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71.
Rotter, Joan (University of Oklahoma Medical Center, Oklahoma City), and Florene C. Kelly. Serological reactions associated with the clumping factor of Staphylococcus aureus. J. Bacteriol. 91:588-594. 1966.-Evidence that the substance which causes staphylococci to clump in the presence of fibrinogen (clumping factor) is antigenically similar in strains which are serologically diverse according to agglutination reactions has been obtained from fibrinogen-cell clumping inhibition tests. Antisera for clumping factor (CF)-positive strains inhibited the clumping reaction of all strains tested. After adsorption with homologous cells or with cells of other CF-positive strains, the antisera no longer inhibited clumping. When antisera were adsorbed with trypsin-treated, CF-positive cells, or with cells of CF-negative mutants, the ability to inhibit the clumping reaction persisted. Antibody to CF activity was not associated with coagulase. Latex coated with extracts derived from the cells of five CF-positive and six CF-negative strains was, in each instance, agglutinated by sera from rabbits immunized with CF-positive cells. After adsorption with trypsinized, CF-positive cells, antisera still agglutinated latex which had been treated with the CF-positive extracts, but not with the CF-negative extracts. Similar results were obtained after antisera were adsorbed with the cells of CF-negative mutants. Cell agglutination titers of sera from rabbits immunized with CF-negative staphylococci were significantly lower than those produced in response to CF-positive cells, regardless of their coagulase activity. If the CF-inhibiting antibody also functions as an agglutinin, it apparently is not solely responsible for this difference. 相似文献
72.
Jacklyn N. Hellwege Nicholette D. Palmer Mark W. Brown Julie T. Ziegler Sandy S. An Xiuqing Guo Ida Y.-D. Chen Kent Taylor Gregory A. Hawkins Maggie C. Y. Ng Elizabeth K. Speliotes Carlos Lorenzo Jill M. Norris Jerome I. Rotter Lynne E. Wagenknecht Carl D. Langefeld Donald W. Bowden 《Human genetics》2015,134(2):203-213
73.
Contemporary theory of spiking neuronal networks is based on the linear response of the integrate-and-fire neuron model derived in the diffusion limit. We find that for non-zero synaptic weights, the response to transient inputs differs qualitatively from this approximation. The response is instantaneous rather than exhibiting low-pass characteristics, non-linearly dependent on the input amplitude, asymmetric for excitation and inhibition, and is promoted by a characteristic level of synaptic background noise. We show that at threshold the probability density of the potential drops to zero within the range of one synaptic weight and explain how this shapes the response. The novel mechanism is exhibited on the network level and is a generic property of pulse-coupled networks of threshold units. 相似文献
74.
Abstract: We recently demonstrated that, unlike in peripheral tissues, the increase in activity of polyamine synthesizing enzymes observed in the brain after acute stress can be prevented by long-term, but not by short-term, treatment with lithium. In the present study we sought to examine the effects of chronic intermittent stress on two key polyamine synthesizing enzymes, ornithine decarboxylase and S-adenosylmethionine decarboxylase, and their modulation by lithium treatment. Adult male rats were subjected to 2 h of restraint stress once daily for 5 days and to an additional delayed stress episode 7 days later. Enzyme activities were assayed 6 h after the beginning of each stress episode. In contrast to the liver, where ornithine decarboxylase activity was increased (300% of the control) only after the first stress episode, the enzyme activity in the brain was increased after each stress episode (to ~170% of the control). Unlike ornithine decarboxylase activity, S-adenosylmethionine decarboxylase activity was slightly reduced after the first episode (86% of the control) but remained unchanged thereafter. After cessation of the intermittent stress period, an additional stress episode 7 days later led again to an increase in ornithine decarboxylase activity in the brain (225% of the control) but not in the liver, whereas S-adenosylmethionine decarboxylase activity remained unchanged. The latter increase in ornithine decarboxylase activity was blocked by lithium treatment during the intervening 7-day interval between stressors. The results warrant the following conclusions: (a) Repetitive application of stressors results in a recurrent increase in ornithine decarboxylase activity in the brain but to habituation of this response in the liver. (b) This brain polyamine stress response can be blocked by long-term (days) lithium treatment. (c) The study implicates an overreactive polyamine response as a component of the adaptive, or maladaptive, brain response to stressful events and as a novel molecular target for lithium action. 相似文献
75.
Varda Shoshan-Barmatz 《The Journal of membrane biology》1988,103(1):67-77
Summary The relationship between Ca2+ release from sarcoplasmic reticulum, induced by elevated pH, tetraphenylboron (TPB–) or chemical modification, and the change in the surface charge of the membranes as measured by the fluorescence intensity of anilinonaphthalene sulfonate (ANS) is examined. The stimulated Ca2+ release is inhibited by dicyclohexylcarbodiimide and external Ca2+. TPB–, but not tetraphenylarsonium (TPA+), causes a decrease in ANS– fluorescence, with 50% decrease occurring at about 5 m TPB–. The decrease in ANS– fluorescence as well as the inhibition of Ca2+ accumulation induced by TPB– are prevented by TPA+. A linear relationship between the decrease in membrane surface potential and the extent of the Ca2+ released by TPB– is obtained. Similar levels of [3H]TPB– bound to sarcoplasmic reticulum membranes were obtained regardless of whether or not the vesicles have taken up Ca2+. The inhibition of Ca2+ accumulation and the [3H]TPB– incorporation into the membranes were correlated. Ca2+ release from sarcoplasmic reticulum, by pH elevation, chemical modification or by addition of NaSCN (0.2 to 0.5m) or the Ca2+ ionophore ionomycin, is also accompanied by a decrease in ANS– fluorescence intensity. However, chemical modification and elevated pH affects the surface potential much less than SCN– or TPB– do. These results suggest that the enhancement of Ca2+ release by these treatments is not due to a general effect on the membrane surface potential, but rather through the modification of a specific protein. They also suggest that membrane surface charges might play an important role in the control mechanism of Ca2+ release. 相似文献
76.
Multilocus genetic determinants of LDL particle size in coronary artery disease families. 总被引:5,自引:0,他引:5 下载免费PDF全文
J. I. Rotter X. Bu R. M. Cantor C. H. Warden J. Brown R. J. Gray P. J. Blanche R. M. Krauss A. J. Lusis 《American journal of human genetics》1996,58(3):585-594
Recent interest in atherosclerosis has focused on the genetic determinants of low-density lipoprotein (LDL) particle size, because of (i) the association of small dense LDL particles with a three-fold increased risk for coronary artery disease (CAD) and (ii) the recent report of linkage of the trait to the LDL receptor (chromosome 19). By utilizing nonparametric quantitative sib-pair and relative-pair analysis methods in CAD families, we tested for linkage of a gene or genes controlling LDL particle sizes with the genetic loci for the major apolipoproteins and enzymes participating in lipoprotein metabolism. We confirmed evidence for linkage to the LDL receptor locus (P=.008). For six candidate gene loci, including apolipoprotein(apo)B, apoAII, apo(a), apoE-CI-CII, lipoprotein lipase, and high-density lipoprotein-binding protein, no evidence for linkage was observed by sib-pair linkage analyses (P values ranged from .24 to .81). However, in addition, we did find tentative evidence for linkage with the apoAI-CIII-AIV locus (chromosome 11) (P=.06) and significant evidence for linkage of the cholesteryl ester transfer protein locus (chromosome 16) (P=.01) and the manganese superoxide dismutase locus (chromosome 6) (P=.001), thus indicating multilocus determination of this atherogenic trait. 相似文献
77.
Evidence of a non-MHC susceptibility locus in type I diabetes linked to HLA on chromosome 6. 总被引:5,自引:0,他引:5 下载免费PDF全文
M Delpine F Pociot C Habita L Hashimoto P Froguel J Rotter A Cambon-Thomsen I Deschamps S Djoulah J Weissenbach J Nerup M Lathrop C Julier 《American journal of human genetics》1997,60(1):174-187
Linkage studies have led to the identification of several chromosome regions that may contain susceptibility loci to type I diabetes (IDDM), in addition to the HLA and INS loci. These include two on chromosome 6q, denoted IDDM5 and IDDM8, that are not linked to HLA. In a previous study, we noticed that the evidence for linkage to IDDM susceptibility around the HLA locus extended over a total distance of 100 cM, which suggested to us that another susceptibility locus could reside near HLA. We developed a statistical method to test this hypothesis in a panel of 523 multiplex families from France, the United States, and Denmark (a total of 667 affected sib pairs, 536 with both parents genotyped), and here present evidence (P = .00003) of a susceptibility locus for IDDM located 32 cM from HLA in males but not linked to HLA in females and distinct from IDDM5 and IDDM8. A new statistical method to test for the presence of a second susceptibility locus linked to a known first susceptibility locus (here HLA) is presented. In addition, we analyzed our current family panel with markers for IDDM5 and IDDM8 on chromosome 6 and found suggestions of linkage for both of these loci (P = .002 and .004, respectively, on the complete family panel). When cumulated with previously published results, with overlapping families removed, the affected-sib-pair tests had a significance of P = .0001 for IDDM5 and P = .00004 for IDDM8. 相似文献
78.
Sustenance,nourishment, and cultivation: plants as living cultural heritage for dispersed Chagossians in Mauritius,Seychelles, and the UK 下载免费PDF全文
Applying a critical heritage studies approach to plants, this article explores how plant knowledge and use, plant exchange, and plant symbolism and materiality feature in the social life of the dispersed Chagossian community in Mauritius, Seychelles, and the UK. First, plant use helps to sustain collective knowledge in new environmental conditions and social settings. Second, plant exchange nourishes kinship and other social relationships within the extended community. Third, plant symbolism and materiality cultivate nostalgic links to idealized homelands in the context of community dispersal. Nevertheless, the capacity of plants to contribute to these social processes is limited by challenges to intergenerational knowledge transmission across time and space, and by environmental, financial, and regulatory constraints on plant migration. The article argues that for the displaced Chagossian community, plants are living cultural heritage with social potential (albeit constrained) in the context of dislocation and loss, ongoing suffering, and geographical dispersal. 相似文献
79.
Tidhar Turgeman Olga Lubinsky Nurit Roth-Bejerano Varda Kagan-Zur Yoram Kapulnik Hinanit Koltai Eli Zaady Shimon Ben-Shabat Ofer Guy Efraim Lewinsohn Yaron Sitrit 《Mycorrhiza》2016,26(4):287-297
The ectendomycorrhizal fungus Terfezia boudieri is known to secrete auxin. While some of the effects of fungal auxin on the plant root system have been described, a comprehensive understanding is still lacking. A dual culture system to study pre mycorrhizal signal exchange revealed previously unrecognized root–fungus interaction mediated by the fungal auxin. The secreted fungal auxin induced negative taproot gravitropism, attenuated taproot growth rate, and inhibited initial host development. Auxin also induced expression of Arabidopsis carriers AUX1 and PIN1, both of which are involved in the gravitropic response. Exogenous application of auxin led to a root phenotype, which fully mimicked that induced by ectomycorrhizal fungi. Co-cultivation of Arabidopsis auxin receptor mutants tir1-1, tir1-1 afb2-3, tir1-1 afb1-3 afb2-3, and tir1-1 afb2-3 afb3-4 with Terfezia confirmed that auxin induces the observed root phenotype. The finding that auxin both induces taproot deviation from the gravity axis and coordinates growth rate is new. We propose a model in which the fungal auxin induces horizontal root development, as well as the coordination of growth rates between partners, along with the known auxin effect on lateral root induction that increases the availability of accessible sites for colonization at the soil plane of fungal spore abundance. Thus, the newly observed responses described here of the root to Terfezia contribute to a successful encounter between symbionts. 相似文献
80.
Themistocles L. Assimes I. -T. Lee Jyh-Ming Juang Xiuqing Guo Tzung-Dau Wang Eric T. Kim Wen-Jane Lee Devin Absher Yen-Feng Chiu Chih-Cheng Hsu Lee-Ming Chuang Thomas Quertermous Chao A. Hsiung Jerome I. Rotter Wayne H.-H. Sheu Yii-Der Ida Chen Kent D. Taylor 《PloS one》2016,11(3)
By means of a combination of genome-wide and follow-up studies, recent large-scale association studies of populations of European descent have now identified over 46 loci associated with coronary artery disease (CAD). As part of the TAICHI Consortium, we have collected and genotyped 8556 subjects from Taiwan, comprising 5423 controls and 3133 cases with coronary artery disease, for 9087 CAD SNPs using the CardioMetaboChip. We applied penalized logistic regression to ascertain the top SNPs that contribute together to CAD susceptibility in Taiwan. We observed that the 9p21 locus contributes to CAD at the level of genome-wide significance (rs1537372, with the presence of C, the major allele, the effect estimate is -0.216, standard error 0.033, p value 5.8x10-10). In contrast to a previous report, we propose that the 9p21 locus is a single genetic contribution to CAD in Taiwan because: 1) the penalized logistic regression and the follow-up conditional analysis suggested that rs1537372 accounts for all of the CAD association in 9p21, and 2) the high linkage disequilibrium observed for all associated SNPs in 9p21. We also observed evidence for the following loci at a false discovery rate >5%: SH2B3, ADAMTS7, PHACTR1, GGCX, HTRA1, COL4A1, and LARP6-LRRC49. We also took advantage of the fact that penalized methods are an efficient approach to search for gene-by-gene interactions, and observed that two-way interactions between the PHACTR1 and ADAMTS7 loci and between the SH2B3 and COL4A1 loci contribute to CAD risk. Both the similarities and differences between the significance of these loci when compared with significance of loci in studies of populations of European descent underscore the fact that further genetic association of studies in additional populations will provide clues to identify the genetic architecture of CAD across all populations worldwide. 相似文献