全文获取类型
收费全文 | 2453篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 7篇 |
金属工艺 | 2篇 |
机械仪表 | 5篇 |
轻工业 | 11篇 |
水利工程 | 1篇 |
无线电 | 6篇 |
一般工业技术 | 10篇 |
冶金工业 | 2400篇 |
原子能技术 | 4篇 |
自动化技术 | 9篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2017年 | 1篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 78篇 |
1998年 | 724篇 |
1997年 | 451篇 |
1996年 | 275篇 |
1995年 | 150篇 |
1994年 | 134篇 |
1993年 | 149篇 |
1992年 | 13篇 |
1991年 | 24篇 |
1990年 | 25篇 |
1989年 | 24篇 |
1988年 | 21篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1983年 | 5篇 |
1982年 | 14篇 |
1981年 | 9篇 |
1980年 | 27篇 |
1979年 | 4篇 |
1978年 | 10篇 |
1977年 | 65篇 |
1976年 | 157篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1964年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有2455条查询结果,搜索用时 31 毫秒
141.
142.
143.
In prokaryotes, DnaK-DnaJ chaperon is involved in the protein degradation catalyzed by proteases La and ClpA/B complex as shown in E. coli. To extend this into eukaryotic cells, we examined the effects of hsp70 genes, SSA1 and SSB1, and DnaJ genes, SIS1 and YDJ1, on the growth of proteasome subunit mutants of the yeast S. cerevisiae. The results identified SSB1 and SIS1 as a pair of chaperon genes specifically involved in efficient protein turnover in the yeast, whose overexpression suppressed the growth defects caused by the proteasome mutations. Moreover, a single amino acid substitution in the putative peptide-binding site of SSB1 protein profoundly enhanced the suppression activity, indicating that the activity is mediated by the peptide-binding activity of this chaperon. Thus SSB1, with its partner DnaJ, SIS1, modulates the efficiency of protein turnover through its chaperon activity. 相似文献
144.
145.
146.
Purification and crystallization of complexes modeling the active state of the fragile histidine triad protein 总被引:1,自引:0,他引:1
Brenner C; Pace HC; Garrison PN; Robinson AK; Rosler A; Liu XH; Blackburn GM; Croce CM; Huebner K; Barnes LD 《Protein engineering, design & selection : PEDS》1997,10(12):1461-1463
Fragile histidine triad protein (Fhit) is a diadenosine triphosphate
(ApppA) hydrolase encoded at the human chromosome 3 fragile site which is
frequently disrupted in tumors. Reintroduction of FHIT coding sequences to
cancer cell lines with FHIT deletions suppressed the ability of these cell
lines to form tumors in nude mice even when the reintroduced FHIT gene had
been mutated to allow ApppA binding but not hydrolysis. Because this
suggested that the tumor suppressor activity of Fhit protein depends on
substrate-dependent signaling rather than ApppA catabolism, we prepared two
crystalline forms of Fhit protein that are expected to model its
biologically active, substrate-bound state. Wild-type and the His96Asn
forms of Fhit were overexpressed in Escherichia coli, purified to
homogeneity and crystallized in the presence and absence of ApppA and an
ApppA analog. Single crystals obtained by vapor diffusion against ammonium
sulfate diffracted X-rays to beyond 2.75 A resolution. High quality native
synchrotron X-ray data were collected for an orthorhombic and a hexagonal
crystal form.
相似文献
147.
Coastal marine ecosystems world-wide are threatened by invasions of nonindigenous species. The ubiquity of marine sibling species identifiable only by genetic analysis suggests that many invasions are cryptic and therefore undetected, causing an underestimation of the actual number and impacts of invading species. We test this hypothesis with European crabs in the genus Carcinus that have invaded five regions globally. Partial 16S ribosomal RNA gene sequences confirm sibling species status of morphologically similar Atlantic C. maenas and Mediterranean C. aestuarii. Based on 16S rRNA haplotypes, crabs from California, New England and Tasmania were all C. maenas. However, we report the cryptic multiple invasion of both species in Japan and South Africa, where only C. aestuarii and C. maenas, respectively, were previously recognized. 相似文献
148.
CNS infections caused by human herpesvirus 1 and human herpesvirus 2-herpes simplex virus type 1 and herpes simplex virus type 2--are reviewed. The major diseases associated with these viruses are meningitis and encephalitis. Two forms of encephalitis are known, neonatal encephalitis and encephalitis occurring after the neonatal period. Both diseases are associated with high mortality and morbidity and require prompt diagnosis and aggressive antiviral chemotherapy. Methods for the specific diagnosis of these infections are reviewed and the value of intrathecal antibody assay and nucleic acid amplification techniques are emphasised. 相似文献
149.
The absolute wavenumbers for 36 lines of the 3-0 band of 12C16O are measured from P(17) at 6271 cm-1 to R(19) at 6405 cm-1, with an uncertainty of about +/-3 x 10(-5) cm-1 (about +/-1 MHz). The experimental positions are compared with the best predicted positions from recent Dunham coefficients. Self-induced pressure lineshifts are determined and reach, at most, about -8 x 10(-3) cm-1 atm-1. Copyright 1997 Academic Press. Copyright 1997Academic Press 相似文献
150.