全文获取类型
收费全文 | 5857篇 |
免费 | 648篇 |
国内免费 | 234篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 119篇 |
妇产科学 | 39篇 |
基础医学 | 1249篇 |
口腔科学 | 321篇 |
临床医学 | 506篇 |
内科学 | 1337篇 |
皮肤病学 | 265篇 |
神经病学 | 288篇 |
特种医学 | 77篇 |
外科学 | 331篇 |
综合类 | 842篇 |
预防医学 | 185篇 |
眼科学 | 72篇 |
药学 | 554篇 |
中国医学 | 235篇 |
肿瘤学 | 288篇 |
出版年
2024年 | 1篇 |
2023年 | 64篇 |
2022年 | 65篇 |
2021年 | 174篇 |
2020年 | 164篇 |
2019年 | 254篇 |
2018年 | 263篇 |
2017年 | 237篇 |
2016年 | 213篇 |
2015年 | 214篇 |
2014年 | 406篇 |
2013年 | 360篇 |
2012年 | 333篇 |
2011年 | 380篇 |
2010年 | 294篇 |
2009年 | 239篇 |
2008年 | 255篇 |
2007年 | 236篇 |
2006年 | 209篇 |
2005年 | 215篇 |
2004年 | 218篇 |
2003年 | 308篇 |
2002年 | 291篇 |
2001年 | 216篇 |
2000年 | 175篇 |
1999年 | 200篇 |
1998年 | 167篇 |
1997年 | 131篇 |
1996年 | 82篇 |
1995年 | 56篇 |
1994年 | 55篇 |
1993年 | 47篇 |
1992年 | 30篇 |
1991年 | 34篇 |
1990年 | 26篇 |
1989年 | 28篇 |
1988年 | 18篇 |
1987年 | 10篇 |
1986年 | 11篇 |
1985年 | 43篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有6739条查询结果,搜索用时 15 毫秒
81.
The contribution of interleukins produced by most inflammatory cells to chronic arthritis is not well understood. Therefore, we investigated the influence of several human recombinant interleukins (IL-1β, IL-2 and IL-6) on joint swelling, on the inflammatory process, and on serological parameters in a novel animal model of arthritis, the human/murine SCID arthritis. In this model an arthritis is induced by implanting human synovial tissue from patients with rheumatoid arthritis (RA) into the knee joint of mice with SCID. These mice tolerate the xenogeneic implant and develop a mixed human/murine pannus tissue. The interleukins were injected daily for 7 or 14 days after implantation. IL-1β led to a significant increase in joint swelling. It intensified the inflammatory process accompanied by enhanced migration of murine inflammatory cells into the knee joint. The production of human IL-6 in the transplanted tissue was stimulated through the application of IL-1β, and the serum level of human IL-6 was thus significantly higher than in controls. We could not observe a significant influence of IL-1β on the production of human IgG or IgM by the implant. The application of human IL-2 had a weak effect similar to that of IL-1β, but without statistical significance. Although IL-6 is a good marker for inflammation in RA, the application of recombined human IL-6 had no influence on the inflammatory process in this model. 相似文献
82.
Kazunori Yoneda Tetsuya Yamamoto Eisaku Ueta Tokio Osaki 《Journal of clinical immunology》1992,12(4):289-299
Lymphokine-activated killer (LAK) cells were induced with low-dose recombinant interleukin 2 (rIL-2) and recombinant interferon- (IFN-) in 28 oral carcinoma patients. The patients received daily intravenous injections of rIL-2 (1.2×105 U/m2) and rIFN- (7.0×104 U/m2), and both natural killer (NK) and LAK activities were periodically examined. A significant increase in CD16+CD57+ and CD16+CD57– NK subsets was observed after the induction. An increase in the T-cell population was also found, with a significant increase in CD3+HLA-DR+, CD8+Leu8–, and CD4+Leu8– cells. Significant increases in NK activity, from the original level of 32.0±13.7 to 49.9±15.2%, and LAK activity, from 4.8±3.5 to 11.0±6.1%, at Day 7 were observed. Both activities were maintained at high levels during the cytokine injections, but greater enhancement of the killing activities could not be obtained subsequently. When NK and LAK activities were investigated in each subpopulation of CD3– and CD16– cells, no remarkable cytotoxic activity could be observed before induction in any subset without NK activity in CD3– cells (31.1±14.3%). At Day 7, NK activity of CD16– cells increased up to 21.4±14.9%, accompanied by an increase in CD3–-cell activity (54.5±20.6%). LAK activities of both subsets were also enhanced, with activity at Day 7 of 6.5±5.6 and 9.4±6.6% in CD16– and CD3– cells, respectively. These increased activities were maintained at the same level during the induction. Phorbol myristate acetate-induced polymorphonuclear leukocyte (PMNL) O
2
–
generation was significantly increased, from the original 81.1±28.1 to 95.6±34.9 pmol/min/104 cells, after 1 week of treatment. Protein kinase C activity in the cytosol decreased, and the activity in the membrane fraction conversely increased. No remarkable adverse effects except for mild fever were observed. Together with LAK induction ability and PMNL enhancement, with scarce toxicity, a combination of low-dose rIL-2 and rIFN- is thought to be useful in cancer treatments. 相似文献
83.
Aim: Several studies have shown that a variety of peptides and cytokines are involved in ovarian regulatory mechanisms; however, their exact function is still unclear. In this work we study whether the administration of peptide α‐melanotropin and the cytokines interleukin‐1β (IL‐1β) and tumour necrosis factor‐α (TNF‐α) on their own modify the release of progesterone in cultured granulosa cells (GC) from pro‐oestrous rats. We also investigate an interaction between these cytokines and α‐melanotropin in the modulation of progesterone secretion. Methods: Granulosa cells were collected from the ovaries of female Wistar rats and cultured for up to 24 h in the presence of different concentrations of α‐melanotropin, cytokines or a combination of both. Progesterone concentration was measured by radioimmunoassay. Results: The addition of α‐melanotropin in a dose of 0.01 and 0.1 mm had no effect on progesterone release, whereas a dose of 1 mm significantly increased progesterone release (P < 0.01) compared with the control culture. Progesterone release was not modified when different concentrations of interleukin‐1β or TNF‐α were added to the cell cultures. However, when interleukin‐1β or TNF‐α were added simultaneously with 1 μm α‐melanotropin, a significant reduction (P < 0.01 for interleukin‐1β and P < 0.05 for TNF‐α) of the steroid release was found with respect to the α‐melanotropin‐treated group. Conclusions: These results lead us to suggest that, although α‐melanotropin stimulates progesterone release in pre‐ovulatory GC, this effect is blocked by the presence of interleukin‐1β or TNF‐α. 相似文献
84.
目的探讨TNF-α、IL-6在慢性乙肝不同阶段的作用及双利肝对于两种细胞因子的影响.方法
55 例慢性乙肝患者在治疗前测定血清TNF-α、IL-6水平及肝功能.在一般保肝治疗基础上口服双利肝,在治疗前后测定血清TNF-α、IL-6水平及肝功能.结果随着肝功能损害加重,TNF-α、IL-6水平显著升高(P<0.01,P<0.05),经过双利肝治疗,患者转氨酶、胆红素、TNF-α水平明显下降(P<0.01),IL-6水平略有上升但无显著性差异(P>0.05).结论慢性乙肝病程中,TNF-α与肝细胞坏死程度有关,可作为病情轻重的判别指示.IL-6与肝脏损伤过程有关.双利肝可明显降低慢性乙肝患者TNF-α水平,有效地改善肝功能. 相似文献
85.
目的 观察脑缺血再灌注后白细胞介素 1受体拮抗剂 (IL 1Ra)mRNA的表达。②方法 采用线栓法制备SD大鼠局灶性大脑中动脉阻塞 (MCAO)动物模型 ,应用RT PCR方法观察脑缺血再灌注对大鼠IL 1RamRNA表达的影响。③结果 MCAO模型大鼠缺血侧大脑皮质再灌注后 12 ,2 4h的IL 1RamRNA表达与正常对照组比较明显增加 (F =39.84,q=9.0 3,15 .91,P <0 .0 0 1) ;缺血侧纹状体缺血再灌注后 12h的IL 1RamRNA表达与正常对照组比较明显增加 (F =7.37,q=6 .5 4,P <0 .0 0 1)。④结论 脑缺血后内源性IL 1RamRNA表达增加 ,可能是机体对缺血性损伤的自我保护机制。 相似文献
86.
目的:研究不同透析膜和内毒素对尿毒素对尿毒症患者外周血单个核细胞(PBMC)白细胞介素-1受体拮抗物(IL-1Ra)基因转录和IL-1Ra合成的影响。方法:细胞和不同透析膜孵育后采用细胞原位杂交检测mRNA水平,PBMC培养后采用酶联免疫吸附试验法测定细胞IL-1Ra水平。结果:不同析膜孵育后的PBMC在未用内毒素刺激情况下IL-1RamRNA水平有显著判别,但IL-1Ra合成量无差异。其中正常人仅有极微量IL-1Ra合成;内毒素刺激下的PBMC IL-1Ra合成明显明显高于未刺激组,与铜仿膜孵育后的合成量明显高于聚砜膜孵育后和对照组。结论:内毒素和透析膜对正常人和尿毒症患者PBMC的IL-1Ra的合成协同作用。 相似文献
87.
将一带有人白细胞的介素2cDNA 的大肠杆菌——酵母菌穿酸质粒转化啤酒酵母Saccharomyces cerevisiae 8534-8c,再将转化子与另一啤酒酵母 Saccharomyces cervisiae CSH83—L 进行杂交,得到二倍体菌株.同时,还研究了单倍体转化子和二倍体菌株在表达重组白细胞介素2上的差异以及不同培养条件下二倍体菌株的表达情况,确定了合适的发酵条件,并进行了五立升自动发酵罐的发酵研究. 相似文献
88.
细胞因子的异常表达对骨髓瘤细胞的恶性增殖起重要作用。本文研究了IL-6、IL-1及TNF 对人骨髓瘤细胞系增殖的影响。KM_2、KM,均能分泌IL-6,以维持自身的增殖。培养体系中加入抗IL-6抗体可抑制瘤细胞的增殖,这种抑制作用可通过加入重组IL-6而逆转.在培养体系中加入重组IL-6和TNF 均可促进KM_2、KM_3的增殖,而IL-1无此作用。培养体系中加入TNF 培养后,上清中IL-6活性增高。我们的结果提示,人骨髓瘤细胞系KM_2、KM_3存在IL-6自分泌增殖机制,而TNF 可加强这种自分泌作用。 相似文献
89.
恶性肿瘤患者血清sIL—2R的检测 总被引:22,自引:2,他引:22
本文采用ELISA夹心法,对66例恶性肿瘤患者血清中可溶性白细胞介素2受体进行检测,以39例健康学生做对照,结果显示恶性肿瘤患者血清slL-2R 含量明显高于对照组(P<0.01)。并对血清sIL-2R 水平在肿瘤诊断及预后判断中的意义进行了探讨。 相似文献
90.
The role of serum in interleukin 1 production by human monocytes activated by endotoxins and their polysaccharide moieties 总被引:3,自引:0,他引:3
Lipopolysaccharides (LPS) as well as polysaccharide (PS) moieties of Bordetella pertussis and Neisseria meningitidis endotoxins induced in vitro interleukin 1 (IL 1) secretion by human monocytes as evaluated by the co-mitogenic assay on C3H/HeJ thymocytes. Because of the role of serum in the specific binding of endotoxins to monocytes mediated by the polysaccharide region [12], experiments were undertaken to study the effect of serum on IL 1 induction. Although the presence of serum is not necessary for the secretion of IL 1 by monocytes stimulated by LPS or PS, the addition of very small amounts of human serum (0.1-1.6%) to the cultures of human adherent cells potentiated the IL 1 secretion, without modifying the background values. Natural anti-B. pertussis antibodies present in the serum were not responsible for the observed phenomenon. Heating at 56 degrees C for 30 min did not alter the enhancing effect. The data presented suggest that the serum component(s) and the IL 1 inducers (LPS or PS) act in synergism by two different pathways since the two signals can be delivered sequentially. 相似文献