全文获取类型
收费全文 | 181932篇 |
免费 | 17312篇 |
国内免费 | 8305篇 |
专业分类
耳鼻咽喉 | 2334篇 |
儿科学 | 4221篇 |
妇产科学 | 1939篇 |
基础医学 | 34035篇 |
口腔科学 | 5545篇 |
临床医学 | 14042篇 |
内科学 | 25464篇 |
皮肤病学 | 4730篇 |
神经病学 | 9988篇 |
特种医学 | 3890篇 |
外国民族医学 | 121篇 |
外科学 | 15573篇 |
综合类 | 27769篇 |
现状与发展 | 55篇 |
预防医学 | 5631篇 |
眼科学 | 3715篇 |
药学 | 14004篇 |
36篇 | |
中国医学 | 5972篇 |
肿瘤学 | 28485篇 |
出版年
2024年 | 430篇 |
2023年 | 2905篇 |
2022年 | 5050篇 |
2021年 | 7062篇 |
2020年 | 6151篇 |
2019年 | 5818篇 |
2018年 | 5928篇 |
2017年 | 6360篇 |
2016年 | 6651篇 |
2015年 | 7420篇 |
2014年 | 10611篇 |
2013年 | 11958篇 |
2012年 | 10111篇 |
2011年 | 11262篇 |
2010年 | 9400篇 |
2009年 | 8984篇 |
2008年 | 9398篇 |
2007年 | 9628篇 |
2006年 | 8796篇 |
2005年 | 8050篇 |
2004年 | 7128篇 |
2003年 | 6186篇 |
2002年 | 5152篇 |
2001年 | 4447篇 |
2000年 | 3650篇 |
1999年 | 3280篇 |
1998年 | 3127篇 |
1997年 | 2837篇 |
1996年 | 2542篇 |
1995年 | 2237篇 |
1994年 | 1974篇 |
1993年 | 1644篇 |
1992年 | 1350篇 |
1991年 | 1297篇 |
1990年 | 980篇 |
1989年 | 916篇 |
1988年 | 870篇 |
1987年 | 732篇 |
1986年 | 670篇 |
1985年 | 873篇 |
1984年 | 792篇 |
1983年 | 539篇 |
1982年 | 595篇 |
1981年 | 447篇 |
1980年 | 373篇 |
1979年 | 284篇 |
1978年 | 193篇 |
1977年 | 155篇 |
1976年 | 118篇 |
1975年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
991.
异体造血干细胞移植的重要并发症是移植物抗宿主病(GVHD),免疫抑制剂是有效防治GVHD的一类药物.在异体造血干细胞移植后应用免疫抑制剂,使得GVHD发生率下降,严重程度减轻.本文对几类主要的免疫抑制剂的作用机理以及在异体造血干细胞移植中作为预防和治疗GVHD的应用作一综述. 相似文献
992.
非小细胞肺癌(NSCLC)是常见的恶性肿瘤,治疗效果不佳,有许多术中证实淋巴结阴性的患者仍在术后出现复发,这可能是由于存在常规病理手段无法发现的微转移病灶所导致。近年来,免疫组化和分子生物学方法已应用于外周血、骨髓及肿瘤附近淋巴结中微转移灶的检测,但是检测微转移灶的指标选择及临床意义目前仍有争论。作者讨论常见的检测NSCLC微转移的方法及检测结果的临床意义。 相似文献
993.
目的:探讨胆囊鳞癌的发病情况、特点、诊断、治疗、预后及预防。方法:结合有关文献复习分析6例胆囊鳞癌的病例。结果:5例行手术治疗,术后两月内死亡3例,另两例至今存活,分别为术后8个月,3个月。1例行B超引导穿刺活检,入院后两周死亡。结论:胆囊鳞癌早期无特异症状,诊断时多已属晚期,手术效果较差。早期诊断、根治性手术有助于胆囊鳞癌的预后。 相似文献
994.
Retrograde endoscopic laser therapy for transitional cell carcinoma of the upper urinary tract 总被引:7,自引:0,他引:7
SOICHI MUGIYA SATOSHI MARUYAMA MASAO NAGATA SHINSUKE HADANO HIROSHI NAGAE 《International journal of urology》2003,10(7):371-376
AIM: The aim of the present study was to investigate the safety and efficacy of endoscopic laser therapy for transitional cell carcinoma (TCC) of the upper urinary tract. METHODS: Tumors of the renal pelvis and ureteropelvic junction were detected by ureteroscopy. The tumors were subjected to biopsy, and after TCC was diagnosed, endoscopic laser therapy (Neodymium-YAG and Holmium-YAG) was conducted using a 6.9 Fr. flexible ureterorenoscope. RESULTS: From January 1997 to April 2002, six patients underwent ureteroscopic treatment. Tumor grade was 1 in four patients and 2 in two patients. Average tumor size was 1.45 cm. Endoscopic treatment was chosen for two patients because of the high medical risk associated with open surgery. Another patient underwent diagnostic ureteroscopy, followed immediately by endoscopic treatment. A further three patients elected to undergo ureteroscopic treatment. One patient with large (3 cm), multifocal and incompletely treated tumors died of metastatic disease 22 months after the initial operation. One patient requested nephroureterectomy one month after endoscopic treatment, and pathological examination of the resected specimen revealed no tumor. The other four patients have been followed up for a mean period of 14 months after initial treatment. Recurrence occurred in one patient, and was successfully treated by repeat endoscopic resection. None of the patients required blood transfusion or emergency open surgery. CONCLUSION: Ureteroscopic treatment of small, localized, low-grade TCC of the upper urinary tract is now a safe and feasible alternative to nephroureterectomy in selected patients. 相似文献
995.
目的 为了降低异基因造血干细胞移植(allo-HSCT)后巨细胞病毒(CMV)感染的相关死亡率,寻求一种更快捷、更特异的诊断CMV感染的分子生物学方法。方法 2001年4月至2003年4月,从79例接受异基因造血干细胞移植的患者中采集了135份外周血标本。采用巢式聚合酶链反应(nested-PCR)方法检测患者外周血中CMVgB DNA,阳性标本做酶切分型,部分行序列测定。结果CMVgB DNA检测中有42例患者(53.9%)的66份标本(48.9%)阳性;对其中阳性患者的45份标本进行了酶切分型,结果 CMV gB1型21例(46.7%),CMV gB2型14例(31.1%),CMV gB3型7例(15.6%),CMV gB4型3例(6.7%)。先后有2种型别的CMV感染者有3例(3.8%)。经分析,CMV gB阳性和CMV gB阴性患者GVHD的发生率分别为81.0%和32.4%(P<0.01);CMV gB1、gB2、gB3以及gB4型Ⅱ~Ⅳ度急性GVHD及慢性GVHD的发生率分别为:81.0%、50.0%、42.9%和0。结论 Nested-PCR方法可快捷特异地检测CMV感染。CMVgB1、2型中,重度急性GVHD和慢性GVHD发生率较高。CMV gB基因分型检测可有效地指导临床抗病毒治疗,且对移植后患者的临床转归有一定的预测价值。 相似文献
996.
目的探讨非清髓异基因外周血造血干细胞移植后致敏供者淋巴细胞输注(DLI)对受者免疫重建及移植物抗宿主病(GVHD)发生率的影响。方法以C57BL/6小鼠(H-2b)为受鼠, BALB/c小鼠(H-2d)为供鼠,建立异基因外周血造血干细胞移植模型(实验组),移植当天受者接受60Coγ射线全身照射,移植后第2天腹腔注射环磷酰胺200 mg/kg。以不行造血干细胞移植,仅行γ射线全身照射和环磷酰胺腹腔注射的正常C57BL/6小鼠为对照。实验组存活小鼠在移植后第28天分别接受致敏供鼠淋巴细胞输注(n=8)、未致敏供鼠淋巴细胞输注(n=8),另有6只不输注供鼠淋巴细胞。移植后检测受者异基因嵌合率,观察GVHD的发生情况以及T淋巴细胞亚群变化,并行供受者间以及供受者与第三方小鼠(昆明鼠)间的单向混合淋巴细胞反应。结果实验组受鼠SRY基因均为阳性,嵌合率为(30.881±3.962)%。DLI后,接受未致敏DLI者均出现不同程度的GVHD,死亡3只(7.5%,3/8),而接受致敏DLI者无明显GVHD及死亡者。移植后45 d,接受致敏DLI者的CD8 T淋巴细胞明显高于正常C57BL/6小鼠(P<0.05),而接受未致敏DLI者的CD8 T淋巴细胞与正常对照的差异无统计学意义(P>0.05),至移植后60 d,接受DLI者的T淋巴细胞亚群接近正常(P>0.05);对照组T淋巴细胞亚群持续低于正常对照(P<0.05)。实验组小鼠淋巴细胞对供者淋巴细胞刺激的反应性均下降(P<0.01),以接受致敏DLI者最明显,而对昆明鼠淋巴细胞刺激的反应性维持正常水平。结论造血干细胞移植后输注致敏供者的淋巴细胞能促进受者的免疫功能重建,并可减少GVHD的发生。 相似文献
997.
Summary In an autopsied case of a 37-year-old man with acquired immune deficiency syndrome (AIDS), multinucleated giant cell encephalopathy was noted in close proximity to multiple nodules of primary lymphoma of the brain. Some multinucleated giant cells and macrophages contained HTLV-III-like viral particles. Nuclear bridges, thin strands connecting individual nuclei with one another, were observed with both light and electron microscopes within some of the multinucleated giant cells. There were also thin tapering nuclear processes, which were probably part of nuclear bridges. The possibility that the nuclear bridges and processes represent amitotic nuclear division is discussed. 相似文献
998.
Neuronal migration and dendritic maturation of the medial cerebellar nucleus in rat embryos: an HRP in vitro study using cerebellar slabs 总被引:2,自引:0,他引:2
The morphological maturation of medial nuclear neurons of fetal rat cerebella was studied using an in vitro assay. Neurons of this nucleus were identified in isolated preparations of rhombencephalon between embryonic days 16 and 20 (E16-E20) by the intracerebellar decussation of their outgrowing axons within the uncinate fascicle. A small crystal of horseradish peroxidase (HRP) applied either in the region containing the inferior cerebellar peduncle or, preferably, in the lateral cerebellum retrogradely labeled contralateral medial nuclear neurons. In the youngest embryos (E16-E17), HRP-marked neurons were situated rostrally at the dorsal surface of the cerebellum. By E18, the cell mass containing labeled neurons had shifted in a rostrocaudal and dorsoventral direction and finally reached the adult position in E19-E20 embryos. Dendritic differentiation of these neurons followed a similar positional gradient, closely corresponding to the pattern of temporal development. From the most immature monopolar forms located dorsally to the virtually adult stellate neurons in a ventral position, it was possible to trace a continuum of intermediary forms grouped into six well-defined stages. Immature monopolar cells first became transversely bipolar. Then, they changed orientation, assuming a longitudinal radial direction. During this stage, neurons sank into the cerebellar parenchyma. As they reached their final destination, these neurons gradually developed dendrites which radiated from the cell body in an adult-like pattern. It is concluded that the medial nuclear neurons occupy a superficial dorsal position in early phases of cerebellar ontogeny, thereafter undergoing a second, inward migration. The main stages of neuronal dendritic differentiation occur between E16 and E20, indicating that the ingrowth of afferent in puts to the medial nucleus most probably occurs rather early and is concomitant with dendritic development. 相似文献
999.
Background Gene therapy by adenovirus-mediated wild-type p53 gene transfer has been shown to inhibit lung cancer growth in vitro, in animal models, and in human clinical trials. The antitumor effect of selective cyclooxygenase (COX)-2 inhibitors has been demonstrated in preclinical studies. However, no information is available on the effects of p53 gene therapy combined with selective COX-2 inhibitor on COX-2 gene expression and growth inhibition of human lung cancer cells. Methods We evaluated the effects of recombinant adenovirus-p53 (Adp53) gene therapy combined with selective CADX-2 inhibitor on the proliferation, apoptosis, cell cycle arrest of human lung adenocarcinoma A549 cell line, and the effects of tumor suppressor exogenous wild type p53 on COX-2 gene expression. Results Ad-p53 gene therapy combined with selective COX-2 inhibitor celecoxib shows significant synergistic inhibition effects on the growth of human lung adenocarcinoma A549 cell line. Exogenous p53 gene can suppress COX-2 gene expression. Conclusions Significant synergistic inhibition effects of A549 cell line by the combined Ad-p53 and selective COX-2 inhibitor celecoxib may be achieved by enhancement of growth inhibition, apoptosis induction and suppression of COX-2 gene expression. This study provides first evidence that the administration of p53 gene therapy in combination with COX-2 inhibitors might be a new clinical strategy for the treatment or prevention of NSCLC. 相似文献
1000.
Monoclonal antibodies (MAbs) against lactoseries carbohydrates were used to study immunohistochemically the olfactory and vomeronasal receptor cells and their axons in the rabbit. MAb 2C5, which recognizes Gal alpha 1----3Gal beta 1----4G1cNAc----R structure, selectively labeled a subset of olfactory receptor cells and the majority of vomeronasal receptor cells. MAb 4C9, which reacts with fucosyl poly-N-acetyllactosamine, identified a subset of vomeronasal receptor cells. The above two MAbs also labeled the axons of these chemosensory receptor cells and thus revealed their axonal projection sites in the main and accessory olfactory bulbs. 相似文献