首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   35202篇
  免费   3173篇
  国内免费   1825篇
耳鼻咽喉   636篇
儿科学   504篇
妇产科学   820篇
基础医学   4159篇
口腔科学   566篇
临床医学   4133篇
内科学   6036篇
皮肤病学   810篇
神经病学   1903篇
特种医学   1205篇
外国民族医学   17篇
外科学   3607篇
综合类   4302篇
现状与发展   4篇
一般理论   7篇
预防医学   2250篇
眼科学   786篇
药学   3633篇
  22篇
中国医学   1671篇
肿瘤学   3129篇
  2024年   60篇
  2023年   424篇
  2022年   663篇
  2021年   1542篇
  2020年   1115篇
  2019年   1172篇
  2018年   1293篇
  2017年   1105篇
  2016年   1055篇
  2015年   1571篇
  2014年   1918篇
  2013年   1911篇
  2012年   2685篇
  2011年   2821篇
  2010年   1799篇
  2009年   1343篇
  2008年   1935篇
  2007年   1848篇
  2006年   1869篇
  2005年   1831篇
  2004年   1341篇
  2003年   1277篇
  2002年   1095篇
  2001年   912篇
  2000年   834篇
  1999年   754篇
  1998年   458篇
  1997年   411篇
  1996年   337篇
  1995年   310篇
  1994年   276篇
  1993年   198篇
  1992年   327篇
  1991年   284篇
  1990年   218篇
  1989年   171篇
  1988年   192篇
  1987年   151篇
  1986年   123篇
  1985年   117篇
  1984年   84篇
  1983年   44篇
  1982年   25篇
  1981年   34篇
  1980年   21篇
  1979年   32篇
  1978年   24篇
  1977年   18篇
  1975年   18篇
  1973年   24篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
81.
目的应用抗核抗体独特型多肽免疫治疗狼疮肾炎小鼠,观察其对狼疮肾炎模型小鼠肾脏的保护作用。方法将35只雌性GVHD狼疮样肾炎小鼠(C57BL/10×DBA/2)F1分为3组,肾炎模型对照组(10只),口服多肽实验组(10只),皮下注射多肽实验组(15只)。3组小鼠均于24周龄处死,观察3组小鼠体质量、尿蛋白、肾脏组织学及血清IL-6水平的变化。结果在给予多肽12周时,皮下注射组和口服多肽组小鼠肾脏损害较对照组明显减轻;血清IL-6水平也较对照组明显降低。在给予多肽10周时,皮下注射组小鼠体质量明显高于对照组小鼠,12周时口服组体质量也明显高于对照组。给予多肽4周时,皮下注射组小鼠尿蛋白明显少于对照组,8周时口服组尿蛋白也明显少于对照组。结论口服独特型多肽对GVHD狼疮样肾炎小鼠肾脏同样有保护作用。  相似文献   
82.
The purpose of this study was to investigate whether (18)F-FDG PET/CT is useful for localizing dystonic cervical muscles in patients with idiopathic cervical dystonia (ICD) by comparing disease severity before and disease severity after botulinum toxin (BT) injection into hypermetabolic muscles. METHODS: Six patients with ICD underwent (18)F-FDG PET/CT. Dystonic muscles suitable for BT injection therapy were defined as those showing diffusely increased (18)F-FDG uptake. RESULTS: Hypermetabolic cervical muscles were identified in all 6 patients. In 2 patients who underwent PET/CT both in a supine position and in a sitting position during (18)F-FDG uptake, abnormal hypermetabolic muscles were observed by PET/CT only when patients were in the sitting position with their heads and necks in the adopted abnormal involuntary posture. Symptoms were significantly improved in 4 patients who underwent BT injection therapy guided by PET/CT and who were clinically monitored. CONCLUSION: (18)F-FDG PET/CT is potentially useful for identifying dystonic cervical muscles for BT therapy in patients with ICD.  相似文献   
83.
Hybrid tumours are very rare salivary gland lesions composed of two or more different tumoural entities in a single neoplasm that arise within a definite topographical region. In most cases adenoid cystic carcinoma has been the predominant component in these lesions. In this study we describe two patients with hybrid tumours located in the palate, one in a 49-year-old woman and one in a 71-year-old man. The first case involved adenoid cystic carcinoma and mucoepidermoid carcinoma, and the patient in the second case exhibited adenoid cystic carcinoma and epithelial-myoepithelial carcinoma. Both patients were treated with surgery and radiotherapy, and there has been no evidence of recurrence after 13 and 36 months of follow-up, respectively. The recognition of the histologic component with the higher grade of malignancy in every case of hybrid tumour of the salivary glands is a necessary step to determine the biological behaviour and, consequently, to determine the proper therapeutic approach.  相似文献   
84.
目的探讨腹膜后脓肿的病因,诊断和治疗。方法回顾性分析了1990-2004年诊断和治疗腹膜后脓肿33例的临床资料。结果急性坏死性胰腺炎后20例,胆囊切除胆总管探查术后4例,十二指肠损伤2例,阑尾穿孔3例,肾结石4例。超声检查确诊80%(20/25),CT检查确诊100%(22/22)。经腹部腹膜后脓肿切开置管引流25例,手术1~4次不等,后腰部切开引流8例。手术后并发应激性胃粘膜损伤致消化道出血7例,成人呼吸窘迫综合征(ARDS)5例,急性肾功能衰竭3例,死亡4例。治愈时间1~6个月,平均3.5个月。结论及时明确诊断,进行有效引流并加强营养支持是治疗成功的关键。  相似文献   
85.
The FIGNL1 gene was proven to be a new subfamily member of ATPases associated with diverse cellular activities (AAA proteins). In this in vitro study, the AAA proteins inhibited osteoblast proliferation and stimulated osteoblast differentiation. We showed that FIGNL1 may play some regulatory role in osteoblastogenesis. INTRODUCTION: The fidgetin-like 1 (FIGNL1) gene encodes a new subfamily member of ATPases associated with diverse cellular activities (AAA proteins). Although the FIGNL1 protein localizes to both the nucleus and cytoplasm, the function of FIGNL1 remains unknown. In a previous study, we identified several genes that mediate the anabolic effects of basic fibroblast growth factor (bFGF) on bone by using microarray data. FIGNL1 was one of the genes that downregulated >2-fold in MC3T3-E1 cells after treatment with bFGF. Therefore, this study was aimed to identify and confirm the function of FIGNL1 on osteoblastogenesis. MATERIALS AND METHODS: We examined the effect of the FIGNL1 gene on proliferation, differentiation, and apoptosis in mouse osteoblast cells (MC3T3-E1 and mouse primary calvarial cells) using flow cytometry, RT-PCR, cell proliferation assay, and cell death assay. MC3T3-E1 cells and mouse calvarial cells were transfected with small interfering RNA (siRNA) directed against the FIGNL1 or nontargeting control siRNA and examined by cell proliferation and cell death assays. Also, FIGNL1 was fused to enhance green fluorescent protein (EGFP), and the EGFP-fused protein was transiently expressed in MC3T3-E1 cells. RESULTS: Reduced expression of FIGNL1 by bFGF and TGF-beta1 treatment was verified by RT-PCR analysis. Overexpression of FIGNL1 reduced the proliferation of MC3T3-E1 and calvarial cells, more than the mock transfected control cells did. In contrast, siFIGNL1 transfection significantly increased the proliferation of osteoblasts, whereas overexpression of FIGNL1 did not seem to alter apoptosis in osteoblasts. Meanwhile, overexpression of FIGNL1 enhanced the mRNA expression of alkaline phosphatase (ALP) and osteocalcin (OCN) in osteoblasts. In contrast, siFIGNL1 decreased the expression of ALP and OCN. A pEGFP-FIGNL1 transfected into MCT3-E1 cells had an initially ubiquitous distribution and rapidly translocated to the nucleus 1 h after bFGF treatment. CONCLUSIONS: From these results, we proposed that FIGNL1, a subfamily member of the AAA family of proteins, might play some regulatory role in osteoblast proliferation and differentiation. Further analyses of FIGNL1 will be needed to better delineate the mechanisms contributing to the inhibition of proliferation and stimulation of osteoblast differentiation.  相似文献   
86.
87.
AIM: Benign childhood epilepsy with centro-temporal spikes (BCECTS) is the most common idiopathic partial epilepsy in children. Treatment attitudes remain a controversial issue. We examine features that could suggest refractoriness at onset. METHODS: We retrospectively reviewed the medical records of 144 children with BCECTS diagnosed at the Division of Pediatric Neurology, Asan Medical Center, from March 1, 1995, to April 30, 2002 and treated with AEDs. The patients were subdivided into two groups according to the number of antiepileptic drugs used for effective seizure control. RESULTS: Of the 144 patients, 75 were male and 69 were female, with a mean age at seizure-onset of 7.2 +/- 2.3 years (range, 2.1-14.3 years); 119 children were taking one antiepileptic drug (AED) (Group A), and 25 were taking more than one (Group B). There were no significant group differences in female-to-male ratio, prescribed AEDs, number of seizures before the start of treatment, interval between seizure-onset and start of treatment, presence of secondarily generalized seizures, or presence of bilateral EEG abnormalities. The groups differed however, in mean age at seizure onset (7.6 +/- 2.2 years versus 5.1 +/- 1.9 years, p < 0.05) and percentage of patients with seizure-onset before 3 years (p < 0.05). CONCLUSIONS: When treated with AEDs, children with BCECTS usually respond well. However, an earlier onset of seizures is associated with more frequent seizures and initial refractoriness to medical treatment.  相似文献   
88.
肝移植围手术期出凝血功能障碍的防治   总被引:3,自引:0,他引:3  
目的 探讨肝移植围手术期出凝血功能障碍的防治。方法 回顾性分析我院 2 0 0 2年 6月~ 2 0 0 3年 12月施行的 6 1例肝移植病例。结果  6 1例肝移植术前肝功能ChildC级 35例 (5 7 4 % ) ,ChildB级 2 6例 (4 2 6 % ) ,ChildC组的患者术中凝血指标 (INR)的变化程度大于ChildB组 (P <0 0 5 )。与凝血有关的并发症中大出血 5例 (8 2 % ) ,肾衰 6例 (9 8% ) ,肝动脉血栓形成 5例 (8 2 % ) ,手术开展两阶段对比 ,第二阶段主要因限制了大量凝血药及血制品的使用 ,并发症明显减少。结论 掌握好不同时期、不同患者出血和血栓形成的平衡是防治肝移植围手术期出凝血功能障碍的关键  相似文献   
89.
目的 探讨失血性休克大鼠肠上皮细胞线粒体DNAATPase 6 ,8基因表达及线粒体功能的改变 ,为阐述休克肠道靶学说和线粒体能量代谢提供分子生物学基础。 方法  2 4只Wistar大鼠随机分为休克前组和休克 1,2 ,3,4 ,5h组。采用RT -PCR方法观察线粒体ATPase 6 ,8mRNA量的改变。用透射电镜观察、生物体视学测量线粒体形态 ,用Clark氧电极测线粒体呼吸功能。 结果 失血性休克 1,2h ,ATPase 6 ,8基因表达增强 ,以后渐减弱 ,至休克 5h表达最低 ,ATPase 6 ,8基因表达分别降为正常的 6 9.3%和 78.4 % (P <0 .0 1和P <0 .0 5 )。失血性休克 2h和5h ,线粒体平均截面积、长径、面密度、体密度均显著增加 (P <0 .0 1) ,休克 5h时分别为休克前的2 .0 ,1.4 5 ,1.4 7,2 .2 2倍。休克 5h ,线粒体比表面和数密度分别下降 32 %和 2 4 % (P <0 .0 1和P <0 .0 5 ) ,嵴和基质破坏明显。失血性休克后肠上皮细胞线粒体呼吸控制率和氧化磷酸化效率比休克前显著降低 (P <0 .0 1)。 结论 失血性休克时大鼠肠上皮细胞线粒体DNAATPase 6 ,8基因表达下调 ,线粒体呼吸功能出现障碍 ,线粒体超微结构发生了改变  相似文献   
90.
影响肝外伤手术死亡的危险因素分析   总被引:3,自引:1,他引:2  
目的分析影响肝外伤手术死亡的危险因素,探讨其临床意义。方法根据AAST和ISS标准,回顾性分析90例肝外伤手术病例,对影响手术死亡的危险因素进行单因素比较和Logistic回归分析。结果死亡15例,其中Ⅲ级2例、Ⅳ级4例、Ⅴ级9例,总体手术死亡率17%。Ⅳ~Ⅴ级肝外伤手术方式的单因素比较提示:清创性肝切除术的相对危险度是0.73;而规则性肝切除术、肝静脉或肝后下腔静脉修补术相对危险度分别是1.32、1.52。Logistic回归分析提示:ISS分会和术中失血量是影响手术死亡率的2个独立因素。结论ISS分值、术中失出血量和手术方式是影响肝外伤手术死亡的3个重要因素,娴熟的手术技能和合理的手术方式可以减少术中出血量和降低手术死亡率。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号