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   5399篇
  免费   324篇
  国内免费   80篇
耳鼻咽喉   28篇
儿科学   261篇
妇产科学   54篇
基础医学   995篇
口腔科学   159篇
临床医学   621篇
内科学   657篇
皮肤病学   40篇
神经病学   396篇
特种医学   121篇
外科学   402篇
综合类   497篇
现状与发展   1篇
预防医学   507篇
眼科学   51篇
药学   331篇
  3篇
中国医学   635篇
肿瘤学   44篇
  2023年   74篇
  2022年   113篇
  2021年   242篇
  2020年   192篇
  2019年   145篇
  2018年   136篇
  2017年   219篇
  2016年   206篇
  2015年   189篇
  2014年   347篇
  2013年   334篇
  2012年   278篇
  2011年   330篇
  2010年   275篇
  2009年   229篇
  2008年   239篇
  2007年   206篇
  2006年   152篇
  2005年   172篇
  2004年   126篇
  2003年   136篇
  2002年   138篇
  2001年   101篇
  2000年   81篇
  1999年   70篇
  1998年   70篇
  1997年   78篇
  1996年   67篇
  1995年   59篇
  1994年   74篇
  1993年   53篇
  1992年   62篇
  1991年   39篇
  1990年   41篇
  1989年   32篇
  1988年   41篇
  1987年   34篇
  1986年   41篇
  1985年   44篇
  1984年   52篇
  1983年   28篇
  1982年   35篇
  1981年   36篇
  1980年   35篇
  1979年   21篇
  1978年   26篇
  1977年   20篇
  1976年   13篇
  1974年   12篇
  1973年   10篇
排序方式: 共有5803条查询结果,搜索用时 15 毫秒
71.
目的:研究外源笥三磷酸腺苷(adenosine triphosphate,ATP)是否能够进入低温保存大鼠肝脏细胞内。方法:采用大鼠肝脏持续低温机器灌流保存模型,利用放射自显影技术判定[α-^32P]ATP是否进入细胞内。结果:灌流液中不加[α-^32P]ATP的A组光镜照片显示大鼠肝细胞内外均未见特异性标记银粒显影,而灌流液中含37MBq[α-^32P]ATP的B组光镜照片显示大鼠肝细胞内可见多个大小不等的[α-^32P]ATP自显影银粒分布,而肝窦及肝小叶中央静脉等血管内则几乎无黑色自显银粒分布。结论:外源性ATP能够进入低温保存大鼠肝细胞内。  相似文献   
72.
提出“位、时、象”三法,从空间、时间和形态3个角度认识六经,并根据六经病之特点结合临床应用之体会,分析病证的“连续性与间断性”“六经病的单一性与复杂性”“症状的显性与隐性”“因果关系”“脉证关系”“伤寒与杂病的关系”,以期为临床应用经方治疗疾病提供思路。  相似文献   
73.
经桡动脉行冠状动脉造影(CAG)术后使用弹力绷带进行加压止血,患者手腕经常出现肿胀、疼痛、麻木等症状,而使用上肢垫抬高肢体有利于促进静脉回流,减轻症状,但是,临床以往使用的上肢垫存在种种弊端,无法满足使用需求。该研究设计了一种多功能充气式介入术后上肢垫,用于经桡动脉行CAG术后抬高、制动、冷敷术肢,可以缓解术肢肿胀、疼痛,减少皮下出血,提高患者的舒适度。  相似文献   
74.
Rapid rise in plasma glucagon induced by acute cold exposure in man and rat   总被引:1,自引:0,他引:1  
The effect of acute cold exposure on the concentration of glucagon in the blood was investigated in man and in intact and adrenalectomized rats.In man fasted overnight acute cold exposure, which caused a twofold increase in O2-consumption resulted in a rapid rise in plasma glucagon. The levels of insulin and blood glucose remained unaltered, while the concentration of serum free fatty acids and -hydroxybutyrate increased.In fasted intact rats acute cold exposure lead to similar effects. A close parallelism between the rise in plasma glucagon and the concentration of hepatic cycloAMP was observed. Adrenalectomy did not impair the cold induced rise in plasma glucagon and hepatic cycloAMP.It is concluded that acute cold exposure caused a rapid rise in the concentration of plasma glucagon leading to an increase in the concentration of hepatic cycloAMP, thus enhancing the rate of hepatic gluconeogenesis and ketogenesis. As these alterations were similar in the absence of glucocorticoids and medulla-derived catecholamines, it is suggested that glucagon may play a role in the metabolic adaptation to acute cold exposure.  相似文献   
75.
Summary The effects of changes in oxygen supply and oxygen demands on fiber cross-sectional areas, capillary dersities and capillary to fiber ratios were determined in three skeletal muscles of rat. The muscles examined were the vastus lateralis, soleus, and diaphragm. Reduced oxygen supply was produced by subjecting rats to ambient hypoxia, and increased oxygen demands were produced by subjecting rats to low ambient temperatures or treatment with thyroxin. Capillaries were visualized by injecting fluorescent dyes into the circulation. Muscles were quick frozen at resting lengths to preserve normal fiber geometry and were subsequently sectioned on a cryostat. All of the muscles sampled from animals in the experimental groups had elevated capillary densities. However, capillary to fiber ratios were not increased significantly in any muscle, for any experimental condition. Thus, all of the observed differences in capillarity were due to changes in the intrinsic rate of muscle fiber growth. Further, the relations of capillary density and capillary to fiber ratio to fiber area were the same as those obtained during normal maturation, suggesting that capillary growth is closely linked to the intrinsic rate of fiber growth.  相似文献   
76.
Blood storage and blood transfusion have beenimportantclinical work.In recentyears,the demandfor the quality of blood transfusion is getting higher.Great progress has been made in blood storage tech-nique and more and more reports on change in bloodcomponents during storage have been published.However,reports on dynamic changes in blood com-ponentsin bank- stored blood are stillrare.The paperinvestigated the dynamic change of blood componentsF :c and AT- in blood stored in blood bank un-der…  相似文献   
77.
伤寒史学研究成果简述   总被引:1,自引:0,他引:1  
建国以来有关伤寒史学的研究成果表现在相关人物、相关著作、相关事件、学术关系及阶段特征五个方面。前期研究成果 ,尚不足以充分展示伤寒学历史地位和现实意义 ,更无充分依据昭示其未来之发展方向 ,因而有必要继续深入开展伤寒史学研究  相似文献   
78.
We found two patterns of leptomeningeal storage that reflect two basic visceral storage patterns in Fabry disease. (i) A generalized-type leptomeningeal storage pattern, affecting all main leptomeningeal cell types (external arachnoideal epithelium, fibroblasts, vessel wall elements), was a consistent finding in three cases of classical generalized visceral phenotype. (ii) A localized leptomeningeal storage pattern was expressed, to a high degree, solely in the external arachnoidal epithelium; this pattern was found in one case with the variant visceral-restricted-type storage (confined to the cardiocytes). Thus, the external arachnoidal epithelium may be particurlarly susceptible to Fabry lipid storage, probably caused by a distinctly larger sustained lysosomal lipid load as compared to other cell types.  相似文献   
79.
The relationship between physical stability of freeze-dried cakes and protein stability during storage was studied using -galactosidase as a model protein and inositol as an excipient. Amorphous samples freeze-dried from solutions containing the enzyme and various concentrations of inositol in sodium phosphate buffer (50 mM, pH 7.4) were stored for 7 days over P2O5 at 40 to 70°C. Structural collapse and inositol crystallization were observed in some of the samples, depending on the formulation and storage temperature. The physical stability of freeze-dried samples was also studied by differential scanning calorimeter (DSC). Inositol showed a protein-stabilizing effect when its amorphous form was retained during storage, regardless of structural collapse. However, crystallization of inositol during storage removed its stabilizing effect. Addition of water-soluble polymers such as dextran, Ficoll and carboxymethyl cellulose sodium salt (CMC-Na) preserved activity of the enzyme by preventing inositol crystallization.  相似文献   
80.
Mucolipidoses II is a rare lysosomal storage disorder with autosomal recessive inheritance. There cases with typical clinical features in early infancy like coarse facial features, severe psychomotor retardation and joint contractures are being reported. All the cases had no mucopolysacchariduria. These cases had normal values of lysosomal enzymes in leucocytes but markedly increased values in serum thus confirming mucolipidoses II. Despite the fact that there is no specific treatment, genetic counselling and prenatal diagnosis is indicated.  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