全文获取类型
收费全文 | 5602篇 |
免费 | 397篇 |
国内免费 | 230篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 68篇 |
妇产科学 | 72篇 |
基础医学 | 879篇 |
口腔科学 | 177篇 |
临床医学 | 380篇 |
内科学 | 577篇 |
皮肤病学 | 110篇 |
神经病学 | 578篇 |
特种医学 | 269篇 |
外国民族医学 | 1篇 |
外科学 | 464篇 |
综合类 | 791篇 |
现状与发展 | 1篇 |
预防医学 | 434篇 |
眼科学 | 73篇 |
药学 | 496篇 |
1篇 | |
中国医学 | 236篇 |
肿瘤学 | 553篇 |
出版年
2024年 | 21篇 |
2023年 | 79篇 |
2022年 | 163篇 |
2021年 | 296篇 |
2020年 | 162篇 |
2019年 | 179篇 |
2018年 | 145篇 |
2017年 | 147篇 |
2016年 | 176篇 |
2015年 | 150篇 |
2014年 | 294篇 |
2013年 | 335篇 |
2012年 | 232篇 |
2011年 | 278篇 |
2010年 | 232篇 |
2009年 | 249篇 |
2008年 | 269篇 |
2007年 | 264篇 |
2006年 | 250篇 |
2005年 | 214篇 |
2004年 | 151篇 |
2003年 | 184篇 |
2002年 | 155篇 |
2001年 | 153篇 |
2000年 | 124篇 |
1999年 | 104篇 |
1998年 | 93篇 |
1997年 | 115篇 |
1996年 | 94篇 |
1995年 | 79篇 |
1994年 | 94篇 |
1993年 | 69篇 |
1992年 | 61篇 |
1991年 | 68篇 |
1990年 | 57篇 |
1989年 | 80篇 |
1988年 | 59篇 |
1987年 | 51篇 |
1986年 | 50篇 |
1985年 | 55篇 |
1984年 | 29篇 |
1983年 | 21篇 |
1982年 | 31篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 17篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1974年 | 4篇 |
排序方式: 共有6229条查询结果,搜索用时 15 毫秒
21.
采用人外周血淋巴细胞非程序DNA合成(UDS)试验和人胚肺成纤维细胞转化试验,测试了煤焦沥青烟雾提取物(ECTPF)对人体细胞的细胞毒性和遗传毒性。UDS试验结果表明,ECTPF可使淋巴细胞UDS值明显增加,并有剂量一反应关系。引起半数淋巴细胞死亡的浓度(LC50)为33.8μg/ml。细胞转化试验表明,ECTPF能诱发人胚肺成纤维细胞明显的形态学转化,且转化细胞具有部分恶性转化细胞的特性。引起半数人胚肺成纤维细胞生长抑制的浓度为41.3μg/ml。实验结果提示,ECTPF是一种具有细胞毒性和遗传毒性的物质。 相似文献
22.
三种淫羊藿的总黄酮分极提取物对小鼠免疫功能的影响 总被引:2,自引:0,他引:2
观察了巫山淫羊藿、柔毛淫羊藿和粗毛淫羊获的总黄酮正丁醇提取物(代号A1、A2、A3)和巫山淫羊藿总黄酮乙酸乙酯提取物(B1)对正常小鼠免疫功能的影响。结果;A1可以明显促进脾脏抗体形成细胞的功能(P<0.05),A2、A3虽也有一定的促进作用,但无统计学意义;4种提取物在体外实验中均没有协同ConA诱导牌细胞增殖作用,只有提取物浓度在100μg/ml时,有一定抑制作用。4种提取物对24小时培养脾细胞存活率无明显影响。 相似文献
23.
24.
25.
吴在东 《安徽卫生职业技术学院学报》2005,4(2):76-77,75
探索军工研究所发展民品产业之路.本文对军工研究所发展民品产业进行了优劣势分析,继而从机制转换,组织结构,产品战略,市场营销,人才队伍建设等方面提出了一些改革措施. 相似文献
26.
研究了苏乐康、绿茶提取物对~(60)钴γ射线和雌性激素联合诱发叙利亚金黄地鼠胚胎细胞恶性转化的抑制能力,并用脉冲辐解技术,对其抑制机制进行初步探讨。实验结果表明,苏乐康、绿茶提取物对γ射线和雌性激素联合诱发的金黄地鼠胚胎细胞恶性转化的抑制率分别为70.15%(P<0.05)和81.59%(P<0.05),它们的这种抑制能力与其清除超氧阴离子的能力有关, 相似文献
27.
Preeti G. Lal Roopa S. Ghirnikar Lawrence F. Eng 《Journal of molecular neuroscience : MN》1996,29(1):93-104
Glial fibrillary acidic protein (GFAP) is the principal intermediate filament protein found in mature astrocytes. Although
the exact function of GFAP is poorly understood, it is presumed to stabilize the astrocyte’s cytoskeleton and help in maintaining
cell shape. Previous studies from our laboratory have shown that when astrocytes were cocultured with primary Schwann cells
(pSCs), astrocytes became hypertrophied and fibrous with intensely positive GFAP staining and segregated Schwann cells (SCs)
into pockets. In order to understand the functional role of GFAP in this already established astrocyte-SC coculture model,
we generated GFAP-negative cell lines from a GFAP-positive astrocytoma cell line and cocultured both the cell lines with pSCs.
Our studies demonstrate that the GFAP-positive cell line put out processes toward the SCs, whereas the GFAP-negative cells
did not form processes and the majority of the cells remained round. The most significant and interesting finding of this
study, however, is the formation of elaborate processes by SCs when grown in coculture with the astrocytoma cells, unlike
SCs cultured alone, which showed their typical bipolar spindle-shaped morphology. The extent of processes did not seem to
be dependent on GFAP, since SCs cultured with both the cell lines formed similar processes. This coculture model may be useful
in elucidating the factor(s) responsible for the formation of processes by SCs and can be further help in our understanding
of the mechanism of morphological transformation of SCs. 相似文献
28.
Summary With the wider availability of magnetic resonance imaging cavernous malformations are being recognised with increasing frequency in those patients presenting with intractable epilepsy. Surgical resection is the treatment of choice. However, because these lesions are usually small and may be located in eloquent areas stereotactic resection should be considered. Stereotactically-guided resection of pathologically verified cavernous angiograms was performed in 10 patients in this series presenting with epilepsy (8 males, 2 females, mean age 32 years). Eight patients presented with medically intractable epilepsy (5 complex partial seizures, 3 grand mal seizures). Of the remaining patients one experienced multiple episodes of haemorrhage and the other headaches (with a non-diagnostic scan) both in association with epilepsy. Pre-operative localisation of the motor strip was determined in one case by functional MRI. Following resection of these lesions all patients experienced improved seizure control with a mean follow-up period of 22 months. The mean postoperative hospital stay was 5.1 days with no surgical complications recorded. We conclude that stereotactically-guided resection offers significant advantages in the management of cavernous malformations.Surgical indications for operative resection would include medically refractory epilepsy, repeated haemorrhage and those cases where there is diagnostic uncertainty. 相似文献
29.
商陆多糖Ⅰ(PEP Ⅰ)10,20mg·kg~1 ip能显著抑制S180生长,最大抑瘤率可达51.7%,Cy 10mg·kg~1 ip.抑瘤率为55.1%,两者合用抑瘤率为68.6%,PEP-Ⅰ治疗能显著促进脾脏增生,但不影响体重,PEP-Ⅰ治疗后,小鼠的T淋巴细胞转化及白介素2(IL-2)产生能力显著高于对照组,计数外周白细胞,骨髓有核细胞并用[~3H]TdR参入法观察rmGM-CSF刺激骨髓细胞增殖.结果表明PEP-Ⅰ与Cy合用治疗至d 11的外周白细胞数,骨髓有核细胞数和骨髓细胞的增殖能力显著高于单用Cy组,以上实验结果说明EPP-Ⅰ可能通过增强T淋巴细胞功能来抑制移植性肿瘤生长,并具有保护造血功能的作用。 相似文献
30.
N. Hirabuki T. Miura M. Mitomo K. Harada T. Hashimoto R. Kawai T. Kozuka 《Neuroradiology》1988,30(5):390-394
Summary Four patients with dural arteriovenous malformation (AVMs) draining into the cavernous sinus, who presented ophthalmic manifestations, were studied by magnetic resonance (MR) imaging. In all patients signal decrease in the involved cavernous sinus was demonstrated in coronal spinecho (SE) imaging. It is attributable to rapid venous flow in the sinus, and this high velocity signal loss is a fairly pathognomonic finding in this condition. We stress the validity of MR imaging in the primary diagnosis of dural AVMs with ophthalmic symptoms. 相似文献