首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   33篇
  免费   0篇
化学   6篇
力学   8篇
数学   16篇
物理学   3篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2017年   1篇
  2013年   7篇
  2012年   2篇
  2011年   2篇
  2010年   4篇
  2009年   1篇
  2006年   2篇
  2005年   1篇
  2003年   1篇
  2000年   1篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1983年   1篇
  1959年   2篇
  1939年   1篇
排序方式: 共有33条查询结果,搜索用时 15 毫秒
11.
A comparison of shadow prices and reimbursement rates of hospital services   总被引:1,自引:0,他引:1  
The purpose of this paper is to calculate shadow prices of hospital services and compare them to the reimbursement rates those hospitals receive. These shadow prices are calculated by estimating a multiple-output distance function and applying a dual Shephard's lemma, a technique suggested by Färe and Grosskopf [8]. In contrast to cost functions, distance functions require no price data and do not presume cost minimization. We apply this technique to a sample of California hospitals operating in 1986. We find that hospitals engaged in selective contracting for Medi-Cal patients exhibit closer agreement between relative shadow prices and relative reimbursement rates (Medi-Cal relative to private patients) than noncontracting hospitals.Contact author.  相似文献   
12.
13.
X-ray Thomson scattering has enabled us to measure the temperature of a shocked layer, produced in the laboratory, that is relevant to shocks emerging from supernovas. High energy lasers are used to create a shock in argon gas which is probed by x-ray scattering. The scattered, inelastic Compton feature allows inference of the electron temperature. It is measured to be 34 eV in the radiative precursor and ~60 eV near the shock. Comparison of energy fluxes implied by the data demonstrates that the shock wave is strongly radiative.  相似文献   
14.
Supersonic plasma outflows driven by multi-beam, high-energy lasers, such as Omega and NIF, have been and will be used as platforms for a variety of laboratory astrophysics experiments. Here we propose a new way of launching high density and high velocity, plasma jets using multiple intense laser beams in a hollow ring formation. We show that such jets provide a more flexible and versatile platform for future laboratory astrophysics experiments. Using high resolution hydrodynamic simulations, we demonstrate that the collimated jets can achieve much higher density, temperature and velocity when multiple laser beams are focused to form a hollow ring pattern at the target, instead of focused onto a single spot. We carried out simulations with different ring radii and studied their effects on the jet properties. Implications for laboratory collisionless shock experiments are discussed.  相似文献   
15.
We have performed high-energy-density physics experiments with large radiative fluxes, relevant to radiative shocks in our universe. These experiments were performed at the Omega Laser facility and used a laser irradiance of 7.2 × 1014 W cm?2 to launch a Be disk into low-density Xe gas. The radiative shocks were observed early in time as the dense shocked Xe layer began to form. The average shock position indicates that the shock is moving over 130 km s?1. Data are compared to simulation output from the CRASH code, which was developed at the Center for Radiative Shock Hydrodynamics at the University of Michigan.  相似文献   
16.
Drug delivery and cell transplantation require minimally invasive deployment strategies such as injection through clinically relevant high‐gauge needles. Supramolecular hydrogels comprising dodecyl‐modified hydroxypropylmethylcellulose and poly(ethylene glycol)‐block‐poly(lactic acid) have been previously demonstrated for the delivery of drugs and proteins. Here, it is demonstrated that the rheological properties of these hydrogels allow for facile injectability, an increase of cell viability after injection when compared to cell viabilities of cells injected in phosphate‐buffered saline, and homogeneous cell suspensions that do not settle. These hydrogels are injected at 1 mL min?1 with pressures less than 400 kPa, despite the solid‐like properties of the gel when at rest. The cell viabilities immediately after injection are greater than 86% for adult human dermal fibroblasts, human umbilical vein cells, smooth muscle cells, and human mesenchymal stem cells. Cells are shown to remain suspended and proliferate in the hydrogel at the same rate as observed in cell media. The work expands on the versatility of these hydrogels and lays a foundation for the codelivery of drugs, proteins, and cells.  相似文献   
17.
The relationship between Malmquist productivity change and profitability is developed in this paper. Our theoretical construct is applied to Swedish pharmacies.  相似文献   
18.
    
Zusammenfassung Durch die Anwendung dampfförmiger Reagenskomponenten lassen sich Prüfröhrchenreaktionen verwirklichen, die dieser Technik aus Gründen der Reagensstabilität bisher verschlossen waren.Die dampfförmige Komponente ist innerhalb des Prüfröhrchens getrennt in einer Ampulle untergebracht, die erst unmittelbar vor der Prüfung auf einfache Weise geöffnet wird. So können metastabile, sehr reaktionsfähige Reagensgemische unmittelbar vor oder während der Prüfung nascierend erzeugt werden. Das Prinzip des Verfahrens wird erläutert an der Bestimmung von Formaldehyd, Tetrachlorkohlenstoff, Methylbromid und Methan im Gemisch mit Luft.  相似文献   
19.
20.
In this paper we analyze resource allocation distinguishing between the decision of when to begin allocation and over how many periods to apply the resources. We present analytical results for specific production technologies under different returns to scale assumptions, under capacity constraints and for production with technical change. Using a dynamic activity analysis framework we show how to compute in general optimal solutions for resource intensity use.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号