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   38098篇
  免费   3735篇
  国内免费   1110篇
耳鼻咽喉   253篇
儿科学   825篇
妇产科学   489篇
基础医学   5372篇
口腔科学   1392篇
临床医学   3050篇
内科学   5664篇
皮肤病学   705篇
神经病学   2838篇
特种医学   865篇
外国民族医学   6篇
外科学   2504篇
综合类   3881篇
现状与发展   10篇
一般理论   2篇
预防医学   3186篇
眼科学   990篇
药学   6701篇
  26篇
中国医学   2337篇
肿瘤学   1847篇
  2024年   138篇
  2023年   758篇
  2022年   1311篇
  2021年   1784篇
  2020年   1610篇
  2019年   1535篇
  2018年   1478篇
  2017年   1620篇
  2016年   1685篇
  2015年   1699篇
  2014年   2404篇
  2013年   3879篇
  2012年   1960篇
  2011年   2075篇
  2010年   1676篇
  2009年   1705篇
  2008年   1702篇
  2007年   1688篇
  2006年   1500篇
  2005年   1282篇
  2004年   1137篇
  2003年   975篇
  2002年   789篇
  2001年   621篇
  2000年   508篇
  1999年   460篇
  1998年   442篇
  1997年   392篇
  1996年   360篇
  1995年   307篇
  1994年   271篇
  1993年   274篇
  1992年   262篇
  1991年   243篇
  1990年   203篇
  1989年   198篇
  1988年   208篇
  1987年   194篇
  1986年   174篇
  1985年   211篇
  1984年   223篇
  1983年   128篇
  1982年   167篇
  1981年   123篇
  1980年   118篇
  1979年   106篇
  1978年   76篇
  1977年   75篇
  1976年   66篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
香菇多糖抗炎作用的实验研究   总被引:5,自引:0,他引:5  
目的:研究香菇多糖的抗炎作用。方法:用二甲苯所致小鼠耳肿胀、鸡蛋清所致小鼠足跖肿胀等急性炎症以及滤纸片诱发小鼠肉芽组织增生所致小鼠慢性炎症模型进行试验。结果:香菇多糖能抑制二甲苯所致的小鼠耳肿、鸡蛋清所致小鼠足跖肿胀;与此同时对滤纸片诱发小鼠肉芽组织增生形成有抑制作用。结论:香菇多糖具有一定抑制急慢性炎症反应作用。其抗炎作用的机制,值得进一步研究。  相似文献   
2.
本研究选择10μg/ml、20μg/ml、40μg/ml浓度的溴氰菊酯处理白纹伊蚊C6/36细胞,以MMC作为阳性对照物,观察溴氰菊酯处理24h后对C6/36细胞染色体畸变率和姐妹染色单体互换(SCE)频率的影响。结果显示,三个浓度的溴氰菊酯对C6/36细胞染色体畸变率均没有显著影响(P<0.05);溴氰菊酯浓度在40μg/ml时可诱导C6/36细胞SCE频率轻度增高(P>0.05),而溴氰菊酯浓度在10μg/ml、20μg/ml时,对C6/36细胞SCE频率没有诱导作用。表明溴氰菊酯对C6/36细胞的遗传学效应较弱  相似文献   
3.
BACKGROUND: Levels of an immunoregulatory and anti-inflammatory cytokine IL-10 are reduced in asthmatic airways, potentially contributing to more intense inflammation. Triamcinolone has anti-inflammatory properties and the anti-inflammatory effects of montelukast and formoterol have been discussed. OBJECTIVE: The purpose of this study was to define the effect of treatment with triamcinolone, montelukast and formoterol on the serum level of IL-10, eosinophil blood counts, eosinophil cationic response (ECP) and clinical parameters (symptom score, FEV1 and PC20H) in children with moderate asthma. METHODS: An 8-week, placebo-controlled and randomized, double-blind trial was carried out. The subjects were 91 children with moderate atopic asthma who were allergic to dust mite. Patients were randomly allocated to receive 400 microg triamcinolone (n = 19), 5 or 10 mg (according to age) montelukast (n = 18), 24 microg formoterol (n = 18) or placebo (n = 36). RESULTS: Seventy-nine children completed the study. After treatment with triamcinolone and montelukast the level of IL-10 in blood serum significantly increased, eosinophil blood counts and ECP levels significantly decreased and all clinical parameters improved; treatment with formoterol had no effect on IL-10 level, eosinophil blood counts in serum and bronchial hyper-reactivity; ECP level significantly decreased after treatment and asthma symptoms and FEV1 improved significantly. Mean IL-10 levels in serum before and after treatment with triamcinolone were 7.23 pg/mL with 95% CI, 6.74 -7.72% and 14.24 pg/mL with 95% CI, 11.6-16.88%, respectively (P < 0.001); with montelukast they were 6.59 pg/mL with 95% CI, 6.26-7.23% and 10.94 pg/mL with 95% CI, 8.24-12.65%, respectively (P < 0.002); with formoterol they were 7.06 pg/mL with 95% CI, 6.61-7.52% and 7.04 pg/mL with 95% CI, 6.15-7.93%. We found statistically significant correlations between serum level of IL-10 and serum level of ECP after treatment with triamcinolone and montelukast. CONCLUSION: This study demonstrates that one possible way by which triamcinolone and montelukast contribute to inhibition of inflammation is by increasing IL-10 levels.  相似文献   
4.
5.
In this review, we critically evaluate the evidence for local IgE production in allergic rhinitis mucosa and the concept of local allergy in non-atopic idiopathic rhinitis. Significantly, fewer studies have focused on the disease pathways associated with non-allergic rhinitis compared with their allergic counterparts. Recently, there's been a revival of the hypothesis concerning the existence of local tissue-specific allergic disease confined to the nasal mucosa of some systemically non-atopic rhinitis subjects. Providing the evidence for local mucosal IgE production in allergic rhinitis is a pre-requisite to reviewing its existence in non-allergic rhinitis. In addition, practical and theoretical approaches useful in the detection of allergy in non-allergic rhinitis will be discussed. Furthermore, successful therapeutic regimens used in the treatment of non-allergic rhinitis will be examined as these could provide an insight into the underlying pathophysiology of this common but poorly understood disease.  相似文献   
6.
BACKGROUND: Stress can aggravate the allergic inflammation, but determinants of disturbed immune regulation are largely unknown. OBJECTIVE: To determine systemic immunological, local inflammatory and functional airway responses to stress in healthy and atopic individuals. METHODS: Forty-one undergraduate students, 22 with allergy of whom 16 had asthma, and 19 healthy controls, were studied in a low-stress period and in association with a large exam. Subjects completed questionnaires on stress and health behaviours, underwent lung function tests, bronchial methacholine challenge, measurements of exhaled nitric oxide and urine cortisol. Blood cells were phenotyped, and cytokines from mononuclear blood cells were analysed. RESULTS: Perceived stress and anxiety increased in both groups during the exam period while cortisol increased only in the atopy group. Cytokine production decreased broadly in response to stress in both groups, which was paralleled by an increase in the proportion of regulatory T cells (CD4(+)CD45RO(+)CD25(bright)). Interestingly, atopic individuals, but not controls, reacted with a decreased T-helper type 1/T-helper type 2 (Th1/Th2) ratio and a decrease in natural killer (NK) cell numbers in response to stress. In control subjects only, exhaled nitric oxide decreased and forced expiratory volume in one second increased during stress. CONCLUSION: Atopic and non-atopic subjects shared some immune changes in response to stress, such as a dramatic decline in cytokines and an increase in the number of regulatory T cells in peripheral blood. However, other stress-induced immune changes were unique to atopic individuals, such as a skewed Th1/Th2 ratio and reduced NK cell numbers, indicating that some pathogenic mechanisms in atopics may be more strongly affected by stress than others.  相似文献   
7.
Summary Bayesian analysis is given of a random effects binary probit model that allows for heteroscedasticity. Real and simulated examples illustrate the approach and show that ignoring heteroscedasticity when it exists may lead to biased estimates and poor prediction. The computation is carried out by an efficient Markov chain Monte Carlo sampling scheme that generates the parameters in blocks. We use the Bayes factor, cross‐validation of the predictive density, the deviance information criterion and Receiver Operating Characteristic (ROC) curves for model comparison.  相似文献   
8.
This paper proposes that an individual's self-assessed health (SAH) does not only suffer from systematic reporting bias and adaptation bias but is also biased owing to confounding health norm effects. Using 13 waves of the British Household Panel Survey covering the period 1991–2005, I show that, while there is a negative and statistically significant correlation between SAH and individuals' own health problem index, this negative effect reduces with the average number of health problems per (other) family member. The relative health bias is small, however, which implies that measures of SAH may not suffer seriously from systematic health norm bias. This is an important finding for researchers working with SAH data as it indicates that we do not have to worry too much about controlling for confounding influences from the health of other household members when estimating SAH regression equations.  相似文献   
9.
纸本与数字的交互:手机阅读的最佳效果   总被引:1,自引:0,他引:1  
随着全球3G商用的推进和拥有大容量存储能力的智能终端的日益普及,手机正逐步演变成为一个新型的数字阅读终端。利用手机进行电子阅读的全新模式,正以前所未有的普及速度冲击着人们的阅读习惯。而这趋势也逐渐为"阅读"进行重新的定义。对于每一个读者而言,在这样一个信息化的时代里,手机阅读和纸本阅读的交互使用、取长补短,才是获得最佳阅读效果的最有效方式。  相似文献   
10.
李艳芳  邱龄 《当代医学》2010,16(3):9-11
目的探讨单独应用阿托伐他汀与联合应用阿托伐他汀和匹格列酮对高危心血管人群颈动脉内膜中层厚度(CIMT)、高敏C反应蛋白(hs-CRP)、基质金属蛋白酶-9(MMP-9)、脂联素及脂质状况的影响。方法90名有心血管危险因素的患者被随机分为两组:单独应用阿托伐他汀治疗组、联合应用阿托伐他汀和匹格列酮治疗组,分别检测两组患者治疗前及治疗六个月后的CIMT、hs-CRP、脂联素、MMP-9的血浆水平及检测血脂水平。结果单独应用阿托伐他汀及联合应用阿托伐他汀和匹格列酮均显示CIMT的显著降低(P〈0.001),无组间差异(P〉0.05)。两组的MMP-9在治疗后均较治疗前降低,有统计学意义(P〈0.05),但组间无统计学差异(P〉0.05)。两组对h-CRP、脂联素及血脂水平均有有意义的影响,组间有统计学差异,联合用药组提示影响更显著(P〈0.05)。联合用药组血浆脂联素水平明显升高而单独应用阿托伐他汀组未被观察到。结论阿托伐他汀明显改善CIMT,联合应用阿托伐他汀和匹格列酮对脂质状况和炎症因子有额外的影响。  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