全文获取类型
收费全文 | 17000篇 |
免费 | 1867篇 |
国内免费 | 1233篇 |
专业分类
耳鼻咽喉 | 107篇 |
儿科学 | 392篇 |
妇产科学 | 171篇 |
基础医学 | 3554篇 |
口腔科学 | 594篇 |
临床医学 | 1405篇 |
内科学 | 4414篇 |
皮肤病学 | 380篇 |
神经病学 | 936篇 |
特种医学 | 348篇 |
外国民族医学 | 1篇 |
外科学 | 1532篇 |
综合类 | 2191篇 |
现状与发展 | 1篇 |
预防医学 | 601篇 |
眼科学 | 186篇 |
药学 | 1615篇 |
1篇 | |
中国医学 | 1093篇 |
肿瘤学 | 578篇 |
出版年
2024年 | 53篇 |
2023年 | 368篇 |
2022年 | 758篇 |
2021年 | 1029篇 |
2020年 | 1035篇 |
2019年 | 760篇 |
2018年 | 713篇 |
2017年 | 819篇 |
2016年 | 791篇 |
2015年 | 783篇 |
2014年 | 1350篇 |
2013年 | 1478篇 |
2012年 | 922篇 |
2011年 | 982篇 |
2010年 | 810篇 |
2009年 | 784篇 |
2008年 | 831篇 |
2007年 | 816篇 |
2006年 | 732篇 |
2005年 | 616篇 |
2004年 | 513篇 |
2003年 | 451篇 |
2002年 | 437篇 |
2001年 | 367篇 |
2000年 | 320篇 |
1999年 | 282篇 |
1998年 | 250篇 |
1997年 | 209篇 |
1996年 | 195篇 |
1995年 | 154篇 |
1994年 | 140篇 |
1993年 | 79篇 |
1992年 | 81篇 |
1991年 | 53篇 |
1990年 | 35篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 13篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
目的:进一步研究G-CSF在维甲酸致高白细胞症中的作用。方法:用RT-PCR、Northernblotting方法检测NB4细胞经全反式维甲酸(ATRA)作用后G-CSF mRNA表达的变化,同时用ELISA方法检测细胞培养上清液中G-CSF蛋白水平的变化;采用流式细胞技术检测NB4细胞经ATRA作用后G-CSF受体蛋白表达的变化。结果:ATRA可从基因水平上调NB4细胞中G-CSF表达,并可增加NB4细胞表面G-CSF受体的表达,G-CSF受体表达增加出现的时间虽然稍晚于G-CSF表达增加出现的时间,但仍然在较早期阶段,此时,细胞形态学和NBT实验均证实BN4细胞处于部分分化阶段。结论:在ATRA治疗APL过程中,G-CSF及其受体表达增加可能协同参与了高白细胞症的发生。 相似文献
32.
C. Olgart Höglund J. Axén C. Kemi S. Jernelöv J. Grunewald C. Müller-Suur Y. Smith R. Grönneberg A. Eklund P. Stierna M. Lekander 《Clinical and experimental allergy》2006,36(8):982-992
BACKGROUND: Stress can aggravate the allergic inflammation, but determinants of disturbed immune regulation are largely unknown. OBJECTIVE: To determine systemic immunological, local inflammatory and functional airway responses to stress in healthy and atopic individuals. METHODS: Forty-one undergraduate students, 22 with allergy of whom 16 had asthma, and 19 healthy controls, were studied in a low-stress period and in association with a large exam. Subjects completed questionnaires on stress and health behaviours, underwent lung function tests, bronchial methacholine challenge, measurements of exhaled nitric oxide and urine cortisol. Blood cells were phenotyped, and cytokines from mononuclear blood cells were analysed. RESULTS: Perceived stress and anxiety increased in both groups during the exam period while cortisol increased only in the atopy group. Cytokine production decreased broadly in response to stress in both groups, which was paralleled by an increase in the proportion of regulatory T cells (CD4(+)CD45RO(+)CD25(bright)). Interestingly, atopic individuals, but not controls, reacted with a decreased T-helper type 1/T-helper type 2 (Th1/Th2) ratio and a decrease in natural killer (NK) cell numbers in response to stress. In control subjects only, exhaled nitric oxide decreased and forced expiratory volume in one second increased during stress. CONCLUSION: Atopic and non-atopic subjects shared some immune changes in response to stress, such as a dramatic decline in cytokines and an increase in the number of regulatory T cells in peripheral blood. However, other stress-induced immune changes were unique to atopic individuals, such as a skewed Th1/Th2 ratio and reduced NK cell numbers, indicating that some pathogenic mechanisms in atopics may be more strongly affected by stress than others. 相似文献
33.
34.
目的探讨急性高血压性脑出血患者细胞间粘附分子-1(ICAM-1)在血肿周围脑组织和正常脑组织中的表达及其意义。方法选择30例行开颅手术治疗的急性高血压性脑出血患者,采用免疫组化技术检测ICAM-1在血肿周围脑组织及正常脑组织中的表达。结果实验组血肿周围脑组织可见ICAM-1的表达水平上调,其表达水平明显高于正常脑组织的表达水平(P<0.01)。神经元和血管内皮细胞共同表达ICAM-1,且神经元表达较明显。结论ICAM-1在人类高血压性脑出血血肿周围脑组织的表达水平上调,其表达上调可能参与了血肿周围脑组织的白细胞浸润,最终引发炎性反应和继发性脑损伤。 相似文献
35.
目的:观察柔肝消瘕饮对肝硬化大鼠肝组织病理形态学和血清、肝组织IL-1β、IL-6含量的影响。方法:采用复合因素造模法复制肝硬化大鼠模型,以复方鳖甲软肝片为对照,观察柔肝消瘢饮对肝硬化大鼠肝组织病理形态学、血清和肝组织IL-1β、IL-6含量的影响。结果:与正常组比较,模型组大鼠出现肝小叶损害,纤维组织增生,假小叶形成,血清IL-1β、IL-6含量和肝组织IL-6含量均明显升高(P〈0.01或P〈0.05);与模型组比较,各治疗组肝组织病理损害减轻,血清IL-1β和肝组织IL-6含量均有明显下降,差异有显著性意义(P〈0.01或P〈0.05);与对照组比较,高剂量组血清IL-6含量明显降低(P〈0.05)。结论:柔肝消瘢饮能显著下调肝硬化大鼠血清IL-1β、IL-6含量和肝组织IL-6含量,具有减轻肝硬化炎症损害,改善肝组织病理形态学作用。 相似文献
36.
韩英 《中国医院用药评价与分析》2007,7(6):421-424
目的:从循证医学的角度解析炎性肠病药物治疗的相关进展。旨在提高对临床证据的认知,帮助临床医生评估新的治疗,从批判的视角重新看待以往的治疗。方法:收集国外近期相关文献进行评价。结果及结论:炎性肠病(IBD)的发病机制尚不清楚,众多的治疗方案可供选择。因此,循证医学研究结果有非常重要的临床指导意义。IBD的研究方面取得了可喜的进步。但是,有关CD活动指数(CDAI)和临床分型系统仍有待于改进。通过循证医学的研究证据有望确定安全和易于耐受的药物,并能发现目前诊治方面存在的缺陷和问题,更好地解决患者的病痛。 相似文献
37.
Modulation of cytokine production from an EpiOcular corneal cell culture model in response to Staphylococcus aureus superantigen 总被引:3,自引:0,他引:3
A Thakur PhD A Clegg MSc A Chauhan MSc MDP Willcox PhD 《Clinical & experimental ophthalmology》1997,25(4):43-45
The present study investigated the hypothesis that Staphylococcus aureus enterotoxin B (SEE) produces epithelial cell death and releases inflammatory cytokines that produce stromal infiltration during contact lens induced peripheral ulceration. Epithelial cells were incubated with different doses of SEB for various time periods. Culture supernatants were assayed for cytokines IL- lo, IL-6 and chemotactic agents IL-8 and LTB,. SEE induced the production of IL- I p and IL-8. Epithelial cells exposed for longer periods (48 h) with low concentrations of SEB produced significantly higher levels (N0.02) of IL-Ip and IL-8 (P<0.05) compared t o a 24 h exposure. SEB did not induce the production o f IL-6 and 相似文献
38.
39.
Masanori Honma Yumiko Hayakawa Hiromi Kosugi Fumitomo Koizumi 《Journal of oral pathology & medicine》1998,27(8):399-404
The expression of mRNA encoding the inflammatory cytokines interleukin-1α (IL-1α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor α (TNF-α) have been examined in radicular cysts by in situ hybridization. Furthermore, the biological activity of the contents of radicular cysts (RCC) has been assayed by adding extracts of RCC to cultured human gingival fibroblasts (HGFs) and analyzing the culture medium for the release of inflammatory cytokines. In the epithelial layer, keratinocytes expressed all cytokine mRNAs examined at various levels. Basal layer cells expressed mRNA for each cytokine. In the subepithelial granulation tissue of the cysts, fibroblasts and macrophages expressed mRNA for IL-6, IL-8, IL-1β and TNF-α mRNA at varying levels; especially clear expression of TNF-α and IL-1β mRNA was detected on macrophages. The infiltrating lymphoid cells, largely composed of T cells and plasma cells, expressed these cytokine mRNAs, especially those encoding IL-6 and IL-8, at various levels. In vitro analysis indicated dose-dependent release of both IL-6 and IL-8 by HGFs in response to RCC. After heating to 100°C for 10 min, RCC almost completely failed to stimulate IL-6 release from HGFs. Furthermore, anti-IL-1β antibody (neutralization test) did not prevent the stimulation of IL-6 release by RCC. Significant amounts of IL-6 and IL-8 were detected in RCC in two cases, and a trace amount of IL-1β was detected in one case. This study demonstrated the wide expression of mRNA encoding inflammatory cytokines in radicular cyst tissues, and RCC itself was capable of stimulating 1L-6 and 1L-8 production from HGFs. 相似文献
40.
Detection of cytoplasmic IL-1 beta in peripheral blood mononuclear cells from intensive care unit (ICU) patients. 总被引:1,自引:0,他引:1 下载免费PDF全文
Cytokines including IL-1 beta have been implicated in the pathophysiology of sepsis and the systemic inflammatory response. It is believed that certain critically ill patients may be 'primed' with respect to cytokine production, and that subsequent 'triggers' may cause exaggerated cytokine production in these patients with exacerbation of their clinical condition; however, no means of identifying 'primed' patients has been described. The presence of cytoplasmic IL-1 beta within peripheral blood mononuclear cells (PBMC) from patients in the ICU was investigated as a means of identifying 'primed' patients, using fluorescent antibody labelling and flow cytometry. The study revealed that PBMC from ICU patients had a different staining pattern for IL-1 beta than those from healthy subjects, and that PBMC from certain ICU patients did indeed stain strongly for IL-1 beta; however, the presence of these strongly staining cells was not associated with clinical condition or outcome. It is concluded that whilst it might be possible to identify 'primed' patients in the ICU using this technique, this is of no clinical value as a predictor of clinical course. 相似文献