22)mmol/L(P<0.01);TC由(1.96±0.32)mmol/L增至(2.42±0.21)mmol/L(P<0.01).结论:高果糖膳食可导致机体严重IR,是建立IR大鼠模型的有效手段;该模型同时伴有血清脂代谢各相关指标的明显异常,血脂的变化既是IR的结果,也是IR向纵深发展的原因和必要条件.  相似文献   
7.
抑郁症患者的血糖、血脂水平及其与症状关系的对照研究   总被引:2,自引:0,他引:2  
目的了解抑郁症患者糖脂代谢的情况及其与精神症状的关系。方法以HAMD17和HAMA评定92例近期未服用精神药物的抑郁症患者的精神症状,了解他们简易体质参数、测定其空腹血糖和血脂,并与60例健康者组成的对照组进行比较。结果抑郁症组的甘油三酯(TG)、空腹血糖(FBS)值显著高于对照组(P<0.001),而高密度脂蛋白胆固醇(LDL—ch)、载脂蛋白A1(ApoA1)值显著低于对照组(P<0.01);血浆总胆固醇(TC)、高密度脂蛋白胆固醇(HDL—ch)和载脂蛋白B(ApoB)两组之间无显著性差异(P>0.05);相关分析发现,抑郁症患者的HAMA总分、精神性焦虑因子分以及躯体性焦虑因子分与TG水平呈正相关(P<0.01或P<0.05)。结论抑郁症患者存在一定的糖脂代谢异常,临床医师应该对抑郁症患者的血糖、血脂进行监测,以便早期发现,早期治疗。  相似文献   
8.
AIMS: Metabolic responses to manipulation of the plasma free fatty acid (FFA) concentration were assessed in six healthy men via cross-over design to determine whether FFAs independently influence insulin sensitivity. METHODS: Intramyocellular lipid (IMCL) was measured by proton magnetic resonance spectroscopy and insulin sensitivity via frequently sampled intravenous glucose tolerance test (IVGTT) after 67 h of two identical low carbohydrate/high fat (LC) diets which were used to elevate IMCL and plasma FFAs. To uncouple the influence of FFAs and IMCL on insulin sensitivity, FFAs were suppressed 30 min prior to and during IVGTT in one treatment [LC + nicotinic acid (NA)] by NA ingestion. RESULTS: Vastus lateralis IMCL was significantly elevated in LC (13.3 +/- 1.1 x 10(-3)) and LC + NA (13.5 +/- 1.1 x 10(-3)) (P < 0.01 for both), but was not different between conditions (P > 0.05). Plasma FFAs were raised in LC (0.79 +/- 0.08 mmol/l) and LC + NA (0.80 +/- 0.11 mmol/l) (P < 0.01 for both) and were significantly reduced by NA ingestion prior to (0.36 +/- 0.05 mmol/l, P < 0.01) and during IVGTT (P < 0.05) in LC + NA. Despite marked differences in plasma FFA availability, insulin sensitivity and glucose tolerance were not different between LC and LC + NA (P > 0.05 for both). CONCLUSIONS: Plasma FFAs appear to exert no immediate effect on insulin sensitivity/glucose tolerance independent of their action on intracellular lipid moieties. Further research is required to elucidate the duration of FFA suppression required to restore insulin sensitivity following lipid-induced insulin resistance.  相似文献   
9.
The relationship between high-density-lipoprotein (HDL) particle size subclasses and the levels of the major lipoprotein lipids was studied in 74 men consecutively referred to the lipid clinic. HDL (density 1.070-1.21 kg l-1) was separated by polyacrylamide gradient gel electrophoresis (GGE) into five size-defined subclasses, in order of decreasing size as follows: HDL2b, HDL2a, HDL3a, HDL3b and HDL3c. Cholesterol and triglyceride concentrations in very-low-density (VLDL), low-density (LDL) and high-density (HDL) lipoproteins were determined. The level of VLDL triglycerides was negatively correlated with HDL2b (r = -0.66, P less than 0.0001), and positively correlated with HDL3b concentrations (r = 0.65, P less than 0.0001). Both correlations were restricted to subjects with VLDL triglyceride concentrations of less than 1.80 mmol l-1, i.e. those with normotriglyceridaemia. Patients with a history of myocardial infarction and/or angina pectoris (n = 18) had significantly lower HDL2b levels than subjects with asymptomatic hyperlipidaemia (n = 50), i.e. 0.16 vs. 0.22 mg protein ml-1 (P less than 0.05), despite essentially similar cholesterol and triglyceride levels in the VLDL, LDL and HDL fractions, including HDL2 and HDL3 cholesterol.  相似文献   
10.
高脂血症对血浆t-PA和PAI-1活性的影响   总被引:2,自引:0,他引:2  
目的 探讨高脂血症患者的纤溶系统的变化。方法 选取正常人及高脂血症者,测定其血脂、血浆t—PA和PAI-1活性。结果 高脂血症组比正常人血浆t—PA活性下降,而PAI-1的活性有升高;在TG及LDL-C升高者,其血浆t—PA活性比正常人血浆t—PA活性降低,而血浆PAI-1活性比正常人升高;单纯TC升高者血浆PAI-1活性接近正常人组,而血浆t—PA活性比正常人组明显降低。结论 高脂血症对纤溶系统有一定的影响,其中甘油三酯和LDL-C对纤溶系统的影响更明显,而胆固醇对纤溶系统也有一定的影响。  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