全文获取类型
收费全文 | 50298篇 |
免费 | 4851篇 |
国内免费 | 1480篇 |
专业分类
耳鼻咽喉 | 214篇 |
儿科学 | 1765篇 |
妇产科学 | 432篇 |
基础医学 | 5986篇 |
口腔科学 | 1004篇 |
临床医学 | 5298篇 |
内科学 | 11018篇 |
皮肤病学 | 1014篇 |
神经病学 | 2565篇 |
特种医学 | 788篇 |
外国民族医学 | 6篇 |
外科学 | 3256篇 |
综合类 | 8236篇 |
现状与发展 | 5篇 |
一般理论 | 1篇 |
预防医学 | 3519篇 |
眼科学 | 663篇 |
药学 | 5708篇 |
32篇 | |
中国医学 | 3515篇 |
肿瘤学 | 1604篇 |
出版年
2024年 | 247篇 |
2023年 | 1021篇 |
2022年 | 1652篇 |
2021年 | 2392篇 |
2020年 | 2228篇 |
2019年 | 1877篇 |
2018年 | 1789篇 |
2017年 | 2028篇 |
2016年 | 2249篇 |
2015年 | 1996篇 |
2014年 | 3694篇 |
2013年 | 3977篇 |
2012年 | 3879篇 |
2011年 | 3906篇 |
2010年 | 2998篇 |
2009年 | 2802篇 |
2008年 | 2635篇 |
2007年 | 2218篇 |
2006年 | 1923篇 |
2005年 | 1700篇 |
2004年 | 1353篇 |
2003年 | 1087篇 |
2002年 | 934篇 |
2001年 | 815篇 |
2000年 | 646篇 |
1999年 | 539篇 |
1998年 | 502篇 |
1997年 | 411篇 |
1996年 | 392篇 |
1995年 | 304篇 |
1994年 | 279篇 |
1993年 | 275篇 |
1992年 | 249篇 |
1991年 | 202篇 |
1990年 | 188篇 |
1989年 | 159篇 |
1988年 | 137篇 |
1987年 | 137篇 |
1986年 | 114篇 |
1985年 | 142篇 |
1984年 | 108篇 |
1983年 | 76篇 |
1982年 | 76篇 |
1981年 | 59篇 |
1980年 | 50篇 |
1979年 | 41篇 |
1978年 | 36篇 |
1977年 | 32篇 |
1976年 | 30篇 |
1974年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
本文用胶固素酶联免疫吸附试验检测了16例缺血性脑血管病(ICD)患者,14例出血性脑血管病(HCD)患者和20例健康正常人的血清IgE型循环免疫复合物(CID)水平。结果显示ICD组和HCD组IgE-CIC水平明显高于正常组(分别为P<0.001和P<0.05)。ICD组与HCD组间没有显著差异(P>0.02)。提示脑血管病的发生与IgE-CIC的形成有关。 相似文献
72.
J. M. Greally L. Y. Boone S. G. Lenkey S. L. Wenger M. W. Steele 《American journal of medical genetics. Part A》1992,44(3):334-339
A child with manifestations of acrogeria and metageria, two “premature aging” syndromes, is presented. Because of his indistinct phenotype and because the question has been previously raised as to whether these conditions are separate, we propose the designation of acrometageria to describe this phenotypic continuum. As there is much in common clinically between acrometageria and the syndrome of type III procollagen deficiency (Ehlers-Danlos type IV), it might be presumed that a similar pathogenesis for acrometageria exists. This possibility has been tested previously, without demonstrating specific quantitative or qualitative deficits, but with some indirect evidence that collagen metabolism is deranged in these patients. One such crude indicator is the elevation of urinary hyaluronic acid levels, demonstrated in our patient and also observed in the phenotypically distinct Werner and Hutchinson-Gilford premature aging syndromes. On one hand, it could be argued that this supports the concept that premature aging syndromes exist as a biological continuum. On the other hand, it is equally valid to argue that syndromes of premature aging are so described merely because they include recognizable changes of normal aging and that the demonstration of an underlying mutation in a collagen gene, for example, invalidates their study as models of accelerated normal aging. © Wiley-Liss, Inc. 相似文献
73.
本文动用自制t-PA单克隆抗体建立t-PA:Aa夹心ELISA法。结合t-PA:A、PAI:A测定,对50例正常人,87例肝病,47例冠心病和19例深静脉血栓 成患者的血浆t-PA:Ag、t-PA:A、PAI:A水平进行了研究。 相似文献
74.
Induction of type II collagen-specific antibody production in blood lymphocyte cultures of rhesus monkeys (Macaca mulatta) with collagen-induced arthritis using the immobilized native antigen.
下载免费PDF全文
![点击此处可从《Clinical and experimental immunology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Peripheral blood mononuclear cells (PBMC) from Rhesus monkeys previously immunized with bovine type II collagen to induce arthritis were cultured with the same antigen. Because the native protein is poorly soluble in culture medium a heating step is often used. The antigen in this form induced PBMC proliferation, but epitopes for the induction of antibody production and arthritis were lost. To keep the native protein intact it was coated on affigel beads. With the immobilized antigen specific antibody production could be induced. 相似文献
75.
Summary This study describes reduced motor nerve conduction velocity and increased resistance to hypoxia-induced conduction failure in sciatic nerves of rats after four weeks of streptozotocin-induced diabetes (both effects were significant at p <0.05). These changes occurred in the absence of any deficit in the steady-state ouabain-sensitive adenosine triphosphatase (ATPase) activity of sciatic nerve endoneurial homogenates. The addition of 10 nmol/l insulin to endoneurial homogenates from control animals resulted in a 34% increase in ouabain-sensitive ATPase activity and a 19% reduction in ouabain-insensitive ATPase activity (both p <0.01). This stimulation of ouabain-sensitive ATPase activity by insulin did not occur in homogenates from diabetic rats. Treating diabetic rats daily with the aldose reductase inhibitor, imirestat (1 mg/kg) improved nerve conduction velocity (p <0.05) but was without effect upon the resistance to hypoxic conduction blockade or the deficit in insulin-stimulated oubain-sensitive ATPase activity. These data suggest that in streptozotocin-diabetic rats the functional disorders of reduced motor nerve conduction velocity and increased resistance to hypoxic conduction blockade do not share a common aetiology and that impaired nerve conduction is not related to reduced maximal potential oubain-sensitive ATPase activity. 相似文献
76.
小檗碱对大鼠阴茎海绵体磷酸二酯酶5mRNA水平的影响 总被引:3,自引:0,他引:3
目的 :检测大鼠阴茎海绵体中磷酸二酯酶 5 (PDE5 )mRNA的表达 ,进而探讨小檗碱 (berberine ,Ber)的分子作用机制。 方法 :通过逆转录酶链反应 (RT PCR)技术检测大鼠阴茎海绵体中PDE5mRNA的表达。 结果 :大鼠阴茎海绵体中有PDE5A1和PDE5A2mRNA的表达 ,以PDE5A2为主要的异构酶。与内参照 β 肌动蛋白相比 ,对照组、Ber孵育 1和 3h组的PDE5A1及PDE5A2基因mRNA的相对表达量分别为 :0 .2 2± 0 .0 2 ,0 .4 1± 0 .0 1 ;0 .1 5± 0 .0 1 ,0 .34± 0 .0 2 ;0 .1 0± 0 .0 1 ,0 .1 2± 0 .0 1。与对照组相比 ,PDE5A1、PDE5A2的mRNA表达 ,在Ber孵育 1h组降低了 32 %和 1 7%,3h组降低了 5 5 %和 71 %,其中尤以应用Ber 3h后PDE5A2的mRNA减少最为明显 (n =5 ,P <0 .0 1 )。 结论 :Ber对NO cGMP信号通路的下游关键酶 (PDE5 )具有一定的调控作用 ,尤其是抑制PDE5A2的mRNA表达 ,为Ber治疗勃起功能障碍的分子机制之一。 相似文献
77.
Manolo Piccirilli Jacopo Lenzi Catia Delfinis Guido Trasimeni Maurizio Salvati Antonino Raco 《Child's nervous system》2006,22(10):1332-1337
Case reports The authors report their experience about three children (two girls, one boy; average age 1.6 years) with a spontaneous regression of optic gliomas. All of them had a previous diagnosis of neurofibromatosis type 1 (NF 1). None of them underwent surgery or biopsy nor received chemotherapy or radiotherapy. The complete regression was documented by MRI scans performed during a mean follow-up of 6.3 years.Literature review Moreover, the authors analyze the features of the 16 cases previously reported in English literature of spontaneously regressed optic gliomas with an overview of the different therapeutic strategies. The knowledge that this kind of tumor, particularly in young patients, may regress is important in the decision of the best therapeutic approach. 相似文献
78.
Jasper E Visser Bastiaan R Bloem Bart P C van de Warrenburg 《Movement disorders》2007,22(7):1024-1026
Progressive myoclonic ataxia, also referred to as Ramsay Hunt syndrome, is characterized by a combination of myoclonus and cerebellar ataxia, infrequently accompanied by tonic-clonic seizures. Its differential diagnosis overlaps with progressive myoclonic epilepsy, a syndrome with myoclonus, tonic-clonic seizures, progressive ataxia and dementia. In patients with progressive myoclonic epilepsy, specific diseases can frequently be recognized, but the diagnostic yield in progressive myoclonic ataxia is much lower. We describe a patient who presented with multifocal myoclonus in his thirties and who later developed cerebellar ataxia and focal dystonia. His father was similarly affected. Genetic studies revealed a mutation in the protein kinase C gamma (PRKCG) gene, known to cause spinocerebellar ataxia type 14 (SCA-14). This case illustrates that both myoclonus and dystonia are part of the clinical spectrum in SCA-14 and that myoclonus can even be the presenting symptom. We suggest that SCA-14 should be considered in the differential diagnosis of progressive myoclonic ataxia. 相似文献
79.
移植肾组织TGF-β1和MMP-2表达及IV型胶原沉积与慢性移植肾肾病的关系 总被引:1,自引:0,他引:1
目的 探讨移植肾组织中转化生长因子β1(TGF-β1)和基质金属蛋白酶2(MMP-2)的表达及IV型胶原沉积与慢性移植肾肾病(CAN)的关系.方法 对18例CAN患者进行了移植肾切除术.光镜下观察切除的肾组织标本并根据其纤维化的程度进行分期,用免疫组织化学技术和图像分析法检测移植肾组织中TGF-β1和MMP-2表达量及IV型胶原沉积情况,并分析患者血肌酐(Cr)和尿素氮(BUN)的水平与移植肾纤维化程度的关系.结果 随着患者移植肾纤维化程度的加重,血清肌酐、尿素氮及肾组织中TGF-β1、IV型胶原基因表达量均增加,MMP-2表达量于移植肾纤维化早期明显升高,并随移植肾纤维化程度加重而逐渐降低.结论 移植肾组织中TGF-β1表达量增高及IV型胶原沉积可以促进CAN的进程,而MMP-2则可抑制其进展. 相似文献
80.
高奉浔 《中国人民解放军军医大学学报》1989,(1)
Eight cases of mesenchymal chondrosarcoma either of skeletal(5 cases) or extrasketetalorigin (3 cases) are reported. According to histopathological and diagnostic criteria,mesenchymal chondrosarcoma were classified into two types cartilage isiand cell type andundifierentiated small cell type It is believed that the application of this classification in the study ofmesenchymal chondrosarcoma is helptul the estimation of its malignancy and choice of treatmentas well al in the prediction of its prognosis. Mesenchymal chondrosarcoma is a highly malignant neoplasm with poor prognosis. None ofthe patients in this series survived more than five years after they were diagnosed. The diffentialdiagnosis of malignant lymphoma, chondrosarcoma, hemangiopericytosarcoma, etc. was discussed.My data support the assumption that mesenchymal chondrosarcoma originates from the secondarymesenchyme rather than the primary mesenchyme. 相似文献