全文获取类型
收费全文 | 18315篇 |
免费 | 1563篇 |
国内免费 | 1409篇 |
专业分类
耳鼻咽喉 | 210篇 |
儿科学 | 190篇 |
妇产科学 | 205篇 |
基础医学 | 2039篇 |
口腔科学 | 345篇 |
临床医学 | 2413篇 |
内科学 | 2763篇 |
皮肤病学 | 124篇 |
神经病学 | 961篇 |
特种医学 | 547篇 |
外国民族医学 | 16篇 |
外科学 | 1941篇 |
综合类 | 3365篇 |
现状与发展 | 5篇 |
一般理论 | 5篇 |
预防医学 | 1197篇 |
眼科学 | 428篇 |
药学 | 1941篇 |
4篇 | |
中国医学 | 917篇 |
肿瘤学 | 1671篇 |
出版年
2024年 | 44篇 |
2023年 | 293篇 |
2022年 | 726篇 |
2021年 | 878篇 |
2020年 | 703篇 |
2019年 | 606篇 |
2018年 | 649篇 |
2017年 | 612篇 |
2016年 | 579篇 |
2015年 | 850篇 |
2014年 | 1026篇 |
2013年 | 849篇 |
2012年 | 1283篇 |
2011年 | 1545篇 |
2010年 | 969篇 |
2009年 | 724篇 |
2008年 | 898篇 |
2007年 | 1002篇 |
2006年 | 955篇 |
2005年 | 944篇 |
2004年 | 664篇 |
2003年 | 613篇 |
2002年 | 549篇 |
2001年 | 479篇 |
2000年 | 427篇 |
1999年 | 427篇 |
1998年 | 301篇 |
1997年 | 311篇 |
1996年 | 218篇 |
1995年 | 222篇 |
1994年 | 168篇 |
1993年 | 121篇 |
1992年 | 128篇 |
1991年 | 101篇 |
1990年 | 83篇 |
1989年 | 69篇 |
1988年 | 82篇 |
1987年 | 57篇 |
1986年 | 46篇 |
1985年 | 32篇 |
1984年 | 18篇 |
1983年 | 9篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的观察和研究敏感期内、末不同时限单眼斜视(monocularstrabismus,MS)和单眼剥夺(monoculardeprivation,MD)幼猫视皮质、外侧膝状体的脑源性神经营养因子(brainderivedneurotrophicfactor,BDNF)的可塑性变化。从形态学、分子神经生物学角度探讨不同时限MS和MD幼猫视 相似文献
42.
Evidence for an essential role of reactive oxygen species in the genesis of late preconditioning against myocardial stunning in conscious pigs. 总被引:13,自引:1,他引:12 下载免费PDF全文
J Z Sun X L Tang S W Park Y Qiu J F Turrens R Bolli 《The Journal of clinical investigation》1996,97(2):562-576
Conscious pigs underwent a sequence of 10 2-min coronary occlusions, each separated by 2 min of reperfusion, for three consecutive days (days 1, 2, and 3). On day 1, pigs received an i.v. infusion of a combination of antioxidants (superoxide dismutase, catalase, and N-2 mercaptopropionyl glycine; group II, n = 9), nisoldipine (group III, n = 6), or vehicle (group I [controls], n = 9). In the control group, systolic wall thickening (WTh) in the ischemic-reperfused region on day 1 remained significantly depressed for 4 h after the 10th reperfusion, indicating myocardial "stunning." On days 2 and 3, however, the recovery of WTh improved markedly, so that the total deficit of WTh decreased by 53% on day 2 and 56% on day 3 compared with day 1 (P < 0.01), indicating the development of a powerful cardioprotective response (late preconditioning against stunning). In the anti-oxidant-treated group, the total deficit of WTh on day 1 was 54% less than in the control group (P < 0.01). On day 2, the total deficit of WTh was 85% greater than that observed on day 1 and similar to that observed on day 1 in the control group. On day 3, the total deficit of WTh was 58% less than that noted on day 2 (P < 0.01). In the nisoldipine-treated group, the total deficit of WTh on day 1 was 53% less than that noted in controls (P < 0.01). On days 2 and 3, the total deficit of WTh was similar to the corresponding values in the control group. These results demonstrate that: (a) in the conscious pig, antioxidant therapy completely blocks the development of late preconditioning against stunning, indicating that the production of reactive oxygen species (ROS) on day 1 is the mechanism whereby ischemia induces the protective response observed on day 2; (b) antioxidant therapy markedly attenuates myocardial stunning on day 1, indicating that ROS play an important pathogenetic role in postischemic dysfunction in the porcine heart despite the lack of xanthine oxidase; (c) although the administration of a calcium-channel antagonist (nisoldipine) is as effective as antioxidant therapy in attenuating myocardial stunning on day 1, it has no effect on late preconditioning on day 2, indicating that the ability of antioxidants to block late preconditioning is not a nonspecific result of the mitigation of postischemic dysfunction on day 1. Generation of ROS during reperfusion is generally viewed as a deleterious process. Our finding that ROS contribute to the genesis of myocardial stunning but, at the same time, trigger the development of late preconditioning against stunning supports a complex pathophysiological paradigm, in which ROS play an immediate injurious role (as mediators of stunning) followed by a useful function (as mediators of subsequent preconditioning). 相似文献
43.
44.
45.
目的:介绍枕下-颞下联合入路切除颞骨良性肿瘤的方法及体会。方法:对3例颞枕骨化纤维瘤、颞骨纤维异常增殖症、颞骨血管瘤的巨大颞骨良性肿瘤,均采用枕下-颞下联合入路(倒钩形切口)。辅以显微外科技术进行手术摘除肿瘤。结果:3例均基本完整切除肿瘤,无颅内外感染、脑脊液漏、迷路及颅神经损伤等并发症,经术后随访1.5年~2年未发现肿瘤复发。结论:采用枕下-颞下联合入路切除颞枕骨良性肿瘤可获理想的暴露,最大范围切除肿瘤,可避免损伤毗邻的颅神经、血管以及内耳结构,值得推广。 相似文献
46.
Nm23 protein expression was analyzed by immunohistochemical staining using formalin-fixed, paraffin-embedded sections from 39 cases with osteosarcomas and compared with the histologic findings and early metastasis for the purpose of detecting nm23 expression in osteosarcoma and elucidating the clinical significance of its expression. Immunoreactivity of nm23 protein was detected in 48.7% of the total cases. There was no statistical difference between nm23 expression and early metastasis, but there was a trend for cases with nm23 expression to progress to early metastasis within 1 year after operation. The role of nm23 as a tumor metastasis suppressor in osteosarcomas appeared less prominent. 相似文献
47.
静脉注射硝酸甘油诱导大鼠脑膜核因子-κB表达增强 总被引:4,自引:0,他引:4
目的观察偏头痛大鼠模型不同时相脑膜核因子-κB(NF-κB)的表达特征.方法采用静脉注射硝酸甘油(GTN)法建立大鼠偏头痛模型,应用免疫组织化学法观察对照组、GTN iv 后0.5,1.0, 1.5, 2.0, 4.0 h组脑膜NF-κB阳性染色细胞的分布,采用Western印迹法观察相应时间点脑膜核NF-κB的蛋白表达量.结果 GTN iv后0.5 h即出现大鼠脑膜NF-κB核阳性反应和核NF-κB蛋白表达量增高,1.5 h核NF-κB蛋白表达量达高峰,然后逐渐回落,至4 h接近正常水平.结论 GTN iv后早期脑膜呈时限性核NF-κB蛋白表达增强,提示NF-κB蛋白表达增强可能与偏头痛有关. 相似文献
48.
变应性鼻炎患者可溶性白细胞介素—2受体的测定 总被引:9,自引:0,他引:9
为探讨可溶性白细胞介素-2受体在变应性鼻炎中的作用机理,采用双抗体夹心酶联免疫吸附测定(ELISA)法测定39例变应性鼻炎患者,19例慢性鼻炎患者和15例健康人血清及鼻分泌物SIL-2R水平。结果发现变应性鼻炎患者血清SIL-2R水平高于慢性鼻炎患者及健康人(P〈0.001)。提示SIL-2在变应性鼻炎的发病中起重要作用。 相似文献
49.
50.
报告因骨疡型及胆脂瘤型中耳炎而行乳突根治术的1112例中并发弥漫性浆液性迷路炎4例,发生率为0.36%,听力损失严重,经抗炎治疗,尽快施行乳突根治术,配合应用扩张血管,皮质激素,神经营养药物等治疗,获得良好效果,认为本病一经确诊后应尽快施行手术,这样不仅能解除骨疡型及胆脂瘤型中耳炎的危险性,而且还尽可能地挽救患耳的听力,尤其对两侧耳重度听力损失者意义更大。 相似文献