全文获取类型
收费全文 | 17706篇 |
免费 | 1452篇 |
国内免费 | 574篇 |
专业分类
耳鼻咽喉 | 154篇 |
儿科学 | 401篇 |
妇产科学 | 437篇 |
基础医学 | 3902篇 |
口腔科学 | 339篇 |
临床医学 | 1268篇 |
内科学 | 2990篇 |
皮肤病学 | 697篇 |
神经病学 | 1121篇 |
特种医学 | 210篇 |
外国民族医学 | 1篇 |
外科学 | 1586篇 |
综合类 | 2378篇 |
现状与发展 | 1篇 |
预防医学 | 766篇 |
眼科学 | 182篇 |
药学 | 1748篇 |
3篇 | |
中国医学 | 560篇 |
肿瘤学 | 988篇 |
出版年
2024年 | 33篇 |
2023年 | 216篇 |
2022年 | 364篇 |
2021年 | 635篇 |
2020年 | 654篇 |
2019年 | 555篇 |
2018年 | 545篇 |
2017年 | 653篇 |
2016年 | 746篇 |
2015年 | 773篇 |
2014年 | 1243篇 |
2013年 | 1320篇 |
2012年 | 1177篇 |
2011年 | 1352篇 |
2010年 | 1073篇 |
2009年 | 913篇 |
2008年 | 898篇 |
2007年 | 811篇 |
2006年 | 708篇 |
2005年 | 628篇 |
2004年 | 575篇 |
2003年 | 442篇 |
2002年 | 321篇 |
2001年 | 256篇 |
2000年 | 271篇 |
1999年 | 189篇 |
1998年 | 187篇 |
1997年 | 230篇 |
1996年 | 294篇 |
1995年 | 285篇 |
1994年 | 219篇 |
1993年 | 206篇 |
1992年 | 115篇 |
1991年 | 103篇 |
1990年 | 78篇 |
1989年 | 61篇 |
1988年 | 49篇 |
1987年 | 49篇 |
1986年 | 40篇 |
1985年 | 50篇 |
1984年 | 69篇 |
1983年 | 54篇 |
1982年 | 58篇 |
1981年 | 46篇 |
1980年 | 38篇 |
1979年 | 34篇 |
1978年 | 20篇 |
1977年 | 22篇 |
1976年 | 22篇 |
1975年 | 18篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
目的研究六味通脉胶囊对动脉硬化闭塞症(ASO)患者外周血白细胞介素-6(IL-6)和肿瘤坏死因子-α(TNF-α)含量变化及T细胞亚群的影响,并进一步探讨该复方中药抗ASO的作用机制。方法将93例符合入选标准的ASO患者,采用双盲双模拟研究方法,随机分为治疗组和对照组,从T细胞亚群(CD3+、CD4+、CD8+、CD4+/CD8+)I、L-6、TNF-α含量变化等方面进行前瞻性对比治疗研究。结果ASO患者存在免疫功能的低下,血液IL-6、TNF-α含量明显升高,与健康人比较有显著性差异(P<0.05或0.01)。经3个疗程的治疗后,2组患者的各观察指标均有不同程度的改善,与治疗前比较有显著性差异(P<0.05或0.01);治疗后治疗组与对照组比较,有显著性差异(P<0.05或0.01)。结论六味通脉胶囊能明显提高免疫功能,降低血液IL-6、TNF-α的含量。六味通脉胶囊对ASO患者的预后影响与提高免疫功能及降低血液IL-6、TNF-α的含量有关。 相似文献
72.
[目的]探讨干扰素-γ(IFN-γ)对支气管哮喘(哮喘)小鼠气道炎症及肺T淋巴细胞和血浆中IgE的影响。[方法]C57BL/6小鼠随机分为正常对照组(A组,10只)、哮喘模型组(B组,10只)、IFN-γ注射组(C组,10只)。采用卵蛋白(OVA)和氢氧化铝致敏、雾化建立哮喘模型,B组、C组分别在致敏同时第1、3、5、9、15、17、20 d,1次/d腹腔注射生理盐水(0.1 m1)和IFN-γ(1 500U)。第22 d收取肺泡灌洗液(BALF)并取其肺T淋巴细胞体外培养及血浆中IgE。分析小鼠BALF和肺部淋巴细胞产生的细胞因子IL-4、IL-5及血浆中IgE水平的变化。[结果]A组无症状,B组哮喘鼠症状重,C组哮喘鼠症状轻。在BALF中嗜酸性粒细胞百分比(EOS%)计数A组0,B组20.1±7.0,C组0.7±0.2。哮喘模型组肺T淋巴细胞中IL-4、IL-5,血浆中IgE显著高于正常对照组(P<0.01),治疗组肺T淋巴细胞中IL-4、IL-5,血浆中IgE显著低于哮喘模型组(P<0.01)。[结论]IFN-γ可以抑制哮喘小鼠气道炎症,其机制之一可能与是抑制肺T淋巴细胞产生的IL-4、IL-5,降低血清中总IgE水平有关。 相似文献
73.
Y. J. LIM A. B. W. YONG G. L. WARNE J. MONTALTO 《Journal of paediatrics and child health》1995,31(1):47-50
Objectives: The study was designed to assess the reliability of measurement of 24-hour urinary 17α-hydroxyprogesterone (17-OHP) by radio-immunoassay (RIA) as an alternative biochemical assessment for monitoring the treatment of congenital adrenal hyperplasia (CAH) due to 21 -hydroxylase deficiency (21 -OHD) and to assess the need for sample purification by column chromatography to improve assay specificity.
Methodology: Morning serum 17-OHP was measured using RIA and 24-hour urinary pregnanetriol using gas chromatography. Twenty-four-hour urinary 17-OHP was measured in samples from 17 prepubertal patients with CAH due to 21 -OHD, and 20 normal prepubertal children as controls. In 24 urine samples, RIA of 17-OHP was performed with and without column chromatography.
Results: There was a good correlation between 24-hour urinary 17-OHP and 24-hour urinary pregnanetriol (r = 0.962, P <0.01) and between 24-hour urinary 17-OHP and morning serum 17-OHP ( r = 0.955, P <0.01). There was no significant difference in the RIA of the urine samples with and without purification by column chromatography.
Conclusions: The measurement of 24-hour urinary 17-OHP is a reliable alternative for the biochemical monitoring of 21-OHD, and RIA specificity is unaffected by omission of column chromatography. 相似文献
Methodology: Morning serum 17-OHP was measured using RIA and 24-hour urinary pregnanetriol using gas chromatography. Twenty-four-hour urinary 17-OHP was measured in samples from 17 prepubertal patients with CAH due to 21 -OHD, and 20 normal prepubertal children as controls. In 24 urine samples, RIA of 17-OHP was performed with and without column chromatography.
Results: There was a good correlation between 24-hour urinary 17-OHP and 24-hour urinary pregnanetriol (r = 0.962, P <0.01) and between 24-hour urinary 17-OHP and morning serum 17-OHP ( r = 0.955, P <0.01). There was no significant difference in the RIA of the urine samples with and without purification by column chromatography.
Conclusions: The measurement of 24-hour urinary 17-OHP is a reliable alternative for the biochemical monitoring of 21-OHD, and RIA specificity is unaffected by omission of column chromatography. 相似文献
74.
Decorin, a collagen-binding small proteoglycan, is considered to have a specific function in the organization or stability of the collagen network. Therefore, alteration of its molecular properties may be of pathophysiological relevance during the development of cartilage damage. It is shown here that normal cartilage from rabbit knee-joint contains glycosaminoglycan chain-bearing core protein fragments of 39, 23, and 18 kDa, each one amounting to approximately 5-6% of the intact decorin core protein. Continuous infusion of human recombinant interleukin-1 alpha for 14 days (200 ng/day) into a knee-joint led in condylar cartilage to a reduction in the amount of intact core protein from 2 micrograms/mg wet tissue to about 1.1 micrograms/mg. The increase in its quantity found after infusion of heat-inactivated interleukin-1 was not statistically significant. The concentration of all three core protein fragments became reduced to a similar extent as the intact core protein under the influence of the cytokine, and additional fragments were not found. Surprisingly, there was a much smaller response to interleukin-1-treatment in patellar cartilage. 相似文献
75.
Benjamin Sadlack Ralf Kühn Hubert Schorle Klaus Rajewsky Werner Müller Ivan Horak 《European journal of immunology》1994,24(1):281-284
Interleukin (IL)-2 and IL-4 are considered as important regulators of growth and differentiation of lymphocytes. We report that in mice made deficient for both IL-2 and IL-4 by gene targeting all major T cell subsets and B cells were normal, indicating that IL-2 and IL-4 are not essential for development of the immune system. Paradoxically, proliferation of T cells was increased in both IL-2- and IL-4-deficient homozygous mice. 相似文献
76.
精神分裂症患者致炎性细胞因子和酪氨酸羟化酶mRNA表达水平的研究 总被引:1,自引:1,他引:0
目的探讨精神分裂症的外周神经免疫机制及其与临床症状的关系。方法检测精神分裂症患者致炎性细胞因子白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF—α)以及酪氨酸羟化酶(TH)的mRNA表达水平,采用逆转录-聚合酶链反应及半定量检测技术,分别检测39例精神分裂症患者(患者组)、25例同胞(同胞组)及30名正常对照(对照组)外周血单个核细胞(PBMC)IL-1β、TNF-α及TH基因表达水平,同时应用阳性和阴性症状量表(PANSS)评定精神分裂症患者临床症状。结果患者组、同胞组及对照组IL-1β的mRNA表达水平分别为1.52±1.01、1.52±1.09和0.74±0.38;TNF—α的mRNA表达水平分别为1.18±0.99、1.01±0.87和0.70±0.29;TH的mRNA表达水平分别为0.55±0.33、0.61±0.32和0.28±0.20。患者组和同胞组的IL-1β、TNF—α、TH的mRNA表达水平均明显高于对照组(P〈0.05或P〈0.01)。患者组IL-1β(r=0.420)、TNF—α(r=0.430)的mRNA表达水平与PANSS的-般病理症状分呈正相关(P〈0.01)。同胞组与对照组合并统计,IL-1β与TNF-α的mRNA表达水平呈正相关(r=0.847,P〈0.01);IL-1β与TH的mRNA表达水平呈正相关(r=0.666,P〈0.01)。患者组仅IL-1β与TNF—α的mRNA表达水平呈正相关(r=0.942,P〈0.01)。结论精神分裂症患者PBMC细胞TH、IL-1β和TNF—α的mRNA表达水平高于正常,且与精神分裂症的-般病理症状显著相关。 相似文献
77.
休克期切痂对烫伤大鼠全身和肠道局部免疫功能的影响 总被引:3,自引:3,他引:0
目的 观察休克期切痂对烫伤大鼠全身和肠道局部免疫功能的影响 ,探讨其可能的机制。 方法 选用 96只Wistar大鼠。取其中 2 4只大鼠的躯干部皮肤冻存于液氮中 ,另取 8只作正常对照组。余下 6 4只造成 30 %TBSAⅢ度烫伤后 ,随机分为A组 2 4只 ,伤后不作任何处理 ;B组 2 4只 ,伤后 2 4h腹腔注射等渗盐水 5 0ml/kg,一次性切痂后用上述冻存异体皮覆盖 ;C组 1 6只 ,伤后 72h进行处理 ,方法同B组。检测A、B组大鼠伤后 2、4、8d和C组伤后 4、8d及正常对照组大鼠的脾淋巴细胞增殖功能、血浆和肠组织白细胞介素 (IL)2水平、肠黏液分泌型免疫球蛋白A(sIgA)及肠组织中二胺氧化酶 (DAO)含量的变化。 结果 各时相点下A、B、C组大鼠脾淋巴细胞增殖功能、血浆IL 2水平、肠组织IL 2及肠黏液sIgA含量均较正常对照组减少。B组伤后 4、8d和C组伤后 8d的脾淋巴细胞增殖功能接近正常对照组 ,血浆和肠组织IL 2水平明显高于A组 (P <0.0 1)。伤后 4、8d,B组肠黏液sIgA含量分别为 (3.5 1± 2 .1 4 )、(3.0 3± 0 .95 )mg/g,C组分别为 (1 .4 0± 0 .6 4 )、(1 .5 2± 1 .2 6 )mg/g,B组较C组增加近 1倍 (P 0.0 1 )。A组伤后 4、8d肠组织DAO活性低于正常对照组和B组 (P 0.0 5)。结论 休克期切痂有助于烫伤大鼠全身和肠道 相似文献
78.
Peripheral and central injections of recombinant human interleukin-1β (IL-1β) have been shown to decrease social exploration and to induce body weight loss in rats. To characterize the receptor mechanisms of these effects, we used as a tool a specific antagonist of the receptors of IL-1, IL-1ra. Intraperitoneal (i.p.) administration of IL-1ra (8 mg/kg) blocked the effect of i.p. injection of IL-1β (4 μg/rat) on social behaviour but not on body weight. Central administration of IL-1ra (60 μg/rat, i.c.v.) abrogated the effects of centrally administered IL-1β (30 ngn/rat, i.c.v.) on both social behaviour and body weight. Central injection of IL-1ra (4 μg/rat, i.c.v.) also attenuated the effects of i.p. administered IL-1β (4 μg/rat) on social behaviour but not on body weight. These results suggest that the effects of IL-1β on social behavior are mediated centrally and that its effect on the loss of body weight involves different receptor mechanisms. 相似文献
79.
Inhibition of tissue factor surface expression in human peripheral blood monocytes exposed to cytokines 总被引:1,自引:0,他引:1
Interleukin (IL)-4, IL-10, IL-13 and transforming growth factor beta (TGF-β) are known to regulate several monocyte functions, including inhibition of the synthesis of different cytokines. Using quantitative RT-PCR and flow cytometry analysis we investigated the effects of these cytokines on bacterial lipopolysaccharide (LPS)-induced tissue factor (TF) expression in human monocytes. The effects of IL-4 and IL-10 on monocyte chemoattractant protein-1 (MCP-1)- and C-reactive protein (CRP)-induced TF expression were also studied. A direct comparison revealed that IL-4, IL-10 and IL-13 all down-regulated LPS-induced TF expression in a concentration-dependent manner without the need for priming. In contrast, TGF-β required 4 h of priming to inhibit TF expression induced by LPS. IL-10 was the most powerful inhibitor, causing almost complete inhibition at 5 ng/ml. IL-4 and IL-13 exhibited a significantly lower inhibitory capacity even at concentrations of 100 ng/ml. IL-4 and IL-10 showed similar concentration-dependent inhibition of MCP-1- and CRP-induced TF expression. We also showed that the regulatory effect of the interleukins occurred at the mRNA level. In vivo , these inhibitory cytokines may play an important regulatory role in preventing thrombosis. IL-10, in particular, may be a possible candidate as a TF-preventing drug. 相似文献
80.
Yuta Ishizuka Yasushi Ishida Qing-Hua Jin Ayumi Shimokawa Mitsuhiko Saita Kazuo Kato Takato Kunitake Takamitsu Hanamori Yoshio Mitsuyama Hiroshi Kannan 《Brain research》1998,789(1):10
Nitric oxide (NO) has recently been shown to modulate the hypothalamic–pituitary–adrenal axis response to interleukin-1β (IL-1β). We measured levels of nitrite (NO2−) and nitrate (NO3−) in the hypothalamic paraventricular nucleus (PVN) region using an in vivo brain microdialysis technique in conscious rats. Intraperitoneally administered IL-1β produced a significant increase in both NO2− and NO3− levels in the PVN region. We also examined the possible involvement of the abdominal vagal afferent nerves in this effect. In abdominal-vagotomized rats, the increase was significantly attenuated compared to that in sham-operated rats. Our results suggest that the abdominal vagal afferent nerves are involved in intraperitoneally administered IL-1β-induced NO release in the PVN region. 相似文献