全文获取类型
收费全文 | 23172篇 |
免费 | 1931篇 |
国内免费 | 804篇 |
专业分类
耳鼻咽喉 | 197篇 |
儿科学 | 560篇 |
妇产科学 | 587篇 |
基础医学 | 1251篇 |
口腔科学 | 524篇 |
临床医学 | 3424篇 |
内科学 | 5526篇 |
皮肤病学 | 104篇 |
神经病学 | 866篇 |
特种医学 | 674篇 |
外国民族医学 | 7篇 |
外科学 | 2661篇 |
综合类 | 3328篇 |
现状与发展 | 2篇 |
预防医学 | 1426篇 |
眼科学 | 105篇 |
药学 | 2296篇 |
52篇 | |
中国医学 | 1185篇 |
肿瘤学 | 1132篇 |
出版年
2024年 | 93篇 |
2023年 | 528篇 |
2022年 | 913篇 |
2021年 | 1292篇 |
2020年 | 1118篇 |
2019年 | 1012篇 |
2018年 | 942篇 |
2017年 | 970篇 |
2016年 | 958篇 |
2015年 | 915篇 |
2014年 | 1675篇 |
2013年 | 1880篇 |
2012年 | 1348篇 |
2011年 | 1414篇 |
2010年 | 1166篇 |
2009年 | 1038篇 |
2008年 | 989篇 |
2007年 | 971篇 |
2006年 | 954篇 |
2005年 | 812篇 |
2004年 | 646篇 |
2003年 | 567篇 |
2002年 | 507篇 |
2001年 | 424篇 |
2000年 | 349篇 |
1999年 | 252篇 |
1998年 | 238篇 |
1997年 | 215篇 |
1996年 | 208篇 |
1995年 | 203篇 |
1994年 | 160篇 |
1993年 | 131篇 |
1992年 | 138篇 |
1991年 | 116篇 |
1990年 | 104篇 |
1989年 | 92篇 |
1988年 | 79篇 |
1987年 | 65篇 |
1986年 | 51篇 |
1985年 | 67篇 |
1984年 | 48篇 |
1983年 | 42篇 |
1982年 | 41篇 |
1981年 | 39篇 |
1980年 | 32篇 |
1979年 | 21篇 |
1978年 | 25篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Sarah McGarrol PhD Alex Kaley PhD Rachael Eastham PhD Margaret Whitehead PhD Mark Limmer PhD 《Health & social care in the community》2021,29(1):284-293
Gastrointestinal (GI) infections exert a significant public health burden in the United Kingdom and the numbers of episodes are increasing. Younger children are considered particularly vulnerable to infection, and can experience 2–3 GI infections episodes per year, with consequences being more severe for more disadvantaged children, who are much more likely to be admitted to hospital. Few qualitative studies have explored the lived experience of GI infection in the community in the UK. The aim of the study reported here was to contribute to addressing this evidence gap, by examining the consequences of GI infection for ‘normal’ family life. Eighteen mothers with young children who had recently experienced a gastrointestinal infection were recruited from two socioeconomically contrasting neighbourhoods in North West of England. The findings demonstrated that GI infections were particularly disruptive: experienced as disgusting, laborious and stressful and significantly impacted normal family routines. Women felt burdened by the heavy physical and emotional demands of caring for a GI infection, resulting in feelings of isolation and insufficient support in their caring role from male partners. Tensions also arose from interactions with external community organisations, particularly in complying with their regulations on infection which often undermined caregivers knowledge and expertise of what was best for their children. This study challenges assumptions that managing GI infections in the home is unproblematic and experienced by caregivers as a ‘minor ailment.’ Infection control measures need to incorporate insights gleaned from the day-to-day realities of caring for sick children in the community. 相似文献
53.
54.
胃肠道间质瘤的免疫组化诊断及P53和P21表达 总被引:7,自引:0,他引:7
目的:探讨胃肠道间质瘤(GIST)的诊断及鉴别诊断。方法:GIST患50例,进行常规检查及P^53/P^21,HHF-35,vimentin,CD34免疫组化检测。结果:本组50例GIST,恶性34例,交界性10例,良性6例,以胃及小肠为多发(68%)。免疫组化以平滑肌细胞分化为主型占46%,神经源分化型占18%,平滑肌和神经双向分化型18%,未分化型24%。肌肉共同蛋白HHF-35为平滑肌细胞分化最敏感的标志物。未分化型间质瘤的免疫表型为vimentin和CD34阳性。P^53蛋白和P^21蛋白对GIST的良恶性可资鉴别。结论:尽管胃肠道间质瘤光镜下形态相似,但其免疫表型呈异源性,需要做免疫组化准确定性。 相似文献
55.
目的 探讨绝经后阴道出血的病因。方法 分析242例绝经后阴道出血并行诊断性乔宫的临床和病理资料。结果 绝经后阴道出血的主要病理诊断分另是功能性子宫内膜(60.73%)、炎症(28.92%)和恶性肿瘤(10.35%)。结论 内分泌紊乱性疾病是绝经后出血的常见病因,年老妇女恶性肿瘤发生率高。 相似文献
56.
Hughes Jeffrey A. Avrutskaya Anna V. Brouwer Kim L. R. Wickstrom Eric Juliano R. L. 《Pharmaceutical research》1995,12(6):817-824
Purpose. The therapeutic use of antisense oligonucleotides will likely involve their administration over protracted periods of time. The oral route of drug dosing offers many advantages over other possible routes when chronic drug administration is necessary. However, little is known about the potential for oligonucleotide uptake from the gastrointestinal tract. This issue is addressed in the current work.
Methods. We have developed a simple procedure for radiolabeling oligonucleotides by reductive alkylation with 14C-formaldehyde. We have utilized this approach, as well as 5 addition of fluorophores, to prepare labeled methylphosphonate and phosphorothioate oligonucleotides for use in intestinal transport studies. An everted rat gut sac model was employed to compare the transport of oligonucleotides to that of model compounds whose permeation properties are better understood.
Results. We demonstrate that both methylphosphonate and phosphorothioate oligonucleotides are passively transported across the intestinal epithelium, probably by a paracellular route. The rates of transport for both types of oligonucleotides were similar, and were significantly greater than that of the very high MW polymer blue dextran, but were lower than the transport rate of valproic acid, a low MW compound known to have high oral availability.
Conclusions. A significant degree of permeation of oligonucleotides across the gastrointestinal epithelium does occur, but it is still unclear whether this is sufficient to permit effective oral administration of oligonucleotides as drugs. 相似文献
57.
Regression of endometrial hyperplasia after treatment with the gonadotrophin-releasing hormone analogue triptorelin: a prospective study 总被引:4,自引:0,他引:4
Grimbizis G Tsalikis T Tzioufa V Kasapis M Mantalenakis S 《Human reproduction (Oxford, England)》1999,14(2):479-484
Endometrial hyperplasia is thought to be caused by the prolonged, unopposed oestrogenic stimulation of the endometrium. The regression of hyperplastic back to normal endometrium is the main purpose of any conservative treatment in order to prevent development of adenocarcinoma. The aim of this study was to evaluate the regression of hyperplastic to normal endometrium in patients with various forms of endometrial hyperplasia after treatment with the gonadotrophin-releasing hormone analogue (GnRHa) triptorelin for 6 months. Fifty-six patients with endometrial hyperplasia were enrolled in this trial; 39 patients (group I) presented simple hyperplasia, 14 (group II) complex hyperplasia and three (group III) atypical complex hyperplasia. All patients were treated with triptorelin for 6 months. Bleeding control during treatment was excellent. A post-treatment curettage for estimation of endometrial histology was performed on 54 out of 56 patients 100.1 +/- 44.7 days after the last triptorelin dose, following the restoration of pituitary function. Regression of hyperplastic to normal endometrium was observed in 32 (86.5%) out of 37 patients in group I and in 12 (85.7%) out of 14 in group II. Persistence of simple hyperplasia was found in five (14.5%) out of 37 patients in group I. Persistence of complex hyperplasia was found in 1 (7.1%) out of 14 patients and progression to atypical complex hyperplasia in another one (7.1%) woman in group II. In some of these cases, the presence of risk factors such as obesity, diabetes mellitus and ovulatory disturbances may contribute to the disease persistence despite therapy. On the other hand, in group III, none of the three patients had normal post-treatment endometrial histology. It seems, therefore, that in cases of endometrial hyperplasia without atypia, the administration of the GnRHa triptorelin is associated with high regression rates to normal endometrium. Conversely, the presence of atypia seems to be a poor prognostic factor. Treatment tolerance and bleeding control during therapy is excellent. 相似文献
58.
We studied the discharge pattern of single motor units (SMUs) in the left and right biceps muscles from a patient with nonspastic weakness of the left arm. Detailed statistical analysis of the behavior of discharge patterns of 4 of 4 single motor units on the affected side showed abnormalities with characteristic features of an upper motor neuron lesion. Five out of 5 single motor units recorded from the right biceps were normal. An upper motor neuron lesion affecting the left arm, predicted by our results, was confirmed by magnetic resonance imaging (MRI), which showed a lesion in the right precentral gyrus. It appears that changes in single motor unit firing characteristics, caused by an upper motor neuron lesion, can be detected at a time when there is no evidence of increased "tone" and/or hyperreflexia (spasticity) in the affected extremity. 相似文献
59.
The effects on the nicotinic activation of the coeliac plexus neurons of nitric oxide (NO) released within the coeliac plexus by gastric mechanoreceptors, in particular during gastroduodenal inhibitory reflex, were assessed. This study was performed in the rabbit on an in vitro preparation of the coeliac plexus connected to the stomach and the duodenum. The electrical activity of ganglionic neurons was recorded with intracellular recording techniques. Water-filled balloons were used for gastric distensions and recording of duodenal motility. When a 10-s train of pulses (20-40Hz) of supramaximal intensity was applied to the splanchnic nerves, gradual depression of nicotinic activation occurred. Gastric distension (50 mL, 7.5 min) modulated this depression phenomenon by inhibiting or facilitating the nicotinic activation. In the neurons impaled during the recording of duodenal motility, gastric distension triggered an inhibition of nicotinic activation concomitantly with a gastroduodenal inhibitory reflex organized by the coeliac plexus. If the gastric distensions were performed while the coeliac plexus was superfused by a NO scavenger, the nicotinic activation was unaffected and the gastroduodenal inhibitory reflex was abolished. Moreover, when the coeliac plexus was superfused with an inhibitor of nitric oxide synthase, gastric distensions were without effect on the nicotinic activation. These results demonstrate that NO released within the coeliac plexus by gastric mechanoreceptors, in particular during the gastroduodenal inhibitory reflex, modulates the central nicotinic activation of coeliac plexus neurons, so NO released within a prevertebral ganglion by gastric afferent fibres, in particular during the organization by this ganglion of a reflex regulating the gastrointestinal tract motility, also exerts a gating of the central inputs to the ganglionic neurons. 相似文献
60.
Watanabe T Mikami A Shigedo Y Motonishi M Honda H Kyotani K Uruha S Terashima K Teshima Y Sugita Y Takeda M 《Psychiatry and clinical neurosciences》2000,54(3):338-339
Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AHI) were investigated in six cases of upper airway resistance syndrome (UARS) and 11 cases of obstructive sleep apnea syndrome (OSAS). The severity of negative Pes was represented by the highest peak (Pes Max) and the number of increased episodes (more than 13.5 cmH2O) per h (NPesI13.5). There was no significant correlation between Pes indices and AHI. Pes Max and NPesI13.5 were not different among severe OSAS (AHI > 30), mild OSAS (AHI < 30) and UARS. Apnea hypopnea index failed to represent the severity of negative Pes, which is an important aspect of the pathophysiology of sleep-disordered breathing. 相似文献