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961.
Natural forest reserves provide a rare opportunity to study forest dynamics after the cessation of human management. Inventories
were carried out in 1996 and 2006 in an oak (Quercus spp.) dominated forest reserve formerly managed as coppice forest using the Bitterlich sampling method, an inventory method
with a fixed angle of sight to select trees based on their stem diameter. The total living stand volume increased from 245.2
to 276.5 m3/ha (+12.8%) over the 10-year period. This net increase resulted from the growth of individual trees (+3.7%), the ingrowths
of young trees (+17.7%) and tree mortality between 1996 and 2006 (−8.6%). Tree mortality included 14.8 m3/ha of standing deadwood and 6.2 m3/ha of fallen deadwood. Stand dynamics differed among tree species: the volume of oak (Quercus spp.) increased due to strong growth and low mortality, whereas hornbeam (Carpinus betulus) showed a decrease in stand volume due to high mortality and low growth. The findings suggest an increase in oak dominance
at the expense of hornbeam although inventories repeated over longer time periods would be needed for confirmation. Our data
indicate that the Bitterlich sampling method can be used for assessing tree species dynamics and structural changes in natural
forest reserves, but some important processes (seedling recruitment, wood decomposition) would need to be investigated separately.
Zusammenfassung In einem von Eiche (Quercus spp.) dominierten Naturwaldreservat wurde in den Jahren 1996 und 2006 auf einer Fl?che von 29 ha eine Inventur mittels der Winkelz?hlprobe nach Bitterlich durchgeführt. Der Gesamtvorrat erh?hte sich in der 10-j?hrigen Beobachtungsperiode von 245.2 m3/ha auf 276.5 m3/ha. Im Durchschnitt konnten 14.8 m3/ha stehendes Totholz und 6.2 m3/ha liegendes Totholz ermittelt werden. Die Mortalit?tsrate lag zwischen 1996 und 2006 bei 8.6%. Hainbuche (Carpinus betulus) zeigte aufgrund der hohen Mortalit?t und dem geringen Einwuchs im Vergleich zur Eiche und den anderen Baumarten eine Abnahme im Gesamtvorrat. Die Ergebnisse erlauben einen Einblick in die dynamischen Prozesse unter nahezu natürlichen Bedingungen. Die Eignung der Winkelz?hlprobe für die Beurteilung der Dynamik und die Analyse von strukturellen Ver?nderungen wird kritisch diskutiert.相似文献
962.
Allelic ladders and reference genotypes for a rigorous standardization of poplar microsatellite data 总被引:1,自引:0,他引:1
Georg Rathmacher Marc Niggemann Hanna Wypukol Karl Gebhardt Birgit Ziegenhagen Ronald Bialozyt 《Trees - Structure and Function》2009,23(3):573-583
A correct identification of members of the poplar hybrid complex Populus × canadensis is essential in breeding programs and studies in introgressive gene flow. Molecular marker protocols have been developed
for this purpose. However, due to missing standards, these techniques have so far not been suited to the transfer of results
between different laboratories. We present here a powerful system of nuclear microsatellite DNA (nSSR) fingerprints, standardized
by allelic ladders and reference genotypes. Seven nSSR loci provided fingerprints of 65 commercial poplar clones. Their alleles
were used to construct allelic ladders. Thus, a first standardized register of poplar clones is now available. All procedures
were optimized according to simplified DNA extraction protocols, multiplexed PCR and electrophoresis procedures. Corresponding
data originating from two different electrophoretic platforms in different laboratories were congruent when the allelic ladder
was used. Unambiguous differentiation of the clones was based on a very low probability of identity (PI) of 1.95 × 10−8. Our results revealed discrepancies between clone denotations and genetic fingerprints. This suggests that, potentially,
members of the clone collection could have been mixed up, thus confirming the demand for rigorous standards. The protocol
presented can be exploited in a manifold way, e.g. to enlarge the present clonal molecular data base, or to use it for purposes
of certification and control. Furthermore, the allelic ladders are recommended for use in poplar population genetic studies
across different laboratories. The allelic ladders and single sample reference genotypes can be obtained on demand. 相似文献
963.
964.
Elsholz B Nitsche A Achenbach J Ellerbrok H Blohm L Albers J Pauli G Hintsche R Wörl R 《Biosensors & bioelectronics》2009,24(6):1737-1743
For the sensitive detection of amplicons derived from diagnostic PCR, a novel electrical low-density microarray is applied and compared to state-of-the-art quantitative real-time PCR. The principle of the electrochemical method and the effective use for analysis are described. Interdigitated array gold electrodes (IDA-E) embedded into a silicon chip are the core technology of the fully automated compact biosensor system, basing on enzyme coupled electrochemical detection. The biointerface is built up with thiol-modified capture oligonucleotides on gold and mediates the specific recognition of hybridised target DNA amplified with uniplex or multiplex PCR. In here we show the potential of the designed electrical microarray to function as an advanced screening method for the parallel detection of a panel of the four pathogens Bacillus anthracis, Yersinia pestis, Francisella tularensis and ortho pox viruses (genus), which are among the most relevant biowarfare agents. PCR products, generated from 10 to 50 gene equivalents, have been detected reproducibly. The experiments with varying pathogen amounts showed the good reliability and the high sensitivity of the method, equivalent to optical real-time PCR detection systems. Without PCR the total assay time amounts to 27 min. The advantage of the combination of multiplex-PCR with electrical microarray detection avoiding intensive PCR probe labelling strategies is illustrated. 相似文献
965.
Abuelgasim Elzein Jürgen Kroschel Paul Marley Georg Cadisch 《Biocontrol Science and Technology》2009,19(4):349-367
The effect of vacuum packaging on the shelf-life and handling of Pesta granules and seed treatment made with chlamydospores of Fusarium oxysporum strains Foxy2, PSM197 or their mixture was studied at 4°C and 22±3°C over 1 year. In addition, the effects of co-incorporated amendments [urea in Pesta or co-delivered fungicides (Ridomil Gold®, Apron XL®) on coated sorghum seeds], and coating material (Arabic gum ‘AG’, SUET Binder ‘SB’) on the viability of Striga-mycoherbicides were evaluated. Storage under vacuum packaging did not enhance shelf-life of the formulated Striga-mycoherbicidal products after 12 months of storage regardless of the treatment used. The co-incorporated urea into Pesta granules significantly reduced the viability of mycoherbicides, but less so at 4°C (58% strain-stability after 12 months). No significant differences between the coating materials in maintaining the viability of mycoherbicides were observed. The shelf-life of isolates on coated seeds significantly decreased when adding Ridomil Gold®. However, at 4°C, the fungicide Apron XL® allowed better survival of Foxy2 and PSM197 by maintaining their averaged half-lives (t 0.5) by an additional 6 months compared to Ridomil Gold®. In general, Striga-mycoherbicidal product combinations exhibited a significantly higher shelf-life when stored at 4°C than at 22±3°C. The absence of a positive effect of vacuum packaging on shelf-life of Striga-mycoherbicidal products reflects the tolerance of the formulated fungal propagules (chlamydospores) to withstand an oxygen enriched environment and allows their handling and distribution through ordinary packaging systems in Africa. The high compatibility between Striga-mycoherbicides and the co-delivered fungicide Apron XL®, and the fungal storage stability allows simultaneous control of Striga and fungal cereal diseases within an integrated pest management (IPM). 相似文献
966.
Georg Zizka Marco Schmidt Katharina Schulte Patricio Novoa Raquel Pinto Konstantin König 《Biodiversity and Conservation》2009,18(9):2449-2471
Chile is home to 23 species of Bromeliaceae, including 2 subspecies and 4 varieties. Twenty species are endemic to the country.
We examined 883 herbarium specimens from 27 herbaria for our treatment of the Bromeliaceae for the “Flora de Chile”. These
data and field observations resulted in a comprehensive database that we used to generate distribution maps for each species.
We applied ecological niche modelling to reveal distribution areas and centers of Bromeliaceae diversity. We further analysed
the collecting dates of the herbarium specimens to assess possible changes in species abundance. In this study we assess the
conservation status of the bromeliad species in Chile. IUCN categories were assigned to the 27 bromeliad taxa as follows:
Critically endangered: 4, Endangered: 6, Vulnerable: 11, Near threatened: 2, Least concern: 4. No species has become “Extinct”
up to now. We also put forth a hypothesis about their biogeographic history. 相似文献
967.
A fundamental question in biology is how animal segmentation arose during evolution. One particular challenge is to clarify whether segmental ganglia of the nervous system evolved once, twice, or several times within the Bilateria. As close relatives of arthropods, Onychophora play an important role in this debate since their nervous system displays a mixture of both segmental and non-segmental features. We present evidence that the onychophoran “ventral organs,” previously interpreted as segmental anlagen of the nervous system, do not contribute to nerve cord formation and therefore cannot be regarded as vestiges of segmental ganglia. The early axonal pathways in the central nervous system arise by an anterior-to-posterior cascade of axonogenesis from neuronal cell bodies, which are distributed irregularly along each presumptive ventral cord. This pattern contrasts with the strictly segmental neuromeres present in arthropod embryos and makes the assumption of a secondary loss of segmentation in the nervous system during the evolution of the Onychophora less plausible. We discuss the implications of these findings for the evolution of neural segmentation in the Panarthropoda (Arthropoda + Onychophora + Tardigrada). Our data best support the hypothesis that the ancestral panarthropod had only a partially segmented nervous system, which evolved progressively into the segmental chain of ganglia seen in extant tardigrades and arthropods. 相似文献
968.
969.
Ioannis G. Goudakos Christian König Philip B. Schöttle William R. Taylor Navrag B. Singh Ian Roberts Florian Streitparth Georg N. Duda Markus O. Heller 《Journal of biomechanics》2009,42(15):2590-2596
The mechanical environment during stair climbing has been associated with patellofemoral pain, but the contribution of loading to this condition is not clearly understood. It was hypothesized that the loading conditions during stair climbing induce higher patellofemoral pressures, a more lateral force distribution on the trochlea and a more lateral shift and tilt of the patella compared to walking at early knee flexion. Optical markers for kinematic measurements were attached to eight cadaveric knees, which were loaded with muscle forces at instances of walking and stair climbing cycles at 12° and 30° knee flexion. Contact mechanics were determined using a pressure sensitive film. At 12° knee flexion, stair climbing loads resulted in higher peak pressure (p=0.012) than walking, more lateral force distribution (p=0.012) and more lateral tilt (p=0.012), whilst mean pressure (p=0.069) and contact area (p=0.123) were not significantly different. At 30° knee flexion, although stair climbing compared to walking loads resulted in significantly higher patellofemoral mean (p=0.012) and peak pressures (p=0.012), contact area (p=0.025), as well as tilt (p=0.017), the medial–lateral force distribution (p=0.674) was not significantly different. No significant differences were observed in patellar shift between walking and stair climbing at either 12° (p=0.093) or 30° (p=0.575) knee flexion. Stair climbing thus leads to more challenging patellofemoral contact mechanics and kinematics than level walking at early knee flexion. The increase in patellofemoral pressure, lateral force distribution and lateral tilt during stair climbing provides a possible biomechanical explanation for the patellofemoral pain frequently experienced during this activity. 相似文献
970.
Kratzer A Buchebner M Pfeifer T Becker TM Uray G Miyazaki M Miyazaki-Anzai S Ebner B Chandak PG Kadam RS Calayir E Rathke N Ahammer H Radovic B Trauner M Hoefler G Kompella UB Fauler G Levi M Levak-Frank S Kostner GM Kratky D 《Journal of lipid research》2009,50(2):312-326
Liver X receptors (LXRs) are important regulators of cholesterol and lipid metabolism. LXR agonists have been shown to limit the cellular cholesterol content by inducing reverse cholesterol transport, increasing bile acid production, and inhibiting intestinal cholesterol absorption. Most of them, however, also increase lipogenesis via sterol regulatory element-binding protein-1c (SREBP1c) and carbohydrate response element-binding protein activation resulting in hypertriglyceridemia and liver steatosis. We report on the antiatherogenic properties of the steroidal liver X receptor agonist N,N-dimethyl-3beta-hydroxy-cholenamide (DMHCA) in apolipoprotein E (apoE)-deficient mice. Long-term administration of DMHCA (11 weeks) significantly reduced lesion formation in male and female apoE-null mice. Notably, DMHCA neither increased hepatic triglyceride (TG) levels in male nor female apoE-deficient mice. ATP binding cassette transporter A1 and G1 and cholesterol 7alpha-hydroxylase mRNA abundances were increased, whereas SREBP1c mRNA expression was unchanged in liver, and even decreased in macrophages and intestine. Short-term treatment revealed even higher changes on mRNA regulation. Our data provide evidence that DMHCA is a strong candidate as therapeutic agent for the treatment or prevention of atherosclerosis, circumventing the negative side effects of other LXR agonists. 相似文献