全文获取类型
收费全文 | 89955篇 |
免费 | 7341篇 |
国内免费 | 40篇 |
出版年
2023年 | 542篇 |
2022年 | 954篇 |
2021年 | 1812篇 |
2020年 | 1355篇 |
2019年 | 1587篇 |
2018年 | 2322篇 |
2017年 | 2055篇 |
2016年 | 2992篇 |
2015年 | 3876篇 |
2014年 | 3995篇 |
2013年 | 5259篇 |
2012年 | 6223篇 |
2011年 | 5957篇 |
2010年 | 3667篇 |
2009年 | 3250篇 |
2008年 | 4224篇 |
2007年 | 4104篇 |
2006年 | 3847篇 |
2005年 | 3810篇 |
2004年 | 3810篇 |
2003年 | 3356篇 |
2002年 | 2811篇 |
2001年 | 2228篇 |
2000年 | 2231篇 |
1999年 | 1816篇 |
1998年 | 948篇 |
1997年 | 803篇 |
1996年 | 849篇 |
1995年 | 696篇 |
1994年 | 642篇 |
1993年 | 617篇 |
1992年 | 1176篇 |
1991年 | 1038篇 |
1990年 | 947篇 |
1989年 | 910篇 |
1988年 | 884篇 |
1987年 | 844篇 |
1986年 | 764篇 |
1985年 | 749篇 |
1984年 | 703篇 |
1983年 | 527篇 |
1982年 | 443篇 |
1981年 | 408篇 |
1980年 | 382篇 |
1979年 | 507篇 |
1978年 | 420篇 |
1977年 | 342篇 |
1975年 | 340篇 |
1974年 | 362篇 |
1973年 | 354篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
21.
Morphological taxonomy of simple Hyphomycetes is complicated by the frequent occurrence of pleoanamorphism. In some groups
of yeast-like fungi, uncommon synanamorphs are diagnostic. Differences in conidiogenesis do not always delimit natural groups.
Some nomenclatural problems are mentioned, with an emphasis on the need of neotypification. Prospects are sketched for future
taxonomic research. 相似文献
22.
C Chong-Cerrillo M E Selsted E M Peterson L M de la Maza 《The journal of peptide research》2003,61(5):237-242
Four antimicrobial peptides, protegrin-1, RTD-1, cryptdin-4, and indolicidin, were tested for their ability to inhibit the in vitro growth of Chlamydia trachomatis serovars E, L2, and mouse pneumonitis (MoPn). In general, protegrin-1 was found to have the strongest anti-chlamydial activity. Overall, of the three serovars tested, L2 was the most susceptible while MoPn was the most resistant to these peptides. 相似文献
23.
24.
25.
M. de Kwaadsteniet C. A. van Reenen L. M. T. Dicks 《Probiotics and antimicrobial proteins》2010,2(2):61-65
The potential of nisin F as an antimicrobial agent in treating subcutaneous skin infections was tested in vivo by infecting C57BL/6 mice with a bioluminescent strain of Staphylococcus aureus (Xen 36). Strain Xen 36 has the luxABCDE operon located on a native plasmid. Mice were grouped into four groups: Infected with strain Xen 36 and treated with nisin F, infected with strain Xen 36 and treated with saline (placebo), not infected and treated with nisin (control) and not infected and not treated (control). The immune systems of the mice were suppressed with deksamethasone. Mice were treated with either nisin F or sterile physiological saline 24 and 48 h after infection with subcutaneously injected S. aureus Xen 36 (4 × 106 CFU). Histology and bioluminescent flux measurements revealed no significant difference between infected mice treated with nisin and saline, respectively. However, infected mice treated with nisin F had an increased number of polymorphonuclear cells when compared with infected mice treated with saline. Also, not infected mice treated with nisin F had an influx of polymorphonuclear cells. Nisin F is thus ineffective in combating deep dermal staphylococcal infections. The apparent immune modulation of nisin when subcutaneously injected has to be investigated. 相似文献
26.
27.
Genome-wide analysis of the SET DOMAIN GROUP family in grapevine 总被引:1,自引:0,他引:1
The SET DOMAIN GROUP (SDG) proteins represent an evolutionarily-conserved family of epigenetic regulators present in eukaryotes
and are putative candidates for the catalysis of lysine methylation in histones. Plant genomes analyses of this family have
been performed in arabidopsis, maize, and rice and functional studies have shown that SDG genes are involved in the control
of plant development. In this work, we describe the identification and structural characterization of SDG genes in the Vitis vinifera genome. This analysis revealed the presence of 33 putative SDG genes that can be grouped into different classes, as it has
been previously described for plants. In addition to the SET domain, the proteins identified possessed other domains in the
different classes. As part of our study regarding the growth and development of grapevine, we selected eight genes and their
expression levels were analyzed in representative vegetative and reproductive organs of this species. The selected genes showed
different patterns of expression during inflorescence and fruit development, suggesting that they participate in these processes.
Furthermore, we showed that the expression of selected SDGs changes during viral infection, using as a model Grapevine Leafroll
Associated Virus 3-infected symptomatic grapevine leaves and fruits. Our results suggest that developmental changes caused
by this virus could be the result of alterations in SDG expression. 相似文献
28.
Transcriptional regulatory network triggered by oxidative signals configures the early response mechanisms of japonica rice to chilling stress 总被引:3,自引:0,他引:3
29.
Inhibitory effect of the flavonoid silymarin on the erythrocyte hemolysis induced by phenylhydrazine
A Valenzuela T Barría R Guerra A Garrido 《Biochemical and biophysical research communications》1985,126(2):712-718
The flavonoid silymarin, which is used as a therapeutical agent in the treatment of liver diseases, can inhibit the hemolysis and lipid peroxidation induced by phenylhydrazine on erythrocytes obtained from rats treated with the flavonoid. This effect is ascribed to the antioxidant properties as a free radical scavenger exhibited by the flavonoid. Silymarin failed to inhibit the glutathione depletion induced by phenylhydrazine on erythrocytes. It is proposed that the flavonoid acts at the membrane level of the cell avoiding the lipid peroxidative and fluidizing effect of phenylhydrazine. 相似文献
30.