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941.
Evaluation of 23S rRNA PCR primers for use in phylogenetic studies of bacterial diversity 总被引:1,自引:0,他引:1
Hunt DE Klepac-Ceraj V Acinas SG Gautier C Bertilsson S Polz MF 《Applied and environmental microbiology》2006,72(3):2221-2225
The availability of a diverse set of 23S rRNA gene sequences enabled evaluation of the specificity of 39 previously published and 4 newly designed primers specific for bacteria. An extensive clone library constructed using an optimized primer pair resulted in similar gene richness but slightly differing coverage of some phylogenetic groups, compared to a 16S rRNA gene library from the same environmental sample. 相似文献
942.
943.
Pfefferle D Brauch K Heistermann M Hodges JK Fischer J 《Proceedings. Biological sciences / The Royal Society》2008,275(1634):571-578
In a number of primate species, females utter loud and distinctive calls during mating. Here we aim to clarify the information content and function of Barbary macaque (Macaca sylvanus) copulation calls by testing (i) whether or not copulation calls advertise the female fertile phase and (ii) whether and how copulation calls influence male ejaculatory behaviour. In order to do this, we combined hormone measurements with acoustic analysis and behavioural observations. In contrast to a previous study implying that the structure of copulation calls indicates the timing of the fertile phase, our results, using objective endocrine criteria for assessing ovulation, provide evidence that the structure of copulation calls of female Barbary macaques does not reveal the timing of the fertile phase. More importantly, females seem to influence the likelihood of ejaculation by calling versus remaining silent and by adjusting the timing of call onset. Females make use of this ability to influence mating outcome to ensure ejaculatory matings with almost all males in the group. In addition, calls given during ejaculatory copulations differ from those during non-ejaculatory copulations, providing information about mating outcome for listeners. We conclude that in this species, copulation calls apparently serve to enhance sperm competition and maximize paternity confusion. 相似文献
944.
A series of 7,8- and 8,9-fused pyrimidinone, aminopyrimidine and pyridone derivatives of 8-carboxamidocyclazocine (8-CAC) have been prepared and evaluated in opioid receptor binding assays. Targets were designed to corroborate a pharmacophore hypothesis regarding the bioactive conformation of the carboxamide of 8-CAC. In addition to the results from this study strongly supporting this pharmacophore hypothesis, a number of novel compounds with high affinity to opioid receptors have been identified. 相似文献
945.
Sahr AE Sindelar DK Alexander-Chacko JT Eastwood BJ Mitch CH Statnick MA 《American journal of physiology. Regulatory, integrative and comparative physiology》2008,295(2):R463-R471
An analog of the trans-3,4-dimethyl-4-(3-hydroxyphenyl)piperidine series (LY255582) exhibits high in vitro binding affinity and antagonist potency for the mu-, delta-, and kappa-opioid receptors. In vivo, LY255582 exhibits potent effects in reducing food intake and body weight in several rodent models of obesity. In the present study, we evaluated the effects of LY255582 to prevent the consumption of a highly palatable (HP) diet (a high-fat/high-carbohydrate diet) both when the food was novel and following daily limited access to the HP diet. Additionally, we examined the effects of consumption of the HP diet and of LY255582 treatment on mesolimbic dopamine (DA) signaling by in vivo microdialysis. Consumption of the HP diet increased extracellular DA levels within the nucleus accumbens (NAc) shell. Increased DA in the NAc shell was not related to the quantity of the HP diet consumed, and the DA response did not habituate following daily scheduled access to the HP diet. Interestingly, treatment with LY255582 inhibited consumption of the HP diet and the HP diet-associated increase in NAc shell DA levels. Moreover, the increased HP diet consumption observed following daily limited access to the HP diet was completely prevented by LY255582 treatment. LY255582 may be a useful tool in understanding the neural mechanisms involved in the reinforcement mechanisms regulating food intake. 相似文献
946.
Martínez DE Costa ML Gomez FM Otegui MS Guiamet JJ 《The Plant journal : for cell and molecular biology》2008,56(2):196-206
Massive degradation of photosynthetic proteins is the hallmark of leaf senescence; however the mechanism involved in chloroplast protein breakdown is not completely understood. As small 'senescence-associated vacuoles' (SAVs) with intense proteolytic activity accumulate in senescing leaves of soybean and Arabidopsis, the main goal of this work was to determine whether SAVs are involved in the degradation of chloroplastic components. SAVs with protease activity were readily detected through confocal microscopy of naturally senescing leaves of tobacco (Nicotiana tabacum L.). In detached leaves incubated in darkness, acceleration of the chloroplast degradation rate by ethylene treatment correlated with a twofold increase in the number of SAVs per cell, compared to untreated leaves. In a tobacco line expressing GFP targeted to plastids, GFP was re-located to SAVs in senescing leaves. SAVs were isolated by sucrose density gradient centrifugation. Isolated SAVs contained chloroplast-targeted GFP and the chloroplast stromal proteins Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) and glutamine synthetase, but lacked the thylakoid proteins D1 and light-harvesting complex II of the photosystem II reaction center and photosystem II antenna, respectively. In SAVs incubated at 30 degrees C, there was a steady decrease in Rubisco levels, which was completely abolished by addition of protease inhibitors. These results indicate that SAVs are involved in degradation of the soluble photosynthetic proteins of the chloroplast stroma during senescence of leaves. 相似文献
947.
948.
Guenoune-Gelbart D Elbaum M Sagi G Levy A Epel BL 《Molecular plant-microbe interactions : MPMI》2008,21(3):335-345
Virus spread through plasmodesmata (Pd) is mediated by virus-encoded movement proteins (MPs) that modify Pd structure and function. The MP of Tobacco mosaic virus ((TMV)MP) is an endoplasmic reticulum (ER) integral membrane protein that binds viral RNA (vRNA), forming a vRNA:MP:ER complex. It has been hypothesized that (TMV)MP causes Pd to dilate, thus potentiating a cytoskeletal mediated sliding of the vRNA:MP:ER complex through Pd; in the absence of MP, by contrast, the ER cannot move through Pd. An alternate model proposes that cell-to-cell spread takes place by diffusion of the MP:vRNA complex in the ER membranes which traverse Pd. To test these models, we measured the effect of (TMV)MP and replicase expression on cell-to-cell spread of several green fluorescent protein-fused probes: a soluble cytoplasmic protein, two ER lumen proteins, and two ER membrane-bound proteins. Our data support the diffusion model in which a complex that includes ER-embedded MP, vRNA, and other components diffuses in the ER membrane within the Pd driven by the concentration gradient between an infected cell and adjacent noninfected cells. The data also suggest that the virus replicase and MP function together in altering Pd conductivity. 相似文献
949.
RGK proteins constitute a novel subfamily of small Ras-related proteins that function as potent inhibitors of voltage-dependent (VDCC) Ca(2+) channels and regulators of actin cytoskeletal dynamics. Within the larger Ras superfamily, RGK proteins have distinct regulatory and structural characteristics, including nonconservative amino acid substitutions within regions known to participate in nucleotide binding and hydrolysis and a C-terminal extension that contains conserved regulatory sites which control both subcellular localization and function. RGK GTPases interact with the VDCC beta-subunit (Ca(V)beta) and inhibit Rho/Rho kinase signaling to regulate VDCC activity and the cytoskeleton respectively. Binding of both calmodulin and 14-3-3 to RGK proteins, and regulation by phosphorylation controls cellular trafficking and the downstream signaling of RGK proteins, suggesting that a complex interplay between interacting protein factors and trafficking contribute to their regulation. 相似文献
950.
Dana M. Hawley James Briggs André A. Dhondt Irby J. Lovette 《Conservation Genetics》2008,9(3):637-643
Well-characterized species introductions provide opportunities to compare the genetic signatures of known founder effects
across classes of molecular markers. The release of small numbers of house finches (Carpodacus mexicanus) into the eastern United States in the 1940s led to substantial interest in the effects of this introduction on genetic diversity
in this now abundant species, an issue that has been highlighted by a recent Mycoplasma disease epidemic that most intensively affects the introduced and potentially genetically depauperate house finch populations.
Previous studies comparing genetic diversity levels in native and introduced house finch populations produced seemingly disparate
results: comparisons based on amplified fragment length polymorphism, RFLP mtDNA, and allozyme markers found essentially equivalent
levels of diversity in eastern and western populations, whereas microsatellite markers showed clear reductions in diversity
in the introduced populations. Here we employ sequence variation at the ND2 mtDNA locus to further compare levels of diversity
between the four native and five introduced house finch populations that were previously examined in the microsatellite study.
We found substantially lower ND2 haplotype richness and diversity across all introduced populations of house finches. The
majority of sequence variation (78%) was detected within subpopulations, with the remainder (22%) explained by the historical
status of each population (native or introduced). Our results are consistent with previous microsatellite evidence for a founder
effect during the introduction of eastern house finches, and suggest that the mtDNA founder effect was particularly severe,
likely owing to a male-biased sex ratio at the time of introduction coupled with the lower effective population size of clonally
inherited markers. We discuss how the inconsistencies between past studies of house finch diversity can inform the usefulness
of distinct marker sets for detecting molecular signatures of founder events. 相似文献