全文获取类型
收费全文 | 652篇 |
免费 | 32篇 |
国内免费 | 4篇 |
出版年
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 22篇 |
2012年 | 30篇 |
2011年 | 32篇 |
2010年 | 19篇 |
2009年 | 26篇 |
2008年 | 23篇 |
2007年 | 29篇 |
2006年 | 40篇 |
2005年 | 36篇 |
2004年 | 46篇 |
2003年 | 35篇 |
2002年 | 51篇 |
2001年 | 11篇 |
2000年 | 9篇 |
1999年 | 14篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 17篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 10篇 |
1985年 | 6篇 |
1984年 | 8篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有688条查询结果,搜索用时 15 毫秒
1.
2.
Summary The chemical nature of the thickened plasma membrane of cornified cells in stratified squamous epithelium was investigated in comparison with that in noncornified epithelium. Localizations of transglutaminase, molecular weight 92000 daltons, and detection of epidermal cysteine proteinase inhibitor were effected with a monoclonal antibody and a monospecific rabbit anti-inhibitor immunoglobulin, respectively, directed to the antigens. N-(7-dimethylamino-4-methylcoumarinyl) maleimide was used to demonstrate S-S cross-linking. In all keratinizing epithelia, the enzyme and inhibitor were deposited on membranes of granular cells. S-S bonds were formed in cornification with the appearance of electron-dense material by the inner leaflet. Both enzyme and inhibitors occurred on the corneal epithelium, but S-S linkage and the thickened plasma membrane did not form even at the last stage of maturation. On the other hand, the internal vaginal epithelium in the proestrous stage without keratinization contained the enzyme, but neither inhibitor nor S-S linkage. Both antigens and S-S bonds were detected when keratinization proceeded during estrus. The staining patterns in the epithelium near the vaginal introitus were identical to those in the skin. Cuboidal and simple epithelia exhibited none of those constituents. The findings indicated that heterogenous components contribute to modification of the plasma membrane of cornified cells, but S-S cross-linkages are associated exclusively with formation of the ultrastructurally unique membrane structure. In addition, findings suggested hormonal regulation in the chemical modification of the membrane in estrogen-sensitive internal vaginal epithelium. 相似文献
3.
4.
Summary A 444leucine to proline mutation detected by a NciI polymorphism in the human glucocerebrosidase gene was studied to investigate the correlation of the three clinical phenotypes of Gaucher disease with this mutation in 11 Japanese patients with Gaucher disease (type I, 8 patients; type II, 1 patient; type III, 2 patients) and to determine the feasibility of the use of genomic probe DNA for carrier detection and prenatal diagnosis in 8 Japanese families with Gaucher disease and agreeable to family study (type I, 6 families; type III, 2 families). The homoallelic 444leucine to proline mutation was found only in patients with type I disease. Of the 8 type I patients, 5 had the homoallelic mutation and 2 had one mutant allele. One patient with type II disease did not have this mutant allele. Of the 2 type III patients, one had a single mutant allele whereas the other exhibited no mutation of this kind. These results suggest that the 444leucine to proline mutation is very common in the type I (non-neuronopathic form) disease and is not tightly associated only with neuronopathic types of Gaucher disease in Japanese patients. These findings seem to conflict with others showing that this mutation is partially responsible for the occurrence of neuronopathic Gaucher disease. Thus, the NciI polymorphism will not be useful for the diagnosis of subtypes of Gaucher disease. Carrier detection was feasible in three families with type I disease of the 8 families analyzed by the NciI polymorphism. 相似文献
5.
Hiroshi Yonemitsu Koichiro Shimomura Motoyoshi Satake Shunji Mochida Masahiko Tanaka Thoru Endo Akira Kaji 《Plant cell reports》1990,9(6):307-310
Hairy roots were obtained following inoculation of the stems of Lobelia inflata L. with Agrobacterium rhizogenes strain ATCC 15834. These hairy roots contained agropine and mannopine. In addition, lobeline was detected by HPLC and confirmed by mass spectrometry. Various media were tested for the growth of hairy roots as well as for the content of lobeline in hairy roots. The growth rate of hairy roots cultured in Nitsch and Nitsch's medium was approximately one third of those cultured in other media. The lobeline content of hairy roots (18–54 g/g dry weight) cultured in these media was the same order of magnitude compared with that of roots of L. inflata (24 g/g dry weight) cultivated in pots. The hairy roots cultured in Nitsch and Nitsch's medium were morphologically different from those cultured in other media.Abbreviations MS medium
Murashige and Skoog's medium
- 1/2 MS medium
one-half strength of the standard Murashige and Skoog's medium
- B5 medium
Gamborg's B5 medium
- NN medium
Nitsch and Nitsch's medium
- FW
fresh weight
- DW
dry weight 相似文献
6.
Shunji Sugii Takao Tsuji Takeshi Honda Toshio Miwatani 《FEMS microbiology letters》1988,49(3):463-465
Abstract The hemagglutinating activity of the B subunit(s) of the heat-labile toxin (LTh - B) produced by human enterotoxigenic Escherichia coli was studied by hemagglutination and hemagglutination inhibition. Very strong hemagglutination of both neuraminidase- and pronase-treated human erythrocytes was induced by the LTh - B whereas that of intact ones was induced weakly or not at all by the LTh - B at the highest concentration used. Enhancement in hemagglitination of these human erythrocytes by the LTh - B was about 8- to 512-fold for type A and B erythrocytes and 16-fold for type O erthrocytes, respectively. On the other hand, no hemagglutination of intact and treated sheep erythrocytes was found by the LTh - B at the highest concentration used. Hemagglutination of pronase-treated human type B erythrocytes by the LTh - B was inhibited by galactose and melibiose among mono-, di- and polysaccharides used as inhibitors. These findings suggest that the LTh - B is a bacterial lectin specific for galactose-linked residues. 相似文献
7.
A flower-inducing substance of high molecular mass, extracted from Lemna paucicostata, was purified to homogeneity. It had characteristics of a polypeptide, with an amino-terminal sequence of Leu-Val-Gly-Asn-Thr, and induced formation of flower buds of L. paucicostata 151 at a concentration of 10−10 molar. 相似文献
8.
Guanidinoethanesulfonic acid (GES) is known to induce convulsive seizures when administered intracisternally to rabbits and cats. The effects of GES on behavior, electroencephalographic recording and brain monoamine levels were examined in mice. When GES (900 nmol) was intraventricularly injected into mice, focal clonic movements of the face, vibrissae and ears together with twitching of the limbs were observed 0.5–1 min after the injection. Hypersensitivity was observed up to 7 min after the injection, after which the mice behaved normally. GES also induced sporadic spike discharges on electrocorticogram. The levels of 5-hydroxytryptamine (5-HT) of the GES-injected mice were lower than those of the saline-injected mice in the hippocampus, diencephalon, pons-medulla oblongata and cerebellum 5 min after the injection. No changes in the norepinephrine or dopamine levels were found after the GES injection. The level of 5-hydroxyindoleacetic acid increased in the striatum and cerebellum 5 min after the GES injection. These results suggest that GES-induced convulsive activities enhance the serotonergic neuroactivity in order to suppress the convulsions. 相似文献
9.
10.
Evidence for direct binding of Clostridium botulinum type E derivative toxin and its fragments to gangliosides and free fatty acids 总被引:4,自引:0,他引:4
Y Kamata S Kozaki G Sakaguchi M Iwamori Y Nagai 《Biochemical and biophysical research communications》1986,140(3):1015-1019
Clostridium botulinum type E derivative toxin and its heavy chain bound to gangliosides GT1b, GD1a and GQ1b and saturated and unsaturated free fatty acids with chain lengths of 14-20 carbons. The L-H-1 fragment lacking the carboxyl-terminal portion of the heavy chain bound to free fatty acids but not to gangliosides. These observations led us to a new hypothesis on the mechanism of binding between botulinum toxin and gangliosides; the carboxyl-terminal portion (H-2 fragment) of the heavy chain binds to an oligosaccharide residue of gangliosides and then the amino-terminal portion (H-1 fragment) interacts with the hydrophobic portion of gangliosides consisting of fatty acids. 相似文献