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141.
Genes encoding the neuron-specific phosphoprotein synapsin I (SYN1), the glycoprotein tissue inhibitor of metalloproteinases (TIMP), the proto-oncogene A-raf-1 (ARAF1), and properdin (PFC), a positive regulator of the alternative pathway of human complement, lie within a conserved synteny encompassing the proximal short arm of the human X chromosome (Xp21.1-p11) and the centromeric end of the mouse X chromosome (A1-A5). We have used a mouse interspecific cross to demonstrate genetic linkage of Syn-1, Timp, and Araf and also show physical linkage, with Timp lying only 10 kb from Araf, within an intron of the Syn-1 gene. Detailed restriction mapping shows that Timp is transcribed in the same direction as Araf but in the opposite direction to the Syn-1 gene. Analysis of the corresponding region of the human X chromosome indicates a similar arrangement and in addition shows that the properdin gene lies within 5 kb of the 5' end of the synapsin I gene. 相似文献
142.
Background
Decisions on treatment are guided, not only by the potential for benefit, but also by the nature and severity of adverse drug reactions. However, some researchers have found numerous deficiencies in trial reports of adverse effects. We sought to confirm these findings by evaluating trials of drug therapy published in seven eminent medical journals in 1997. 相似文献143.
Pere Mir-Artigues Richard M. Twyman Derry Alvarez Pedro Cerda Bennasser Merce Balcells Paul Christou Teresa Capell 《Biotechnology and bioengineering》2019,116(10):2526-2539
By the end of 2017, the Food and Drug Administration had approved a total of 77 therapeutic monoclonal antibodies (mAbs), most of which are still manufactured today. Furthermore, global sales of mAbs topped $90 billion in 2017 and are projected to reach $125 billion by 2020. The mAbs approved for human therapy are mostly produced using Chinese hamster ovary (CHO) cells, which require expensive infrastructure for production and purification. Molecular pharming in plants is an alternative approach with the benefits of lower costs, greater scalability, and intrinsic safety. For some platforms, the production cycle is also much quicker. But do these advantages really stack up in economic terms? Earlier techno-economic evaluations have focused on specific platforms or processes and have used different methods, making direct comparisons challenging and the overall benefits of molecular pharming difficult to gauge. Here, we present a simplified techno-economic model for the manufacturing of mAbs, which can be applied to any production platform by focusing on the most important factors that determine the efficiency and cost of bulk drug manufacturing. This model develops economic concepts to identify variables that can be used to achieve cost savings by simultaneously modeling the dynamic costs of upstream production at different scales and the corresponding downstream processing costs for different manufacturing modes (sequential, serial, and continuous). The use of simplified models will help to achieve meaningful comparisons between diverse manufacturing technologies. 相似文献
144.
Derry K Mercera Claire M Melvillea Karen P Scotta Harry J Flinta 《FEMS microbiology letters》1999,179(2):485-490
Natural transformation of Streptococcus bovis JB1 was demonstrated after development of competence in normal culture medium. Transformation efficiencies were not significantly increased when heat-inactivated horse serum was added to the medium before growth. This is the first time that a resident rumen bacterial species has been shown to be naturally transformable. Transformation allowed the acquisition of plasmids or integration of sequences into the chromosome. No transformation was observed in the presence of undiluted autoclaved or filter-sterilised ovine rumen fluid or filter-sterilised ovine saliva, suggesting that transformation in the ruminant digestive tract is a rare event, although transformation was observed in the presence of 1% and 0.5% filter-sterilised rumen fluid. The use of natural transformation of S. bovis should facilitate further molecular biological studies on this species. 相似文献
145.
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147.
Spatial environmental gradients can promote adaptive differences among conspecific populations as a result of local adaptation or phenotypic plasticity. Such divergence can be opposed by various constraints, including gene flow, limited genetic variation, temporal fluctuations, or developmental constraints. We focus on the constraint that can be imposed when some populations are found in locations characterized by low levels of an essential nutrient. We use scales of wild fish to investigate phenotypic effects of spatial variation in a potentially limiting nutrient—calcium. If scale calcium (we use “scalar” calcium for consistency with the physiology literature) simply reflects environmental calcium availability, we expect higher levels of scalar calcium in fish from calcium‐rich water, compared to fish from calcium‐poor water. To consider this “passive response” scenario, we analyzed scalar calcium concentrations from three native fish species (Lepomis gibbosus, Percina caprodes, and Perca flavescens) collected at multiple sites across a dissolved calcium gradient in the Upper St. Lawrence River. Contradicting the “passive response" scenario, we did not detect strong or consistent relationships between scalar calcium and water calcium. Instead, for a given proportional increase in water calcium across the wide environmental gradient, the corresponding proportional change in scalar calcium was much smaller. We thus favor the alternative “active homeostasis” scenario, wherein fish from calcium‐poor water are better able to uptake, mobilize, and deposit calcium than are fish from calcium‐rich water. We further highlight the importance of studying functional traits, such as scales, in their natural setting as opposed to only laboratory studies. 相似文献
148.
Peter M. Vitousek Martin J. Kennedy Louis A. Derry Oliver A. Chadwick 《Oecologia》1999,121(2):255-259
We used isotopes of Sr to quantify weathering versus atmospheric sources of foliar Sr in 34 Hawaiian forests on young volcanic
soils. The forests varied widely in climate, and in lava flow age and texture. Weathering supplied most of the Sr in most
of the sites, but atmospheric deposition contributed 30–50% of foliar Sr in the wettest rainforests. A stepwise multiple regression
using annual precipitation, distance from the ocean, and texture of the underlying lava explained 76% of the variation in
Sr isotope ratios across the sites. Substrate age did not contribute significantly to variation in Sr isotope ratios in the
range of ages evaluated here (11–3000 years), although atmospheric sources eventually dominate pools of biologically available
Sr in Hawaiian rainforests in older substrates (≥150,000 years).
Received: 25 January 1999 / Accepted: 23 June 1999 相似文献
149.
Derry D. Koob 《Journal of phycology》1975,11(Z1):41-45
The populations of Asterionella formosa Hass. in two subalpine lakes in the Rawah Wild Area, Colorado, were composed of colonies of five distinct size classes Based on frustule length. The spring bloom in these two lakes was dominated by cells of the Beta or Gamma population, whereas the fall pulse was dominated by cells of the Alpha and Beta, or Alpha populations. The Beta population was physiologically unique in that it was parasitized by the chytrid Rhizophidium planktonicum Canter. The development of the parasite population could not be correlated with the concentration or the growth phase of the host population. The occurrence of parasitism did not noticeably affect the population growth patterns of the Asterionella populations. 相似文献