全文获取类型
收费全文 | 81793篇 |
免费 | 6066篇 |
国内免费 | 2511篇 |
专业分类
耳鼻咽喉 | 132篇 |
儿科学 | 2022篇 |
妇产科学 | 934篇 |
基础医学 | 4770篇 |
口腔科学 | 140篇 |
临床医学 | 10649篇 |
内科学 | 24621篇 |
皮肤病学 | 135篇 |
神经病学 | 1646篇 |
特种医学 | 3923篇 |
外国民族医学 | 10篇 |
外科学 | 6413篇 |
综合类 | 15951篇 |
现状与发展 | 5篇 |
预防医学 | 4339篇 |
眼科学 | 784篇 |
药学 | 8845篇 |
77篇 | |
中国医学 | 3439篇 |
肿瘤学 | 1535篇 |
出版年
2024年 | 225篇 |
2023年 | 1264篇 |
2022年 | 2308篇 |
2021年 | 3288篇 |
2020年 | 3324篇 |
2019年 | 2836篇 |
2018年 | 2904篇 |
2017年 | 2920篇 |
2016年 | 3097篇 |
2015年 | 3000篇 |
2014年 | 5622篇 |
2013年 | 6831篇 |
2012年 | 4792篇 |
2011年 | 4938篇 |
2010年 | 4146篇 |
2009年 | 3804篇 |
2008年 | 3552篇 |
2007年 | 3762篇 |
2006年 | 3355篇 |
2005年 | 2926篇 |
2004年 | 2502篇 |
2003年 | 2269篇 |
2002年 | 1878篇 |
2001年 | 1743篇 |
2000年 | 1450篇 |
1999年 | 1258篇 |
1998年 | 1065篇 |
1997年 | 1090篇 |
1996年 | 993篇 |
1995年 | 932篇 |
1994年 | 832篇 |
1993年 | 604篇 |
1992年 | 606篇 |
1991年 | 493篇 |
1990年 | 458篇 |
1989年 | 379篇 |
1988年 | 364篇 |
1987年 | 322篇 |
1986年 | 305篇 |
1985年 | 382篇 |
1984年 | 331篇 |
1983年 | 154篇 |
1982年 | 216篇 |
1981年 | 189篇 |
1980年 | 197篇 |
1979年 | 114篇 |
1978年 | 85篇 |
1977年 | 82篇 |
1976年 | 67篇 |
1975年 | 33篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
对广西武鸣华侨农场4158人进行基线普查,410人进行膳食调查和作8小时夜尿电解质测定,并将高血压低发区广西的资料与高发区的北京作对比.结果显示,体重指数高是高血压一个重要的危险因素,而体重过重又与膳食中摄入碳水化合物和总热量大有关.另一主要的危险因素是钠,膳食中摄入钠高,尿Na和Na/K比值高者,血压水平和高血压的患病率亦高. 相似文献
162.
《Journal of thoracic oncology》2007,2(8):780-781
Pericardial mesothelioma remains a disease with a bleak prognosis. We report the case of a patient with metastases to liver and good response to pemetrexed and carboplatin-based combination chemotherapy and consequent prolonged progression-free survival. 相似文献
163.
164.
Stefan Farese Kushiar Shojaati Bert Kadereit Felix J Frey Markus G Mohaupt 《Nephrology, dialysis, transplantation》2006,21(7):1984-1987
Volume expansion in the presence of elevated aldosterone availabilityis a hallmark of normal pregnancy. Intravascular volume depletioncharacterizes severe pregnancy-associated disease conditionssuch as intra-uterine growth retardation, chronic hypertensionor pre-eclampsia [1]. Two hypotheses have been forwarded toexplain volume depletion in pregnancy: the first hypothesischarges inappropriate sensing of vascular overfilling,resulting in an increased transendothelial loss of fluid tothe extravascular compartment. In contrast, the second hypothesisfocuses on vascular underfilling due to inappropriatelylow aldosterone levels. The second hypothesis is based on theassumption that a compensatory increase in the circulating fluidvolume is required in normal pregnancy to support fetal substratedelivery. According to the second concept, maternal blood pressureincreases due to counter-regulatory mechanisms when placentalblood supply is reduced [2]. In support of the underfillinghypothesis are observations that a 相似文献
165.
Respiratory symptoms associated with the use of azodicarbonamide foaming agent in a plastics injection molding facility 总被引:1,自引:0,他引:1
L W Whitehead T G Robins L J Fine D J Hansen 《American journal of industrial medicine》1987,11(1):83-92
Respiratory health variables were studied cross-sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre- and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross-sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose-effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foaming agent. 相似文献
166.
目的:探讨维甲酸对自发性高血压大鼠(SHR)心肌、血管平滑肌增殖的影响和肾素-血管紧张素-醛固酮系统(RAS)所起的作用。方法:18只SHR大鼠随机分为全反式维甲酸治疗组、对照组、卡托普利治疗组,每组6只。分别予治疗组和对照组皮下注射全反式维甲酸(ATRA)10mg/Kg体重或溶媒,高血压药物治疗组予卡托普利0.25mg/Kg体重管饲,每天一次,均疗程4周。疗程结束后观察各组SHR大鼠心肌、血管平滑肌(VSMC)增殖细胞核抗原(PCNA)的变化以及心肌ACE-mRNA、ACE2-mRNA的表达。结果:维甲酸治疗组心肌、血管平滑肌增殖细胞核抗原(PCNA)表达显著低于对照组(P<0.01),卡托普利治疗组的PCNA表达也显著低于对照组(P<0.01),但维甲酸治疗组与卡托普利组比较也有显著差异(P<0.01);维甲酸治疗组ACE-mRNA的表达低于卡托普利组及对照组(P<0.01),卡托普利组ACE-mRNA的表达也低于对照组(P<0.01);而维甲酸组ACE2-mRNA的表达则高于对照组及卡托普利组(P<0.01),后两组之间则无显著差异(P>0.05)。结论:维甲酸能抑制SHR模型心肌、血管平滑肌PCNA的表达,并在增加ACE2-mRNA表达的同时减少ACE-mRNA的表达,从而有可能干预增殖性血管疾病的病程。 相似文献
167.
门静脉高压经肾静脉自发性分流的多层CT诊断 总被引:2,自引:0,他引:2
目的:探讨肝硬化门静脉高压时经肾静脉自发分流的CT表现与诊断。方法:220例临床确诊为肝硬化门静脉高压的患者行多层螺旋CT检查,扫描参数:准直/有效层厚/重建间隔为5mm/6.5mm/2.0mm(180例)或2.5mm/3.2mm/1.6mm(40例)。双期增强扫描:动脉期延迟26~28s,门脉期延迟55~60s。对图像进行电影显示,对有异常血管的病例分别完成薄层块最大强度投影(TS-MIP)和容积显示(VR)三维血管成像。结果:经肾静脉分流26例(11.8%),其中脾左肾静脉分流20例,胃左肾静脉分流16例(同时有此2种分流12例),门脉右肾静脉分流2例。肾门周围静脉增多、增粗7例。结论:自发性门脉-肾静脉分流并不少见,多层螺旋CT增强扫描及血管造影可有效显示分流血管,有助于指导临床诊断和治疗。 相似文献
168.
肝硬化门静脉高压症内毒素血症的治疗 总被引:2,自引:0,他引:2
目的 研究肝硬化门静脉高压症 (PHC)病人内毒素血症治疗方法及其对预后的影响。方法 选 3 6例 PHC择期手术病人 ,随机分为治疗组 (n=18)和对照组 (n=18) ;治疗组入院后除保肝、纠正低蛋白血症及贫血等术前一般准备外 ,另行每日服用中药茵陈小承气汤和稀生理盐水碘伏液灌肠术等 ,对照组行 PHC的常规术前准备。观察两组病人术前血浆内毒素(PE)水平变化和术后全身炎症反应综合症 (SIRS)、多脏器障碍综合症 (MODS)的发生率等。结果 入院时所有 PHC病人均存在不同程度的内毒素血症。经过术前准备 ,治疗组术前 PE水平由 0 .13 9± 0 .0 2 2 Eu/ m l降至 0 .12 2± 0 .0 2 4 Eu/ m l(P<0 .0 5 ) ,对照组则下降不明显 (P>0 .0 5 )。术后治疗组的 SIRS、MODS的发生率和死亡率分别为 :11.1%、5 .6%、0 % ;对照组则分别为 :4 4 .4 %、2 7.8%、5 .6%。术后胃肠功能的恢复时间 :治疗组 (78.3± 2 1.2 h)比对照组 (13 8.4± 4 2 .5 h)显著缩短 (P<0 .0 0 1)。结论 应用茵陈小承气汤结合稀生理盐水碘状液清洁胃肠道 ,可以降低 PHC病人由于细菌易位所致的内毒素血症以及其对机体的损害 ,从而减少 PHC病人术后 SIRS、MODS的发生率及死亡率 相似文献
169.
Summary The monocrofaline-induced structural changes of small pulmonary arteries in rat and their relationship with pulmonary hypertension
and right ventricular hypertrophy were observed by determining the right ventricular systolic pressure, and by light and electron
microscope and morphometry. One to 38 days after last injection of monocrotaline (MCT), a medial thickening and lumen marrrowing
of the circular muscular arteries (CMA), accompanying terminal (TB) and respiratory bronchioles (RB), were found. And there
after the lumen of CMA, accompanying TB, became dilated, and its medial thickness (MT) decreased, whereas the histopathologic
changes of the partially muscular arteries (PMA), accompanying RB, became severe, their MT increased continuously, and finally
reached the peak value on Day 50. At the first day after last MCT treatment, inflammation and muscularization were found in
PMA and nonmuscular arteries (NMA), and became more severe with the cause of disease. Therefore, the intra-acinar pulmonary
arteries, both CMA and PMA, increased in number while the NMA decreased in number significantly because of the structural
remodeling. Four days after MCT treatment, the right ventricular systolic pressure began to rise, and reached its peak value
on Day 50. Eight days after MCT injection, right ventricular hypertrophy developed, and became most significant from Day 23
to Day 30. The results suggest that structural remodeling, i.e. muscularization, of intra-acinar pulmonary arteries plays
an important role in the development of pulmonary hypertension and right ventricular hypertrophy. 相似文献
170.
本文应用单克隆抗体检测33例原发性肺癌病人治疗前后外周血中T淋巴细胞亚群变化。结果提示:肺癌病人外周血中T细胞亚群明显有别于正常人,主要表现为T_H细胞降低和T_S细胞升高以及T_H/T_S比值明显倒置。短期观察结果表明,肺癌病人外周血中T_S细胞持续升高和T_H/T_S比值持续降低者,预后不良。临床检测T细胞亚群变化及它们的动态变化可作为判断宿主抗肿瘤免疫功能状态、病情发展和预后的敏感指标。 相似文献