全文获取类型
收费全文 | 2890篇 |
免费 | 193篇 |
国内免费 | 159篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 108篇 |
妇产科学 | 45篇 |
基础医学 | 403篇 |
口腔科学 | 28篇 |
临床医学 | 113篇 |
内科学 | 591篇 |
皮肤病学 | 55篇 |
神经病学 | 215篇 |
特种医学 | 42篇 |
外科学 | 217篇 |
综合类 | 538篇 |
预防医学 | 147篇 |
眼科学 | 48篇 |
药学 | 129篇 |
1篇 | |
中国医学 | 410篇 |
肿瘤学 | 88篇 |
出版年
2024年 | 21篇 |
2023年 | 49篇 |
2022年 | 144篇 |
2021年 | 141篇 |
2020年 | 116篇 |
2019年 | 83篇 |
2018年 | 92篇 |
2017年 | 95篇 |
2016年 | 118篇 |
2015年 | 134篇 |
2014年 | 284篇 |
2013年 | 235篇 |
2012年 | 204篇 |
2011年 | 251篇 |
2010年 | 186篇 |
2009年 | 151篇 |
2008年 | 150篇 |
2007年 | 126篇 |
2006年 | 101篇 |
2005年 | 77篇 |
2004年 | 58篇 |
2003年 | 60篇 |
2002年 | 31篇 |
2001年 | 38篇 |
2000年 | 28篇 |
1999年 | 35篇 |
1998年 | 17篇 |
1997年 | 21篇 |
1996年 | 21篇 |
1995年 | 17篇 |
1994年 | 24篇 |
1993年 | 17篇 |
1992年 | 14篇 |
1991年 | 8篇 |
1990年 | 15篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有3242条查询结果,搜索用时 15 毫秒
1.
肾综合征出血热患者T细胞亚群数量与白细胞介素2,4水平变化的关系 总被引:2,自引:0,他引:2
采用ABC免疫组化染色法及单克隆抗体夹心法ELISA,同步检测了34例肾综合征出血热(HFRS)患者外周血T细胞亚群数量和血清白细胞介素2和4(IL-2、IL-4)水平。发现HFRS病程中各T细胞亚群数量均有不同程度的升高,其中CDS阳性T细胞在各病期均有升高。IL-4水平升高仅见于发热期.而IL-2的升高主要在低血压期和少尿期。病程中有CD4/CD8比值的下降甚至倒置。这种比值的变化与IL-2和IL-4的动态变化有一定的相关性。结果揭示,在HFRS发病机理中存在Thl型和Th2型免疫反应等多种免疫病理机制。 相似文献
2.
干燥综合征是一种以口眼干燥为特征,主要累及外分泌腺的弥漫性结缔组织病。其发病可能与病毒感染、遗传和性激素异常等多种因素有关,在这些因素的共同作用下,机体免疫异常,组织损伤。与该病关系较密切的病毒有EB病毒、丙型肝炎病毒、巨细胞病毒、反转录病毒等。病毒在干燥综合征的发病机制中可能起重要的作用。 相似文献
3.
Genetic contributions to Parkinson's disease 总被引:8,自引:0,他引:8
Sporadic Parkinson's disease (PD) is a common neurodegenerative disorder, characterized by the loss of midbrain dopamine neurons and Lewy body inclusions. It is thought to result from a complex interaction between multiple predisposing genes and environmental influences, although these interactions are still poorly understood. Several causative genes have been identified in different families. Mutations in two genes [α-synuclein and nuclear receptor-related 1 (Nurr1)] cause the same pathology, and a third locus on chromosome 2 also causes this pathology. Other familial PD mutations have identified genes involved in the ubiquitin–proteasome system [parkin and ubiquitin C-terminal hydroxylase L1 (UCHL1)], although such cases do not produce Lewy bodies. These studies highlight critical cellular proteins and mechanisms for dopamine neuron survival as disrupted in Parkinson's disease. Understanding the genetic variations impacting on dopamine neurons may illuminate other molecular mechanisms involved. Additional candidate genes involved in dopamine cell survival, dopamine synthesis, metabolism and function, energy supply, oxidative stress, and cellular detoxification have been indicated by transgenic animal models and/or screened in human populations with differing results. Genetic variation in genes known to produce different patterns and types of neurodegeneration that may impact on the function of dopamine neurons are also reviewed. These studies suggest that environment and genetic background are likely to have a significant influence on susceptibility to Parkinson's disease. The identification of multiple genes predisposing to Parkinson's disease will assist in determining the cellular pathway/s leading to the neurodegeneration observed in this disease. 相似文献
4.
P. Bertram K. -H. Treutner G. Winkeltau H. -J. Booß G. Staatz Prof. Dr. V. Schumpelick 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1993,378(4):249-254
Zusammenfassung Die Pneumatosis cystoides intestinii (PCI), das Auftreten submuköser oder subseröser, gasgefüllter Zysten in der Wand des Gastrointestinaltrakts, tritt als seltene Erkrankung ohne eindeutige Geschlechtspräferenz vorwiegend in der 3. bis 5. Lebensdekade auf. Atiopathogenetisch werden unterschiedliche Faktoren diskutiert, am wahrscheinlichsten ist eine bakterielle Ursache (Clostridium perfringens) in Verbindung mit einer minimalen Unterbrechung der Mukosaintegrität. Eine pathognomonische Symptomatik gibt es nicht, das klinische Bild reicht von asymptomatischen Zufallsbefunden bis zur Hämatochezie. Die Diagnose wird durch den Nachweis der Gaseinschlüsse mittels Abdomenübersichtsaufnahme und Kolonkontrasteinlauf gestellt. Als Behandlungsmethoden für symptomatische Patienten stehen Sauerstofftherapie, Antibiotikagabe (Metronidazol) und in schweren Fällen die Resektion des betroffenen Darmabschnitts zur Verfügung.
Pneumatosis cystoides intestinalis (PCI), a condition involving submucosal or subserosal gas-containing cysts of the wall of the gastrointestinal tract, is a rare entity. It is mostly diagnosed between the third and fifth decades of life without a clear sexual predominance. Different aetiopathogenetic factors are under discussion, the most probable being a bacteriologic cause (Clostridium perfringens) in combination with minimal leaks in mucosal barrier. There are no pathognomonic symptoms; the clinical picture ranges from incidental findings to haematochezia. Diagnosis is based on plain abdominal film and X-ray following barium enema. Methods of treatment in symptomatic cases are oxygen and antibiotic (metronidazole) therapies and, in severe cases, resection of the diseased part of the intestine.相似文献
5.
实验性急性胰腺炎肺内细胞凋亡状况及其意义的初步探讨 总被引:6,自引:3,他引:3
目的:探讨重症急性胰腺炎时肺内细胞凋亡的状况及其在肺损伤发病机制中的意义。方法:以不同浓度牛磺胆酸钠液逆行胰胆管注射造成大急急性水肿性胰腺炎(AEP)与急性坏死性胰腺炎(ANP)两种模型,测定血浆TNF-α与内毒素水平的动态变化,免疫组化检测肺内TNF-α的表达,并以TUNEL法结合激光扫描共聚焦显微镜检测肺组织切片内细胞凋亡的情况。结果:正常时大鼠肺内偶见淋巴细胞及纤维母细胞等发生凋亡,诱导AEP或ANP后凋亡细胞数量无明显变化。随着肺损伤的出现,少许浸润的炎细胞、肺泡上皮细胞及血管内皮细胞等发生了凋亡。凋亡指数(‰)在ANP组呈一过性下降,在ANP组表现为持续下降,在6h后各时点均显著低于AEP组相应值(P<0.05)。分析表明,ANP组血中TNF-α、内毒素含量的增加与凋亡指数的变化存在负相关(P<0.05)。结论:ANP时肺内浸润的以中性粒细胞为代表的大量炎细胞出现延迟凋亡,这种现象可能是肺损伤发生的重要前提,同时内毒素血症及TNF-α的过度合成可能是中性粒细胞延迟凋亡的部分原因。 相似文献
6.
Douglas M. Silverstein Ira Greifer Vaughn Folkert Boyce Bennett Howard E. Corey Adrian Spitzer 《Pediatric nephrology (Berlin, Germany)》1994,8(6):752-753
We report a patient who developed Henoch-Schönlein purpura (HSP) 13 years after he presented with IgA nephropathy (IgAN). In both HSP and IgAN renal biopsy most commonly reveals focal proliferative glomerulonephritis on light microscopy and immunofluorescence displays mesangial IgA deposits. In addition, patients with HSP or IgAN have elevated serum IgA levels, circulating IgA immune complexes, IgA-bearing lymphocytes, immunoglobulin-producing cells, and binding of IgG to glomerular components of similar molecular weight. The occurrence of both diseases in the same patient or the same families and the presence of immune abnormalities compatible with HSP or IgAN in relatives of patients with these diseases suggest a common pathogenesis. 相似文献
7.
急性病毒性心肌炎的发病机制和临床特征 总被引:2,自引:0,他引:2
急性病毒性心肌炎是由病毒侵犯引起心肌本身的病变,包括病毒感染对心肌的损害、细胞免疫以及多种细胞因子等介导的心肌损害和微血管损伤。这些变化损害心脏功能和结构,而危及生命。且近年发病呈逐年上升趋势,其发病症状隐匿突然,加重了其危害性。本文就急性病毒性心肌炎发病机制和临床特征进行总结。 相似文献
8.
肖永俭 《山东中医药大学学报》1990,(1)
通过大量循经疼痛病例观察,认为循经疼痛与经循线上的损伤、大脑皮层机能、植物神经机能状态、植物神经末梢结构的特殊联系有关。提出探求循经疼痛的病因对研究牵涉痛与经络的关系、防止手术损伤经络、治疗某些顽固性疼痛有重要意义。 相似文献
9.
Relationships between Activators and Inhibitors of Plasminogen, and the Progression of Small Abdominal Aortic Aneurysms 总被引:1,自引:0,他引:1
J. S. Lindholt B. Jrgensen G. -P. Shi E. W. Henneberg 《European journal of vascular and endovascular surgery》2003,25(6):546-551
OBJECTIVE: plasmin is a common activator of the known proteolytic systems involved in the aneurysmal degradation, and is reported to be associated with the expansion of abdominal aortic aneurysms (AAA). The aim of this study was to study the activating pathways of plasminogen as predictors of the progression of AAA. MATERIALS AND METHODS: one hundred and twelve of 122 male patients with a small AAA (def.: +3cm) were interviewed, examined, had blood samples taken at diagnosis, and scanned annually for 1-5 years (mean 3.5 years), and referred for surgery if the AAA exceeded 5cm in diameter.A random sample of 70 of the 112 cases had plasma levels of urokinase-like-plasminogen activator (uPA), tissue-type-plasminogen activator (tPA), plasminogen-activator-inhibitor-1 (PAI-1), macrophage inhibiting factor (MIF), tumour-growth-factor-beta1 (TGF-beta1), homocysteine, and serum levels of IgA-antibodies against Chlamydia pneumoniae (IgA-CP) and Cotinine (a nicotine metabolite) measured. Spearmans correlation analysis was used for statistics. RESULTS: the annual expansion rate correlated positively with tPA, IgA-CP and S-Cotinine; r =0.37 (p=0.002), 0.29 (p=0.006) and 0.24 (p=0.038), while PAI1, uPA, TGF-beta1, homocysteine, and MIF did not. S-Cotinine did also correlate positively with tPA, r=0.24 (p=0.049). CONCLUSION: the aortic matrix degradation in AAA may be partly caused by an activation of plasminogen by tPA, but apparently not by uPA, which usually dominates matrix degradation. Smoking seems to be a factor for this pathway, while the pathways of IgA-CP and MIF, a new marker of aneurysmal progression, seem different. The latter observations suggest that other proteolytic pathways are involved in the aortic wall degradation in AAA. 相似文献
10.