全文获取类型
收费全文 | 71814篇 |
免费 | 4190篇 |
国内免费 | 2785篇 |
专业分类
耳鼻咽喉 | 64篇 |
儿科学 | 848篇 |
妇产科学 | 265篇 |
基础医学 | 4091篇 |
口腔科学 | 155篇 |
临床医学 | 10994篇 |
内科学 | 15605篇 |
皮肤病学 | 113篇 |
神经病学 | 11189篇 |
特种医学 | 3006篇 |
外国民族医学 | 1篇 |
外科学 | 2675篇 |
综合类 | 15379篇 |
现状与发展 | 1篇 |
预防医学 | 2432篇 |
眼科学 | 139篇 |
药学 | 7353篇 |
99篇 | |
中国医学 | 4143篇 |
肿瘤学 | 237篇 |
出版年
2024年 | 567篇 |
2023年 | 929篇 |
2022年 | 1636篇 |
2021年 | 2353篇 |
2020年 | 2303篇 |
2019年 | 1864篇 |
2018年 | 1797篇 |
2017年 | 1988篇 |
2016年 | 2165篇 |
2015年 | 2221篇 |
2014年 | 4614篇 |
2013年 | 4481篇 |
2012年 | 4358篇 |
2011年 | 4586篇 |
2010年 | 3881篇 |
2009年 | 3601篇 |
2008年 | 3686篇 |
2007年 | 3735篇 |
2006年 | 3671篇 |
2005年 | 3176篇 |
2004年 | 2603篇 |
2003年 | 2352篇 |
2002年 | 2066篇 |
2001年 | 1912篇 |
2000年 | 1692篇 |
1999年 | 1433篇 |
1998年 | 1128篇 |
1997年 | 1084篇 |
1996年 | 829篇 |
1995年 | 719篇 |
1994年 | 698篇 |
1993年 | 544篇 |
1992年 | 471篇 |
1991年 | 449篇 |
1990年 | 365篇 |
1989年 | 337篇 |
1988年 | 300篇 |
1987年 | 286篇 |
1986年 | 255篇 |
1985年 | 321篇 |
1984年 | 259篇 |
1983年 | 185篇 |
1982年 | 191篇 |
1981年 | 192篇 |
1980年 | 132篇 |
1979年 | 98篇 |
1978年 | 79篇 |
1977年 | 51篇 |
1976年 | 44篇 |
1974年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
对156例急性心肌梗塞进行临床分析。结果显示墓碑形S—T段抬高组CK值、心梗后心绞痛(PIA)、严重心律失常、心衰发生率,以及一周内死亡率较通常式抬高组显著增高。结论:墓碑形S—T段抬高可作为判断急性心肌梗塞预后不良的一项参考指标。 相似文献
62.
目的 分析小脑梗塞CT和MRI表现,探讨CT和MRI对小脑梗塞的诊断价值。方法对18例小脑梗塞的CT和MRI图像进行回顾分析。结果CT和MRI不同程度显示了小脑梗塞的影像学改变,各有其特点,且与病程长短和病灶大小有关。结论MRI的影像学价值较CT更胜一筹。 相似文献
63.
Neutrophil superoxide release and interleukin 8 in acute myocardial infarction: distinction between complicated and uncomplicated states 总被引:2,自引:0,他引:2
K. RIESENBERG R. LEVY A. KATZ S. GALKOP & F. SCHLAEFFER 《European journal of clinical investigation》1997,27(5):398-404
Superoxide release in neutrophils and sera levels of interleukin 8 (IL-8) were determined in 15 patients with complicated acute myocardial infarction (MI) and 15 patients with uncomplicated MI. All patients showed increased superoxide release in unstimulated and stimulated neutrophils compared with healthy control subjects, indicating priming of these cells. Superoxide release of unstimulated or stimulated neutrophils was found to be significantly higher in patients with complicated MI than in patients with uncomplicated MI. Thrombolytic therapy did not affect the rates of superoxide release. The neutrophil chemoattractant/activator IL-8 was detected in the sera of all patients, with significantly higher levels in those with complicated MI. The highest levels of IL-8 were detected at admission to the Coronary Care Unit and significantly decreased thereafter, suggesting its contribution to neutrophil-mediated tissue injury. The high levels of IL-8 may be one of the major contributors to the priming of neutrophils in these patients. 相似文献
64.
Gary W Thickbroom Michelle L Byrnes Rick Stell Frank L Mastaglia 《Movement disorders》2003,18(4):395-402
Previous work has suggested that there may be a widespread disturbance of motor control mechanisms in patients with cervical dystonia. In the present study, we used transcranial magnetic stimulation to investigate the topography of the corticomotor projection to the abductor pollicis brevis (APB) muscle in 10 subjects with idiopathic torticollis. Threshold-adjusted stimuli were delivered at multiple scalp sites during a low-level voluntary contraction of the APB, and maps were generated of motor evoked potential amplitude versus scalp site. The cortical maps for the APB on the side opposite to the direction of head rotation were displaced laterally or posteriorly in all subjects and reverted to a more normal position after botulinum toxin injection of the cervical muscles in 5 subjects. The findings point to a reversible reorganisation of the corticomotor representation of the hand on the same side as the sternocleidomastoid (SCM) muscle that is involved in producing the dystonia. These results provide further evidence for the involvement of cortical centres and for a more widespread abnormality of motor control mechanisms in focal dystonia. The findings also support the notion that head turning is chiefly mediated by the hemisphere ipsilateral to the direction of the head rotation by means of a corticomotor projection to the contralateral SCM. 相似文献
65.
Summary This study evaluates local variations of the cerebral vasomotor responses to hypercapnia and haemorrhagic hypotension in a pig model. Four laser Doppler flow probes were used in each pig. There was considerable variation in laser Doppler signals between the four probes in baseline recordings. The increases in flow after CO2 administration in 7 pigs had a mean coefficient of variation of 0.43 ± 0.31, and the flow changes after blood loss in another 7 pigs had a mean coefficient of variation of 0.45 ± 0.34. The range of flow changes within each animal was large; the probe with the highest CO2 response showed on the average a 273% ± 157% larger CO2 response than the probe with the lowest CO2 response. Correspondingly, the probe with the best preserved blood flow after blood loss had on the average a flow value of 93% ± 12% of the baseline value, while the probe that changed most with haemorrhage had a flow value of 44% ± 24% of the baseline value. Single laser Doppler recordings have been used for the monitoring of cerebral blood flow in neurosurgical critical care, but our results suggest that a single laser Doppler flow probe is not an adequate method to monitor vasoreactivity in neurosurgical patients because flow signals from one probe may be unrepresentative for other sites in the brain. 相似文献
66.
67.
The distribution of the specific radioactivity and the incorporation into protein of [3H]-tryptophan and [3H]valine at varying layers from surface to centre were measured in incubated slices of cerebral cortices from infant and adult rats. Specific radioactivity in free amino acids was in both age groups highest in the intact surface layer. Incorporation of tryptophan into protein was even in slices from adult rats but much less than the average in the surface layers in slices from infant rats. Incorporation of valine exhibited similar heterogeneity in both age groups. The results suggest in brain slice preparations a zonal compartmentation of amino acid and protein metabolism which varies for different amino acids. 相似文献
68.
Summary Experimental testicular torsion must be used for certain studies of clinical relevance, but most experimental models either do not provide hemodynamic alteration comparable to the clinical situation or cannot guarantee reproducibility. Using a rat model arterial perfusion and hemorrhagic infarction were correlated to the degree of both intra- and extravaginal testicular torsion. Arterial inflow was measured sequentially with radiolabelled microspheres, hemorrhagic infarction was judged by the increase of testicular weight. Maximal hemorrhagic infarction and reproducible values were found when the spermatic cord was twisted togehter with the tunica vaginalis for 360°–540°. 相似文献
69.
We examined the relation between various drugs used for treating high blood pressure and the incidence of acute myocardial infarction with a case-control design. Four hospitals taking care of all patients in Oslo with acute myocardial infarction participated with a total of 95 hypertensive men and women under 75 years of age who had had an acute myocardial infarction. A total of 329 age and sex matched controls were hypertensive citizens in Oslo without myocardial infarction. Frequency of treatment with drugs and odds ratio of risks with these drugs were calculated. The risk (odds ratio) of myocardial infarction for drug treatment during the last five years versus non drug treatment was 0.70 (95% confidence interval 0.42-1.18). The risk for diuretics and bT-blockers tested against no treatment was 0.91 (0.52-1.61). The corresponding risk for vasodilating drugs was 0.43 (0.20-0.91). Four weeks of exposure to aL-blockers, on the other hand, tested against other drug treatments, indicated an odds ratio of 4.62 (1.01-24.0) for individuals with a history of angina. These data confirm that treatment with diuretics and bT-blockers has only little effect on the incidence of myocardial infarction. As a whole, vasodilators are associated with a significant reduction in this incidence, but aL-blockers enhance the risk in patients with angina. 相似文献
70.
高血压鼠局部脑梗塞后脑超微结构改变动态观察 总被引:3,自引:0,他引:3
本文选用肾血管性高血压鼠(RHR)复制大脑中动脉闭塞(MCAO)模型,其后2h至7d分8次取不同区域脑组织进行透射电镜动态观察超微结构的改变。显示局部脑梗塞后发生全脑性改变,其损害程度和出现时间梗塞区最早,以坏死为主,呈完全不可逆性损害;边缘区稍后,主要是微血管塌陷和微血栓形成及部分脑细胞坏死,呈部分可逆性损害,远隔区和镜区最迟,以内皮和星形细胞水肿为主,呈可逆性损害,认为用RHR复制MCAO,更接近于高血压性脑血管损害基础上发生脑梗塞的临床病理改变,全脑超微结构的动态性改变中微血管损害起着重要作用。 相似文献