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   5187篇
  免费   249篇
  国内免费   130篇
耳鼻咽喉   23篇
儿科学   119篇
妇产科学   59篇
基础医学   727篇
口腔科学   168篇
临床医学   410篇
内科学   995篇
皮肤病学   242篇
神经病学   584篇
特种医学   104篇
外国民族医学   1篇
外科学   410篇
综合类   629篇
预防医学   199篇
眼科学   86篇
药学   392篇
中国医学   86篇
肿瘤学   332篇
  2023年   45篇
  2022年   64篇
  2021年   119篇
  2020年   125篇
  2019年   255篇
  2018年   229篇
  2017年   171篇
  2016年   137篇
  2015年   164篇
  2014年   316篇
  2013年   308篇
  2012年   265篇
  2011年   293篇
  2010年   244篇
  2009年   300篇
  2008年   296篇
  2007年   353篇
  2006年   191篇
  2005年   203篇
  2004年   163篇
  2003年   109篇
  2002年   82篇
  2001年   84篇
  2000年   65篇
  1999年   90篇
  1998年   48篇
  1997年   46篇
  1996年   41篇
  1995年   39篇
  1994年   41篇
  1993年   31篇
  1992年   33篇
  1991年   37篇
  1990年   23篇
  1989年   21篇
  1988年   27篇
  1987年   22篇
  1986年   23篇
  1985年   59篇
  1984年   49篇
  1983年   25篇
  1982年   40篇
  1981年   29篇
  1980年   33篇
  1979年   33篇
  1978年   32篇
  1977年   30篇
  1976年   47篇
  1975年   38篇
  1973年   22篇
排序方式: 共有5566条查询结果,搜索用时 15 毫秒
51.
Summary The present study concerns the immunocytochemical localization of S-100 protein and subunits in the cells of human lymphoreticular tissue and their related tumours. The subunit is mainly localized in dendritic cells, most likely the dendritic reticulum cells (DRCs) located within the germinal centers, while the subunit is mainly localized in the interdigitating reticulum cells (IRCs) in the paracortical area and in Histiocytosis X cells. No immunoreactivity for either subunit was found in the majority of normal lymphocytes, macrophages, malignant lymphoma cells, or xanthoma cells.The DRCs and IRCs are generally considered to show different distribution in the lymphoid tissues and demonstrate some difference in their immunocytochemical and enzyme-histochemical features. It is suggested that S-100 subunits can be used as useful markers for these two types of dendritic cells and investigation of these subunits may provide more information for the study of human lymphoreticular system.  相似文献   
52.
Summary Presence and distribution of S-100 protein (S-100), neuron-specific enolase (NSE), cytokeratin polypeptides, glial fibrillary acidic protein (GFAP), vimentin, actin, lysozyme and pituitary hormones (prolactin, hGH, ACTH, -FSH, -LH, -TSH, alpha subunit) in folliculo-stellate cells (FSC) were studied in seven normal human pituitary glands and 28 pituitary adenomas using peroxidase-antiperoxidase and the avidin-biotin immunohistochemical techniques. Approximately 5% of the cells of the adenohypophysis were agranular, non-hormon-producing FSC most of which showed a conspicuous and strong reaction with S-100 antibodies but some were, in addition, GFAP- and vimentin-positive. In contrast to endocrine cells (EC), FSC were not decorated by antibodies to NSE or cytokeratins. In addition to supportive functions, these cells, due to their close special relationship to EC, seem to have transport and other metabolic functions yet to be elucidated. By their S-100 reactivity and their distribution FSC are comparable to glial cells of the central and schwann and satellite cells of the peripheral nervous system (PNS) as well as to supportive cells in neuroendocrine organs and related tumors (e.g., pheochromocytomas, paragangliomas, carcinoids). With one exception, S-100 reactive FSC were not found in pituitary adenomas. The immunohistochemical demonstration of S-100 protein in pituitary tissue is, therefore, a reliable aid in the discrimination between adenomas and normal pituitary tissue, particularly in small and poorly preserved specimens. In one adenoma FSC were found in addition to ACTH-producing tumor cells. This seems to be an extremely rare event suggesting a combination tumor.Supported in part by Fonds zur Förderung der wissenschaftlichen Forschung (no. 4708) to H. Denk  相似文献   
53.
【目的】 分析国际顶级综合类科技期刊公众传播模式及特点,为我国科技期刊公众传播能力建设提供建议。【方法】 以Altmetric Top 100入选论文数量最多的NatureScience和PNAS三刊为研究对象,剖析其在公众传播产品、媒体传播体系和新闻媒体人才支撑等方面的模式和特征。对照分析我国最有影响力的综合类科技期刊《国家科学评论》和《科学通报》的公众传播特点。【结果】 以《国家科学评论》和《科学通报》为代表的我国综合类科技期刊的公众传播能力提升迅速,但仍存在新闻传媒人才短缺、期刊集约化程度不高、公众传播机制尚未建立等问题。【结论】 我国综合类科技期刊需要着力增强传媒人才培育、集约化品牌发展、公众传播机制建设,以促进我国科技期刊公众传播能力提升。  相似文献   
54.
目的探讨联合检测神经元特异性烯醇化酶(NSE)、 S100B、超敏C-反应蛋白(hs-CRP)及美国国立卫生研究院卒中量表(NIHSS)评分对急性脑梗死患者病情严重程度的评估价值。方法选取我院2019年1月至2020年3月收治的急性脑梗死患者80例,依据改良Rankin量表(mRS)评分将其分为重度组(mRS评分≥3分,n=36)及轻度组(mRS评分<3分,n=44);另选取同期在我院行健康体检的40例患者作为健康组。比较三组的NSE、 S100B、 hs-CRP及NIHSS评分。结果重度组的NSE、 S100B、 hs-CRP、 NIHSS评分均高于轻度组及健康组(P <0.05);Pearson分析显示,NSE、 S100B、 hs-CRP及NIHSS评分与急性脑梗死病情严重程度呈正相关(r>0, P <0.05)。结论 NSE、 S100B、 hs-CRP及NIHSS评分与急性脑梗死患者病情严重程度呈正相关,联合检测具有客观性。  相似文献   
55.
目的 评价缺氧缺血性脑病(HIE)新生儿脑脊液(CSF)和血浆中神经元特异性稀醇化酶(NSE)、S-100蛋白(S-100protein,S-100)、髓鞘碱性蛋白(MBP)、肌酸磷酸激酶脑型同工酶(CK-BB)等党课 经系统特异性蛋白质与新生儿HIE程度及预后的关系。方法 新生儿HIE患儿55例,无中枢神经系统疾患的患儿16例作为对照,取CSF和血浆检测上述4种神经系统特异性蛋白质水平。NSE、S-100、MBP用放射免疫试剂盒检测,CK-BB用酶法及琼脂糖电泳法检测,存活出院的患儿定期随访。结果 CSF的NSE、S-100、MBP、CK-BB及血浆NSE、CK-BB均与HIE程度相关,但只有CSF的神经系统特异性蛋白质才能较准确地反映患儿的远期预后,其中敏感性、特异性最高的指标是NSE和S-100。结论 CSF的NSE和S-100是判断HIE患儿脑损伤程度、预测远期预后的可靠指标。  相似文献   
56.
《Neuro-Chirurgie》2021,67(3):249-254
BackgroundMild traumatic brain injury (mTBI) is one of the most common causes of emergency department visits around the world. Up to 90% of injuries are classified as mTBI. Cranial computed tomography (CCT) is a standard diagnosis tool to identify intracranial complications in adults with mTBI. Alternatively, children can be admitted for inpatient observation with CCT scans performed only on those with clinical deterioration. The use of blood biomarkers is a supplementary tool for identifying patients at risk of intracerebral lesions who may need imaging.MethodWe realised a bibliographic state of art providing a contemporary clinical and laboratory framework for blood biomarker testing in mTBI management.ResultsThe S100B protein is the only biomarker that can be used today in the clinical routine for management of mTBI with appropriate evidence-based medicine. Due to its excellent negative predictive value, S100B protein is an alternative choice to CCT scanning for mTBI management with considered, consensual and pragmatic use. In this state of art, we propose points to help clinicians and clinical pathologists use serum S100B protein in the clinical routine. A state of art on the different biomarkers (GFAP, UCH-L1, NF [H or L], tau, H-FABP, SNTF, NSE, miRNAs, MBP) is also conducted. Some of these other biomarkers, used alone (GFAP, UCH-L1) or in combination (GFAP + H-FABP ± S100B ± IL10) can improve the specificity of S100B.ConclusionUsing a bibliographic state of art, we highlighted the added values of the blood biomarkers for the clinical management of mTBI.  相似文献   
57.
Summary The immunohistochemical distribution of S-100 protein in patients with Down's syndrome was investigated as part of a study aimed at ascertaining a possible involvement in the syndrome (trisomy 21) of this protein, which has recently been shown to be coded in chromosome 21. No appreciable differences in the cell distribution of the antigen could be observed between patients with Down's syndrome and normal subjects. The possibility of an overexpression or abnormal expression of the molecule as a consequence of chromosome 21 triplication, not detectable by immunocytochemical methods alone, remains to be investigated.Supported in part by grants from Consiglio Nazionale delle Ricerche and Ministero della Pubblica Istruzione to F. M. and L. L.  相似文献   
58.
目的:了解髓母细胞瘤发生、分化及其病理生物学行为,方法:46 例手术切除髓母细胞瘤组织用免疫组织化学方法对胶质酸性蛋白( G F A P)、中间丝结蛋白(vim entin)、神经纤维( N F)、增殖细胞核抗原( P C N A)、抑癌基因p53 及 S100 蛋白进行检测。结果: G F A P、vim entin、 P C N A、 S100 蛋白阳性率分别为 71.11% 、43.44% 、92.00% 、52.17% ,阳性指数分别为46.25‰、17.00‰、875.40‰、8.42‰。 N F表达极弱,而p53 几乎不表达。结论:髓母细胞瘤的发生可能与 p53 抑癌基因突变无明显相关;髓母细胞瘤的多数肿瘤细胞向胶质细胞方向分化;髓母细胞生长迅速以及其高度恶性与 P C N A 检测超常表达相一致。  相似文献   
59.
Summary In order to study the cellular origin of muscularization in non-muscular arterioles of the lung, the pulmonary vascular pericytes-culture was established. The terminal lung tissue of the rat was taken out and minced. Then 0.5 % of type IV collagenase solution was added for digestion and the microvascular segments were obtained by screening. The targeted cells were cultured by “selective conditioned media”. Under phase-contrast microscope, the cultured cells were large in size with ragged margin and numerous pseudopodia, which imparted tubule-like structure. There was no contact inhibition in growing cells, so multiple layers developed. When they were confluent, there were morphologically no “hillock and dale” growth pattern as in smooth muscle cells or “weave-like” pattern as in fibroblasts. The ultrastructure of cultured cells showed numerous digital processes, moderate amount of rough and smooth endoplasmic reticulum, rich Golgi’s apparatus, microfilaments, few lysosomes without myofilaments and dense bodies. Immunohistochemical staining revealed that the cultured pericytes had same kind of cellular skeletal protein, α-SM-actin, like smooth muscle cells. The cultured cells also exhibited positive reaction to CD34 antigen and S-100 antigen, which were negative in smooth muscle cells and fibroblasts. The cell growth pattern, ultrastructure and immunological phenotype suggested that the cultured cells had characteristics of vascular pericytes. Pericytes are one of the components of microvascular cells, and the establishment ofin vitro culture technique of pericytes is of significance for further exploration of the muscularization of non-muscular arterioles in lung and the mechanism of structural remodeling of pulmonary vessels. This project was supported by the grant of National Nature Sciences Foundation of China (No. 39570289).  相似文献   
60.
视力客观检测方法的研究   总被引:4,自引:0,他引:4  
目的研究用视觉诱发电位(visualevokedpotential,VEP)作为视力客观检测的可行性。方法对40只视力不等的患眼和50只正常眼,分别记录用不同大小方格(8°、4°、2°、1°、30、15和6)刺激时的VEP波形。结果患眼组和正常组P100振幅及潜时在统计学上有显著性差异。视力与能诱发出波形的最小方格间有明显关系:最小方格为6、15、30和1°,平均视力分别为1.13,0.62,0.18和0.07。视力与P100振幅呈正相关,与潜时呈负相关。结论用诱发出VEP波形的最小方格大小可估计患者的视力范围  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