全文获取类型
收费全文 | 31802篇 |
免费 | 3401篇 |
国内免费 | 572篇 |
专业分类
耳鼻咽喉 | 78篇 |
儿科学 | 1019篇 |
妇产科学 | 170篇 |
基础医学 | 2544篇 |
口腔科学 | 162篇 |
临床医学 | 5759篇 |
内科学 | 5836篇 |
皮肤病学 | 204篇 |
神经病学 | 3762篇 |
特种医学 | 790篇 |
外科学 | 1112篇 |
综合类 | 5001篇 |
现状与发展 | 2篇 |
预防医学 | 3162篇 |
眼科学 | 265篇 |
药学 | 2870篇 |
43篇 | |
中国医学 | 2155篇 |
肿瘤学 | 841篇 |
出版年
2024年 | 142篇 |
2023年 | 601篇 |
2022年 | 1443篇 |
2021年 | 1919篇 |
2020年 | 2120篇 |
2019年 | 1482篇 |
2018年 | 1535篇 |
2017年 | 1621篇 |
2016年 | 1636篇 |
2015年 | 1440篇 |
2014年 | 2854篇 |
2013年 | 2815篇 |
2012年 | 2213篇 |
2011年 | 2264篇 |
2010年 | 1619篇 |
2009年 | 1387篇 |
2008年 | 1239篇 |
2007年 | 1238篇 |
2006年 | 1064篇 |
2005年 | 830篇 |
2004年 | 751篇 |
2003年 | 696篇 |
2002年 | 467篇 |
2001年 | 349篇 |
2000年 | 286篇 |
1999年 | 255篇 |
1998年 | 215篇 |
1997年 | 191篇 |
1996年 | 137篇 |
1995年 | 149篇 |
1994年 | 113篇 |
1993年 | 87篇 |
1992年 | 98篇 |
1991年 | 73篇 |
1990年 | 59篇 |
1989年 | 59篇 |
1988年 | 49篇 |
1987年 | 33篇 |
1986年 | 32篇 |
1985年 | 43篇 |
1984年 | 27篇 |
1983年 | 26篇 |
1982年 | 18篇 |
1981年 | 20篇 |
1980年 | 15篇 |
1979年 | 20篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 11篇 |
1975年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
应用HAg 18-1 ELIsA诊断药盒,对原发性肝癌(PHc)、肝炎及肝炎伴有肝硬化、其他癌(肺癌、胃癌、结肠癌)以及正常人,共400例,进行了血清学的检测。结果显示:HAg 18-1 ELISA阳性检测率,PHC为81%,肝炎及伴有肝硬化为30%,肺癌为36%,胃癌为28%,结肠癌为12%,正常人为0。PHC组HAg 18-1 ELISA检测阳性率显著高于其他各组(P<0.05)。此外PHC 80例中有56例同时伴有AFP的检测,其中AFP 17/56阴性,17例阴性中HAg 18-1 ELISA检测阳性10例(59%),故对AFP检测PHC具有明显协同和补充诊断价值。此药盒操作简便,易于推扩,对PHC的临床诊断和普查提供了新方法。 相似文献
73.
以51例晚期肿瘤患者作为研究对象,对其不同来源的肿瘤浸润淋巴细胞(TIL)进行治疗研究,发现肿瘤组织来源的TIL其有效率及一年生存率明显高于胸腹水及转移淋巴结的TAL;其中肿瘤组织的TIL,胸腹水、转移淋巴结的TAL有效率分别为80.9%、40.0%、46.6%;三者治疗肿瘤患者的一年生存率分别为81.0%、46.7%、60.0%;另外发现胸腹水TAL对实质性肿块治疗疗效较低,为40%,其中静脉滴 相似文献
74.
目的了解糖类代谢相关基因在大鼠肝再生中的表达变化。方法本研究用搜集网站资料和查阅相关论文等方法获得糖类代谢相关基因,用大鼠基因组230 2.0芯片检测它们在大鼠再生肝中的表达情况,用比较手术组和假手术组中基因表达的差异性确定肝再生相关基因。结果初步证实上述基因中118个基因与肝再生相关。肝再生早期[部分肝切除(PH)后0.5~4h]、前期(PH后4~12h)、中期(PH后16~66h)和后期(PH后72~168h)等4个阶段起始表达的基因数为33、6、68和7;基因的总表达次数为68、44、210和83。表明肝再生相关基因主要在肝再生启动阶段起始表达,在不同阶段发挥作用。它们共上调205次,下调200次,分为12种表达方式,表明肝再生中糖代谢活动多样和复杂。其中,单糖和糖原代谢、糖蛋白和糖脂(主要为神经节苷脂)合成相关基因几乎在整个肝再生中表达增强,寡糖和糖胺聚糖合成及糖蛋白和糖脂分解相关基因表达下调。结论肝再生与糖代谢密切相关。 相似文献
75.
Cytokine responses to the native and recombinant forms of the major surface glycoprotein of Pneumocystis carinii 下载免费PDF全文
S A THEUS A G SMULIAN D W SULLIVAN P D WALZER 《Clinical and experimental immunology》1997,109(2):255-260
Pneumocystis carinii is a major opportunistic pathogen and leading cause of morbidity in patients with AIDS. The major surface glycoprotein (MSG) of P. carinii, represented by a family of related proteins encoded by unique genes, is highly immunogenic and contains T cell-protective epitopes. We undertook the present study to define the CD4 T helper (Th) response by cytokine secretion to native MSG and a recombinant form of the protein, MSG-B. Spleen cells were collected from Lewis rats and restimulated with both native MSG and MSG-B. Within 24 h, the CD4 cells secreted high levels of interferon-gamma (IFN-γ) in response to both types of antigen, indicative of a Th1 response; however, after 72 h of incubation, only the native MSG stimulated secretion of IL-4 (Th2 response) from the cells. We then investigated whether the presence of IL-4 could alter the predominant Th1 phenotype by the CD4 cells in response to MSG and MSG-B. Cells cultured with native MSG and IL-4 produced low levels of IFN-γ and elevated levels of IL-4. Interestingly, cells incubated with MSG-B and IL-4 reduced production of IFN-γ, but were not stimulated to produce increased levels of IL-4. The presence of anti-IFN-γ antibody in the MSG- or MSG-B-stimulated cultures did not effect the expression of IFN-γ mRNA, suggesting that the generation of Th1 cells in response to MSG or MSG-B was not dependent on IFN-γ. We conclude that native MSG, which contains multiple forms of this antigen, and recombinant MSG elicit different cytokine responses in vitro. These data are not only important to studies of MSG, but may also be relevant to the role of MSG in the immunopathogenesis of P.carinii infection in vivo. 相似文献
76.
Neuroprotective effects of IGF-I against TNFalpha-induced neuronal damage in HIV-associated dementia
Ying Wang J Peruzzi F Lassak A Del Valle L Radhakrishnan S Rappaport J Khalili K Amini S Reiss K 《Virology》2003,305(1):66-76
Human immunodeficiency virus type 1 (HIV-1) infection often results in disorders of the central nervous system, including HIV-associated dementia (HAD). It is suspected that tumor necrosis factor-alpha (TNFalpha) released by activated and/or infected macrophages/microglia plays a role in the process of neuronal damage seen in AIDS patients. In light of earlier studies showing that the activation of the insulin-like growth factor I receptor (IGF-IR) exerts a strong neuroprotective effect, we investigated the ability of IGF-I to protect neuronal cells from HIV-infected macrophages. Our results demonstrate that the conditioned medium from HIV-1-infected macrophages, HIV/CM, causes loss of neuronal processes in differentiated PC12 and P19 neurons and that these neurodegenerative effects are associated with the presence of TNFalpha. Furthermore, we demonstrate that IGF-I rescues differentiated neurons from both HIV/CM and TNFalpha-induced damage and that IGF-I-mediated neuroprotection is strongly enhanced by overexpression of the wt IGF-IR cDNA and attenuated by the antisense IGF-IR cDNA. Finally, IGF-I-mediated antiapoptotic pathways are continuously functional in differentiated neurons exposed to HIV/CM and are likely supported by TNFalpha-mediated phosphorylation of I(kappa)B. All together these results suggest that the balance between TNFalpha and IGF-IR signaling pathways may control the extent of neuronal injury in this HIV-related experimental setting. 相似文献
77.
目的在基因转录水平了解脂类代谢和运输相关基因在大鼠肝再生(LR)中的表达变化和模式。方法用搜集网站资料和查阅相关论文等方法获得参与脂类代谢和运输基因,用大鼠基因组230 2.0芯片检测它们在大鼠再生肝中的表达情况,用比较手术和假手术中基因表达的差异性确定肝再生相关基因。结果初步证实上述基因中193个基因与肝再生相关。肝再生早期[部分肝切除(PH)后0.5~4h]、前期(PH后6~12h)、中期(PH后12~66h)、后期(PH后72~168h)等4个阶段起始表达的基因数为113、20、66和1;基因的总表达次数为250、205、796和293。共上调852次,下调630次,分为27种表达方式。肝再生早期和前期胆汁酸代谢相关基因转录减弱;早期和后期糖皮质激素分解相关基因转录增强;前期和中期磷脂合成相关基因转录增强,磷脂分解相关基因转录减弱;中期脂肪酸、白三烯和鞘糖脂合成相关基因转录增强,甘油三酯和磷脂酰肌醇代谢相关基因转录增强,鞘糖脂分解相关基因转录减弱;中期和后期前列腺素合成和脂肪酸分解相关基因转录增强;几乎在整个肝再生中性激素、糖皮质激素和孕酮合成相关基因转录增强,鞘磷脂代谢相关基因转录增强,脂类运输相关基因转录增强,胆固醇代谢相关基因转录减弱。结论肝再生中脂类代谢和运输变化较大,与肝再生密切相关。 相似文献
78.
脑卒中患者抑郁情绪的初步调查 总被引:2,自引:0,他引:2
赵俊宏 《中国临床心理学杂志》2002,10(1):44-44,46
脑血管病后出现的抑郁情绪是脑卒中常见的并发症 ,抑郁情绪在一定程度上影响卒中患者的肢体功能和社会生活能力的恢复。有流行病学调查发现 ,脑卒中后抑郁的发生率为 4 0 %~ 5 0 % [1] ,然而对脑卒中患者抑郁情绪的特点少有报道 ,为观察脑卒中对患者心理的影响 ,我们对 6 3例脑卒中患者的抑郁水平进行了分析。1 对象与方法1.1 研究对象6 3例患者均为我院住院患者 ,经颅脑CT或MR确诊。其中缺血性脑卒中 4 7例 ,出血性脑卒中 16例。首次发病 38例 ,两次及两次以上发病 2 5例。男性 4 0例 ,女性 2 3例。年龄最大 82岁 ,最小 38岁 ,平均 … 相似文献
79.
Masahiro Yasuda Shogo Tanaka Hiroshi Arakawa Yasuho Taura Yuichi Yokomizo Shigeo Ekino 《Anatomical record (Hoboken, N.J. : 2007)》2002,266(4):207-217
The calf contains two types of Peyer's patches (PPs): jejunal and ileal. The ileal PP has been thought to be equivalent to the bursa of Fabricius (BF) as a central lymphoid organ. The morphologies of ileal and jejunal PPs in the calf were compared with those of the BF and the caecal tonsil (CT) in the chicken. Immunoglobulin G–positive (IgG+) cells appear in the follicles of them all and exhibited a dendritic appearance after birth. We investigated whether the IgG in these follicles was produced in situ. IgG‐producing cells were detected in the follicular medullas of the jejunal PP and the CT, but not in those of the ileal PP and the BF. CD4+ cells were distributed in the follicular medullas of the jejunal PP and the CT, but not in those of the ileal PP and the BF. The data suggest that Ig class switching occurs in both jejunal PP follicles and CT follicles, but does not occur in either the ileal PP follicles or the bursal follicles. Because CD4+ T cells would be prerequisite for Ig class switching in these follicles, IgG+ cells of the follicular medullas in the ileal PP and the BF would trap immune complexes from the gut lumen. The primary B‐cell repertoire might be selected by gut‐derived antigens in the ileal PP and the BF before seeding the periphery. Anat Rec 266:207–217, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
80.
Korppi M 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2002,110(7-8):515-522
Seven paediatric studies on community-acquired pneumonia with serological methods for both viruses and bacteria have been published, allowing the evaluation of concomitant multiple etiological findings. In these studies, dual viral infection has been present in 0-14%, dual bacterial infection likewise in 0-14%, and mixed viral-bacterial infection in 3-30% of the pneumonia cases. The results confirm former clinical observations that respiratory viruses often pave the way for airway-colonising bacteria. The measured frequency of multiple infections has been dependent on the available test panel, mainly on the tests used for pneumococcal aetiology. Mixed viral-bacterial infections have been especially common in young children under 2 years of age, reflecting the high frequency of respiratory syncytial virus infections and their tendency to induce bacterial co-infections. No microbe-specific viral-bacterial associations have been demonstrated. The clinical implications of mixed viral-bacterial infections, compared with viral infections alone or bacterial infections alone, have so far remained unresolved. Current guidelines recommend antibiotic therapy for all community-acquired pneumonia cases in children. 相似文献