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   20789篇
  免费   1846篇
  国内免费   385篇
耳鼻咽喉   132篇
儿科学   1114篇
妇产科学   162篇
基础医学   1629篇
口腔科学   96篇
临床医学   2781篇
内科学   4429篇
皮肤病学   131篇
神经病学   710篇
特种医学   526篇
外国民族医学   1篇
外科学   1764篇
综合类   3788篇
现状与发展   1篇
预防医学   1777篇
眼科学   154篇
药学   2227篇
  40篇
中国医学   1180篇
肿瘤学   378篇
  2024年   54篇
  2023年   375篇
  2022年   684篇
  2021年   1210篇
  2020年   1505篇
  2019年   767篇
  2018年   720篇
  2017年   830篇
  2016年   908篇
  2015年   882篇
  2014年   1664篇
  2013年   1692篇
  2012年   1426篇
  2011年   1429篇
  2010年   1062篇
  2009年   945篇
  2008年   894篇
  2007年   916篇
  2006年   758篇
  2005年   661篇
  2004年   569篇
  2003年   528篇
  2002年   311篇
  2001年   267篇
  2000年   221篇
  1999年   202篇
  1998年   183篇
  1997年   182篇
  1996年   135篇
  1995年   142篇
  1994年   107篇
  1993年   84篇
  1992年   95篇
  1991年   73篇
  1990年   52篇
  1989年   53篇
  1988年   49篇
  1987年   48篇
  1986年   34篇
  1985年   53篇
  1984年   49篇
  1983年   24篇
  1982年   38篇
  1981年   30篇
  1980年   29篇
  1979年   19篇
  1978年   21篇
  1977年   7篇
  1976年   11篇
  1973年   6篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
51.
SUMMARY: The effect of mild acute tubular injury on the progression of tubulointerstitial fibrosis was studied in pair-fed uninephrectomized male Wistar rats with established adriamycin nephrosis ( n = 34). Rats were stratified into three groups according to endogenous creatinine clearance (CrCl), proteinuria (Upr) and body weight (BW): (i) group 1 (Fe, n = 12) received a single intraperitoneal injection of ferric nitrilotriacetate (5 mg Fe/kg BW); (ii) group 2 (G, n = 10) three daily subcutaneous injections of gentamicin (60 mg/kg BW) and; (iii) group 3 (C, n = 12) saline injections. Serial CrCl (day 2, day 5, weeks 2, 4, 6 and 8) and renal histology (week 8) were examined following administration of nephrotoxin. CrCl was reduced on d2 (Fe: 0.78 ± 0.23 mL/min; mean ± SD) and day 5 (G: 0.91 ± 0.36 mL/min) as compared with C (1.22 ± 0.12 mL/min; P <0.05). There was no change in the serum creatinine and functional recovery occurred by d5 (Fe) and week 2 (G). Upr decreased transiently in G at week 2 (G: 482 ± 208 mg/day vs C: 716 ± 233; P = 0.05) despite similar food intake, baseline Upr and CrCl. At week 8, CrCl in Fe (0.84 ± 0.40 mL/min) was similar to C (0.84 ± 0.58 mL/min), whereas in G it remained stable (1.27 ± 0.39 mL/min; P <0.05). By morphometric analysis, mean relative interstitial volume (RIV) and glomerulosclerosis (GS) in Fe (RIV: 28.5 ± 13.4%; GS: 10.3 ± 12.3%) was no different to C (RIV: 24.5 ± 12.5%; GS: 20.9 ± 20.0%), whereas both parameters were reduced in G (RIV: 14.1 ± 8.1%; GS: 4.0 ± 4.8%; P <0.05). Mild gentamicin nephrotoxicity therefore reduced the progression of adriamycin nephrosis. the mechanism of this finding is unclear, but it may relate to altered glomerular and tubular cell handling of protein.  相似文献   
52.
本文观察分析了13例特发性甲状旁腺功能低下患者、查PTH6例。患者血清中除有本病低血钙、高血磷的固有特征外,其它微量元素也有改变,如血清镁值减低。这与文献[1]的报道相符。碱性磷酸酶2例明显升高。磷廓清率S例降低。肾小管磷重吸收率5例升高。放免甲功:抗甲状腺微粒体2例升高。T细胞亚群1例低于正常值。本病有家族性,与遗传有关。  相似文献   
53.
应用脉冲多普勒超声心动图对30例使用1,6-二磷酸果糖的肺炎心衰患儿进行心室舒缩功能指标的观测,并以20例常规治疗的心衰患儿及20例正常儿为对照组,评价1,6-二磷酸果糖的疗效。结果表明,1,6-二磷酸果糖能明显改善PEP、PEP/ET、PEP/R-R、FVI和SV等心室收缩功能指标及PFVE、E/A、PFVA等心室舒张功能指标,使心功能恢复正常。1,6-二磷酸果糖对肺炎心衰引起的心肌缺血、缺氧有保护作用。  相似文献   
54.
目的:利用单光子发射计算机断层摄影(SPECT)半定量分析有效控制与控制不良的MRI阴性的全面性强直阵挛发作癫(GTCS)病人的局部脑血流差异,探讨脑血流灌注与其预后的关系.材料和方法:对29例有效控制的和12例控制不佳的MRI阴性的GTCS病人进行发作间期99mTc-ECD-SPECT脑血灌流显像,10例年龄匹配的健康人作对照,用感兴趣区(ROI)的不对称指数(%AI)进行半定量分析.将SPECT分析结果与病人的临床表现与EEG相比较.结果:①控制不佳组与有效控制组在丘脑和基底节区的%AI存在显著性差异(P<0.05);②控制不佳组SPECT脑显像的异常率(83.3%,10/12)明显高于有效控制组的异常率(17.2%,5/29),两组具有显著性差异(P<0.01);而两组病人的EEG异常率分别为58.3%、44.8%(7/12、13/29),无显著性差异(P>0.05).结论:控制不佳的MRI阴性的GTCS病人往往存在发作间期的低血流灌注脑区,提示癫的难治性;而控制良好的病人多无明显异常发现,可能预后较好.  相似文献   
55.
重症肺炎患者中性粒细胞胞吐作用的改变   总被引:3,自引:0,他引:3  
目的 研究重症肺炎患者中性粒细胞的功能改变。方法 采用免疫化学法测定 32例重症肺炎患者中性粒细胞胞吐作用和氧化酶反应的变化 ,并与健康对照组比较。结果 重症肺炎患者血液中性粒细胞的基础和PMA刺激的胞吐作用均明显下降 (P <0 .0 1) ;重症肺炎患者的基础和PMA刺激的反应性氧属 (ROS)产生明显增加 ;重症肺炎患者肺部中性粒细胞释放乳铁蛋白、髓过氧化物酶 (MPO)和ROS增加 ,PMA刺激后相似 ;肺炎的严重性与血液中性粒细胞释放乳铁蛋白呈负相关。结论 重症肺炎患者中性粒细胞胞吐作用明显受损 ,与预后相关。  相似文献   
56.
关木通引起慢性间质性肾炎7例报告   总被引:3,自引:0,他引:3  
目的 观察关木通所致慢性肾损伤的临床和病理改变特点。方法 本组 7例中 ,男 5例 ,女 2例。 3例服关木通汤药 ,4例服含关木通成药。分析服用时间、累积总量与肾损害首发症状及症状出现时间、肾功能和肾病理改变的关系。结果 汤药组 :服药时间平均 3 3 3个月 ,累积总量平均 82 9 3 g ,首发症状为乏力 3例 ,夜尿增多 2例 ,平均时间为 8 3个月 ,Cr平均 40 2 μmol/L。肾病理 :3例均为重度寡细胞性肾间质纤维化 ,肾小管广泛萎缩。成药组 :服药时间平均 7 5个月 ,累积总量平均 13 6g ,乏力 3例 ,夜尿增多 1例 ,恶心呕吐、头痛头晕 1例 ,平均18 8个月 ,Cr 3 62 8μmol/L。肾病理为重度寡细胞性间质纤维化和灶状纤维化各 2例 ,肾小管灶状萎缩 3例 ,广泛萎缩 1例。结论 汤药组关木通积累大 ,发病时间早 ,肾病理改变重。提示关木通所致肾损其临床表现、病理改变与服用关木通时间、剂量相关。  相似文献   
57.
糖尿病合并肺炎患者支气管肺泡灌洗液细胞学分析   总被引:1,自引:1,他引:0  
目的评价糖尿病合并肺炎病人抗生素治疗2周后支气管肺泡灌洗液(bronchoalveolar lavage fluid,BALF)中细胞学成分的特点,并与非糖尿病的肺炎病人进行比较,了解病灶局部炎症反应及吸收与非糖尿病组有否区别。方法抗生素治疗2周行支气管肺泡灌洗,测定BALF中细胞数、分类及淋巴细胞亚群。复查胸部X光片,对比两组之间BALF中细胞成分及肺部阴影完全吸收占病人的百分比。结果抗炎治疗2周后,糖尿病合并肺炎病人虽然外周血WBC已经恢复正常,但BALF中中性粒细胞的比率明显高于非糖尿病肺炎组(分别为54.89±11.23;27.02±6.95,P<0.05),且淋巴细胞亚群中CD4、CD4/CD8(分别为20.69±5.56;65%)。也较非糖尿病肺炎病人低(43.22±11.03;96%,P<0.01),治疗2周后,非糖尿病肺炎组肺部阴影吸收率为68%,糖尿病合并肺炎组为43.5%(P>0.05)。结论抗生素治疗2周后糖尿病合并肺炎组肺部局部炎症反应仍然存在,肺部阴影有延迟吸收倾向。  相似文献   
58.
RATIONALE: A small percentage of patients with idiopathic generalized epilepsy (IGE) do not respond to medical therapy. Generalized tonic-clonic (GTC) seizures are especially debilitating and can be associated with severe injuries. The benefit, safety and effect of corpus callosotomy (CC) in patients with IGE have not been studied. METHODS: We reviewed patients with presumed IGE who underwent CC between 1991 and 2000. Criteria for selection included history, examination, brain imagining, interictal and ictal EEG. All patients had refractory and debilitating tonic-clonic seizures (GTCS) and had failed four or more antiepileptic drugs. Seizure frequency was calculated per month over the last year and pre-operative baseline was compared to last follow-up using paired t-tests. IQ, executive function, language and verbal, non-verbal memory and quality of life (QOL) was compared before and after surgery. Serial EEGs after surgery were reviewed. RESULTS: There were nine patients (seven men), mean age 37.9 (range: 22-49), mean IQ 87.3 (range: 75-107). All had anterior CC. Mean follow-up time was 5.4 years (range: 0.6-10.3 years). One patient died from sudden death in epilepsy 9 months after surgery. There was a significant reduction of GTC seizures from 6.3 to 1.1 (p<0.005). Four patients had more than 80% and eight more than 50% reduction. Of five patients with absence seizures, two became seizure free and one had more than 80% reduction and two worsened slightly, and of three with myoclonic seizures one had more than 90% reduction. One patient had completion of the CC with improvement of myoclonus and absence seizures, but not of GTC seizures and suffered a disconnection syndrome. Another had right frontal focal resection without improvement after new seizures of focal onset. Cognitive testing showed a good outcome (improved or no change) in all cognitive domains. Post-surgical EEG showed new focal slowing and sharp waves. There was no change in QOL. CONCLUSION: CC can be effective in reducing GTC, absence and myoclonic seizures in patients with refractory IGE. These findings suggest that interhemispheric communication of the cerebral cortices plays an important role in the generation of seizures in IGE. Anterior CC appears safe while complete callosotomy has a risk of disconnection syndrome.  相似文献   
59.
栾杰  尹立岩  马燕  李东 《山东医药》2006,46(22):3-4
目的 探讨支原体肺炎肺外损伤患儿细胞免疫、细胞因子状况和胸腺肽的治疗效果。方法 采用流式细胞仪和酶标仪检测31例支原体肺炎肺外损伤组患儿急性期、恢复期血中CD3CD4、CD8、CD4/CD8干扰素γ(IFNγ)、肿瘤坏死因子α(TNFα水平,并与支原体肺炎组比较。结果 ①急性期支原体肺炎肺外损伤组和支原体肺炎组比较,CD3、CD4显著降低(P〈0.05),TNFα显著升高(P〈0.01),CD8、IFNγ无统计学意义(P〉0.05);②支原体肺炎肺外损伤组急性期和4周后比较,CD3、CD4、IFNγ升高(P〈0.05),TNFα显著降低(P〈0.01),CD8无变化。用胸腺肽治疗患者以上指标变化更明显。结论 支原体肺炎肺外损伤患儿细胞免疫功能低于支原体肺炎患儿;细胞因子中TNFα早期升高,而IFNγ不明显;恢复期TNFα下降,而IFNγ升高明显。用胸腺肽治疗能缩短病程。  相似文献   
60.
For patients with community-acquired pneumonia (CAP), clinical response during the first days of treatment is predictive of clinical outcome. As risk assessments can improve the efficiency of pneumonia management, a prospective cohort study to assess clinical, biochemical and microbiological predictors of early clinical failure was conducted in patients with severe CAP (pneumonia severity index score of >90 or according to the American Thoracic Society definition). Failure was assessed at day 3 and was defined as death, a need for mechanical ventilation, respiratory rate >25/min, PaO2 <55 mm Hg, oxygen saturation <90%, haemodynamic instability, temperature >38 degrees C or confusion. Of 260 patients, 80 (31%) had early clinical failure, associated mainly with a respiratory rate >25/minute (n = 34), oxygen saturation <90% (n = 28) and confusion (n = 20). In multivariate logistic regression analysis, failure was associated independently with altered mental state (OR 3.19, 95% CI 1.75-5.80), arterial PaH <7.35 mm Hg (OR 4.29, 95% CI 1.53-12.05) and PaO2 <60 mm Hg (OR 1.75, 95% CI 0.97-3.15). A history of heart failure was associated inversely with clinical failure (OR 0.30, 95% CI 0.10-0.96). Patients who failed to respond had a higher 28-day mortality rate and a longer hospital stay. It was concluded that routine clinical and biochemical information can be used to predict early clinical failure in patients with severe CAP.  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