全文获取类型
收费全文 | 61篇 |
免费 | 0篇 |
国内免费 | 5篇 |
专业分类
系统科学 | 1篇 |
教育与普及 | 1篇 |
理论与方法论 | 1篇 |
现状及发展 | 16篇 |
研究方法 | 2篇 |
综合类 | 45篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2013年 | 1篇 |
2012年 | 7篇 |
2011年 | 4篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 31 毫秒
1.
Triiodothyronine injected daily to pregnant rats for the last week of gestation (50 microgram/100 g b.wt) increased the specific activities of 5 acid glycosidases in the fetal forebrain and cerebellum. Cortisone (50 mg/100 g b.wt) administered in the same period had no effect on cerebellum acid hydrolases, but decreased their activity in the forebrain. 相似文献
2.
Montgomery KT Lee E Miller A Lau S Shim C Decker J Chiu D Emerling S Sekhon M Kim R Lenz J Han J Ioshikhes I Renault B Marondel I Yoon SJ Song K Murty VV Scherer S Yonescu R Kirsch IR Ried T McPherson J Gibbs R Kucherlapati R 《Nature》2001,409(6822):945-946
Our sequence-tagged site-content map of chromosome 12 is now integrated with the whole-genome fingerprinting effort. It provides accurate and nearly complete bacterial clone coverage of chromosome 12. We propose that this integrated mapping protocol serves as a model for constructing physical maps for entire genomes. 相似文献
3.
Pellegata NS Dieguez-Lucena JL Joensuu T Lau S Montgomery KT Krahe R Kivelä T Kucherlapati R Forsius H de la Chapelle A 《Nature genetics》2000,25(1):91-95
Specialized collagens and small leucine-rich proteoglycans (SLRPs) interact to produce the transparent corneal structure. In cornea plana, the forward convex curvature is flattened, leading to a decrease in refraction. A more severe, recessively inherited form (CNA2; MIM 217300) and a milder, dominantly inherited form (CNA1; MIM 121400) exist. CNA2 is a rare disorder with a worldwide distribution, but a high prevalence in the Finnish population. The gene mutated in CNA2 was assigned by linkage analysis to 12q (refs 4, 5), where there is a cluster of several SLRP genes. We cloned two additional SLRP genes highly expressed in cornea: KERA (encoding keratocan) in 12q and OGN (encoding osteoglycin) in 9q. Here we report mutations in KERA in 47 CNA2 patients: 46 Finnish patients are homozygous for a founder missense mutation, leading to the substitution of a highly conserved amino acid; and one American patient is homozygous for a mutation leading to a premature stop codon that truncates the KERA protein. Our data establish that mutations in KERA cause CNA2. CNA1 patients had no mutations in these proteoglycan genes. 相似文献
4.
5.
Microarray analysis shows that some microRNAs downregulate large numbers of target mRNAs 总被引:11,自引:0,他引:11
Lim LP Lau NC Garrett-Engele P Grimson A Schelter JM Castle J Bartel DP Linsley PS Johnson JM 《Nature》2005,433(7027):769-773
6.
Stephens PJ Tarpey PS Davies H Van Loo P Greenman C Wedge DC Nik-Zainal S Martin S Varela I Bignell GR Yates LR Papaemmanuil E Beare D Butler A Cheverton A Gamble J Hinton J Jia M Jayakumar A Jones D Latimer C Lau KW McLaren S McBride DJ Menzies A Mudie L Raine K Rad R Chapman MS Teague J Easton D Langerød A;Oslo Breast Cancer Consortium 《Nature》2012,486(7403):400-404
All cancers carry somatic mutations in their genomes. A subset, known as driver mutations, confer clonal selective advantage on cancer cells and are causally implicated in oncogenesis, and the remainder are passenger mutations. The driver mutations and mutational processes operative in breast cancer have not yet been comprehensively explored. Here we examine the genomes of 100 tumours for somatic copy number changes and mutations in the coding exons of protein-coding genes. The number of somatic mutations varied markedly between individual tumours. We found strong correlations between mutation number, age at which cancer was diagnosed and cancer histological grade, and observed multiple mutational signatures, including one present in about ten per cent of tumours characterized by numerous mutations of cytosine at TpC dinucleotides. Driver mutations were identified in several new cancer genes including AKT2, ARID1B, CASP8, CDKN1B, MAP3K1, MAP3K13, NCOR1, SMARCD1 and TBX3. Among the 100 tumours, we found driver mutations in at least 40 cancer genes and 73 different combinations of mutated cancer genes. The results highlight the substantial genetic diversity underlying this common disease. 相似文献
7.
应用概率统计方法对混沌信号进行非相干检测 总被引:3,自引:0,他引:3
提出一种基于概率统计的方法, 采用最大似然法和贝叶
斯公式, 在Chaos Shift Keying系统的接收端重构发射端混沌映射, 实现混沌信号的非相干检测. 在系统的发送端, 根据所发送的二进制信号对混沌映射系统进行分叉参数调制, 由于混沌信号对参数条件的敏感性, 所以在不同的参数条件下混沌信号有很大不同, 在接收端采用概率统计方法, 对信号发生的概率进行计算, 根据事件发生概率的不同判断接收到的数字信号. 理论推导和计算机仿真结果基本一致. 相似文献
8.
In this paper, the oxidative degradation of 2, 4-dichlorophenoxyacetic acid (2, 4-D) using Mn2+/H2O2 reagent under UV irradiation was studied. The results show that 2, 4-D was degraded more completely in Mn2+/H2O2 solution than traditional Fenton solutions. The effects of the concentration of Mn2+, H2O2 and pH were also investigated. And under the optimal condition of 1.48×10−4 mol/L, 8.99×10−5 mol/L and pH 3.38, the formation of ·OH was the most, both the decomposition rate of H2O2 and the degradation rate of 2, 4-D were the fastest. In addition, the photoreaction process was monitored using spin-trapping
electron paramagnetic resonance (EPR), and the results indicated that the oxidative process was predominated mainly by the
hydroxyl radical (·OH) gennerated in the system.
Biography: HUANG Yingping (1964–), Professor, Ph. D., research direction: pollution ecology and water pollution control. 相似文献
9.
Ding Xiao-li Huang Ding-fa Yin Jian-hua Chen Yong-qi C. K. Lau Yang Yu-wen Sun Yong-rong Chen Wu He Xiu-feng 《武汉大学学报:自然科学英文版》2003,8(2):671-676
GPS has become an important technology for monitoring deformations of structures and the crust of the Earth. A limiting factor for large-scale use of GPS in such applications is however its high hardware cost. For automatic monitoring of deformations, each point to be monitored needs equipped with a set of GPS instruments. This makes many applications such as routine monitoring of landslides too expensive in most cases. A multi-antenna GPS system has been developed and tested aiming at significantly reducing the cost of GPS when used for monitoring deformations of objects such as slopes. The system uses special hardware and software to allow one GPS receiver to be used with a number of GPS antennas. One set of such equipment can therefore be used to monitor a number of points. The system normally reduces the cost of GPS hardware by a number of folds. Besides, such a system design also eases the tasks of data communication, management and system control. This paper describes the design and system configurations of the multi-antenna GPS system that has been developed by the research team. The system consists of integrated hardware and software components for data acquisition, transmission, processing, analysis and visualization. Integration of the GPS system with conventional slope monitoring systems will also be discussed in brief. 相似文献
10.
Hedgehog signaling in pancreas development and disease 总被引:6,自引:0,他引:6
Since its discovery, numerous studies have shown that the Hedgehog (Hh) signaling pathway plays an instrumental role during
diverse processes of cell differentiation and organ development. More recently, it has become evident that Hh signaling is
not restricted to developmental events, but retains some of its activity during adult life. In mature tissues, Hh signaling
has been implicated in the maintenance of stem cell niches in the brain, renewal of the gut epithelium and differentiation
of hematopoietic cells. In addition to the basal function in adult tissue, deregulated signaling has been implicated in a
variety of cancers, including basal cell carcinoma, glioma and small cell lung cancer. Here, we will focus on the role of
Hh signaling in pancreas development and pancreatic diseases, including diabetes mellitus, chronic pancreatitis and pancreatic
cancer.
Received 5 August 2005; received after revision 4 November 2005; accepted 22 November 2005 相似文献