全文获取类型
收费全文 | 1174篇 |
免费 | 113篇 |
国内免费 | 19篇 |
专业分类
儿科学 | 79篇 |
妇产科学 | 4篇 |
基础医学 | 167篇 |
口腔科学 | 63篇 |
临床医学 | 126篇 |
内科学 | 216篇 |
皮肤病学 | 46篇 |
神经病学 | 40篇 |
特种医学 | 286篇 |
外科学 | 84篇 |
综合类 | 29篇 |
预防医学 | 49篇 |
眼科学 | 13篇 |
药学 | 29篇 |
1篇 | |
肿瘤学 | 74篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 9篇 |
2020年 | 21篇 |
2019年 | 16篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 23篇 |
2015年 | 38篇 |
2014年 | 35篇 |
2013年 | 52篇 |
2012年 | 44篇 |
2011年 | 36篇 |
2010年 | 57篇 |
2009年 | 61篇 |
2008年 | 26篇 |
2007年 | 38篇 |
2006年 | 32篇 |
2005年 | 28篇 |
2004年 | 16篇 |
2003年 | 31篇 |
2002年 | 20篇 |
2001年 | 15篇 |
2000年 | 6篇 |
1999年 | 22篇 |
1998年 | 81篇 |
1997年 | 76篇 |
1996年 | 59篇 |
1995年 | 52篇 |
1994年 | 37篇 |
1993年 | 45篇 |
1992年 | 7篇 |
1991年 | 23篇 |
1990年 | 14篇 |
1989年 | 42篇 |
1988年 | 35篇 |
1987年 | 25篇 |
1986年 | 18篇 |
1985年 | 18篇 |
1984年 | 9篇 |
1983年 | 12篇 |
1982年 | 14篇 |
1981年 | 14篇 |
1980年 | 15篇 |
1979年 | 3篇 |
1978年 | 13篇 |
1977年 | 11篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1954年 | 1篇 |
排序方式: 共有1306条查询结果,搜索用时 16 毫秒
1.
2.
3.
Debra Rivera Irene Kalleveen Catalina Arteaga de Castro Hanneke van Laarhoven Dennis Klomp Wybe van der Kemp Jaap Stoker Aart Nederveen 《NMR in biomedicine》2020,33(4)
High field 31P spectroscopy has thus far been limited to diffuse liver disease. Unlike lower field‐strength scanners, there is no body coil in the bore of the 7 T and despite inadequate penetration depth (<10 cm), surface coils are the current state‐of‐the‐art for acquiring anatomical images to support multinuclear studies. We present a system of proton antennas and phosphorus loops for 31P spectroscopy and provide the first ultrahigh‐field phosphorus metabolic imaging of a tumor in the abdomen. Herein we characterize the degree to which antennas are isolated from underlying loops. Next, we evaluate the penetration depth of the two antennas available during multinuclear examinations. Finally, we combine phosphorus spectroscopy (two loops) with parallel transmit imaging (eight antennas) in a patient. The loops and antennas are inherently decoupled (no added circuitry, <0.1% power coupling). The penetration depth of two antennas gives twice that of conventional loops. The liver and full axial slice of the abdomen were imaged with eight transmit/receive antennas using parallel transmit B1‐shimming to overcome image voids. Phosphorus spectroscopy from a liver metastasis resolved individual peaks for phosphocholine and phosphoethenalomine. Proton antennas are inherently decoupled from phosphorus loops. By using two proton antennas it is possible to perform region‐of‐interest image‐based shimming in over 80% of the liver volume, thereby enabling phosphorus spectroscopy of localized disease. Shimming of the full extent of the abdominal cross‐section is feasible using a parallel transmit array of eight antennas. A system architecture capable of supporting eight‐channel parallel transmit and multinuclear spectroscopy is optimal for supporting multiparametric body imaging, including metabolic imaging, for monitoring the response of patients with liver metastases to cancer treatments and for patient risk stratification. In the meantime, the existing infrastructure using two antennas is sufficient for preliminary studies in metabolic imaging of tumors in the liver. 相似文献
4.
5.
该文对应用游离髂骨瓣修复颌骨缺损的病例进行回顾研究,并分析手术并发症。作者共用26块髂骨肌瓣、1块髂骨肌皮瓣修复18例下颌骨和8例上颌骨缺损。1例因微血管再灌注问题而导致手术失败:3例术后行组织瓣抢救,其中2例吻合口血栓形成,重新吻合血管后抢救成功;10例术后出现股外侧皮神经支配区皮肤麻木,3例并发切口疝,1例供区创口裂开,2例并发口鼻瘘,1例颈部创口感染, 相似文献
6.
7.
目的:基质金属蛋白酶在急性心肌梗死后的心室重构中起着重要作用,但其调节机制目前尚未明确。实验拟通过动物模型的建立及体外细胞培养,观察急性心肌梗死后单个核细胞表面CD147与心肌成纤维细胞基质金属蛋白酶-9 mRNA表达的关系。
方法:实验于2006—08/2007-06在河北省人民医院临床实验中心完成。实验材料:SD大鼠及SD仔鼠(出生1~3d)购自河北医科大学试验动物中心。实验过程中对动物处置符合动物伦理学标准。实验方法:①将30只大鼠随机分为急性心肌梗死组(n=15)和假手术组(n=15),假手术组只过线不结扎。流式细胞分析法检测大鼠术后24h外周血单个核细胞表面CD147表达。②选择SD仔鼠制备心肌成纤维细胞。将单个核细胞与心肌成纤维细胞以细胞数0.5:1,1:1,2:1混合培养24h后,半定量反转录一聚合酶联反应法检测基质金属蛋白酶-9 mRNA表达。当单核细胞与心肌成纤维细胞2:1混合时,加入CD147单克隆抗体1,2,4μL/L,培养24h后检测基质金属蛋白酶-9 mRNA表达。
结果:①急性心肌梗死后外周血单个核细胞表面CD147表达明显增加。②单个核细胞与心肌成纤维细胞混合培养,随着单个核细胞比例的增加,心肌成纤维细胞基质金属蛋白酶-9 mRNA表达增加。③在单个核细胞与心肌成纤维细胞2:1混合培养体系中,随着加入CD147单克隆抗体浓度的增加,基质金属蛋白酶-9 mRNA生成减少。
结论:急性心肌梗死后单个核细胞表面CD147表达明显增加,对心肌成纤维细胞基质金属蛋白酶-9生成起上游调节作用。 相似文献
8.
Jurgen H. Runge Erik M. Akkerman Marian A. Troelstra Aart J. Nederveen Ulrich Beuers Jaap Stoker 《Abdominal imaging》2016,41(11):2123-2131
Purpose
To compare three types of MRI liver iron content (LIC) measurement performed in daily clinical routine in a single center over a 6-year period.Methods
Patients undergoing LIC MRI-scans (1.5T) at our center between January 1, 2008 and December 31, 2013 were retrospectively included. LIC was measured routinely with signal intensity ratio (SIR) and MR-relaxometry (R 2 and R 2*) methods. Three observers placed regions-of-interest. The success rate was the number of correctly acquired scans over the total number of scans. Interobserver agreement was assessed with intraclass correlation coefficients (ICC) and Bland–Altman analysis, correlations between LICSIR, R 2, R 2*, and serum values with Spearman’s rank correlation coefficient. Diagnostic accuracies of LICSIR, R 2 and serum transferrin, transferrin-saturation, and ferritin compared to increased R 2* (≥44 Hz) as indicator of iron overload were assessed using ROC-analysis.Results
LIC MRI-scans were performed in 114 subjects. SIR, R 2, and R 2* data were successfully acquired in 102/114 (89%), 71/114 (62%), and 112/114 (98%) measurements, with the lowest success rate for R 2. The ICCs of SIR, R 2, and R 2* did not differ at 0.998, 0.997, and 0.999. R 2 and serum ferritin had the highest diagnostic accuracies to detect elevated R 2* as mark of iron overload.Conclusions
SIR and R 2* are preferable over R 2 in terms of success rates. R 2*’s shorter acquisition time and wide range of measurable LIC values favor R 2* over SIR for MRI-based LIC measurement.9.
10.
Antonina A Mikocka-Walus Deborah A Turnbull Jane M Andrews Nicole T Moulding Ian G Wilson Hugh AJ Harley David J Hetzel Gerald J Holtmann 《Clin Pract Epidemiol Ment Health》2008,4(1):15