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161.
Ming-Min Lee Mathieu Sicard Marjorie Skeie S. Patricia Stock 《Systematic parasitology》2009,72(2):127-141
A new entomopathogenic nematode, Steinernema boemarei n. sp., is described from southern France. Morphological, molecular (28S and ITS rDNA sequence data) and cross-hybridisation
studies were used for diagnostics and identification purposes. Both molecular and morphological data indicate that the new
species belongs to the ‘glaseri-group’ of Steinernema spp. Key morphological diagnostic traits for S. boemarei n. sp. include the presence of prominent deirids (cervical papillae) on adult males, the morphology of the spicules and gubernaculum,
and the arrangement of the 23 genital papillae of the first generation males. Additionally, morphometric traits of the third-stage
infective juvenile, including total body length (mean 1,103 μm), tail length (mean 86 μm), location of the excretory pore
(mean 91 μm), and D% (mean 63), E% (mean 106) and H% (mean 41) values are definitive. In addition to these morphological characters,
analysis of both 28S and ITS rDNA sequences depict this Steinernema species as a distinct and unique entity. 相似文献
162.
Atmospheric carbon dioxide (CO2) and ozone (O3) concentrations are rising, which may have opposing effects on tree C balance and allocation to fine roots. More information
is needed on interactive CO2 and O3 effects on roots, particularly fine-root life span, a critical demographic parameter and determinant of soil C and N pools
and cycling rates. We conducted a study in which ponderosa pine (Pinus ponderosa) seedlings were exposed to two levels of CO2 and O3 in sun-lit controlled-environment mesocosms for 3 years. Minirhizotrons were used to monitor individual fine roots in three
soil horizons every 28 days. Proportional hazards regression was used to analyze effects of CO2, O3, diameter, depth, and season of root initiation on fine-root survivorship. More fine roots were produced in the elevated
CO2 treatment than in ambient CO2. Elevated CO2, increasing root diameter, and increasing root depth all significantly increased fine-root survivorship and median life span.
Life span was slightly, but not significantly, lower in elevated O3, and increased O3 did not reduce the effect of elevated CO2. Median life spans varied from 140 to 448 days depending on the season of root initiation. These results indicate the potential
for elevated CO2 to increase the number of fine roots and their residence time in the soil, which is also affected by root diameter, root
depth, and phenology. 相似文献
163.
164.
Daniel Aiello Marjorie H. Barnes Esther E. Biswas Subhasis B. Biswas Shen Gu John D. Williams Terry L. Bowlin Donald T. Moir 《Bioorganic & medicinal chemistry》2009,17(13):4466-4476
Antibacterial compounds with new mechanisms of action are needed for effective therapy against drug-resistant pathogens in the clinic and in biodefense. Screens for inhibitors of the essential replicative helicases of Bacillus anthracis and Staphylococcus aureus yielded 18 confirmed hits (IC50 ? 25 μM). Several (5 of 18) of the inhibitors were also shown to inhibit DNA replication in permeabilized polA-deficient B. anthracis cells. One of the most potent inhibitors also displayed antibacterial activity (MIC ~5 μg/ml against a range of Gram-positive species including bacilli and staphylococci) together with good selectivity for bacterial versus mammalian cells (CC50/MIC > 16) suitable for further optimization. This compound shares the bicyclic ring of the clinically proven aminocoumarin scaffold, but is not a gyrase inhibitor. It exhibits a mixed mode of helicase inhibition including a component of competitive inhibition with the DNA substrate (Ki = 8 μM) and is rapidly bactericidal at 4 × MIC. 相似文献
165.
R5 variants of human immunodeficiency virus type 1 preferentially infect CD62L- CD4+ T cells and are potentially resistant to nucleoside reverse transcriptase inhibitors 下载免费PDF全文
166.
Vinay Dhodda Ronald Godiska Jeffrey D. VanWye David Mead Rebecca Hochstein Lynne Sheets Sarah Vande Zande Chris Niebauer Douglas L. Crawford Marjorie F. Oleksiak 《PloS one》2010,5(9)
Background
ExCyto PCR cells provide a novel and cost effective means to amplify DNA transformed into competent bacterial cells. ExCyto PCR uses host E. coli with a chromosomally integrated gene encoding a thermostable DNA polymerase to accomplish robust, hot-start PCR amplification of cloned sequences without addition of exogenous enzyme.Results
Because the thermostable DNA polymerase is stably integrated into the bacterial chromosome, ExCyto cells can be transformed with a single plasmid or complex library, and then the expressed thermostable DNA polymerase can be used for PCR amplification. We demonstrate that ExCyto cells can be used to amplify DNA from different templates, plasmids with different copy numbers, and master mixes left on ice for up to two hours. Further, PCR amplification with ExCyto cells is comparable to amplification using commercial DNA polymerases. The ability to transform a bacterial strain and use the endogenously expressed protein for PCR has not previously been demonstrated.Conclusions
ExCyto PCR reduces pipetting and greatly increases throughput for screening EST, genomic, BAC, cDNA, or SNP libraries. This technique is also more economical than traditional PCR and thus broadly useful to scientists who utilize analysis of cloned DNAs in their research. 相似文献167.
168.
Morales M Arancibia J Lemus M Silva J Gentina JC Aroca G 《Biotechnology letters》2011,33(11):2141-2145
Sulfolobus metallicus is a hyperthermophilic and chemolithoautotrophic archaeon that uses elemental sulfur as an energy source. Its ability to
oxidize H2S was measured either in the presence or absence of elemental sulphur, showing its ability for using both as an energy source.
A biotrickling filter was set up and a biofilm of S. metallicus was established over the support. The maximum removal capacity of the biotrickling filter reached at 55°C was 40 g S/m3h for input loads higher than 70 g S/m3h. Thus, S. metallicus can be used in a biofiltration system for the treatment of waste gas emissions at high temperatures contaminated with H2S. 相似文献
169.
Ueno PM Oriá RB Maier EA Guedes M de Azevedo OG Wu D Willson T Hogan SP Lima AA Guerrant RL Polk DB Denson LA Moore SR 《American journal of physiology. Gastrointestinal and liver physiology》2011,301(4):G612-G622
Alanyl-glutamine (Ala-Gln) has recently been shown to enhance catch-up growth and gut integrity in undernourished children from Northeast Brazil. We hypothesized that the intestinal epithelial effects of Ala-Gln in malnourished weanling mice and mouse small intestinal epithelial (MSIE) cells would include modulation of barrier function, proliferation, and apoptosis. Dams of 10-day-old suckling C57BL/6 pups were randomized to a standard diet or an isocaloric Northeast Brazil "regional basic diet," moderately deficient in protein, fat, and minerals. Upon weaning to their dam's diet on day of life 21, pups were randomized to Ala-Gln solution or water. At 6 wk of age, mice were killed, and jejunal tissue was collected for morphology, immunohistochemistry, and Ussing chamber analysis of transmucosal resistance and permeability. Proliferation of MSIE cells in the presence or absence of Ala-Gln was measured by MTS and bromodeoxyuridine assays. MSIE apoptosis was assessed by annexin and 7-amino-actinomycin D staining. Pups of regional basic diet-fed dams exhibited failure to thrive. Jejunal specimens from undernourished weanlings showed decreased villous height and crypt depth, decreased transmucosal resistance, increased permeability to FITC-dextran, increased claudin-3 expression, and decreased epithelial proliferation and increased epithelial apoptosis (as measured by bromodeoxyuridine and cleaved caspase-3 staining, respectively). Undernourished weanlings supplemented with Ala-Gln showed improvements in weight velocity, villous height, crypt depth, transmucosal resistance, and epithelial proliferation/apoptosis compared with unsupplemented controls. Similarly, Ala-Gln increased proliferation and reduced apoptosis in MSIE cells. In summary, Ala-Gln promotes intestinal epithelial homeostasis in a mouse model of malnutrition-associated enteropathy, mimicking key features of the human disease. 相似文献
170.
Kuipers MA Stasevich TJ Sasaki T Wilson KA Hazelwood KL McNally JG Davidson MW Gilbert DM 《The Journal of cell biology》2011,192(1):29-41
The heterohexameric minichromosome maintenance protein complex (Mcm2-7) functions as the eukaryotic helicase during DNA replication. Mcm2-7 loads onto chromatin during early G1 phase but is not converted into an active helicase until much later during S phase. Hence, inactive Mcm complexes are presumed to remain stably bound from early G1 through the completion of S phase. Here, we investigated Mcm protein dynamics in live mammalian cells. We demonstrate that Mcm proteins are irreversibly loaded onto chromatin cumulatively throughout G1 phase, showing no detectable exchange with a gradually diminishing soluble pool. Eviction of Mcm requires replication; during replication arrest, Mcm proteins remained bound indefinitely. Moreover, the density of immobile Mcms is reduced together with chromatin decondensation within sites of active replication, which provides an explanation for the lack of colocalization of Mcm with replication fork proteins. These results provide in vivo evidence for an exceptionally stable lockdown mechanism to retain all loaded Mcm proteins on chromatin throughout prolonged cell cycles. 相似文献