全文获取类型
收费全文 | 155篇 |
免费 | 33篇 |
国内免费 | 9篇 |
专业分类
基础医学 | 29篇 |
临床医学 | 6篇 |
内科学 | 2篇 |
神经病学 | 7篇 |
特种医学 | 15篇 |
外科学 | 8篇 |
综合类 | 26篇 |
预防医学 | 10篇 |
眼科学 | 3篇 |
药学 | 75篇 |
中国医学 | 7篇 |
肿瘤学 | 9篇 |
出版年
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 10篇 |
2019年 | 4篇 |
2018年 | 9篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 3篇 |
2007年 | 7篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 10篇 |
2003年 | 7篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 8篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 10篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1977年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有197条查询结果,搜索用时 15 毫秒
71.
目的 建立头孢羟氨苄甲氧苄啶胶囊中头孢羟氨苄和甲氧苄啶的含量测定方法。方法 采用褶合光谱法,不经分离同时测定两组分的含量。结果 头孢羟氨苄和甲氧苄啶的平均回收率分别为99.5%(RSD1.02%)和100.0%(RSD:1.53%n=5)。结论 该法准确、简便、快速,可用于该制剂的质量控制。 相似文献
72.
73.
74.
褶合光谱法考察超临界流体萃取牡丹皮中丹皮酚的选择性 总被引:5,自引:0,他引:5
目的:考察采用褶合光谱法分析超临界流体萃取(SFE)选择性的可行性。方法:以超临界流体萃取牡丹皮中的丹皮酚为例,以不同波长段 拾光谱差谱值百分比作指标,观察压力、温度、动态萃取体积、改性剂加入量等因素对萃取选择性的影响,并与超临界界流体色谱(SFC)的结果进行初步比较。结果:褶合光谱法的差谱值方法显示改性剂量是SFE选择性的决定因素,结果与SFC的一致。结论:褶合光谱法可以部分替代某些色谱方法进行 相似文献
75.
S. Go
ro
g B. Herenyi M. Renyei 《Journal of pharmaceutical and biomedical analysis》1992,10(10-12):831-835
Two HPLC systems have been developed for the investigation of flumecinol (3-trifluoromethyl-alpha-ethyl-benzhydrol). The reversed-phase system (LiChrosorb RP-18; methanol-water, 7:3, v/v) enables the isolation and identification of the impurities. The chiral system (Chiralcel OD; hexane-2-propanol, 98:2, v/v) separates the enantiomers of flumecinol and its impurities. The potential of spectral convolution in peak identification in HPLC impurity profiling is demonstrated by an example involving the identification of the 4'-methyl-analogue of flumecinol. 相似文献
76.
计算机辅助褶合曲线分析法在分光光度分析中的应用——Ⅰ.复方新诺明片中SMZ和TMP的含量测定 总被引:2,自引:1,他引:1
本文在Glenn正交函数法的基础上,发展了一种计算机辅助褶合曲线分析法。本法可对混合物中各组分同时进行分别定量。在采集与波长相应的吸收度数据后,计算机将很快提供每一组份的含量以及其他统计信息。本法克服了Glenn法条件选择严格、计算繁杂以及对不相关吸收谱的限制等缺点。用本法测定复方新诺明片中SMZ和TMP的含量,结果相当满意。本文对褶合曲线法的基本原理和计算机程序设计作了扼要的介绍。 相似文献
77.
Estimating the mutation rate from a Luria-Delbrück fluctuation experiment involves estimating the Poisson parameter in a compound Poisson distribution. The efficiency with which this can be estimated depends on how well the other random factors have been characterized. The assumption that cell growth can be represented as a stochastic pure birth or Yule process is biologically unrealistic but contributes little to the bias and variance of a maximum likelihood estimator of the mutation rate. 相似文献
78.
A Second-Order Scheme with Nonuniform Time Steps for a Linear Reaction-Subdiffusion Problem 下载免费PDF全文
Hong-Lin Liao William McLean & Jiwei Zhang 《Communications In Computational Physics》2021,30(2):567-601
It is reasonable to assume that a discrete convolution structure dominatesthe local truncation error of any numerical Caputo formula because the fractional timederivative and its discrete approximation have the same convolutional form. We suggest an error convolution structure (ECS) analysis for a class of interpolation-type approximations to the Caputo fractional derivative. Our assumptions permit the use ofadaptive time steps, such as is appropriate for accurately resolving the initial singularity of the solution and also certain complex behavior away from the initial time.The ECS analysis of numerical approximations has two advantages: (i) to localize (andsimplify) the analysis of the approximation error of a discrete convolution formula ongeneral nonuniform time grids; and (ii) to reveal the error distribution information inthe long-time integration via the global consistency error. The core result in this paper is an ECS bound and a global consistency analysis of the nonuniform Alikhanovapproximation, which is constructed at an offset point by using linear and quadraticpolynomial interpolation. Using this result, we derive a sharp $L^2$-norm error estimateof a second-order Crank-Nicolson-like scheme for linear reaction-subdiffusion problems. An example is presented to show the sharpness of our analysis. 相似文献
79.
Fred Boer Andreas Hoeft Martin Scholz James G. Bovill Antoin G. L. Burm Adrie Hak 《Journal of pharmacokinetics and pharmacodynamics》1996,24(2):197-218
We applied a system dynamics approach to the study of the pulmonary distribution of alfentanil and sufentanil in anesthetized
pigs and patients, respectively. This method allows estimation of the mean transit time through the lungs and calculation
of the volume of distribution of alfentanil in the lungs. In the first part of the study the pulmonary distribution of alfentanil
was studied in six anesthetized pigs during three hemodynamic states (control, partial clamping of the inferior vena cave,
and complete clamping of the right pulmonary artery). In the second part of the study the pulmonary distribution of sufentanil
was studied in 10 patients, scheduled for elective CABG, during and after a constant rate infusion of 10 min. Pulmonary passage
of the opioids was characterized by functions of transit times, derived from the pulmonary arterial and systemic arterial
concentration curves. Pulmonary distribution volumes were calculated from the mean transit time and pulmonary blood flow.
Pulmonary distribution volume of alfentanil during the control measurement was significantly higher (486±88 ml) than during
either partial caval clamping (346±89 ml, p<0.05) or right pulmonary artery clamping (336±56 ml, p<0.05). There was no change
in the extravascular volume of distribution of alfentanil with each hemodynamic state. Pulmonary volume of distribution of
sufentanil in the patients was 22.6 (10.9) L. Pulmonary distribution of opioids can be studied using system dynamics analysis,
both after bolus injection and during and after infusion. This method can be used for periods beyond the initial passage of
the drug through the lungs. 相似文献
80.
目的 探讨利用深度学习在图像处理上的优势与放疗结合是否会使放疗过程更加智能化。方法 生成对抗网络(GAN)是一种利用神经网络的生成模型,输入相关特征可生成高质量剂量分布图像。先使用随机无条件GAN进行模拟分布数据的验证,再使用条件GAN(cGAN)训练肿瘤病例的DICOMRT数据,利用靶区和器官轮廓信息直接生成剂量分布图。结果 对于理想数据验证,GAN生成模拟分布效果优良,通过提取靶区轮廓和真实剂量切片数据使用cGAN训练,得到病例计划靶体积和危及器官的剂量分布。结构中预测值与真实剂量之间最大值和平均值的绝对误差评价表现为[3.57%,3.37%](计划靶体积)、[2.63%,2.87%](脑)、[1.50%,2.70%](临床靶体积)、[3.87%,1.79%](大体肿瘤体积)、[3.60%,3.23%](危及器官-1)、[4.40%,3.13%](危及器官-2)。结论 利用GAN模型可以生成模拟分布数据,同时结合先验知识的cGAN模型可以建立靶区和器官信息与剂量分布之间的关系。通过输入靶区和器官轮廓信息直接快速生成对应的剂量分布,是剂量预测的一种有效尝试。 相似文献