全文获取类型
收费全文 | 44940篇 |
免费 | 4744篇 |
国内免费 | 1920篇 |
专业分类
耳鼻咽喉 | 280篇 |
儿科学 | 606篇 |
妇产科学 | 656篇 |
基础医学 | 6630篇 |
口腔科学 | 1400篇 |
临床医学 | 4159篇 |
内科学 | 8513篇 |
皮肤病学 | 823篇 |
神经病学 | 3073篇 |
特种医学 | 1332篇 |
外国民族医学 | 11篇 |
外科学 | 4470篇 |
综合类 | 6599篇 |
现状与发展 | 13篇 |
预防医学 | 1517篇 |
眼科学 | 1892篇 |
药学 | 5402篇 |
16篇 | |
中国医学 | 2379篇 |
肿瘤学 | 1833篇 |
出版年
2024年 | 139篇 |
2023年 | 851篇 |
2022年 | 1322篇 |
2021年 | 2105篇 |
2020年 | 1862篇 |
2019年 | 1815篇 |
2018年 | 1745篇 |
2017年 | 1765篇 |
2016年 | 1873篇 |
2015年 | 2039篇 |
2014年 | 2816篇 |
2013年 | 4140篇 |
2012年 | 2464篇 |
2011年 | 2679篇 |
2010年 | 2365篇 |
2009年 | 2257篇 |
2008年 | 2305篇 |
2007年 | 2303篇 |
2006年 | 2174篇 |
2005年 | 1893篇 |
2004年 | 1662篇 |
2003年 | 1364篇 |
2002年 | 1205篇 |
2001年 | 945篇 |
2000年 | 815篇 |
1999年 | 658篇 |
1998年 | 553篇 |
1997年 | 443篇 |
1996年 | 427篇 |
1995年 | 376篇 |
1994年 | 279篇 |
1993年 | 261篇 |
1992年 | 219篇 |
1991年 | 211篇 |
1990年 | 134篇 |
1989年 | 127篇 |
1988年 | 126篇 |
1987年 | 120篇 |
1986年 | 92篇 |
1985年 | 119篇 |
1984年 | 103篇 |
1983年 | 68篇 |
1982年 | 65篇 |
1981年 | 92篇 |
1980年 | 51篇 |
1979年 | 49篇 |
1978年 | 40篇 |
1977年 | 26篇 |
1976年 | 21篇 |
1975年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 453 毫秒
71.
Matteo Tosato Valentina Zamboni Alessandro Ferrini Matteo Cesari 《Clinical Interventions in Aging》2007,2(3):401-412
Aging is commonly defined as the accumulation of diverse deleterious changes occurring in cells and tissues with advancing age that are responsible for the increased risk of disease and death. The major theories of aging are all specific of a particular cause of aging, providing useful and important insights for the understanding of age-related physiological changes. However, a global view of them is needed when debating of a process which is still obscure in some of its aspects. In this context, the search for a single cause of aging has recently been replaced by the view of aging as an extremely complex, multifactorial process. Therefore, the different theories of aging should not be considered as mutually exclusive, but complementary of others in the explanation of some or all the features of the normal aging process. To date, no convincing evidence showing the administration of existing “anti-aging” remedies can slow aging or increase longevity in humans is available. Nevertheless, several studies on animal models have shown that aging rates and life expectancy can be modified. The present review provides an overlook of the most commonly accepted theories of aging, providing current evidence of those interventions aimed at modifying the aging process. 相似文献
72.
三氧化二砷纳米微粒对抑制兔血管平滑肌细胞增殖作用的实验研究 总被引:2,自引:0,他引:2
目的 了解纳米微粒与普通剂型的三氧化二砷(As2O3)对抑制体外培养的兔血管平滑肌细胞(VSMC)增殖作用的差别。方法 对照组为不加药物的细胞,实验组为3μmol/L纳米微粒和普通剂型的As2O3,干预体外培养的兔VSMC细胞72h,进行四唑氮盐(MTT)染色测定细胞吸光度(A)值。用流式细胞仪检测细胞凋亡情况,提取细胞DNA,进行凝胶电泳分析,将3组的结果进行比较。结果 3μmol/L纳米剂型的As2O3,干预细胞,细胞数量随作用时间的延长逐渐减少,细胞生长明显受抑制,而普通剂型干预细胞,生长受抑制程度较纳米剂型弱。24h时,对照组、3μmol/L普通剂型组与纳米组,A值分别为0.68±0.10、0.58±0.12、0.33±0.12,48h时分别为0.79±0.11、0.48±0.14、0.28±0.11,72h时分别为0.96±0.13、0.34±0.15、0.20士0.06,差异均有统计学意义(Ⅳ值分别为10.934、15.039、15.539,P值均〈0.01)。流式细胞仪检测,纳米剂型As2O3、普通剂型As2O3干预及对照组的细胞干预48h,细胞增殖率分别为44.97%、58.54%、74.02%,早期凋亡率分别为16.89%、11.27%、11.20%,晚期凋亡率分别为26.56%、23.60%、12.46%,坏死细胞分别为11.58%、6.59%、2.32%。DNA电泳,As2O3干预细胞,可见凋亡梯形条带,部分细胞坏死,呈模糊的无间隔片状条带。纳米剂型药物作用的细胞DNA条带,梯形条带更多、更模糊。结论 As2O3,可以抑制体外培养的VSMC增殖,且纳米剂型As2O3较普通剂型的As2O3,对细胞抑制作用更强。 相似文献
73.
血管内皮生长因子在高原脑水肿形成中作用的实验研究 总被引:4,自引:0,他引:4
目的:探讨血管内皮生长因子(VEGF)在高原脑水肿形成中的作用。方法:建立大鼠模拟高原模型,应用脑干湿重比率法定量脑水肿情况、应用荧光素钠透过率测定BBB通透性、应用实时荧光定量RT-PCR法检测脑组织VEGF mRNA含量以及应用蛋白印迹法半定量脑组织VEGF含量。结果:大鼠在高原24 h后脑组织含水率明显增高(P<0.05),荧光素钠透过率显著增加(P<0.01);VEGF mRNA转录及其表达显著增高(P<0.001)。结论:VEGF表达在高原脑水肿形成中起重要作用。 相似文献
74.
目的探讨单独应用阿托伐他汀与联合应用阿托伐他汀和匹格列酮对高危心血管人群颈动脉内膜中层厚度(CIMT)、高敏C反应蛋白(hs-CRP)、基质金属蛋白酶-9(MMP-9)、脂联素及脂质状况的影响。方法90名有心血管危险因素的患者被随机分为两组:单独应用阿托伐他汀治疗组、联合应用阿托伐他汀和匹格列酮治疗组,分别检测两组患者治疗前及治疗六个月后的CIMT、hs-CRP、脂联素、MMP-9的血浆水平及检测血脂水平。结果单独应用阿托伐他汀及联合应用阿托伐他汀和匹格列酮均显示CIMT的显著降低(P〈0.001),无组间差异(P〉0.05)。两组的MMP-9在治疗后均较治疗前降低,有统计学意义(P〈0.05),但组间无统计学差异(P〉0.05)。两组对h-CRP、脂联素及血脂水平均有有意义的影响,组间有统计学差异,联合用药组提示影响更显著(P〈0.05)。联合用药组血浆脂联素水平明显升高而单独应用阿托伐他汀组未被观察到。结论阿托伐他汀明显改善CIMT,联合应用阿托伐他汀和匹格列酮对脂质状况和炎症因子有额外的影响。 相似文献
75.
秦晓红 《中国介入影像与治疗学》2007,4(5):364-366
目的探讨护理工作在脊髓血管畸形介入治疗中的价值。方法通过对我院介入中心350例脊髓血管畸形患者介入治疗,针对脊髓血管畸形患者的临床特点和介入治疗方法的适应证、操作过程和预后等特点,从护理学的角度对术前、术中、术后等阶段进行讨论分析。结果术前进行有效的心理护理和健康教育;术中与介入医生及技术操作人员进行有机的配合、熟练使用输液微量泵、准确使用相关药物及认真观察病情变化;术后对患者进行严密的护理观察,可减少并发症的发生,将有助于该手术的成功。结论介入护理工作对脊髓血管畸形介入治疗手术的成败起着至关重要的作用。 相似文献
76.
目的:观察外源性VEGF对自体脾组织大网膜内移植后血管再生过程影响。方法:198只昆明种小白鼠随机分为脾切除自体脾组织大网膜内移植组及假手术组,将脾切除自体脾组织大网膜内移植后的小鼠再随机分为实验组(应用外源性VEGF组)和对照组(不用外源性VEGF组)。实验观察组小鼠分别于术后7、15、30d于尾静脉内注射VEGF,最后一次注射后1、7、14、30、60、90d各处死5只,取脾组织标本;对照组于术后观察上述对应时相点后各处死3只,取脾组织标本,进行墨汁灌注血管面密度测定。结果:术后7、15、30d注射VEGF后,较对照组的血管数量明显增多,墨汁灌注显示,实验观察组血管面密度较对照组明显增大。结论:外源性VEGF能够促进移植脾组织内血管生长,改善移植脾组织的血液循环,有利于移植脾组织再生,使其结构恢复更趋完善。 相似文献
77.
Background: We evaluated the endoscopic microvascular architecture of the gastric mucosa in portal hypertension patients using the prototype of narrow band imaging (NBI). Material and Methods: The study included 103 Helicobacter pylori‐negative patients with chronic liver disease (22 without portal hypertension (group 1), 81 with portal hypertension (group 2)). Results: (i) Abnormality of collecting venules, reddening mucosa, red spots, a mosaic‐like pattern, and gastric antral vascular ectasia (GAVE) were observed on the gastric mucosa, and an obscure change in collecting venules (73% vs 14%; P < 0.001), reddening mucosa (49% vs 5%; P < 0.001), red spots (36% vs 5%; P < 0.01) and a mosaic‐like pattern (40% vs 5%; P < 0.01) were more frequently observed in group 2 than in group 1. (ii) On magnifying endoscopy with NBI, the mucosa with an obscure change in collecting venules was demonstrated as dilation of the capillaries surrounding the gastric pits in various degrees, and reddening mucosa was observed as extended and swollen gastric pits and various degrees of dilated and convoluted capillaries surrounding the gastric pits. Red spots were demonstrated as extended and swollen gastric pits, dilated and convoluted capillaries surrounding the gastric pits, and intramucosal hemorrhage around these capillaries. GAVE was recognized as partial and marked dilatation of the capillaries surrounding the gastric pits. Conclusion: Abnormality of collecting venules, swelling of gastric pits, dilatation of capillaries surrounding the gastric pits, intramucosal hemorrhage around capillaries, and partial and marked dilatation of the capillaries were observed on the gastric mucosa in portal hypertension patients. 相似文献
78.
目的:探讨外周血循环内皮细胞(CEC)和糖尿病肾病(DN)的相关性,以及银杏达莫注射液在DN防治中的可能作用。方法:检测65例2型糖尿病患者24h尿白蛋白排泄率(UAER)及CEC数,分析两者的相关性。将UAER为30~300mg·d-1的45例患者随机分为两组,常规治疗组22例,进行常规降血糖、控制血压等治疗;银杏达莫治疗组23例,在常规治疗基础上静脉滴注银杏达莫注射液2周。比较两组治疗前后血糖、血压、UAER及CEC水平的变化。结果:单纯糖尿病(SDM)组和早期糖尿病肾病(EDN)组的外周血CEC水平比对照组(NC)显著性升高,并呈逐渐增高的趋势(P<0.01)。UAER与收缩压(SBP)、外周血CEC水平呈正相关(P<0.01)。EDN组中,银杏达莫治疗后UAER及CEC明显降低(P<0.01);而常规治疗组无明显变化。线性多元逐步回归分析表明,银杏达莫治疗后UAER的改变与CEC数的变化成正相关(P<0.01)。结论:血管内皮细胞(VEC)损伤在DN发生发展中起重要作用,银杏达莫对VEC的保护作用可能是其延缓DN发展的重要机制。 相似文献
79.
Sami Al-Said Ammar Ali Abdul Kader Alobaidy Emad Mojeeb Abdulla Al-Naimi Ahmed A Shokeir 《International journal of urology》2007,14(5):452-454
Xanthogranulomatous orchitis is an extremely rare inflammatory non-neoplastic destructive lesion of the testis. We report a 44-year-old man who presented with right scrotal swelling and two discharging sinuses. Testicular tumor markers were normal. Scrotal ultrasound showed heterogeneous testicular areas and irregular margin of the tunica. Surgical exploration revealed infected, unhealthy testicular tissue with necrosis and tumor-like lesion. Orchidectomy was done and histopathology showed xanthogranulomatous orchitis. 相似文献
80.
Carmine Zoccali Renke Maas Sebastiano Cutrupi Patrizia Pizzini Piero Finocchiaro Francesco Cambareri Vincenzo Panuccio Carmela Martorano Friedrich Schulze Giuseppe Enia Giovanni Tripepi Rainer Boger 《Nephrology, dialysis, transplantation》2007,22(3):801-806
BACKGROUND AND METHODS: The endogenous inhibitor of nitric oxide synthase (NOs) asymmetrical dimethyl-arginine (ADMA) has been implicated as a possible modulator of inducible NOs during acute inflammation. We examined the evolution in the plasma concentration of ADMA measured at the clinical outset of acute inflammation and after its resolution in a series of 17 patients with acute bacterial infections. RESULTS: During the acute phase of inflammation/infection, patients displayed very high levels of C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin and nitrotyrosine. Simultaneous plasma ADMA concentration was similar to that in healthy subjects while symmetric dimethyl-arginine (SDMA) levels were substantially increased and directly related with creatinine. When infection resolved, ADMA rose from 0.62 +/- 0.23 to 0.80 +/- 0.18 micromol/l (+29%, P = 0.01) while SDMA remained unmodified. ADMA changes were independent on concomitant risk factor changes and inversely related with baseline systolic and diastolic pressure. Changes in the ADMA/SDMA ratio were compatible with the hypothesis that inflammatory cytokines activate ADMA degradation. CONCLUSIONS: Resolution of acute inflammation is characterized by an increase in the plasma concentration of ADMA. The results imply that ADMA suppression may actually serve to stimulate NO synthesis or that in this situation plasma ADMA levels may not reflect the inhibitory potential of this methylarginine at the cellular level. 相似文献