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1.
In vitro and in vivo models to study the pathogenesis of thyroid autoimmunity are reviewed. Animal models with experimentally induced or spontaneously developed autoimmune thyroid disease as well as transplantation models have been used extensively in these studies, but also the use of thyroid cell cultures from both humans and animals has contributed to the present state of knowledge. Cytokines may play a role in the pathogenic mechanism in thyroid autoimmunity. The major in vitro and in vivo effects of for example interleukin-1, tumour necrosis factor and gamma-interferon on differentiated thyroid cell functions are inhibitory. The advantage of using cell cultures has been the possibility of studying an influence on thyrocytes from a single agent individually, such as cytokines, hormones or growth factors. The disadvantage is that an organism is under the influence of a multitude of factors that can only be investigated in vivo in intact organisms. Both types of models have therefore been important in the understanding of thyroid autoimmunity. 相似文献
2.
Using the imidate procedure, 2,3,4,6-tetra-O-benzyl-1-O-(N-methylacetimidoyl)-β-d-galactopyranose was condensed with various monosaccharides to provide, in good yield and with high stereoselectivity, α-linked disaccharides. 相似文献
3.
Two NADP-isocitrate dehydrogenase isoenzymes designated as NADP-IDH1 and NADP-IDH2 (EC 1.1.1.42) were identified in pea (Pisum sativum) leaf extracts by diethylaminoethylcellulose chromatography. The predominant form was found to be NADP-IDH1 while NADP-IDH2 represented only about 4% of the total leaf enzyme activity. These enzymes share few common epitopes as NADP-IDH2 was poorly recognized by the specific polyclonal antibodies raised against NADP-IDH1, and as a consequence NADP-IDH2 does not result from a post-translational modification of NADP-IDH1. Subcellular fractionation and isolation of chloroplasts through a Percoll gradient, followed by the identification of the associated enzymes, showed that NADP-IDH1 is restricted to the cytosol and NADP-IDH2 to the chloroplasts. Compared with the cytosolic isoenzyme, NADP-IDH2 was more thermolabile and exhibited a lower optimum pH. The data reported in this paper constitute the first report that the chloroplastic NADP-IDH and the cytosolic NADP-IDH are two distinct isoenzymes. The possible functions of the two isoenzymes are discussed.Abbreviations BSA
bovine serum albumin
- DEAE
diethylaminoethyl
- NADP-IDH
NADP-isocitrate dehydrogenase
- NADP-IDH1
cytosolic NADP-IDH
- NADP-IDH2
chloroplastic NADP-IDH 相似文献
4.
C-Glycosylation of 5,7-dihydroxy-3′,4′,5′-trimethoxyflavone was carried out with acetobromo-α-d-glucose, -α-d-galactose, -α-d-xylose, -β-l-arabinose and -αt-L-rhamnose. The respective 6-C-glycosides and 6, 8-di-C-glycosides (excepted for galactose) were isolated and permethylated. MS and TLC comparison confirmed the proposed structures of five natural tricetin-derived C-glycosides. 相似文献
5.
A fluorescent pigment was isolated from the culture fluid of Methanobacterium thermoautotrophicum strain H. This pigment was shown to be 7,8-didemethyl-8-hydroxy-5-deazariboflavin by various spectroscopic and chromatographic techniques. This compound was previously described as the FO acid hydrolysis fragment of coenzyme F420. On the basis of the time of appearance of the pigment in the course of fermentation, it is suggested that this substance may be an over-produced biosynthetic precursor of F420. 相似文献
6.
The brain organization of butterflyfishes 总被引:2,自引:0,他引:2
Roland Bauchot Jean-Marc Ridet Marie-Louise Bauchot 《Environmental Biology of Fishes》1989,25(1-3):205-219
Synopsis The encephalization indices of angelfishes (Pomacanthidae) and butterflyfishes (Chaetodontidae) are typical of advanced perciform
fishes: both families lie in the upper part of the polygon of teleost indices. The chaetodontids seem to be a little more
encephalized than pomacanthids. The general morphology of the brains in both families is very similar: small olfactory bulbs,
large optic tectum and a cerebellum which covers the brain structures in front of it like a cap. This morphology is shared
by another family of the coral reef biotope, the Acanthuridae. The histological architecture is also typical of advanced teleosts,
with a cortex-like pallium, a laminated nucleus geniculatus (= pretectalis superficialis), a complex valvula cerebelli and
a corpus glomerulosum with a clear neuropile centre. The quantitative analysis of the main subdivisions of the brain, either
from relative volumes or from indices, shows small olfactory bulbs (microsmy) but important telencephalic and diencephalic
centres, large tectal centres (vision) and large cerebellum (precise locomotion). Many of these peculiarities are shared by
other fishes inhabiting coral reefs. The differences between the two families seem to be primarily correlated with food habits:
the angelfishes, which are sponge-feeders and may have an overweight due to the ballast of the sponge-skeleton in their digestive
tract, and which do not need either such good vision or such precise locomotion to pick up their prey, could be a little less
encephalized than the butterflyfishes. 相似文献
7.
8.
Wouters J. T. M. Driehuis F. L. Polaczek P. J. van Oppenraay Marie-Louise H. A. van Andel J. G. 《Antonie van Leeuwenhoek》1980,46(4):353-362
Populations of a Escherichia coli K 12 strain, containing the vector plasmid p BR 322, were grown in chemostat culture under glucose- and phosphatelimited conditions. Resistance to tetracycline and ampicillin were lost after prolonged cultivation, resulting in the production of apparent plasmid-free populations which were more competitive than the original population. This competitiveness between plasmid-free and plasmid-containing populations was greatest in environments where the nutrient restriction was severe. Also during sequential subcultivation in batch cultures loss of plasmid was observed. 相似文献
9.
Two serine racemases (I and II) were isolated from Streptomyces garyphalus. Serine racemase I (molecular weight 93,000) was purified to a single band in an analytical electrofocusing system. Serine racemase II (molecular weight 73,000) was partially purified. Both enzymes used pyridoxal-5-phosphate as cofactor. Besides serine the enzymes utilized alanine as substrate but no other amino acid tested. The K
m values of l-alanine and l-serine for enzyme I were 111 mM and 35 mM respectively. Enzyme I was not inhibited by d-cycloserine but by hydroxylamine. Both substances inhibited enzyme II. The serine racemases may be involved in the biosynthesis of d-cycloserine in S. garyphalus. 相似文献
10.
Using the imidate procedure, 2,3,4,6-tetra-O-benzyl-1-O-(N-methylacetimidoyl)-β-d-galactopyranose was condensed with various monosaccharides to provide, in good yield and with high stereoselectivity, α-linked disaccharides. 相似文献