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   36280篇
  免费   2629篇
  国内免费   1459篇
耳鼻咽喉   119篇
儿科学   1329篇
妇产科学   189篇
基础医学   3599篇
口腔科学   346篇
临床医学   3437篇
内科学   8438篇
皮肤病学   285篇
神经病学   254篇
特种医学   1761篇
外科学   7129篇
综合类   5440篇
现状与发展   3篇
预防医学   1377篇
眼科学   143篇
药学   3495篇
  11篇
中国医学   1902篇
肿瘤学   1111篇
  2024年   69篇
  2023年   540篇
  2022年   857篇
  2021年   1358篇
  2020年   1355篇
  2019年   1325篇
  2018年   1406篇
  2017年   1399篇
  2016年   1245篇
  2015年   1385篇
  2014年   2285篇
  2013年   2439篇
  2012年   2135篇
  2011年   2213篇
  2010年   1852篇
  2009年   1944篇
  2008年   1992篇
  2007年   1924篇
  2006年   1698篇
  2005年   1488篇
  2004年   1147篇
  2003年   960篇
  2002年   781篇
  2001年   728篇
  2000年   597篇
  1999年   501篇
  1998年   492篇
  1997年   402篇
  1996年   381篇
  1995年   353篇
  1994年   361篇
  1993年   265篇
  1992年   290篇
  1991年   223篇
  1990年   222篇
  1989年   168篇
  1988年   216篇
  1987年   166篇
  1986年   132篇
  1985年   127篇
  1984年   124篇
  1983年   55篇
  1982年   126篇
  1981年   98篇
  1980年   107篇
  1979年   78篇
  1978年   64篇
  1977年   62篇
  1976年   58篇
  1973年   43篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
81.
The aim of this study was to evaluate the influence of vascular endothelial growth factor (VEGF) on renal function and on development of interstitial fibrosis (IF) in renal allografts. Tubular and interstitial expressions of VEGF and TNF-α, and density of macrophages in the interstitium were examined in 92 patients with nonrejected kidneys, acute rejection (AR), chronic allograft nephropathy (CAN), borderline changes (BC) and acute cyclosporin A (CsA) toxicity. Follow-up biopsy specimens from patients with AR and BC were evaluated for development of IF. A significant difference in tubular and interstitial VEGF expressions was found between patients with AR, BC, CAN and CsA toxicity (p < 0.001). Macrophage infiltration was positively correlated with VEGF and TNF-α expressions (p < 0.001). VEGF expression increased with increasing expression of TNF-α (p < 0.001). Renal function in first 6 months after initial biopsy was better in patients with marked tubular VEGF expression (p < 0.01); however, in follow-up, development of IF and graft loss was found earlier in these patients (p < 0.01 and p < 0.05, respectively). Increased renal VEGF expression has protective properties immediately following renal allograft but allows for increased risk of early IF, and therefore poor graft outcome in the long term.  相似文献   
82.
后腹腔镜下离断式肾盂成形术   总被引:2,自引:0,他引:2  
目的探讨后腹腔镜下肾盂成形术的临床疗效. 方法腹腔镜下通过后腹腔途径对9例肾盂输尿管连接部狭窄行离断式肾盂成形术并对技术进行改进. 结果 9例手术均获成功,手术时间110~240 min,平均160 min.术中出血量30~80 ml,平均50 ml.术后住院8~18 d,平均11.2 d.术后并发症:皮下气肿(合并阴囊气肿)1例,漏尿2例.术后1~10个月B超示术侧肾盂无积水5例,轻度积水2例,中度积水2例.3例术后5个月IVU显示吻合口通畅. 结论后腹腔镜肾盂成形术微创、效果好,值得推广.  相似文献   
83.
肾癌患者治疗方法的选择   总被引:2,自引:0,他引:2  
目的:探讨肾细胞癌的不同手术方式、术前肾动脉栓塞及免疫治疗的临床应用价值。方法:回顾性分析179例肾细胞癌患者的临床资料。对患者的临床资料分组进行对比,并对治疗效果和随访结果作进一步统计学分析。结果:小肾癌行肾癌根治术与保留肾组织手术效果比较,在手术时间、术后住院时间、术后5年生存率上差异均无统计学意义(P>0.05);78例术前行选择性肾动脉栓塞者,手术证实栓塞效果满意。结论:保肾单位手术是治疗局限性小肾癌的有效手段;较大的肾癌术前进行肾动脉栓塞术便于手术切除病灶,提高了肿瘤的切除率;免疫治疗是继手术治疗之后的又一种主要临床治疗方式,尤其肿瘤疫苗的出现,对于晚期肾癌及转移癌效果明显。  相似文献   
84.
目的 了解、观察葡立胶囊与抗骨增生胶囊联用治疗颈椎病对血清SOD含量及疼痛功能评分的影响。方法 对一组神经根型颈椎病患者,用葡立胶囊与抗骨增生胶囊联合应用治疗3个月,测定血清SOD含量及疼痛功能评分变化。结果 颈椎病患者治疗组血清SOD含量与治疗前相比明显升高,疼痛功能评分治疗前相比明显降低。结论 葡立胶囊与抗骨增生胶囊联合应用可明显缓解症状,提高血清SOD活力,延缓颈椎间盘退变,对治疗颈椎病有明显疗效。  相似文献   
85.
BACKGROUND: Oral submucous fibrosis (OSF) is a chewing habit-related pre-cancerous condition of the oral mucosa affecting predominantly south Asians. It is histopathologically characterized by epithelial atrophy and fibrosis of the subepithelial connective tissue. Fibrosis extends all the way into the muscle layer, leading to difficulty in mouth opening. However, the dynamics of extracellular matrix (ECM) remodeling with OSF progression is largely unknown. METHODS: Forty biopsy specimens of OSF and 10 of normal buccal mucosa were examined for expression/deposition modes of eight ECM molecules by histochemistry, immunohistochemistry, and in situ hybridization. RESULTS: In the early stage of OSF, tenascin, perlecan, fibronectin, collagen type III were characteristically enhanced in the lamina propria and the submucosal layer. In the intermediate stage, the ECM molecules mentioned above and elastin were extensively and irregularly deposited around muscle fibers. In the advanced stage, such ECM depositions decreased and were entirely replaced with collagen type I only. Their gene expression levels varied with progression of fibrosis, but the mRNA signals were confirmed in fibroblasts in the submucosal fibrotic areas. CONCLUSIONS: The results indicate that the ECM remodeling steps in OSF are similar to each phase of usual granulation tissue formation. Restricted mouth opening may be a result of loss of variety of ECM molecules including elastin into the homogeneity of collagen type I replacing muscle fibers.  相似文献   
86.
87.
Focal segmental glomerulosclerosis   总被引:3,自引:0,他引:3  
Over the last 2 decades, we have learnt that focal segmental glomerulosclerosis (FSGS) is a ubiquitous phenomenon underlying the progressive deterioration of many different types of renal diseases in both pediatric and adult populations. FSGS may also be the primary renal lesion, whether in new disease entities such as glycogen storage disease and human immunodeficiency virus infection, or in idiopathic FSGS. Although the mechanism which triggers the development of primary FSGS still remains unknown, laboratory and clinical studies have identified several key pathophysiological events leading to end-stage renal disease. While therapeutic modalities have not changed remarkably, a recent study, although uncontrolled, demonstrated an impressive efficacy of intravenous steroid pulse therapy in inducing remission. Nevertheless, it remains largely unknown whether such a forced remission decreases the overall risk of developing chronic renal failure. Studies have revealed an important pathophysiological role of angiotensin and the therapeutic efficacy of angiotensin converting enzyme inhibitors in progressive loss of renal function in diseases where glomerulosclerosis is secondary; however, it remains to be verified whether these results hold true in primary FSGS. As a result of the improvement in allograft survival rate, the benefit of renal transplant outweighs the risk of recurrence of FSGS, hence transplantation continues to be a vital therapy for FSGS patients who have reached renal failure. Thus, FSGS is not one disease, but rather a range of lesions seen in many settings. The type of lesions and the patient's unique genetic factors contribute to prognosis, and also may dictate choice of optimum therapy.  相似文献   
88.
In the neonate, chronic unilateral ureteral obstruction (UUO) reduces renal blood flow (RBF) of the ipsilateral kidney and increases RBF of the opposite kidney. To determine whether renal nerves mediate or modulate these responses complete left UUO in the neonatal rat was used as a model of severe obstructive uropathy, and was compared with sham-operated controls. At 24–28 days of age, animals underwent left or right mechanical renal denervation or left sham renal denervation. One week after denervation, animals were anesthetized and blood pressure and heart reate were measured. Cardiac output and RBF were determined by the radioactive microsphere technique. UUO increased blood pressure and heart rate, and decreased RBF in the obstructed kidney, regardless of denervation. While left UUO increased RBF to the intact opposite kidney in rats with left renal denervation, this was attenuated by right renal denervation. Thus, in the neonatal rat, UUO modulates systemic renal hemodynamics, possibly through activation of the renin-angiotensin system. While renal nerves do not mediate the vasoconstriction of the obstructed kidney, renal nerves modulate vascular tone of the kidney contralateral to UUO.  相似文献   
89.
90.
肾移植患者血脂,脂蛋白和载脂蛋白变化及其临床意义   总被引:3,自引:1,他引:2  
观察了46例肾移植患者血浆脂质代谢的改变,结果显示,肾移植患者血总胆固醇(TC)、甘油三酯(TG)、极低密度脂蛋白胆固醇(VLDL-C)和载脂蛋白(apo)B100明显升高,而apoAI、apoAIapoCⅡ/apoCⅢ明显降低,同时还观察到,有心脑血管合并症的病者血TC、TG、TC/HDL-c、apoB100升高apoAI降低比合并症的病者更显著。上述结果表明肾移植后脂质代谢有明显改变,且存在加  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