全文获取类型
收费全文 | 6326篇 |
免费 | 571篇 |
国内免费 | 219篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 400篇 |
妇产科学 | 33篇 |
基础医学 | 801篇 |
口腔科学 | 15篇 |
临床医学 | 385篇 |
内科学 | 486篇 |
皮肤病学 | 44篇 |
神经病学 | 334篇 |
特种医学 | 91篇 |
外科学 | 3015篇 |
综合类 | 640篇 |
现状与发展 | 4篇 |
预防医学 | 282篇 |
眼科学 | 270篇 |
药学 | 210篇 |
中国医学 | 34篇 |
肿瘤学 | 47篇 |
出版年
2024年 | 5篇 |
2023年 | 86篇 |
2022年 | 90篇 |
2021年 | 192篇 |
2020年 | 203篇 |
2019年 | 222篇 |
2018年 | 260篇 |
2017年 | 259篇 |
2016年 | 211篇 |
2015年 | 195篇 |
2014年 | 311篇 |
2013年 | 442篇 |
2012年 | 317篇 |
2011年 | 316篇 |
2010年 | 293篇 |
2009年 | 338篇 |
2008年 | 344篇 |
2007年 | 330篇 |
2006年 | 370篇 |
2005年 | 329篇 |
2004年 | 301篇 |
2003年 | 265篇 |
2002年 | 209篇 |
2001年 | 191篇 |
2000年 | 160篇 |
1999年 | 129篇 |
1998年 | 117篇 |
1997年 | 93篇 |
1996年 | 94篇 |
1995年 | 58篇 |
1994年 | 83篇 |
1993年 | 41篇 |
1992年 | 65篇 |
1991年 | 30篇 |
1990年 | 19篇 |
1989年 | 38篇 |
1988年 | 17篇 |
1987年 | 13篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有7116条查询结果,搜索用时 31 毫秒
101.
临床小肠移植排斥反应的防治 总被引:4,自引:0,他引:4
采用环孢素A、雷公藤多甙、甲基氢化泼尼松、前列腺素E1伍用的新型免疫抑制方案,预防小肠移植排斥反应取得满意效果。病人存活310d。经验表明,通过内窥镜和肠粘膜组织病理检查,监测排斥反应简便实用有效。利用聚合酶链反应(PCR)技术研究发现,移植术后供肠细胞向受体组织移居嵌合,而临床无移植物抗宿主病(GVHD)发生。促进细胞移居嵌合可能有利于防止排斥反应的发生。 相似文献
102.
Changes in lymphocyte subset distribution aid in the differential diagnosis of renal allograft dysfunction 总被引:1,自引:0,他引:1
The distribution of selected lymphocyte subset populations in renal transplant patients was used to assist in the differential diagnosis of graft dysfunction. Patients experiencing dysfunction due to rejection showed consistent and significant decreases in relative numbers of CD 8 (cytotoxic/suppressor) lymphocytes. The ratio of CD 4 cells to CD 8 cells in this group of patients was generally greater than 2.00 due to decreases in CD 8 cells. Patients showing graft dysfunction due to viral infections showed consistent and significant increases in CD 8 cells which also bear the HNK-1 or the HLA-Dr determinants. Serial monitoring for these dual-marked lymphocytes on a weekly basis can be of considerable use in determining the etiology of graft dysfunction. Increases in other "activation" markers, including transferrin receptors, CD 38, and a T cell lineage specific activation antigen (TLiSA) were not specific for rejection; in fact, increases in CD38 were more often associated with viral infections. These studies indicated that lymphocyte subset determinations done on a regular basis can help distinguish graft dysfunction due to viral infections from other causes. The ability to distinguish rejection episodes from stable grafts is less obvious. Although the alterations in lymphocyte subset distribution are not entirely specific, they can distinguish viral infections from rejection. 相似文献
103.
Holán V Vítová A Krulová M Zajícová A Neuwirth A Filipec M Forrester JV 《Immunology letters》2005,100(2):211-213
The effects of passive transfer of antisera containing cytotoxic antibodies to allo- and xenoantigens on survival of corneal allografts and xenografts were evaluated in experimental models. Corneas from allogeneic B10 or xenogeneic rat Lewis donors were grafted orthotopically into BALB/c mice. Recipient mice were treated with donor-specific antisera administered at the period of grafting or at 2 weeks after transplantation. Rejection was determined by the severity of corneal opacity using a standard scoring system. Treatment of graft recipients with donor-specific antisera accelerated the onset of graft rejection and significantly shortened survival times of both corneal allografts and xenografts. Corneal xenografts, which had been accepted after treatment with anti-CD4 monoclonal antibody, were acutely rejected by the passive transfer of antiserum against xenoantigens. The results suggest that corneal grafts are vulnerable to antibody-dependent immunity and that cytotoxic antibodies against graft donor antigens can mediate rejection of both corneal allografts and xenografts. 相似文献
104.
Federica Cavallo Alfonso Martin-Fontecha Matteo Bellone Silvia Heltai Evelina Gatti Paola Tornaghi Massimo Freschi Guido Forni Paolo Dellabona Giulia Casorati 《European journal of immunology》1995,25(5):1154-1162
Although the transfection of B7-1 cDNA into a few mouse tumor cell lines can induce anti-tumor T cell immunity, its expression alone is ineffective in many other tumor cell lines tested. We were interested to study what factors limit B7-1 co-stimulatory activity, and decided to investigate whether B7-1 requires the cooperation of ICAM-1 to provide the minimal co-stimulatory signal for establishing an efficient anti-tumor immunity. We show that the transfection of B7-1 cDNA into three ICAM-1+ (plasmocytoma J558L, T lymphomas EL-4 and RMA), but not into two ICAM-1? tumor cell lines (adenocarcinoma TS/A and melanoma B16.F1), is sufficient to induce their complete rejection in syngeneic mice. The expression of ICAM-1 is necessary for the rejection of the B7 expressing tumors, since the primary response elicited by B7-1+ EL-4 and RMA clones expressing reduced levels of ICAM-1 is severely reduced. Furthermore, super-transfection of ICAM-1 cDNA into B7-1+ adenocarcinoma and melanoma clones optimizes their primary rejection. Histologic examination of transfected tumors reveals that B7-1 and ICAM-1 exert a potent pro-inflammatory activity. The intra-tumor infiltration is composed of both eosinophils and lymphomono-cytes, and is already massive 5 days after the tumor challenge. The primary rejection of the B7-1+ ICAM-1+ tumors depends critically on CD8+ T cells, natural killer cells and granulocytes, but is independent of CD4+ T cells. Remarkably, in addition to its effects on the early phases of the immune response, the co-expression of ICAM-1 and B7-1 on tumors is also necessary for the efficient induction of a memory response. In fact, only the primary challenge with B7-1+, ICAM-1+ tumor cells protects the majority of the mice from a second injection of parental tumor cells. Collectively, our findings indicate that B7-1 and ICAM-1 are fundamental components for triggering the primary rejection of tumors and establishing a protective memory response. These findings may help to define new strategies for the rational application of co-stimulation in tumor immunotherapy. 相似文献
105.
目的:通过对男性抢劫罪犯的人格特征,父母教养方式及二者之间的相关性的分析。探讨早期教育及家庭因素对人格发展的影响,从而为干预和预防犯罪提供依据。方法:使用“艾森克人格问卷”“父母养育方式问卷”对113名男性抢劫罪犯及97名正常男性进行对照分析。结果:EPQ显示抢劫罪犯的精神质与神经均高于对照组,而EMBU显示父母偏爱、拒绝,过度保护、处罚严厉等各因子分均明显高于对照组,而父母的惩罚、严厉、拒绝等与精神质、神经质呈显著负相关。结论,不正确的父母养育方式是人格偏差,以致于从事犯罪的危险因素。 相似文献
106.
目的结合移植物细胞因子表达的实验和临床病例研究,探索早期诊断小肠移植急性排斥反应的细胞因子相关的敏感指标。方法①两例短肠综合症患者接受活体小肠移植术。定期或病情变化时随时行内镜组织学检查并测定受体大鼠移植物sIL-2R、IL-4、IL-6和IFN-γ表达水平。②BN-LEW大鼠部分小肠移植,A组:SBT(n=20);B组:SBT+FK506(2.5mg/kg,n=20),术后第1、4、7、14和30天测定受体大鼠移植物sIL-2R、IL-4、IL-6和IFN-γ水平同时取移植肠黏膜行病理组织学检查。结果首例术后67d发生排斥反应,第2例于术后20d和80d分别发生强烈排斥反应。发生排斥反应相应时相均发生IL-2Rα、IFN-γ表达的显著升高,排斥反应控制后IL-2Rα迅速恢复,但IFN-γ仍在较高水平维持较长时间。A组大鼠术后第1天始即显示IL-2Rα、IFN-γ和IL-6表达的显著升高,于术后7d达到最高,移植后14d仍在高水平。B组仅术后第1天出现IL-2Rα、IFN-γ和IL-6表达的迅速升高,第4天已恢复至基本正常。结论移植物IL-2Rα、IFN-γ表达的升高与小肠移植急性排斥反应密切相关,有望成为早期诊断小肠移植急性排斥反应的敏感指标。 相似文献
107.
目的:研究小鼠同种心脏移植急性排斥反应中淋巴细胞趋化因子(lptn)的表达情况及环孢菌素A(cyclosporine A, CsA)的抑制作用。 方法: 改良Banff评分系统判断同种小鼠移植心急性排斥反应程度,RT-PCR检测移植心组织内淋巴细胞趋化因子表达水平,ELISA方法检测心脏移植小鼠脾细胞活化T细胞核因子(NFAT)活性。 结果: C57BL/6-Balb/c急性排斥组小鼠移植术3 d后脾脏显著增大。术后第5、7 d移植心肌间淋巴细胞浸润程度评分分别为2.667±0.577和2.333±0.577。C57BL/6-Balb/c+CsA组小鼠移植术后脾脏肿大明显减轻,术后第5、7 d心肌间淋巴细胞浸润程度评分分别为1.000±0.000和1.333±0.577。急性排斥组和CsA处理组小鼠移植心脏在术后第5 d和第7 d都可检测到Lptn mRNA阳性表达,但CsA处理组Lptn mRNA的表达明显弱于急性排斥组。治疗剂量的CsA可以完全抑制NFATc1活性。 结论: Lptn在早期移植免疫事件中具有重要的作用,CsA仅能部分抑制Lptn mRNA的表达。活化T细胞Lptn的表达调控存在NFAT以外的途径。 相似文献
108.
A new algorithmic-based digital filter processing system for real-time continuous blood pressure (BP) measurement and analysis in freely-moving conscious rats has been developed. Real-time recognition of BP waveforms, real-time noise rejection and determination of representative waveform indexes (WIs) at indicated time points using digital filters and Smirnov's rejection test were realized with this system. Digital filters were applied for two different purposes: waveform segmentation and smoothing the calculations of representative WIs. Smirnov's rejection test was used for real-time noise rejection and yielded an accurate rejection rate of 99.99%. The result was that the digital filter processing and Smirnov's rejection test realized accurate real-time BP measurement and analysis in freely-moving conscious rats using a personal computer. 相似文献
109.
目的 在同种异体大鼠异位心脏移植模型中 ,探讨TLSFJM对急性移植排斥反应的抑制作用及机制。方法 以F344大鼠作为心脏移植受体 ,以LOU/CN大鼠作为心脏移植供体 ,建立大鼠异位心脏移植模型。受体大鼠分为 3组 ,于移植前后分别施以RPMI16 4 0、CsA或TLSFJM。每天观察移植心脏跳动情况 ,并于停跳当天或之前解剖观察。分别取供体大鼠脾细胞作为刺激细胞 ,取受体大鼠脾细胞作为反应细胞 ,进行单向混合淋巴细胞反应。结果 TLSFJM可明显延长大鼠异位移植心脏的存活时间 :RPMI16 4 0对照组移植心脏的存活期全部为 6d ,TLSFJM治疗组最长均可存活 2 7d ,高剂量 (15mg/kg·d)CsA治疗组存活期超过 2 7d。TLSFJM治疗组大鼠脾细胞增殖的cpm值均低于对照组。结论 TLSFJM具有良好的抗急性移植排斥反应作用。TLSFJM对同种异体抗原诱导T细胞增殖的明显抑制 ,可能是其发挥免疫抑制作用的机制之一 相似文献
110.
Myoblasts fail to stimulate T cells but induce tolerance 总被引:1,自引:0,他引:1
Warrens Anthony N.; Zhang Jun Yan; Sidhu Sid; Watt Diana J; Lombardi Giovanna; Sewry Caroline A; Lechler Robert I. 《International immunology》1994,6(6):847-853
Recent interest in myoblast transfer and in the use of myoblastsas vehicles in gene therapy has made it important to understandthe potential immunogenicity of allogeneic or neoantlgen-expresslngmyoblasts. Given the problems of producing a pure populationof myoblasts, In this study we used a tumour-derived musclecell line (TE671), with phenotyplc features of myoblasts, whichwe transfected to express HLA-DR1. However, this cell line wasunable to stimulate either established HLA-DR1-specific alloreactlveT cell clones or a primary alloresponse. Nor could it presenthaemagglutlnln peptide HA 306–324 to DR1-restricted, HA306–324-speciflc T cell clones or lines. Indeed, prelncubatlonwith DR1-expressing TE671 and HA 306–324 rendered suchT cells tolerant as Judged by their subsequent inability toproliferate in response to a DR1+ B cell line plus peptide HA306–324. These results imply that myoblasts do not providecostlmulatory signals, and are therefore unlikely to stimulateallospeclfic T cells following myoblasts transplantation orto initiate neoantlgen-speclfic immune responses following Invivo transfection. 相似文献