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   18671篇
  免费   1102篇
  国内免费   742篇
耳鼻咽喉   105篇
儿科学   221篇
妇产科学   155篇
基础医学   788篇
口腔科学   207篇
临床医学   1302篇
内科学   1996篇
皮肤病学   162篇
神经病学   317篇
特种医学   311篇
外国民族医学   1篇
外科学   6389篇
综合类   2315篇
预防医学   1287篇
眼科学   96篇
药学   2028篇
  21篇
中国医学   2406篇
肿瘤学   408篇
  2024年   48篇
  2023年   523篇
  2022年   815篇
  2021年   1157篇
  2020年   1092篇
  2019年   927篇
  2018年   1018篇
  2017年   1019篇
  2016年   648篇
  2015年   621篇
  2014年   1443篇
  2013年   1497篇
  2012年   1226篇
  2011年   1278篇
  2010年   862篇
  2009年   749篇
  2008年   774篇
  2007年   772篇
  2006年   568篇
  2005年   484篇
  2004年   350篇
  2003年   318篇
  2002年   264篇
  2001年   219篇
  2000年   193篇
  1999年   221篇
  1998年   150篇
  1997年   129篇
  1996年   117篇
  1995年   117篇
  1994年   97篇
  1993年   83篇
  1992年   70篇
  1991年   60篇
  1990年   60篇
  1989年   51篇
  1988年   56篇
  1987年   46篇
  1986年   31篇
  1985年   51篇
  1984年   45篇
  1983年   47篇
  1982年   44篇
  1981年   35篇
  1980年   31篇
  1979年   22篇
  1978年   18篇
  1977年   19篇
  1976年   18篇
  1974年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
健康成人血液流变学与血脂相关性的实验研究   总被引:1,自引:0,他引:1  
目的:研究健康成人血液流变学指标与血脂之间的相关性。方法:抽取西安市某单位健康查体人群各项检查结果齐全的资料117例,其中男性79例,女性38例,将采集的数据进行统计分析。结果:男性和女性之间,TG、HBV、LBV、HRV、LRV、CV、CY均有显著差异(P〈0.05);女性资料中,血脂指标与血液流变学指标的相关性无统计学意义(P〉0.05);男性资料中,血液流变学指标与血脂指标有相关性(P〈0.05)。结论:控制血液粘度和血脂水平是防止和减低心脑血管疾病发生的重要环节。  相似文献   
92.
BackgroundKnee osteoarthritis (KOA) is increasingly prevalent in North American society. The significant societal burden it represents makes it essential to promote and target new treatments in earlier phases of the disease. Among others, subchondroplasty is a newly documented technique using calcium phosphate injection targeting the osteochondral lesions preceding KOA, also known as Bone Marrow Lesions (BMLs). This article aimed to review the existing literature on clinical and radiological outcomes of subchondroplasty in the treatment of BMLs in KOA.MethodA systematic review was performed using PubMed, Embase, Medline and Cochrane Database of Systematic Reviews. Studies on calcium phosphate injections into BMLs for KOA and its clinical and radiological outcomes were screened and reviewed by independent evaluators.ResultsAfter screening, ten articles were included, totaling 540 patients. Follow-up ranged from 6 months to 7 years. Overall, the procedure showed significant functional and quality of life improvement, as well as pain relief, as shown by Patients-Reported Outcomes Measures (PROMs). There were very few complications reported, the most important being leakage of calcium phosphate outside the targeted site. Conversion rate to total knee arthroplasty (TKA) ranged from 14 % to 30 % at 2 years post-procedure. Long term radiological outcomes have been poorly documented.ConclusionsSubchondroplasty is a promising avenue for the treatment of KOA. However, quality evidence is still required before any real conclusions and practical management guidelines can be drawn. Prospective, randomized studies with a control group and a rigorous assessment of long-term clinical and radiological outcomes are recommended.  相似文献   
93.
三七总皂甙对红系祖细胞增殖调控机理的研究   总被引:13,自引:0,他引:13  
王亚平  牛宏 《解剖学杂志》1996,19(2):138-147
采用造血祖细胞体外培养和造血生长因子检测等实验血液学技术,研究三七总皂甙对小鼠红系祖细胞调控的生物学机理。结果表明:三七总皂甙对正常或骨髓抑制一贫血模型小鼠的红系祖细胞增殖有明显促进作用。三七总皂甙亦可提高阿糖胞苷所致祖细胞的“自杀”率;经三七总皂甙诱导制备的脾细胞,L细胞培养上清液和红系祖细胞的直殖具有较高刺激活性。  相似文献   
94.
本文介绍了全面质量管理的概念,并认为TQM实际上是一个数据驱动的管理活动。检验信息系统的优点就在于能够提供各种检验数据,文中阐述了如何利用检验信息系统的这一优点,使其成为医院检验科进行全面质量管理的重要工具。  相似文献   
95.
The enzyme spectrum of pancreatic homogenate was studied in acute experiments on male albino rats during adaptation for 30 days to muscular exertion (forced swimming in water at a temperature of 32±1°C), heat (hyperthermia to 40–41°C), and cold (cooling to 3–4°C) for 3 h. The initial periods of adaptation to these factors (second-twelfth day) were shown to be characterized by a considerable decrease in activity of all the enzymes studied, but later, with adaptation of the animals to these factors, enzyme activity was restored to its original level (18th–24th day), and remained more or less constant until the end of the experiment (30th day). It is suggested that changes in the enzyme spectrum of the pancreas are brought about through the participation of the hypothalamo-hypophyseo-adrenal system in accordance with the principle of the general adaptation syndrome.Laboratory of the Physiology of Digestion and Laboratory of General Physiology, Institute of Physiology, Academy of Sciences of the Uzbek SSR, Tashkent. (Presented by Academician of the Academy of Sciences of the USSR O. G. Gazenko.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 5, pp. 412–414, May, 1979.  相似文献   
96.
G Hagner 《Immunobiology》1984,167(4):389-397
The erythroleukemic K562 cell line was induced to erythroid differentiation by a variety of agents, including hemin, bleomycin, and cytosine arabinoside. The sensitivity of induced cells to binding and lysis by non-sensitized peripheral blood mononuclear cells (MNC) in agarose was studied in relation to the target cell division rate. Differentiated K562 cells formed a lower proportion of conjugates with MNC, when compared with non-induced controls. The reduction correlated significantly with the level of differentiation, irrespective of the inducer and the proliferative status. The differentiation-induced alterations of lysis, however, were strongly influenced by the modification of target cell growth rate which was caused by the differentiating agent. These data suggest that target cell differentiation has distinct effects upon the steps of recognition and lysis by natural killer cells.  相似文献   
97.
伊·普利高津的耗散结构理论中,有一个著名的总熵变公式ds=dse+dsi把上述公式用于人体研究,国内外尚未见报导。在前人对人体热力学系统研究的基础上,本文建立了一个人体熵流的数学模型,为进一步展开研究,提供了有力工具并奠定了可靠的理论基础。  相似文献   
98.
Protein tyrosine phosphatases (PTPases) have recently been recognized as important modulators of various signal transduction pathways in immune cells. Genetic polymorphisms have been described in genes codifying for members of this family of enzymes, and the genetics of PTPases is predicted to play an important role in the etiology of immune diseases and of their clinical variability. The low molecular weight protein tyrosine phosphatase (ACP1 or LMPTP) is one of the few PTPases with a known genetic polymorphism, and has been proposed to be associated with atopic dermatitis in a small sample from an Italian population. In this paper we describe the association of the ACP1 polymorphism with total IgE levels in two independent samples from English and Italian populations. In both the samples the mean value of serum IgE is lower among subjects carrying the BC genotype than in other ACP1 genotypes. The BC genotype is associated with the highest total ACP1 enzymatic activity. Our data suggest that one or both of the ACP1 isoforms exert an inhibitory role on some signal transduction pathway relevant for IgE hyperproduction.  相似文献   
99.
One hundred and sixty-three healthy Chinese subjects of both sexes were studied for serum paraoxonase (PON) polymorphism, and levels of lipids and apolipoproteins in order to examine effects of PON alleles on these parameters. The level of serum triglyceride was significantly higher in high activity allele (PON*B) compared with that in low activity allele (PON*A) in both sexes (P less than 0.01). The subjects with PON A had significantly higher LDL cholesterol (P less than 0.05) and lower Apo A-II and ApoB levels. The influence of serum paraoxonase on serum lipids was estimated further by Spearman's rank correlation. In the males, there was a significant negative correlation of serum paraoxonase activity with total (P less than 0.05) and LDL (P less than 0.01) cholesterol levels, and positive correlation with HDL cholesterol and Apo A-II levels (P less than 0.05). Serum paraoxonase activity had a high positive correlation with serum triglyceride levels in both sexes (P less than 0.001). Serum ApoB level had a positive correlation with the enzyme activity only in females (P less than 0.01). The allelic effect of PON on these parameters was studied by multiple regression analysis. The high activity allele (PON*B) was associated with higher serum triglyceride level (P less than 0.001) and ApoB (P less than 0.001), while it had lowering influence on total cholesterol (P less than 0.05) and LDL cholesterol (P less than 0.005) in men. The average allelic effect of PON was found to be about 22% for serum triglycerides, 11% for LDL cholesterol, 14% for Apo A-II and 19% for Apo B in the present study. This study suggests a possible significant role of serum paraoxonase alleles in the metabolism of serum lipids and apolipoproteins.  相似文献   
100.
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