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   2447篇
  免费   140篇
  国内免费   50篇
耳鼻咽喉   12篇
儿科学   39篇
妇产科学   6篇
基础医学   60篇
口腔科学   45篇
临床医学   295篇
内科学   266篇
皮肤病学   7篇
神经病学   9篇
特种医学   68篇
外科学   854篇
综合类   550篇
预防医学   110篇
眼科学   5篇
药学   164篇
  5篇
中国医学   134篇
肿瘤学   8篇
  2024年   3篇
  2023年   26篇
  2022年   47篇
  2021年   91篇
  2020年   80篇
  2019年   58篇
  2018年   81篇
  2017年   66篇
  2016年   62篇
  2015年   79篇
  2014年   167篇
  2013年   167篇
  2012年   152篇
  2011年   196篇
  2010年   135篇
  2009年   143篇
  2008年   146篇
  2007年   109篇
  2006年   128篇
  2005年   100篇
  2004年   88篇
  2003年   53篇
  2002年   61篇
  2001年   57篇
  2000年   42篇
  1999年   38篇
  1998年   31篇
  1997年   36篇
  1996年   32篇
  1995年   27篇
  1994年   17篇
  1993年   25篇
  1992年   16篇
  1991年   9篇
  1990年   14篇
  1989年   7篇
  1988年   8篇
  1987年   4篇
  1986年   2篇
  1985年   8篇
  1984年   3篇
  1982年   5篇
  1981年   5篇
  1980年   6篇
  1979年   1篇
  1978年   5篇
  1972年   1篇
排序方式: 共有2637条查询结果,搜索用时 328 毫秒
1.
长江北三角平原上所遗存的二十余种记及明代倭患和抗倭战争的古代的碑石文献 ,在数量上据全国各抗倭战区所存的同类文献之首。在内容上 ,对补充旧史的阙失、订正传误、佐证史实、深化研究也有诸多帮助 ,尤其是对廓正对倭寇与倭患问题的认识有着积极的意义  相似文献   
2.
Open, Double-Blind and Long-Term Study of Vigabatrin in Chronic Epilepsy   总被引:5,自引:4,他引:1  
We performed an open, double-blind, and long-term study of vigabatrin (gamma-vinyl-GABA, GVG) in patients with treatment-resistant epilepsy who were receiving only one or at most two standard antiepileptic drugs (AEDs). The novel design included a parallel, double-blind, placebo-controlled phase that minimized the number of patients receiving placebo and allowed determination of the optimum dose of GVG for each patient before initiation of the double-blind phase. The study was divided into four phases. The first phase was a 6-week period of baseline observation. In the second phase, GVG was added openly to previous AEDs for 8 weeks. During the first 2 weeks of this phase, the dose of GVG was increased weekly and then, in the absence of adverse effects, was held constant for the next 6 weeks. At the end of this open phase, seizure frequency during the 6 weeks of constant treatment was compared with the baseline seizure frequency for each patient. Patients who experienced reduction greater than 50% in the frequency of any seizure type during the open phase were defined as responders. These responders were then entered into the third and double-blind phase, in which they were randomly allocated wither to continue active GVG treatment or placebo for 8 weeks. Thirty-three patients entered the study; 31 of 33 patients completed the initial open phase. Twenty patients achieved a reduction greater than or equal to 50% in the frequency of one or more seizure types and were eligible for the double-blind phase; 10 were randomized to continue GVG and 10 were randomized to placebo.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
3.
OBJECTIVE: Although hypercalciuria, a well-established adverse effect of vitamin D3, can be a risk factor of renal stone formation, the risk of nephrolithiasis has not been well defined. The consumption of a diet high in acid precursors is often cited as a risk factor for the development of calcium-based kidney stones. In the present study, we investigated the effect of chronic acid ingestion on kidney stone formation in rats treated with calcitriol (1-25[OH]2 D3). METHODS: Control rats (C-C), calcitriol-treated rats (C-V; three treatments of 0.5 microg of calcitriol per week) and acid-ingested (water containing 0.21 mol/L NH4Cl), calcitriol-treated (three treatments of 0.5 microg of calcitriol per week) rats (A-V) were fed in metabolic cages. After 1 month, urine, blood, kidney and bone samples were analyzed. RESULTS: The A-V rats exhibited elevated serum calcium concentrations, urinary calcium and phosphate excretion, urinary type I collagen cross-linked N-peptide (NTx)/creatinine values, mRNA expression of osteopontin in the kidney, and renal calcium contents as well as decreased bone mineral densities, compared with the C-C and C-V rats. Urinary citrate excretion was lower and NaDC-1 mRNA expression in the kidney was higher in the A-V rats than in the C-C and C-V rats. Calcium phosphate kidney stones were found in the A-V rats. CONCLUSIONS: The ingestion of NH4Cl, an acid precursor, promotes calcium phosphate kidney stone formation in calcitriol-treated rats. The chronic intake of a diet rich in acid precursors may be a risk factor for the development of kidney stones in subjects who are being treated with calcitriol.  相似文献   
4.
Congenital thoracic ectopic kidney is a very rare developmental anomaly and the rarest form of all ectopic kidneys. It is usually asymptomatic and discovered incidentally on routine chest radiography. Herein we reported the first case of staghorn stone in a thoracic kidney managed successfully by percutaneous nephrolithotomy.  相似文献   
5.
目的为探讨肾输尿管结石的临床特点,以提出更好的防治措施。方法对原西南师范大学医院1997-2004年治疗的128例肾输尿管结石病例的临床资料进行统计分析。结果本组病例男女之比为2.05∶1,29岁以下发病103例,占80.5%。2001年起发病呈上升趋势,2003年最高。每年9-10月是发病高峰,占本组病例的31.2%。经体外震波碎石99例,3个月结石排净率为83%,与文献报道的基本一致。结论该校肾输尿管结石患者,男性多于女性,30岁以下居多。发病近年增加,体外震波碎石疗效好。  相似文献   
6.
We report on our experience with routine abdominal ultrasonography in 120 children (aged 3–15 years) with recurrent abdominal pain, in order to determine the diagnostic value of this investigation. Eight children (7%) revealed sonographic abnormalities: gallbladder stone (n = 2), splenomegaly (n = 1) and urogenital abnormalities (n = 5). The recurrent abdominal pain could be explained by these findings in only two (may be three) cases. Conclusion The diagnostic value of abdominal ultra‐sonography in unselected children with recurrent abdominal pain is low. However, the direct visualization of the abdominal structures as being normal may be helpful to the parents and the child in their understanding and acceptance of the benign nature of recurrent abdominal pain. Received: 19 March 1996 / Accepted: 29 January 1997  相似文献   
7.
Cell culture models of calcium phosphate renal stone formation were established using the MDCK cell line. Renal microliths were detected within pseudocysts in three-dimensional soft agar cultures, and were also observed in the basal region of cells lining the cell sheet, and immediately beneath domes or blisters in monolayers and collagen gel cultures. Light and scanning electron microscopy indicated that these microliths had a similar lamellated and spherical appearance to those in humans. These microliths were first detected microscopically after 21 days of culture, and were found to be composed of calcium phosphate by X-ray and microinfrared spectroscopic analyses. These culture models may provide a powerful new tool to study the pathogenesis of renal stone diseases and/or calcium phosphate stone formation in humans and animals.  相似文献   
8.
目的 探讨经内镜乳头气囊扩张术 (EPBD)治疗胆囊切除术后胆总管结石的安全性和疗效。方法 对胆囊切除术后出现黄疸或胆管炎的 31例患者 ,利用EPBD结合取石篮、取石球囊或总攻方法 ,使梗阻于胆总管下段的结石排入肠道。结果  31例患者全部顺利实施EPBD ,共排除结石37颗 ,4例行 2次扩张术 ,术后患者均痊愈出院 ,复查B超无结石残存或胆管扩张。结论 经内镜治疗胆囊切除术后胆总管结石 ,安全、无创、有效 ,有望成为治疗LC术后胆总管结石的首选方法  相似文献   
9.
经皮胆肠吻合口胆道镜治疗肝内胆管复发结石   总被引:1,自引:0,他引:1  
目的探讨经皮胆肠吻合口胆道镜治疗胆管空肠Roux-en-Y吻合术后肝内胆管复发结石的方法及疗效。方法20.0.0年1月~2005年2月,对8例胆肠吻合术后肝内胆管再发结石,采用经皮经空肠输胆襻造口术建立通道,胆道镜经胆肠吻合口进入肝内胆管取石,纠正吻合口和肝内胆管狭窄。结果8例肝内胆管结石均取净,4例胆管狭窄和2例吻合口狭窄解除。8例随访1~3年,肝内胆管无复发结石和再狭窄。结论经皮胆肠吻合口胆道镜治疗肝内胆管复发结石创伤小、安全、可行,效果满意。  相似文献   
10.
High incidence of multiple kidney stone formation has been observed among workers exposed to cadmium (Cd). Citrate is known to be a protective factor against renal stone formation. To study the direct effect of cadmium on citrate uptake by the renal brush border membrane, we exposed isolated rat renal brush border membrane vesicles (BBMV) to cadmium and determined their citrate uptake characteristics. BBMV were prepared by the divalent cation precipitation method. Citrate uptake was measured by the Millipore rapid membrane filtration technique. Preincubation of BBMV with 2 and 10 mM CdCl2 for 1 min significantly inhibited citrate uptake compared with that of BBMV without Cd. Analysis of the time course of citrate uptake during 30-min preincubation of BBMV with 0.5 mM Cd also revealed significant reduction of the uptake compared with that of the control BBMV without preincubation. These findings indicate that preincubation of BBMV with cadmium results in time-dependent and concentration-dependent inhibition of citrate uptake.  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