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991.
Until the mid-1990s, the only microsporidium known to infect bees of the genus Apis was Nosema apis. A second species, Nosema ceranae, was first identified in 1996 from Asian honey bees; it is postulated that this parasite was transmitted from the Asian honey bee, Apis cerana, to the European honey bee, Apis mellifera. Currently, N. ceranae is found on all continents and has often been associated with honey bee colony collapse and other reports of high bee losses. Samples of Africanized drones collected in 1979, preserved in alcohol, were analyzed by light microscopy to count spores and were subjected to DNA extraction, after which duplex PCR was conducted. All molecular analyses (triplicate) indicated that the drones were infected with both N. ceranae and N. apis. PCR products were sequenced and matched to sequences reported in the GenBank (Acc. Nos. JQ639316.1 and JQ639301.1). The venation pattern of the wings of these males was compared to those of the current population living in the same area and with the pattern of drones collected in 1968 from Ribeirão Preto, SP, Brazil, from a location close to where African swarms first escaped in 1956. The morphometric results indicated that the population collected in 1979 was significantly different from the current living population, confirming its antiquity. Considering that the use of molecular tools for identifying Nosema species is relatively recent, it is possible that previous reports of infections (which used only light microscopy, without ultrastructural analysis) wrongly identified N. ceranae as N. apis. Although we can conclude that N. ceranae has been affecting Africanized honeybees in Brazil for at least 34 years, the impact of this pathogen remains unclear.  相似文献   
992.
STING Millennium Suite (SMS) is a new web-based suite of programs and databases providing visualization and a complex analysis of molecular sequence and structure for the data deposited at the Protein Data Bank (PDB). SMS operates with a collection of both publicly available data (PDB, HSSP, Prosite) and its own data (contacts, interface contacts, surface accessibility). Biologists find SMS useful because it provides a variety of algorithms and validated data, wrapped-up in a user friendly web interface. Using SMS it is now possible to analyze sequence to structure relationships, the quality of the structure, nature and volume of atomic contacts of intra and inter chain type, relative conservation of amino acids at the specific sequence position based on multiple sequence alignment, indications of folding essential residue (FER) based on the relationship of the residue conservation to the intra-chain contacts and Calpha-Calpha and Cbeta-Cbeta distance geometry. Specific emphasis in SMS is given to interface forming residues (IFR)-amino acids that define the interactive portion of the protein surfaces. SMS may simultaneously display and analyze previously superimposed structures. PDB updates trigger SMS updates in a synchronized fashion. SMS is freely accessible for public data at http://www.cbi.cnptia.embrapa.br, http://mirrors.rcsb.org/SMS and http://trantor.bioc.columbia.edu/SMS.  相似文献   
993.
Size-selective harvesting of wild ungulates can trigger a range of ecological and evolutionary consequences. It remains unclear how environmental conditions, including changes in habitat, climate, and local weather conditions, dilute or strengthen the effects of trophy hunting. We analyzed horn length measurements of 2,815 male ibex (Capra pyrenaica) that were harvested from 1995 to 2017 in Els Ports de Tortosa i Beseit National Hunting Reserve in northeastern Spain. We used linear mixed models to determine the magnitude of inter-individual horn growth variability and partial least square path models to evaluate long-term effects of environmental change, population size, and hunting strategy on horn growth. Age-specific horn length significantly decreased over the study period, and nearly a quarter (23%) of its annual variation was attributed to individual heterogeneity among males. The encroachment of pine (Pinus spp.) forests had a negative effect on annual horn growth, possibly through nutritional impoverishment. The harvesting of trophy and selective individuals (e.g., small-horned males) from the entire population increased horn growth, probably because it reduced the competition for resources and prevented breeding of these smaller males. Local weather conditions and population size did not influence horn growth. Our study demonstrates how habitat changes are altering the horn growth of male ibex. We suggest that habitat interventions, such the thinning of pine forests, can contribute to securing the sustainability of trophy hunting. Even in situations where size-selective harvesting is not causing a detectable phenotypic response, management actions leading to the expansion of preferred land cover types, such as grass-rich open areas, can have a positive effect on ungulate fitness. Forest encroachment on open meadows and heterogeneous grasslands is pervasive throughout Mediterranean ecosystems. Therefore, our management recommendations can be extended to the landscape level, which will have the potential to mitigate the side effects of habitat deterioration on the phenotypic traits of wild ibex. © 2020 The Wildlife Society.  相似文献   
994.
995.
Throughout Brazil, Cryptococcus neoformans is the cause of cryptococcosis, whereas Cryptococcus gattii is endemic to the northern and northeastern states. In this study, the molecular types of 63 cryptococcal isolates recovered from the cerebrospinal fluid of meningitis patients diagnosed between 2008-2010 in Teresina, Piauí, Brazil, were analysed. Out of the 63 patients, 37 (58.7%) were human immunodeficiency virus (HIV)-positive and 26 (41.3%) were HIV-negative. URA5-restriction fragment length polymorphism analysis identified 37/63 (58.7%) isolates as the C. neoformans VNI genotype, predominantly in HIV-positive patients (32/37, 86.5%), and 24/63 (38.1%) as the C. gattii VGII genotype, mostly in HIV-negative patients (21/26, 80.8%). The occurrence of C. gattii VGII in six apparently healthy children and in seven adolescents/young adults in this region reaffirms the endemic occurrence of C. gattii VGII-induced primary cryptococcosis and early cryptococcal infection. Lethality occurred in 18/37 (48.6%) of the HIV-positive subjects and in 13/26 (50%) of the HIV-negative patients. Our results provide new information on the molecular epidemiology of C. neoformans and C. gattii in Brazilian endemic areas.  相似文献   
996.
The production of monoglycerides by glycerolysis of olive oil catalyzed by lipases from Candida rugosa, Chromobacterium viscosum and Rhizopus sp. immobilized in a hydrophylic polyurethane foam was investigated. The effect of the amount of aqueous phase used for foam polymerization on the competing reactions of glycerolysis and hydrolysis was studied. The highest monoglyceride production was achieved with the C. rugosa lipase which was thus selected for subsequent studies.The extent to which hydrolysis and glycerolysis occur and the influence of the initial a w of the system on both reactions were also investigated. In glycerolytic reaction systems, initial rates of fatty acid release were always higher than in hydrolytic systems. At a w values lower than 0.43, hydrolysis was completely repressed, although glycerolysis still occurred. This suggests that hydrolysis of the ester bond in the glyceride, promoted by glycerol, is the first reaction step.In glycerolysis, initial rates of FFA and DG production increased exponentially with the initial a w of the system.The lowest total conversion (in terms of % TG consumed) at 48 hours was obtained at intermediate a w values; higher conversions at extreme a w indicated an increase in hydrolytic and glycerolytic rates, at high and low a w respectively.The yield of MG increased with decreasing a w . The highest yield of MG (70%, w/w) was obtained at the lowest a w used (0.23). The initial a w of the reaction system is an important parameter in glycerolysis.List of Symbols a w thermodynamic activity of water - C 120 lauric acid - C 140 myristic acid - C 181 oleic acid - DG dediglyceride (s) - FAME fatty acid methyl ester (s) - FFA free fatty acid (s) - FID fire ionization detector - Gly glycerol - n number of replicates - MG monoglyceride (s) - PCA principal component analysis - PU polyurethane - r correlation coefficient - TG triglyceride (s) - TO triolein - significance level The authors are grateful to Prof. L. Beirão da Costa and to Prof. L. Campos, Inst. Sup. de Agronomia (ISA), and to Prof. J.M.S. Cabral, Inst. Sup. Técnico, Lisbon, Portugal, for inspiring discussions and advice, and to Mrs. Marlene Dionísio, ISA, for invaluable help with some of the experimental work.  相似文献   
997.
Optimization of the freeze-drying process needs to characterize the physical state of frozen and dried products. A protocol to measure the collapse temperature of complex biological media such as concentrated lactic acid bacteria using freeze-drying microscopy was first elaborated. Afterward, aqueous solutions of one or several components as well as concentrated lactic acid bacterial suspensions were analyzed in order to study how the structure of these materials is degraded during freeze-drying. A similar behavior toward collapse was observed for all aqueous solutions, which was characterized by two temperatures: the "microcollapse" temperature (T(microc), beginning of a local loss of structure) and the "collapse" temperature (T(c), beginning of an overall loss of structure). For aqueous solutions, these two temperatures were close, differing by less than 3 degrees C. Nevertheless, when lactic acid bacteria were added to aqueous solutions, the collapse temperatures increased. Moreover, the interval between microcollapse and collapse temperatures became larger. Lactic acid bacterial cells gave a kind of "robustness" to the freeze-dried product. Finally, comparing glass transition, measured by differential scanning calorimetry (DSC) and collapse temperature for aqueous solutions with noncrystallizable solutes, showed that these values belonged to the same temperature range (differing by less than 5 degrees C). As suggested in the literature, the glass transition temperature can thus be used as a first approximation of the collapse temperature of these media. However, for lactic acid bacterial suspensions, because the difference between collapse and glass transition temperatures was about 10 degrees C, this approximation was not justified. An elegant physical appearance of the dried cakes and an acceptable acidification activity recovery were obtained, when applying operating conditions during freeze-drying in vials that allowed the product temperature to be maintained during primary drying at a level lower than the collapse temperature of lactic acid bacterial suspensions. Consequently, the collapse temperature T(c) was proposed as the maximal product temperature preserving the structure from macroscopic collapse and an acceptable biological activity of cells.  相似文献   
998.
The somatotropic axis consists of genes that are involved in muscular development. These genes are potential regions of study to identify possible QTL for economically important traits in beef cattle. The aim of this study was to verify the existence of GH1, POU1F1, and GHR polymorphisms in Nellore cattle to verify the influence of selection in these mutations and to analyse the association between molecular markers and body weight at different ages, yearling hip height, carcass fat thickness and loin eye area. Six hundred forty-five animals from the Centro APTA Bovinos de Corte, were genotyped by PCR–RFLP techniques. The association analyses were performed with general mixed models taking into consideration the effect of one marker, and other model taking into consideration interactions between two molecular markers. Only the molecular markers rs81109601 on GH1 and rs109136815 on GHR were polymorphic; however, they were not found to be under selection. The association of the GHR rs109136815 marker and loin eye area was observed (p < 0.05), as well as the effect of interaction between the markers and the female body weight at 550 days of age (p < 0.04). The interaction effect should be considered in situations where the interactivity between two genes is known.  相似文献   
999.
Crk-associated substrate (CAS) is a tyrosine kinase substrate implicated in integrin control of cell behavior. Phosphorylation, by Src family kinases, of multiple tyrosine residues in the CAS substrate domain (SD) is a major integrin signaling event that promotes cell motility. In this study, novel phosphospecific antibodies directed against CAS SD phosphotyrosine sites ("pCAS" antibodies) were characterized and employed to investigate the cellular regulation and localization of CAS SD tyrosine phosphorylation. An analysis of CAS and focal adhesion kinase (FAK) variants expressed in CAS- and FAK-deficient cell lines, respectively, indicated that CAS SD tyrosine phosphorylation is substantially achieved by Src family kinases brought into association with CAS through two distinct mechanisms: direct binding to the CAS Src-binding domain and indirect association through a FAK bridge. Cell immunostaining with pCAS antibodies revealed that CAS SD tyrosine phosphorylation occurs exclusively at sites of integrin adhesion including both nascent focal complexes formed at the edges of extending lamellipodia as well as mature focal adhesions underlying the cell body. These findings further document a role for FAK as an important upstream regulator of CAS SD tyrosine phosphorylation and implicate CAS-mediated signaling events in promoting membrane protrusion/lamellipodium extension during cell motility.  相似文献   
1000.
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