全文获取类型
收费全文 | 2866篇 |
免费 | 184篇 |
国内免费 | 65篇 |
专业分类
耳鼻咽喉 | 97篇 |
儿科学 | 77篇 |
妇产科学 | 30篇 |
基础医学 | 527篇 |
口腔科学 | 40篇 |
临床医学 | 218篇 |
内科学 | 276篇 |
皮肤病学 | 23篇 |
神经病学 | 805篇 |
特种医学 | 163篇 |
外科学 | 182篇 |
综合类 | 251篇 |
预防医学 | 86篇 |
眼科学 | 157篇 |
药学 | 102篇 |
1篇 | |
中国医学 | 20篇 |
肿瘤学 | 60篇 |
出版年
2023年 | 25篇 |
2022年 | 44篇 |
2021年 | 64篇 |
2020年 | 94篇 |
2019年 | 64篇 |
2018年 | 75篇 |
2017年 | 71篇 |
2016年 | 67篇 |
2015年 | 81篇 |
2014年 | 126篇 |
2013年 | 156篇 |
2012年 | 145篇 |
2011年 | 137篇 |
2010年 | 114篇 |
2009年 | 146篇 |
2008年 | 140篇 |
2007年 | 150篇 |
2006年 | 124篇 |
2005年 | 96篇 |
2004年 | 102篇 |
2003年 | 93篇 |
2002年 | 68篇 |
2001年 | 61篇 |
2000年 | 65篇 |
1999年 | 36篇 |
1998年 | 57篇 |
1997年 | 52篇 |
1996年 | 46篇 |
1995年 | 36篇 |
1994年 | 35篇 |
1993年 | 35篇 |
1992年 | 43篇 |
1991年 | 41篇 |
1990年 | 36篇 |
1989年 | 32篇 |
1988年 | 25篇 |
1987年 | 36篇 |
1986年 | 26篇 |
1985年 | 34篇 |
1984年 | 31篇 |
1983年 | 19篇 |
1982年 | 30篇 |
1981年 | 28篇 |
1980年 | 32篇 |
1979年 | 16篇 |
1978年 | 23篇 |
1977年 | 14篇 |
1976年 | 11篇 |
1975年 | 7篇 |
1973年 | 8篇 |
排序方式: 共有3115条查询结果,搜索用时 203 毫秒
991.
本文使用5.25%次氯酸钠消化肺组织,浓集石棉纤维和石棉小体,在相差显微镜下计数。改进了常用的方法,使肺内的焦油、碳尘等与被测物分离完全。方法的精密度CV%=6.7~10.0%,回收率90%。 相似文献
992.
Summary Psammoma bodies at the perivascular area in five cases of meningioma were examined with the electron microscope. In general, meningocytic cells invest the outer aspect of blood vessels, which are constituted by multilayered basal laminae, collagen fibers, microfibrils, and pericytes. Remnants of degenerated cells are observed in some areas of the perivascular space. Matrix vesicles and matrix giant bodies with or without mineralized deposits are also present in those areas. Energy disperisve, X-ray microanalysis evidenced the presence of both calcium and phosphorus (probably hydroxyapatite) mineralized precipitates. Production of psammoma bodies in the perivascular area may indicate that matrix vesicles and matrix giant bodies are derived from degenerated cells, which then sequestrate hydroxyapatite crystals to form psammoma bodies. 相似文献
993.
J. O. Rinne 《Acta neurologica Scandinavica》1991,84(S136):87-90
Neuronal loss in the substantia nigra (SN) in Parkinson's disease (PD) shows a topographical organisation where the lateral part of the SN is more affected. This is - due to projection of the lateral SN mainly to the putamen - reflected in more complete loss of dopamine content in the putamen than in the caudate nucleus. Of the parkinsonian symptoms rigidity and hypokinesia are associated with neuronal loss in the lateral substantia nigra and the resulting dopamine loss in the putamen. Neuronal mechanisms other than degeneration of the nigrostriatal system seem to be involved in the pathophysiology of tremor.
Cognitive impairment and dementia in PD is related to dysfunction of the cortical cholinergic system, especially in the frontal cortex. The brain dopaminergic system, however, contributes as a subcortical component to cognitive impairment in PD.
Clinical studies have shown that selegiline may slow down the progression of PD. We studied postmortem samples of patients treated with selegiline and levodopa and those with levodopa alone. The number of medial nigral neurons was significantly higher in the selegiline group.
Treatment with selegiline might retard the death of nigral neurons, but further studies are needed to confirm the preliminary findings. 相似文献
Cognitive impairment and dementia in PD is related to dysfunction of the cortical cholinergic system, especially in the frontal cortex. The brain dopaminergic system, however, contributes as a subcortical component to cognitive impairment in PD.
Clinical studies have shown that selegiline may slow down the progression of PD. We studied postmortem samples of patients treated with selegiline and levodopa and those with levodopa alone. The number of medial nigral neurons was significantly higher in the selegiline group.
Treatment with selegiline might retard the death of nigral neurons, but further studies are needed to confirm the preliminary findings. 相似文献
994.
海洛因海绵状白质脑病的脑脊液和血清髓鞘碱性蛋白及其抗体检测及意义 总被引:5,自引:0,他引:5
目的 通过对海洛因海绵状白质脑病 (HeroinSpongiformLeukoencephalopathy ,HSLE)患者血清和脑脊液髓鞘碱性蛋白 (myelinbasicprotein ,MBP)及其抗体 (Anti MBP)检测 ,探讨MBP与HSLE的关系。方法 采用酶联免疫吸附法 (ELISA)检测 1 8例HSLE患者、2 3例Heroin成瘾者 (吸毒但无HSLE临床症状者 ) ,1 7例多发性硬化患者(MS组 )、对照组 2 0例 (NC组 )的血清以及脑脊液 (CSF)中MBP及Anti MBP水平。结果 HSLE组、MS组CSF和血清MBP均值明显高于NC组和Heroin成瘾组 (P <0 .0 5) ,HSLE组与MS组CSF、血清MBP均值无统计学差异 (P >0 .0 5) ,Heroin成瘾组血清和CSFMBP均值与NC组间无统计学差异 (P >0 .0 5) ,4组血清和CSF的Anti MBP含量差异不显著 (P >0 .0 5)。结论 HSLE患者CSF及血清中MBP含量增高 ,MBP上升水平与髓鞘损伤程度有关 ,该病的髓鞘存在病理性损害 ,以及血脑屏障 (blood brainbarrier,BBB)的通透性改变。MBP检测可作为HSLE诊断及与海洛因成瘾者鉴别诊断的重要参数 ,它在HSLE病理过程中的作用机制有待进一步研究 相似文献
995.
Extrapyramidal features in Parkinson's disease with and without dementia and dementia with Lewy bodies: A cross-sectional comparative study. 总被引:1,自引:0,他引:1
David J Burn Elise N Rowan Thais Minett Jonathon Sanders Pat Myint Jonathon Richardson Alan Thomas Jane Newby Jenny Reid John T O'Brien Ian G McKeith 《Movement disorders》2003,18(8):884-889
Risk factors predicting an increased risk of dementia in Parkinson's disease (PD) are not fully established. The dementia associated with PD (PDD) closely resembles dementia with Lewy bodies (DLB). Based upon a high frequency of non-dopaminergic mediated clinical features in DLB, we predicted that a motor subtype comprising postural instability and balance problems would be more common in PDD. We examined extrapyramidal, cognitive, and affective features in 38 PD, 43 PDD, and 26 DLB patients in a cross-sectional study design. Motor subtype was subdivided into postural-instability gait difficulty (PIGD) or tremor (TD) dominant. The PIGD-subtype was more common in PDD (88% of cases) and DLB (69% of cases) groups compared with the PD group (38% of cases), in which TD and PIGD sub-types were more equally represented (P < 0.001). Although the mean depression scores overall were modest, PDD patients scored significantly higher than PD, but not DLB patients (Cornell; P = 0.006, and Geriatric Depression scale, GDS-15; P = 0.001), while within the PD group, those patients with a PIGD subtype had greater depression scores than the TD subtype (GDS-15; P < 0.05). We conclude that non-dopaminergic motor features are frequent in PDD. Neurodegeneration within the cholinergic system is likely to mediate many of these motor problems, as well as playing a significant role in determining the neuropsychiatric symptomatology of both PDD and DLB. 相似文献
996.
The distribution of basal ganglia lesions, including the amygdala, striatum (caudate nucleus, putamen), pallidum, and substantia nigra, were reinvestigated in 19 Japanese autopsy cases of ‘Pick complex’, consisting of five patients with corticobasal degeneration (CBD), 10 patients with Pick's disease with Pick bodies (PDPB), and four patients with generalized variant of Pick's disease (gvPD). The lesions in the amygdala, striatum, and pallidum were classified into three categories (severe, moderate, and slight). The lesions in the substantia nigra were qualitatively judged, compared with normal controls. In CBD, basal ganglia lesions in all five cases were uniform: the pallidum showed severe lesions, the striatum moderate lesions, the amygdala slight lesions, and obvious neuronal loss of the substantia nigra was verified in all five cases. Basal ganglia lesions in 10 cases of PDPB were also uniform: the amygdala disclosed severe to moderate lesions, the striatum moderate to slight lesions, the pallidum slight lesions, while obvious neuronal loss of the substantia nigra was found in only two of nine cases in which this structure was examined. Furthermore, basal ganglia lesions in all four cases of gvPD were uniform: the caudate nucleus showed severe lesions, the putamen and amygdala severe to moderate lesions, the pallidum moderate to slight lesions, and obvious neuronal loss of the substantia nigra was confirmed in all four cases. This study, using conventional staining such as hematoxylin‐eosin and Holzer, clarified that there were prominent lesions in the pallidum in CBD, in the amygdala in PDPB, and in the caudate nucleus in gvPD, respectively. In addition, nigral involvement was usually found in CBD and gvPD, but was rarely seen in PDPB. These neuropathological findings may help to elucidate the pathological heterogeneity of basal ganglia lesions in ‘Pick complex’. 相似文献
997.
Pulmonary vasculature in Fabry''s disease 总被引:1,自引:0,他引:1
998.
肢体异物处理的几个问题 总被引:5,自引:0,他引:5
肢体异物是骨科常见损伤,以缝针、木屑、玻璃最多。金属异物X线显示清晰,但易忽视其取出难度,木质类异物X线不显影、久治不愈的深部窦道常提示有X线不显影的异物存在,撞击性玻璃损伤常并发神经、血管、肌腱断裂,切取不慎易加重损伤。异物摘除前应作好充分准备,避免手术失败和发生继发性损伤。 相似文献
999.
本文报告眼球内异物150例(153只眼),其中男性131例,女性19例;年龄8~62岁.受伤眼别:右眼62眼,左眼81眼,双眼10眼.异物存留时间自24小时至40年.异物存留部位:前房(15眼);晶状体(11眼),前玻璃体(44眼),后玻璃体(70眼),后极部(10眼),后巩膜壁(3眼).阐明手术方法.异物的大小:有的1mm以下,大的12mm.对手术前后视力做了比较.并发症共有7种。本文与前10年统计对比,眼外伤明显增多,但眼球内异物明显减少。 相似文献
1000.
H. Djouhri K. Marsot-Dupuch A. Joutel M. Kujas M. D. Brette F. Artuis J. M. Tubiana 《European radiology》1998,8(2):286-288
A case of chronic chemical meningitis occurring after a radical mastoidectomy is reported. Imaging and surgical findings
were suggestive of a dissemination of cholesteatoma debris within the subarachnoid spaces. Chemical meningitis has been described
in epidermoid and dermoid cyst rupture. This report illustrates that clinicians should be aware of this possible complication.
Skull base imaging is mandatory before considering the diagnosis of idiopathic meningitis. Only treatment of the abnormal
communication between cerebrospinal fluid and middle ear may eradicate the origin of this rare meningitis.
Received 6 January 1997; Revision received 4 April 1997; Accepted 4 August 1997 相似文献