全文获取类型
收费全文 | 265篇 |
免费 | 28篇 |
国内免费 | 16篇 |
专业分类
化学 | 64篇 |
力学 | 7篇 |
综合类 | 8篇 |
数学 | 142篇 |
物理学 | 88篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 12篇 |
2021年 | 9篇 |
2020年 | 12篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 16篇 |
2013年 | 29篇 |
2012年 | 15篇 |
2011年 | 11篇 |
2010年 | 26篇 |
2009年 | 19篇 |
2008年 | 14篇 |
2007年 | 19篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 9篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
排序方式: 共有309条查询结果,搜索用时 140 毫秒
81.
82.
Benoit Deprez Damien Bosc Julie Charton Cyril Couturier Rebecca Deprez-Poulain Marion Flipo Florence Leroux Baptiste Villemagne Nicolas Willand 《Molecules (Basel, Switzerland)》2021,26(19)
Chemical biology and drug discovery are two scientific activities that pursue different goals but complement each other. The former is an interventional science that aims at understanding living systems through the modulation of its molecular components with compounds designed for this purpose. The latter is the art of designing drug candidates, i.e., molecules that act on selected molecular components of human beings and display, as a candidate treatment, the best reachable risk benefit ratio. In chemical biology, the compound is the means to understand biology, whereas in drug discovery, the compound is the goal. The toolbox they share includes biological and chemical analytic technologies, cell and whole-body imaging, and exploring the chemical space through state-of-the-art design and synthesis tools. In this article, we examine several tools shared by drug discovery and chemical biology through selected examples taken from research projects conducted in our institute in the last decade. These examples illustrate the design of chemical probes and tools to identify and validate new targets, to quantify target engagement in vitro and in vivo, to discover hits and to optimize pharmacokinetic properties with the control of compound concentration both spatially and temporally in the various biophases of a biological system. 相似文献
83.
探讨了PCR法鉴定牛早期胚胎性别时所用的引物,反应缓冲液中Mg2+浓度,循环反应的次数及可能造成污染的各种因素对性别鉴定结果的影响.并对18个胚胎进行了性别鉴定,移植38枚性别鉴定后的胚胎,成功产下2头与预测性别一致的牛犊,胚胎性别可鉴率为94.1%,预测性别符合率为100%. 相似文献
84.
Nan Zhang Ya-Bo Wu Jun-Wang Lu Chu-Wen Sun Li-Jie Shou Hai-Zhou Xu 《中国物理C(英文版)》2020,44(9):095107-095107-8
Based on the dynamics of single scalar field slow-roll inflation and the theory of reheating, we investigate the generalized natural inflationary (GNI) model. We introduce constraints on the scalar spectral index \begin{document}$n_{s}$\end{document} ![]()
![]()
and the tensor-to scalar ratio r for the \begin{document}$\Lambda$\end{document} ![]()
![]()
CDM \begin{document}$+r$\end{document} ![]()
![]()
model, according to the latest data from Planck 2018 TT, TE, EE+low E+lensing (P18) and BICEP2/Keck 2015 season (BK15), i.e., with \begin{document}$n_{s}=0.9659\pm0.0044$\end{document} ![]()
![]()
at 68% confidence level (CL), and \begin{document}$r<0.0623$\end{document} ![]()
![]()
at 95% CL. We find that the GNI model is favored by P18 and BK15 in the ranges \begin{document}$\log_{10}(f/M_{p})= 0.62^{+0.17}_{-0.18}$\end{document} ![]()
![]()
and \begin{document}$m=0.35^{+0.13}_{-0.23}$\end{document} ![]()
![]()
at 68% CL. In addition, the corresponding predictions of generalized and two-phase reheating are discussed. It follows that the parameter m has significant effect on the model behavior. 相似文献
85.
86.
In this paper, we study the permutation flow shop scheduling problems with deteriorating jobs on no-idle dominant machines. The objective is to minimize one of the two regular performance criteria, namely, makespan and total completion time. For each objective, the following dominant machines constraint: idm, ddm, idm–ddm and ddm–idm are considered. We present a polynomial time solution algorithm for each of the four cases. 相似文献
87.
Kwang-Hua W. Chu 《International Journal of Theoretical Physics》2007,46(11):2753-2757
We generalize some of those results which are closely related to the canonical kinetic term in k-essence formalism by further tuning the parameter (β). The scale factor a(t) could be negative and decreasing within a specific range of β (≡−1/ω, ω : the equation-of-state parameter) during the initial evolutional period. 相似文献
88.
Samiulla DS Vaidyanathan VV Arun PC Balan G Blaze M Bondre S Chandrasekhar G Gadakh A Kumar R Kharvi G Kim HO Kumar S Malikayil JA Moger M Mone MK Nagarjuna P Ogbu C Pendhalkar D Rao AV Rao GV Sarma VK Shaik S Sharma GV Singh S Sreedhar C Sonawane R Timmanna U Hardy LW 《Molecular diversity》2005,9(1-3):131-139
Natural product analogs are significant sources for therapeutic agents. To capitalize efficiently on the effective features of naturally occurring substances, a natural product-based library production platform has been devised at Aurigene for drug lead discovery. This approach combines the attractive biological and physicochemical properties of natural product scaffolds, provided by eons of natural selection, with the chemical diversity available from parallel synthetic methods. Virtual property analysis, using computational methods described here, guides the selection of a set of natural product scaffolds that are both structurally diverse and likely to have favorable pharmacokinetic properties. The experimental characterization of several in vitro ADME properties of twenty of these scaffolds, and of a small set of designed congeners based upon one scaffold, is also described. These data confirm that most of the scaffolds and the designed library members have properties favorable to their utilization for creating libraries of lead-like molecules.These authors have contributed equally to this work. 相似文献
89.
We investigate the computational complexity of deterministic sequencing problems in which unit-time jobs have to be scheduled on a single machine subject to chain-like precedence constraints. NP-hardness is established for the cases in which the number of late jobs or the total weighted tardiness is to be minimized, and for several related problems involving the total weighted completion time criterion. 相似文献
90.
Networks of queues with finite and infinite source customers have been used to study the interaction between the batch jobs and interactive jobs in computer systems. Earlier Kaufman ([1], PP-345-348) developed accurate approximations for a simple nonproduct form network of this type. In this paper we offer exact solutions for the same model with one finite source customer. We study both FIFO and LIFO disciplines at the contention node. The results are derived for the case where the finite source think time and service time distributions are generalized hyperexponential. 相似文献