全文获取类型
收费全文 | 9363篇 |
免费 | 484篇 |
国内免费 | 145篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 367篇 |
妇产科学 | 74篇 |
基础医学 | 335篇 |
口腔科学 | 2篇 |
临床医学 | 4172篇 |
内科学 | 2318篇 |
皮肤病学 | 10篇 |
神经病学 | 33篇 |
特种医学 | 630篇 |
外科学 | 648篇 |
综合类 | 890篇 |
预防医学 | 144篇 |
药学 | 298篇 |
2篇 | |
中国医学 | 35篇 |
肿瘤学 | 29篇 |
出版年
2024年 | 18篇 |
2023年 | 110篇 |
2022年 | 228篇 |
2021年 | 245篇 |
2020年 | 264篇 |
2019年 | 218篇 |
2018年 | 278篇 |
2017年 | 203篇 |
2016年 | 198篇 |
2015年 | 275篇 |
2014年 | 606篇 |
2013年 | 549篇 |
2012年 | 483篇 |
2011年 | 597篇 |
2010年 | 481篇 |
2009年 | 558篇 |
2008年 | 599篇 |
2007年 | 596篇 |
2006年 | 528篇 |
2005年 | 493篇 |
2004年 | 398篇 |
2003年 | 299篇 |
2002年 | 220篇 |
2001年 | 247篇 |
2000年 | 207篇 |
1999年 | 153篇 |
1998年 | 89篇 |
1997年 | 102篇 |
1996年 | 96篇 |
1995年 | 76篇 |
1994年 | 67篇 |
1993年 | 53篇 |
1992年 | 47篇 |
1991年 | 40篇 |
1990年 | 35篇 |
1989年 | 28篇 |
1988年 | 30篇 |
1987年 | 30篇 |
1986年 | 30篇 |
1985年 | 19篇 |
1984年 | 32篇 |
1983年 | 19篇 |
1982年 | 29篇 |
1981年 | 22篇 |
1980年 | 20篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 8篇 |
1976年 | 15篇 |
1974年 | 8篇 |
排序方式: 共有9992条查询结果,搜索用时 15 毫秒
21.
目的:应用超声心动图观察红花注射液对冠心病心肌缺血患者左室舒张功能的影响。方法:随机将76例冠心病心肌缺血患者分为2组,其中38例在常规药物基础上加用红花注射液治疗为红花组,其他38例应用常规药物治疗为常规治疗组,2组均连续用药14天,对心肌缺血及心功能的相关指标作对比观察。用药前后采用常规超声心电图联合组织多普勒显像(TDI)对左室舒张功能进行检测。结果:治疗后ST段压低的次数及其持续时间与心肌缺血总负荷2组均有明显减少,与治疗前比较,有非常显著性差异(P0.01),2组疗效比较,红花组优于常规治疗组(P0.01)。红花组左室舒张功能指标(E、A、E/A、DC、Ea、Aa、Ea/Aa、E/Ea)明显改善(P0.01),常规治疗组治疗前后差异无统计学意义(P0.05)。用药期间,患者无严重不良反应。结论:红花注射液对冠心病心肌缺血有显著疗效,且能改善左室舒张功能。 相似文献
22.
Aim of the study
Based on screening for vasoactive traditional Chinese medicinal herbs, the present study was performed to investigate the vasoactive effects of an ethyl acetate extract from leaves of Morus alba (L.) (ELM) on rat thoracic aorta and the mechanisms underlying these effects.Materials and methods
Isolated rat thoracic rings were mounted in an organ bath system and the effects of ELM on their responses were evaluated.Results
ELM (0.125–32.000 g/l) induced a concentration-dependent relaxation (P < 0.01 vs. control) both in endothelium-intact and -denuded aortas precontracted by high K+ (6 × 10−2 M) or 10−6 M phenylephrine (PE). In endothelium-denuded aortas, ELM at the EC50 concentration reduced Ca2+-induced contraction (P < 0.01 vs. control) after PE or KCl had generated a stable contraction in Ca2+-free solution. And after incubation with verapamil, ELM induced contraction in endothelium-denuded aortas precontracted by PE (P < 0.01 vs. control); this was abolished by ruthenium red (P < 0.01 vs. ELM-treated endothelium-denuded group; P > 0.05 vs. control), but not by heparin (P > 0.01 vs. ELM-treated endothelium-denuded group; P < 0.01 vs. control).Conclusions
The results showed that ELM had dual vasoactive effects, and the relaxation was greater than the contraction. The relaxation was mediated by inhibition of voltage- and receptor-dependent Ca2+ channels in vascular smooth muscle cells, while the contraction occurred via activation of ryanodine receptors in the sarcoplasmic reticulum. 相似文献23.
Moayad Khatib Gabby Elbaz-Greener Orna Nitzan Soboh Soboh Avi Peretz Evgeni Hazanov Wadia Kinany Yusra Halahla Liza Grosman-Rimon Helene Houle Offer Amir Shemy Carasso 《Journal of digital imaging》2022,35(6):1654
Lower respiratory infection was reported as the most common fatal infectious disease. Community-acquired pneumonia (CAP) and myocardial injury are associated; yet, true prevalence of myocardial injury is probably underestimated. We assessed the rate and severity of myocardial dysfunction in patients with CAP. Admitted patients diagnosed with CAP were prospectively recruited. All the patients had C-reactive protein (CRP), brain natriuretic peptide (BNP), and high-sensitivity cardiac troponin (hs-cTnl) tests added to their routine workup. 2D/3D Doppler echocardiography was done on a Siemens Acuson SC2000 machine ≤ 24 h of diagnosis. 3D datasets were blindly analyzed for 4-chamber volumes/strains using EchobuildR 3D-Volume Analysis prototype software, v3.0 2019, Siemens-Medical Solutions. Volume/strain parameters were correlated with admission clinical and laboratory findings. The cohort included 34 patients, median age 60 years (95% CI 55–72). The cohort included 18 (53%) patients had hypertension, 9 (25%) had diabetes mellitus, 7 (21%) were smokers, 7 (21%) had previous myocardial infarction, 4 (12%) had chronic renal failure, and 1 (3%) was on hemodialysis treatment. 2D/Doppler echocardiography findings showed normal ventricular size/function (LVEF 63 ± 9%), mild LV hypertrophy (104 ± 36 g/m2), and LA enlargement (41 ± 6 mm). 3D volumes/strains suggested bi-atrial and right ventricular dysfunction (global longitudinal strain RVGLS = − 8 ± 4%). Left ventricular strain was normal (LVGLS = − 18 ± 5%) and correlated with BNP (r = 0.40, p = 0.024). The patients with LVGLS > − 17% had higher admission blood pressure and lower SaO2 (144 ± 33 vs. 121 ± 20, systolic, mmHg, p = 0.02, and 89 ± 4 vs. 94 ± 4%, p = 0.006, respectively). hs-cTnl and CRP were not different. Using novel 3D volume/strain software in CAP patients, we demonstrated diffuse global myocardial dysfunction involving several chambers. The patients with worse LV GLS had lower SaO2 and higher blood pressure at presentation. LV GLS correlated with maximal BNP level and did not correlate with inflammation or myocardial damage markers. 相似文献
24.
目的:移植转染胰岛素样生长因子-1(IGF-1)的骨髓基质细胞(MSC)到心肌梗死大鼠模型中,观察心肌细胞的凋亡和心功能的变化。方法:采用结扎法制作心肌梗死大鼠模型,用含pBabe-puro/IGF-1的病毒液感染MSC,移植MSC进入梗死心肌边缘。将实验分为心肌梗死组(MI)、心梗单纯移植细胞组(MI+MSC)、心梗移植感染空质粒细胞组(MI+MSC-pBabe-puro)、心梗移植感染IGF-1质粒的细胞组(MI+MSC-pBabe-puro/hIGF-1)。免疫组化检测炎性反应的时间,决定细胞移植的时间点。术后4周,通过TUNEL法检测心肌的细胞凋亡,超声心动图检测心功能的变化。结果:免疫组化结果显示梗死后第7天的ED1细胞的阳性数比第2天明显降低(P<0.05);转染IGF-1的MSC移植到心梗的心肌中,和转染空质粒的MSC以及未作转染的MSC组比较,明显减少心肌的细胞凋亡(P<0.05);且射血分数、左室壁厚度、左室短轴缩短率明显提高(P<0.05)。结论:转染IGF-1的MSC移植到心梗大鼠心肌内,可能是通过减少心肌的细胞凋亡来改善心功能。 相似文献
25.
本实验对STZ—DM大鼠的主动脉进行了超微结构观察。结果显示,DM大鼠血浆胰岛素水平明显降低,血糖含量明显增高、血浆TC、LDL—C、LDL—C/HDL—C、TC/HDL-C值明显增高,HDL—C明显降低,与对照组比较均有显著差异(P<0.01)。电镜下,DM大鼠主动脉有早期AS病变。结果表明,急性实验性DM,由胰岛素绝对缺乏所致的高血糖、高TC、高LDL—C以及低HDL—C血症,可能与主动脉早期AS病变的形成密切相关。 相似文献
26.
27.
28.
29.
S.R. Mittal 《Indian heart journal》2013,65(1):53-58
BackgroundTo evaluate efficacy of post exercise tissue velocity imaging in diagnosing more than 70% coronary artery stenosis.MethodTwenty patients with angiographically proved significant coronary artery disease and 26 healthy controls were evaluated. Pulsed wave tissue velocity imaging was performed at rest and immediately after treadmill stress test. Medial and lateral part of mitral annulus and medial and lateral part of tricuspid annulus were evaluated.ResultNo change or reduction in systolic annular velocity after exercise at any of the four sites identified patients of significant coronary artery disease with 75% sensitivity and 73% specificity. Rise in the ratio of early diastolic inflow velocity to the corresponding early diastolic annular velocity above the identified site-specific cut-off value had sensitivity of 85% but specificity of 34.6%. A combination of no change or decrease in late diastolic annular velocity and no change or decrease in systolic annular velocity at any of the four sites had sensitivity of 75% and specificity of 88.46%.ConclusionPost exercise tissue velocity imaging can provide a useful, objective parameter for detection of ischemic heart disease on stress testing. 相似文献
30.
K. Geofi George Pakkirisamy Gobu Raja Selvaraj Jayaraman Balachander 《Indian heart journal》2013,65(1):88-90
We report a rare coronary artery anomaly–anomalous origin of the left anterior descending artery from the pulmonary artery in a 40-year-old woman. The uniqueness of this case is the absence of any significant morbidity from this condition in adulthood which is in contrast to other reported cases where patients present with myocardial infarction, congestive heart failure, and sometimes death during the early infantile period.1 相似文献