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1.
Polyacrylamide vertical gel electrophoresis was used to separate the caseins of sows' milk. Polymorphism was found in a region of the gels designated Cn3. The Cn3 polymorphism consists of two bands which appear to be controlled by two codominant alleles designated Cn
3
A
and Cn
3
B
. Homozygotes possess one band and heterozygotes posses both bands of equal intensity giving the following phenotypes: Cn3A, Cn3AB, and Cn3B. A chi-square test for goodness of fit of the observed phenotypes to that expected by the Hardy-Weinberg equilibrium formula and a segregation analysis of eight matings involving 19 female progeny conform to the hypothesis that the Cn3 polymorphism is controlled by two codominant autosomal alleles. Further family studies will be necessary to confirm the genetic control of the Cn3 polymorphism.Deceased. 相似文献
2.
P O Gerrits R W Horobin M J Hardonk 《The journal of histochemistry and cytochemistry》1989,37(2):173-176
Placing 2-microns sections of tissue-free glycol methacrylate on top of tissue sections is a simple way of forming semipermeable membranes to enhance enzyme histochemical staining. For demonstrating alkaline phosphatase in glycol methacrylate-embedded kidney by a standard azo dye method, such membranes enabled incubation times to be reduced to 1-2 hr, with azo dye reaction product being more crisply localized as compared to sections stained without membranes. Such effects are possible because the membranes are highly permeable to small molecules (e.g., substrate and diazonium salt), slightly permeable to molecules of moderate size (e.g., the final reaction product), and impermeable to large molecules (e.g., alkaline phosphatase and other tissue biopolymers). The implications of these findings for enzyme histochemistry and for enzyme-labeled antibody staining are discussed. 相似文献
3.
The classic Mallory-Cason staining procedure has been modified for application to sections "on tape" obtained from large deep frozen tissue specimens. These 20 microns cryosections are collected on tape from a large heavy duty cryomicrotome. The stained sections provide anatomical details that are not revealed by other techniques. The merit of this procedure is found in the support of modern medical modalities, both for research and educational purposes. 相似文献
4.
Involvement of an activation protein in the methanol:2-mercaptoethanesulfonic acid methyltransferase reaction in Methanosarcina barkeri. 总被引:3,自引:2,他引:1 下载免费PDF全文
P J Daas K A Gerrits J T Keltjens C van der Drift G D Vogels 《Journal of bacteriology》1993,175(5):1278-1283
Methanol:5-hydroxybenzimidazolylcobamide methyltransferase (MT1) is the first of two enzymes required for transfer of the methyl group of methanol to 2-mercaptoethanesulfonic acid in Methanosarcina barkeri. MT1 binds the methyl group of methanol to its corrinoid prosthetic group only when the central cobalt atom of the corrinoid is present in the highly reduced Co(I) state. However, upon manipulation of MT1 and even during catalysis, the enzyme becomes inactivated as the result of Co(I) oxidation. Reactivation requires H2, hydrogenase, and ATP. Ferredoxin stimulated the apparent reaction rate of methyl group transfer. Here we report that one more protein fraction was found essential for the overall reaction and, more specifically, for formation of the methylated MT1 intermediate. The more of the protein that was present, the shorter the delay of the start of methyl group transfer. The maximum velocity of methyl transfer was not substantially affected by these varying amounts of protein. This demonstrated that the protein was involved in the activation of MT1. Therefore, it was called methyltransferase activation protein. 相似文献
5.
Isolation and characterization of plasma membrane-associated cortical granules from sea urchin eggs 总被引:9,自引:6,他引:3 下载免费PDF全文
Cortical granules, which are specialized secretory organelles found in ova of many organisms, have been isolated from the eggs of the sea urchins Arbacia punctulata and Strongylocentrtus pupuratus by a simple, rapid procedure. Electron micropscope examination of cortical granules prepared by this procedure reveals that they are tightly attached to large segments of the plasma membrane and its associated vitelline layer. Further evidence that he cortical granules were associated with these cell surface layers was obtained by (125)I-labeling techniques. The cortical granule preparations were found to be rich in proteoesterase, which was purified 32-fold over that detected in a crude homogenate. Similarly, the specific radioactivity of a (125)I-labeled, surface glycoprotein was increased 40-fold. These facts, coupled with electron microscope observations, indicate the isolation procedure yields a preparation in which both the cortical granules and the plasma membrane-vitelline layer are purified to the same extent. Gel electrophoresis of the membrane-associated cortical granule preparation reveals the presence of at least eight polypeptides. The major polypeptide, which is a glycotprotein of apparent mol wt of 100,000, contains most of the radioactivity introduced by (125)I-labeling of the intact eggs. Lysis of the cortical granules is observed under hypotonic conditions, or under isotonic conditions if Ca(2+) ion is present. When lysis is under isotonic conditions is induced by addition of Ca(2+) ion, the electron-dense contents of the granules remain insoluble. In contrast, hypotonic lysis results in release of the contents of the granule in a soluble form. However, in both cases the (125)I-labeled glycoprotein remains insoluble, presumably because it is a component of either the plasma membrane or the vitelline layer. All these findings indicate that, using this purified preparation, it should be possible to carry out in vitro studies to better define some of the initial, surface-related events observed in vivo upon fertilization. 相似文献
6.
Aggregation-dependent turnover of flagellar adhesion molecules in chlamydomonas gametes 总被引:8,自引:7,他引:1 下载免费PDF全文
Previous studies on flagellar adhesion in chlamydomonas (Snell, W. and S. Roseman. 1979. J. Biol. Chem. 254:10820-10829.) have shown that as gametes adhere to flagella isolated from gametes of the opposite mating type, the adhsiveness of the added flagella but not of the gametes is lost. The studies reported here show that the addition of protein synthesis inhibitors (cycloheximide [CH] or anisomycin) to the medium of such cell- flagella mixtures causes the cells to lose their adhesiveness. This loss, however, occurs only after the cells have interacted with 4-8 flagella/cell and does not occur if the cells are kept in CH (7 h) without aggregating. The availability of an impotent (imp) mating type plus (MT(+)) mutant (provided by U.W. Goodenough), which adheres but is unable to undergo the fusion that normally follows adhesion, made it possible to determine whether a similar loss of adhesiveness occurs in mixtures of matting type minus (mt(-)) and imp mt(+) gametes. In the absence of inhibitor, mt(-) and imp mt(+) gametes adhered to each other (without fusing) for several hours; however, in the presence of CH or anisomycin, the gametes began to de-adhere 35 min after mixing, and, by 90 min, 100 percent of the cells were single again. This effect was reversible, and the rapid turnover of cells were single again. This effect was reversible, and the rapid turnover of molecules involved in adhesion occurred only during adhesion inasmuch as gametes pretreated for 4 h with CH were able to aggregate in CH for the same length of time as nonpretreated cells aggregated in CH. By the addition of CH at various times after the mt(-) and imp mt(+) gametes were mixed, measurements were made of the “pool size” of the molecules involved in adhesion. The pool reached a minimum after 25 min of aggregation, rapidly increased for the next 25 min, and then leveled off at the premixing level. These results suggest that flagellar adhesion in chlamydomonas causes modification of surface molecules (receptors, ligands), which brings about their inactivation and stimulates their replacement. 相似文献
7.
Jiang Y. Tsui C. K. M. Ahmed S. A. Hagen F. Shang Z. Gerrits van den Ende A. H. G. Verweij P. E. Lu H. de Hoog G. S. 《Mycopathologia》2020,185(4):613-627
Mycopathologia - Emmonsia crescens is known as an environmental pathogen causing adiaspiromycosis in small rodents. As the generic name Emmonsia is no longer available for this species, its... 相似文献
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Bianca T. A. de Greef Janneke G. J. Hoeijmakers Emma E. Wolters Hubertus J. M. Smeets Arthur van den Wijngaard Ingemar S. J. Merkies Catharina G. Faber Monique M. Gerrits 《PloS one》2016,11(2)