全文获取类型
收费全文 | 140篇 |
免费 | 34篇 |
国内免费 | 13篇 |
专业分类
系统科学 | 15篇 |
现状及发展 | 43篇 |
研究方法 | 12篇 |
综合类 | 116篇 |
自然研究 | 1篇 |
出版年
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 12篇 |
2017年 | 17篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 15篇 |
2013年 | 7篇 |
2012年 | 10篇 |
2011年 | 13篇 |
2010年 | 10篇 |
2009年 | 6篇 |
2008年 | 9篇 |
2007年 | 11篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 3篇 |
1999年 | 4篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1971年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 218 毫秒
131.
132.
Zusammenfassung Immunologischer Nachweis von Amöbiasis gelingt auch durch indirekte Hämagglutination und durch Gel-Diffusion. 相似文献
133.
134.
Pleiotropic defects in lymphocyte activation caused by caspase-8 mutations lead to human immunodeficiency 总被引:40,自引:0,他引:40
Chun HJ Zheng L Ahmad M Wang J Speirs CK Siegel RM Dale JK Puck J Davis J Hall CG Skoda-Smith S Atkinson TP Straus SE Lenardo MJ 《Nature》2002,419(6905):395-399
Apoptosis is a form of programmed cell death that is controlled by aspartate-specific cysteine proteases called caspases. In the immune system, apoptosis counters the proliferation of lymphocytes to achieve a homeostatic balance, which allows potent responses to pathogens but avoids autoimmunity. The CD95 (Fas, Apo-1) receptor triggers lymphocyte apoptosis by recruiting Fas-associated death domain (FADD), caspase-8 and caspase-10 proteins into a death-inducing signalling complex. Heterozygous mutations in CD95, CD95 ligand or caspase-10 underlie most cases of autoimmune lymphoproliferative syndrome (ALPS), a human disorder that is characterized by defective lymphocyte apoptosis, lymphadenopathy, splenomegaly and autoimmunity. Mutations in caspase-8 have not been described in ALPS, and homozygous caspase-8 deficiency causes embryonic lethality in mice. Here we describe a human kindred with an inherited genetic deficiency of caspase-8. Homozygous individuals manifest defective lymphocyte apoptosis and homeostasis but, unlike individuals affected with ALPS, also have defects in their activation of T lymphocytes, B lymphocytes and natural killer cells, which leads to immunodeficiency. Thus, caspase-8 deficiency in humans is compatible with normal development and shows that caspase-8 has a postnatal role in immune activation of naive lymphocytes. 相似文献
135.
在间歇精馏塔单塔操作优化的基础上,实行多塔生产调度的优化。适当地安排各座塔的处理任务,按一定的规律交替地处理原料和中间产物,使其所需的时间为最短。本文提出的启发式优化调度方案简单易行,得到的生产调度直方图直观易读。仿真结果表明,经济效益显著,且可推广解决类似的工业生产调度问题。 相似文献
136.
In recent years, a wide variety of studies have applied soft systems methodology (SSM) to address the complexities of the messy situations. This paper seeks to identify 1) application areas and 2) application levels of the use of SSM in dealing with problematical situations. To do so, 149 articles published between 2000 and 2015 were studied. The findings revealed the application of SSM in new application areas such as sustainable development, knowledge management and project management. The results of this study also indicated that researchers applied SSM at three levels: SSM as a process of inquiry, SSM as an action-oriented methodology, and the hybrid use of SSM. Based on the findings, SSM at the level of a single methodology for bringing out changes has been less welcomed by researchers, but the application levels of inquiry processes and hybrid approaches have been more utilized. This suggests that in the correspondence of SSM with the nature or situation of problems, a sort of incommensurability is witnessed. Factors arising from the nature of the problem, inadequate mastery of the researcher over SSM or the limitations of SSM can exert an influence on this incommensurability. 相似文献
137.
A data-mining approach to biomarker identification from protein profiles using discrete stationary wavelet transform 下载免费PDF全文
Hussain Montazery-Kordy Mohammad Hossein Miran-Baygi Mohammad Hassan Moradi 《浙江大学学报(自然科学英文版)》2008,9(11):863-870
Objective: To develop a new bioinformatic tool based on a data-mining approach for extraction of the most informative proteins that could be used to find the potential biomarkers for the detection of cancer. Methods: Two independent datasets from serum samples of 253 ovarian cancer and 167 breast cancer patients were used. The samples were examined by surfaceenhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The datasets were used to extract the informative proteins using a data-mining method in the discrete stationary wavelet transform domain. As a dimensionality reduction procedure, the hard thresholding method was applied to reduce the number of wavelet coefficients. Also, a distance measure was used to select the most discriminative coefficients. To find the potential biomarkers using the selected wavelet coefficients, we applied the inverse discrete stationary wavelet transform combined with a two-sided t-test. Results: From the ovarian cancer dataset, a set of five proteins were detected as potential biomarkers that could be used to identify the cancer patients from the healthy cases with accuracy, sensitivity, and specificity of 100%. Also, from the breast cancer dataset, a set of eight proteins were found as the potential biomarkers that could separate the healthy cases from the cancer patients with accuracy of 98.26%, sensitivity of 100%, and specificity of 95.6%. Conclusion: The results have shown that the new bioinformatic tool can be used in combination with the high-throughput proteomic data such as SELDI-TOF MS to find the potential biomarkers with high discriminative power. 相似文献
138.
Hamid Ashrafi Rahmatollah Emadi Mohammad Hosein Enayati 《矿物冶金与材料学报》2014,21(7):711-719
The aim of this study was to produce bulk nanocrystalline Al/Al12(Fe,V)3Si alloys by mechanical alloying (MA) and subsequent hot pressing (HP) of elemental powders. A nanostructured Al-based solid solution was formed by MA of elemental powders for 60 h. After HP of the as-milled powders at 550℃ for 20 min, the Al12(Fe,V)3Si phase was precipitated in a nanocrystalline Al matrix. Scanning electron microscopy (SEM) images of the bulk samples represented a homogeneous and uniform microstructure that was superior to those previously obtained by rapid solidification-powder metallurgy (RS-PM). Nanostructured Al-8.5Fe-1.3V-1.7Si and Al-11.6Fe-1.3V-2.3Si alloys ex-hibited high HV hardness values of~205 and~254, respectively, which are significantly higher than those reported for the RS-PM counter-parts. 相似文献
139.
Martín-García R de León N Sharifmoghadam MR Curto MÁ Hoya M Bustos-Sanmamed P Valdivieso MH 《Cellular and molecular life sciences : CMLS》2011,68(17):2907-2917
Chs5p is a component of the exomer, a coat complex required to transport the chitin synthase Chs3p from the trans-Golgi network
to the plasma membrane. The Chs5p N-terminal region exhibits fibronectin type III (FN3) and BRCT domains. FN3 domains are
present in proteins that mediate adhesion processes, whereas BRCT domains are involved in DNA repair. Several fungi—including
Schizosaccharomyces pombe, which has no detectable amounts of chitin—have proteins similar to Chs5p. Here we show that the FN3 and BRCT motifs in Chs5p
behave as a module that is necessary and sufficient for Chs5p localization and for cargo delivery. The N-terminal regions
of S. cerevisiae Chs5p and S. pombe Cfr1p are interchangeable in terms of Golgi localization, but not in terms of exomer assembly, showing that the conserved
function of this module is protein retention in this organelle and that the interaction between the exomer components is organism-specific. 相似文献
140.
Mohammad Mohammadi 《Journal of forecasting》2017,36(7):859-866
The best prediction of generalized autoregressive conditional heteroskedasticity (GARCH) models with α‐stable innovations, α‐stable power‐GARCH models and autoregressive moving average (ARMA) models with GARCH in mean effects (ARMA‐GARCH‐M) are proposed. We present a sufficient condition for stationarity of α‐stable GARCH models. The prediction methods are easy to implement in practice. The proposed prediction methods are applied for predicting future values of the daily SP500 stock market and wind speed data. 相似文献