全文获取类型
收费全文 | 8137篇 |
免费 | 668篇 |
国内免费 | 277篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 43篇 |
妇产科学 | 32篇 |
基础医学 | 923篇 |
口腔科学 | 25篇 |
临床医学 | 415篇 |
内科学 | 380篇 |
皮肤病学 | 24篇 |
神经病学 | 2064篇 |
特种医学 | 256篇 |
外国民族医学 | 2篇 |
外科学 | 918篇 |
综合类 | 666篇 |
预防医学 | 125篇 |
眼科学 | 2592篇 |
药学 | 309篇 |
2篇 | |
中国医学 | 204篇 |
肿瘤学 | 56篇 |
出版年
2024年 | 40篇 |
2023年 | 160篇 |
2022年 | 291篇 |
2021年 | 380篇 |
2020年 | 335篇 |
2019年 | 274篇 |
2018年 | 318篇 |
2017年 | 298篇 |
2016年 | 290篇 |
2015年 | 285篇 |
2014年 | 472篇 |
2013年 | 640篇 |
2012年 | 384篇 |
2011年 | 408篇 |
2010年 | 324篇 |
2009年 | 326篇 |
2008年 | 380篇 |
2007年 | 351篇 |
2006年 | 337篇 |
2005年 | 248篇 |
2004年 | 206篇 |
2003年 | 230篇 |
2002年 | 170篇 |
2001年 | 142篇 |
2000年 | 128篇 |
1999年 | 114篇 |
1998年 | 140篇 |
1997年 | 135篇 |
1996年 | 111篇 |
1995年 | 92篇 |
1994年 | 80篇 |
1993年 | 79篇 |
1992年 | 67篇 |
1991年 | 76篇 |
1990年 | 69篇 |
1989年 | 54篇 |
1988年 | 54篇 |
1987年 | 54篇 |
1986年 | 55篇 |
1985年 | 84篇 |
1984年 | 71篇 |
1983年 | 60篇 |
1982年 | 63篇 |
1981年 | 53篇 |
1980年 | 40篇 |
1979年 | 28篇 |
1978年 | 25篇 |
1977年 | 20篇 |
1976年 | 13篇 |
1975年 | 8篇 |
排序方式: 共有9082条查询结果,搜索用时 15 毫秒
31.
Chia-Hung Lu MD Ming Yao MD Hon-Man Liu MD Ya-Fang Chen MD 《Journal of neuroimaging》2007,17(2):184-187
We report the findings of spinal magnetic resonance imaging (MRI) in 2 patients who had undergone intrathecal chemotherapy and presented with the subacute onset of ascending numbness and weakness. MRI revealed a symmetric hyperintensity at the posterior columns of the spinal cord from the lower cervical region down to the conus medullaris level on T2-weighted images, and no abnormal enhancement. The imaging findings are similar to those seen in subacute combined degeneration (SCD), but the serum vitamin B(12) levels were normal in these 2 cases. 相似文献
32.
LIUQingrui LIFengluan HANYing GUOLiru 《现代电生理学杂志》2004,11(1):22-24
目的:探讨皮质基底节变性(CBD)患者的临床和神经电生理特征。方法:对29例临床诊断为CBD患者,系统分析其临床症状、体征、常规化验检查、脑CT/MRI、SPECT以及神经电生理改变,并与其它疾病相对比。结果:结果显示,29例患者均出现不对称性帕金森样表现,皮层功能受损占79.3%,其它功能障碍占37.9%。21例患者脑CT或MRI显示不对称性脑萎缩,SPECT显示额顶区低灌注表现,以受损肢体的功能区较明显。EEG显示19例患者出现不对称性慢波,伴有肌阵挛的15例病人,表面肌电图显示患肢随意运动时可诱发巨大电位,皮层反应增强,SEP无特殊变化,运动诱发电位检查,26例患者中枢运动传导时间正常。结论:CBD是一种累及皮层和基底节、病程以缓慢进展为特征的变性性疾病。大部分患者可出现帕金森综合征样表现,皮层及其他运动功能障碍。脑影象学显示额顶叶萎缩。神经电生理检查表现为皮层兴奋性增强,而锥体束传导功能正常。 相似文献
33.
Yumiko Motoi Masashi Takanashi Masako Itaya Kazuhiko Ikeda Yoshikuni Mizuno Hideo Mori 《Neuropathology》2004,24(1):60-65
In the present case, a patient in whom limb apraxia and asymmetrical parkinsonism developed suggesting corticobasal degeneration, is reported. Neuropathologic examination revealed numerous tufted astrocytes in the precentral cortex in addition to the characteristic pathologic findings of PSP. Therefore, on the basis of clinicopathologic features, atypical progressive supranuclear palsy was diagnosed. In addition, the brain tissue of the present patient was investigated with an antibody specific for four‐repeat tau (4R‐tau). In the precentral cortex, numerous tau‐positive tufted astrocytes, pretangles, and threads were positive for 4R‐tau. Using a confocal microscopy we demonstrated that tufted astrocytes positive for 4R‐tau were adjacent to astrocytes positive for GFAP. The present findings suggest that accumulation of four‐repeat tau in astrocytes is a degenerative process rather than a reactive process. 相似文献
34.
Transection of an optic nerve (ON) is followed by slow removal of myelin. We studied microglia for the expression of molecules that characterize activated myelin phagocytosing macrophages: MAC-1, FcγII/III receptor (FcR), MAC-2, and F4/80. In-vitro, microglia expressed all molecules and phagocytosed myelin. In-vivo, intact ON displayed high levels of MAC-1, little FcR and F4/80, and no MAC-2. The expression of these molecules was upregulated differentially in in-vivo degenerating ON: MAC-1 uniformly, FcR and F4/80 variably, and MAC-2 sporadically. The distribution of MAC-2 expression correlated best with a pattern of sporadic structural degeneration. Thus in-vivo, ON injury is followed by deficient microglia activation, which we suggest contributes significantly to the slow clearance of myelin. 相似文献
35.
老年黄斑变性的视网膜色素上皮及其视功能的改变 总被引:2,自引:0,他引:2
目的:应用黄斑区密集点矩阵视野并结合眼底荧光血管造影电脑眼底图像分析老年黄斑变性视网膜色素上皮损害与DMMM的视野光敏感度的改变,找出改变的规律有评价其应用价值。方法:用Humphrey-640视野计自行设计DMMM检测AMD干性组51人64只眼湿性且23人27只眼,用Zeiss公司生产的KONTRONELEKTRONIK Inage Analysis Division-计算机图像分析仪总丢失量显 相似文献
36.
Emine Sözeri Dietrich Feist Hans Ruder Karl Schärer 《Pediatric nephrology (Berlin, Germany)》1997,11(3):307-311
Renal lesions have repeatedly been described in Wilson’s disease (WD). We investigated the excretion of total protein, albumin,
low (LMW) and high molecular weight (HMW) proteins, N-acetyl-β-D-glucosaminidase (NAG), and calcium, as well as creatinine clearance, in 24-h urine samples of 41 patients with WD aged 6 – 37
(mean 17) years who had been treated for a period of 0 – 15 (mean 4.5) years with D-penicillamine (900 mg/day). The amount of all protein excreted was significantly increased compared with controls, 39% of
patients presenting with total proteinuria more than two standard deviations from the mean of controls. The changes in protein
excretion depended on the duration of treatment. LMW proteinuria was elevated almost exclusively in the first 2 years after
the start of treatment, indicating early tubular damage. This is supported by an initially high excretion of β2-microglobulin, NAG, and calcium. Increased excretion of HMW proteins, including albumin, persisted over longer periods, which
suggests glomerular injury in some patients, possibly related to the use of D-penicillamine. Creatinine clearance remained roughly within normal limits. We propose that renal function should regularly
be checked in patients with WD.
Received October 26, 1995; received in revised form August 27, 1996; accepted September 20, 1996 相似文献
37.
Summary. A prevalence study of Ureaplasma urealyticum (UU) infection of the male genital tract was carried out in Shanghai between March 1992 and June 1995. Significantly higher frequency of UU infection was found among infertile males (549/1416) as compared to fertile controls (34/375). Examination of 8 specimens each from infertile men and fertile subjects by electron microscopy, immunogold and immunofluorescence techniques, demonstrated adhesion of Ureaplasma urealyticum to the membrane of spermatozoa and exfoliated germ cells. In addition, gold particles on Ureaplasma urealyticum were found to be adhered to the sperm surface in 4 of the 8 samples. Strong specific anti-UU fluorescence was detected in 6 of 8 samples, mainly on the midpieces and post-acrosomal regions of the spermatozoa.
To further study the effects of Ureaplasma urealyticum on fertility, 47 male Sprague-Dawley (SD) rats were infected artificially with Ureaplasma urealyticum serotype 8 (T960). Morphological changes in the seminiferous tubules were observed 3–5 weeks after inoculation in the sacrificed animals. Dramatic impairment of spermatogenesis of both testes was found in 11 rats. Mating experiment confirmed infertility in 12 of 40 rats. Offsprings of the infected rats were significantly smaller than those of controls in terms of prenatal weights and birthweights. 相似文献
To further study the effects of Ureaplasma urealyticum on fertility, 47 male Sprague-Dawley (SD) rats were infected artificially with Ureaplasma urealyticum serotype 8 (T960). Morphological changes in the seminiferous tubules were observed 3–5 weeks after inoculation in the sacrificed animals. Dramatic impairment of spermatogenesis of both testes was found in 11 rats. Mating experiment confirmed infertility in 12 of 40 rats. Offsprings of the infected rats were significantly smaller than those of controls in terms of prenatal weights and birthweights. 相似文献
38.
39.
Fredrik Ghosh Karl Engelsberg Robert V. English Robert M. Petters 《Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie》2007,245(6):835-846
Background The purpose of this study was to explore neuroretinal transplantation in a large animal model of severe retinitis pigmentosa
and to establish graft development, long-term survival, graft-host integration, and effects on the host retina.
Methods Rhodopsin transgenic pigs, aged 6 months, received in one eye a fetal full-thickness neuroretinal sheet in the subretinal
space by means of vitrectomy and retinotomy. Six months postoperatively, eyes were studied in the light microscope and with
immunohistochemical markers. Full-field electroretinography (ERG) was performed at 4 and 6 months.
Results Laminated grafts with well-organized photoreceptors, rod bipolar cells, and Müller cells were found in five of six eyes. Neuronal
connections between graft and host retina were not seen. In the five eyes containing a graft, the number of surviving rods
in the host retina was significantly higher compared with unoperated eyes. The ERG did not reveal any significant difference
in b-wave amplitude between operated and control eyes, but the cone-derived response in operated eyes increased significantly
from 4 to 6 months while the rod response in control eyes decreased significantly.
Conclusions Fetal full-thickness neuroretina can be transplanted safely to an eye with severe retinal degeneration. In their major part,
the transplants develop a normal laminated morphology and survive for at least 6 months. Graft and host retinal neurons do
not form connections. Retinal function in the host is reduced initially by the surgical trauma, but the presence of a well-laminated
graft counteracts this effect and rescues rods from degeneration.
Supported by The Foundation Fighting Blindness (grant# C-NC02-798-0078), The Faculty of Medicine, University of Lund, The
Swedish Research Council, The Princess Margaretas Foundation for Blind Children, The 2nd ONCE International Award for New
Technologies for the Blind. 相似文献
40.
预变神经段修复神经缺损的实验研究 总被引:5,自引:2,他引:3
目的探讨不同预变时间组移植神经对神经再生的影响。方法以SD大鼠的不同预变时间组的尺神经作为移植神经,修复其正中神经的缺损。实验侧按移植神经预变时间的不同分为0、1、2、3、4、8周共6组,每组6只SD大鼠。移植后12周,检测实验侧趾屈肌群的张力、最大收缩力、再生神经的形态及神经轴突的截面积。结果用预变1周的尺神经修复正中神经后,其趾屈肌群的张力及最大收缩力的恢复率达到正常对照组的81.1%及85.9%。显微镜下观察,预变1周组和其它各时间组相比,其再生的神经轴突最多,发育最成熟。结论用预变1周的神经段修复神经缺损,其神经再生能力最佳 相似文献