全文获取类型
收费全文 | 230篇 |
免费 | 8篇 |
国内免费 | 3篇 |
专业分类
系统科学 | 1篇 |
现状及发展 | 100篇 |
研究方法 | 25篇 |
综合类 | 110篇 |
自然研究 | 5篇 |
出版年
2019年 | 2篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 11篇 |
2011年 | 17篇 |
2010年 | 2篇 |
2009年 | 1篇 |
2008年 | 7篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 9篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1975年 | 3篇 |
1974年 | 6篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1970年 | 7篇 |
1969年 | 7篇 |
1968年 | 4篇 |
1967年 | 10篇 |
1966年 | 1篇 |
1965年 | 5篇 |
1964年 | 4篇 |
1955年 | 1篇 |
排序方式: 共有241条查询结果,搜索用时 0 毫秒
211.
212.
Fractionation of a human spermagglutinating serum 总被引:3,自引:0,他引:3
213.
214.
Isolation of the two paragonial substances deposited into the spermatophores ofAcanthoscelides obtectus (Coleoptera,Bruchidae) 总被引:1,自引:0,他引:1
A. K. Das J. Huignard M. Barbier A. Quesneau-Thierry 《Cellular and molecular life sciences : CMLS》1980,36(8):918-920
Summary Aqueous extracts from spermatophores ofAcanthoscelides obtectus (Coleoptera, Bruchidae) have been chromatographed on Sephadex G 25 and G 15 columns, the active fractions being further purified by preparative SiO2 TLC. The isolation and properties of 2 biologically active compounds are reported. The paragonial substance A has a favourable action upon oogenesis, is a low molecular weight molecule (500–1000) and gives 1 single amino acid on hydrolysis, corresponding to glycin on TLC. The paragonial substance B is toxic, or an inhibitor of oogenesis at lower concentration, thus showing an antagonistic effect. 相似文献
215.
Mutations in LGI1 cause autosomal-dominant partial epilepsy with auditory features. 总被引:28,自引:0,他引:28
Sergey Kalachikov Oleg Evgrafov Barbara Ross Melodie Winawer Christie Barker-Cummings Filippo Martinelli Boneschi Chang Choi Pavel Morozov Kamna Das Elita Teplitskaya Andrew Yu Eftihia Cayanis Graciela Penchaszadeh Andreas H Kottmann Timothy A Pedley W Allen Hauser Ruth Ottman T Conrad Gilliam 《Nature genetics》2002,30(3):335-341
The epilepsies are a common, clinically heterogeneous group of disorders defined by recurrent unprovoked seizures. Here we describe identification of the causative gene in autosomal-dominant partial epilepsy with auditory features (ADPEAF, MIM 600512), a rare form of idiopathic lateral temporal lobe epilepsy characterized by partial seizures with auditory disturbances. We constructed a complete, 4.2-Mb physical map across the genetically implicated disease-gene region, identified 28 putative genes (Fig. 1) and resequenced all or part of 21 genes before identifying presumptive mutations in one copy of the leucine-rich, glioma-inactivated 1 gene (LGI1) in each of five families with ADPEAF. Previous studies have indicated that loss of both copies of LGI1 promotes glial tumor progression. We show that the expression pattern of mouse Lgi1 is predominantly neuronal and is consistent with the anatomic regions involved in temporal lobe epilepsy. Discovery of LGI1 as a cause of ADPEAF suggests new avenues for research on pathogenic mechanisms of idiopathic epilepsies. 相似文献
216.
Summary
Streptomyces species 3M grew in peptone yeast extract medium with 1000 g/ml K2Cr2O7. Incubation of the chromate with different cell fractions in the presence of NADH and NADPH resulted in a decrease of Cr6+ in the reaction mixture. The level of Cr6+ was reduced by 82.7% by a particulate cell fraction obtained by centrifugation at 105,000×g for 1 h, in the presence of NADH. The reducing enzyme was associated with this cell fraction. The enzyme was constitutive and reduced Cr6+ to Cr3+. 相似文献
217.
Summary The free energy of transfer ( G
t
0
) of KBrO3 and KIO3 from water to 10, 20 and 30% dioxane-water mixtures have been studied from conductometric measurements. The G
t
0
values are in the order of BrO
3
–
>IO
3
–
. 相似文献
218.
Summary The free enrgies of transfer (G
t
0
) of H+, Cl–, Br–, I– and SCN– ions from water to 10, 20, 30 and 40% dioxanewater mixtures have been studied from potentiometric measurements. For anions the G
t
0
values are in the order Cl–>Br–>SCN–>I–. 相似文献
219.
In vitro studies showed that the flavonoid aglycones apigenin, luteolin and kaempferol inhibited the hyaluronidase activity of five different venoms dose-dependently. They were also able to delay the venom action when injected into mice. Naringenin, catechin and flavonoid glycosides had no effect. The flavonoids with unsubstituted hydroxyl groups at C-positions 5, 7 and 4′, a double bond between carbons 2 and 3, as well as a ketone group at position 4, exhibited potent inhibitory actions on the venom hyaluronidases. 相似文献
220.
The polyunsaturated fatty acids (PUFAs), linoleic acid (LA), alpha linolenic acid (ALA), gamma linolenic acid (GLA), arachidonic acid (AA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), showed inhibition of growth of both normal and abnormal (Molt-4) human lymphocytes, and inhibition was concentration-dependent. Interestingly, the production of the lymphokine Interleukin-2 (IL-2) was elevated in Molt-4 cells, but it was reduced in the normal human lymphocytes. Addition of GLA or IL-2 or a combination of both showed enhancement of SO
2
–
and of lipid peroxidation levels, which were significantly higher in Molt-4 cells than in the normal lymphocytes. Reduction of protein concentration was also observed in both types of cells during this treatment. The data showed that the antiproliferative effects of GLA and IL-2 may partly be exerted through the elevated production of superoxide free radicals and peroxidatin products. This is a novel finding and therefore, further exploitation of combinations of PUFAs and IL-2 may be a possible way of combating cancer cell growth. 相似文献