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51.
HRR25, a putative protein kinase from budding yeast: association with repair of damaged DNA 总被引:27,自引:0,他引:27
M F Hoekstra R M Liskay A C Ou A J DeMaggio D G Burbee F Heffron 《Science (New York, N.Y.)》1991,253(5023):1031-1034
In simple eukaryotes, protein kinases regulate mitotic and meiotic cell cycles, the response to polypeptide pheromones, and the initiation of nuclear DNA synthesis. The protein HRR25 from the budding yeast Saccharomyces cerevisiae was defined by the mutation hrr25-1. This mutation resulted in sensitivity to continuous expression of the HO double-strand endonuclease, to methyl methanesulfonate, and to x-irradiation. Homozygotes of hrr25-1 were unable to sporulate and disruption and deletion of HRR25 interfered with mitotic and meiotic cell division. Sequence analysis revealed two distinctive regions in the protein. The NH2-terminus of HRR25 contains the hallmark features of protein kinases, whereas the COOH-terminus is rich in proline and glutamine. Mutations in HRR25 at conserved residues found in all protein kinases inactivated the gene, and these mutants exhibited the hrr25 null phenotypes. Taken together, the hrr25 mutant phenotypes and the features of the gene product indicate that HRR25 is a distinctive member of the protein kinase superfamily. 相似文献
52.
Görig C Coenen RT Stades FC Djajadiningrat-Laanen SC Boevé MH 《American journal of veterinary research》2006,67(1):134-144
OBJECTIVE: To examine the practical aspects, accuracy, and reproducibility of 2 new automatic handheld tonometers in dogs and compare them with results for 2 established applanation tonometers. ANIMALS: 15 freshly enucleated canine eyes for manometric evaluation and 20 conscious research dogs, 20 client-owned dogs, and 12 dogs with acute glaucoma for clinical tonometry. PROCEDURE: Calibration curves were determined for all 4 tonometers on 15 enucleated canine eyes. Intraocular pressure (IOP) was measured with each tonometer consecutively in conscious dogs, with the MacKay-Marg applanation tonometer as the reference device. Measurements were repeated in 20 sedated dogs. An induction-impact tonometer was evaluated clinically on dogs with acute glaucoma. Additionally, measurements obtained by an experienced and an inexperienced examiner and with or without use of topical anesthesia were compared. RESULTS: The portable pneumatonometer was cumbersome and time-consuming. Compared with results for the reference applanation tonometer, and confirmed by manometry, the portable pneumatonometer increasingly underestimated actual IOP values with increasing IOP. The induction-impact tonometer provided accurate and reproducible measurement values. There was a significant strong correlation between the IOP values obtained by the 2 examiners (r2, 0.82) and also with or without topical anesthesia (r2, 0.86). In dogs with glaucoma, the fitted line comparing values for the reference applanation tonometer and induction-impact tonometer closely resembled an ideal 1:1 relationship. CONCLUSIONS AND CLINICAL RELEVANCE: Use of the portable pneumatonometer in dogs appears to have disadvantages. The induction-impact tonometer appears to provide a promising alternative to the use of applanation tonometers in dogs. 相似文献
53.
Renzo Bonifazi Jrmie Vandenplas Jan ten Napel Roel F Veerkamp Mario P L Calus 《Journal of animal science》2021,99(9)
In beef cattle maternally influenced traits, estimates of direct-maternal genetic correlations (rdm) are usually reported to be negative. In international evaluations, rdm can differ both within countries (rdm_WC) and between countries (rdm_BC). The rdm_BC are difficult to estimate and are assumed to be zero in the current model for international beef cattle evaluations (Interbeef). Our objective was to investigate re-ranking of international estimated breeding values (IEBVs) in international beef cattle evaluations between models that either used estimated values for rdm or assumed them to be 0. Age-adjusted weaning weights and pedigree data were available for Limousin beef cattle from ten European countries. International EBVs were obtained using a multi-trait animal model with countries modeled as different traits. We compared IEBVs from a model that uses estimated rdm_BC (ranging between −0.14 and +0.14) and rdm_WC (between −0.33 and +0.40) with IEBVs obtained either from the current model that assumes rdm_BC to be 0, or from an alternative model that assumes both rdm_BC and rdm_WC to be 0. Direct and maternal IEBVs were compared across those three scenarios for different groups of animals. The ratio of population accuracies from the linear regression method was used to further investigate the impact of rdm on international evaluations, for both the whole set of animals in the evaluation and the domestic ones. Ignoring rdm_BC, i.e., replacing estimated values with 0, resulted in no (rank correlations > 0.99) or limited (between 0.98 and 0.99) re-ranking for direct and maternal IEBVs, respectively. Both rdm_BC and rdm_WC had less impact on direct IEBVs than on maternal IEBVs. Re-ranking of maternal IEBVs decreased with increasing reliability. Ignoring rdm_BC resulted in no re-ranking for sires with IEBVs that might be exchanged across countries and limited re-ranking for the top 100 sires. Using estimated rdm_BC values instead of considering them to be 0 resulted in null to limited increases in population accuracy. Ignoring both rdm_BC and rdm_WC resulted in considerable re-ranking of animals’ IEBVs in all groups of animals evaluated. This study showed the limited impact of the current practice of ignoring rdm_BC in international evaluations for Limousin weaning weight, most likely because the estimated rdm_BC was close to 0. We expect that these conclusions can be extended to other traits that have reported rdm values in the range of rdm_WC values for weaning weight in Limousin. 相似文献
54.
55.
Monicah Mucheru-Muna Pieter Pypers Daniel Mugendi James Kung’u Jayne Mugwe Roel Merckx Bernard Vanlauwe 《Field Crops Research》2010
Smallholder farmers in East-Africa commonly intercrop maize (Zea mays L.) with grain legumes to maximize utilisation of land and labour, and attain larger crop yields. Conventionally, one legume line is intercropped between each pair of maize lines. This study evaluated the potential of a modified two-by-two staggered arrangement (MBILI) to increase crop yields and economic benefits in two sites in Central Kenya with contrasting soil fertility levels during 7 consecutive seasons. Common beans (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.) and groundnut (Arachis hypogaea L.) were grown as legume intercrops. The MBILI system resulted in increased maize yields in both sites, and increased cowpea yields in the poor site. In the fertile site, using beans as an intercrop was most profitable, and the MBILI system increased net benefits by 40%, relative to the conventional system. In the poor site, groundnut and cowpea were better adapted, and the MBILI system increased net benefit by 12–37%. Positive effects of the MBILI system were most pronounced in the poor site, but occurred independent of soil fertility level. Rainfall amounts and distribution varied widely, but the MBILI system increased yields both under conditions of ample and inadequate rainfall. N balances were negative with beans and groundnut, but neutral with cowpea as the intercrop. A modest N fertilizer application is therefore essential to sustain yields in the long term, especially when beans or groundnuts are intercropped. In conclusion, the MBILI system, when combined with adjusted nutrient inputs, resulted in superior and robust improvements in crop yields and economic benefits, relative to the conventional intercropping system. 相似文献
56.
Immune deficiency and altered immunity are among the best characterized and strongest known risk factors of non-Hodgkin lymphomas (NHL). For instance, chronic inflammation or certain disturbances in the immune system are associated with an increased lymphoma risk. Occupational and environmental factors (i.e., dioxin) as well as lifestyle factors (i.e., obesity) may contribute to these risk factors. The precise role of these factors in the etiology of NHL, however, is still not entirely clear. Although the existing epidemiologic studies have not revealed consistent patterns of perturbations of the immune system by these factors, the findings might suggest an adverse impact on both the humoral and cell-mediated immune system. 相似文献
57.
Marleen M. P. Cobben Jana Verboom Paul F. M. Opdam Rolf F. Hoekstra René Jochem Marinus J. M. Smulders 《Landscape Ecology》2012,27(2):227-237
In response to climate change a species may move, adapt, or go extinct. For the adaptability of a population its genetic diversity
is essential, but climate change-induced range shifts can cause a loss of genetic diversity. We investigated how landscape
structure affects the level and distribution of genetic diversity in metapopulations subject to climate change-induced range
shifts. For this we used the spatially explicit, individual-based model METAPHOR which simulates metapopulation demography
and genetics under different temperature increase scenarios. The results indicated that increasing total habitat area may
enhance the maintenance of the genetic diversity in metapopulations while they are shifting their range under climate change.
However, the results also showed that a high level of total habitat area did not prevent the populations in the newly colonised
habitat area of being depleted of much of the original genetic diversity. We therefore conclude that enhancing landscape connectivity
may lead to a delayed loss of genetic diversity in metapopulations under climate change, but that additional measures would
be necessary to ensure its long-term conservation. Importantly, our simulations also show that a landscape which could be
regarded as well-structured under stable climatic conditions, may be inferior for the conservation of genetic diversity during
a range shift. This is important information for landscape management when developing strategies for the in situ conservation
of genetic variation in natural populations under climate change. 相似文献
58.
Daniel Makori Menge Mana Kano-Nakata Akira Yamauchi Roel Rodriguez Suralta Daigo Makihara 《Journal of Agronomy and Crop Science》2020,206(3):322-337
Drought cycling and soil re-watering trends due to intermittent rainfall patterns are key stress factors that influence rice growth and yield under upland cultivation conditions. However, upland rice adaptation responses to fluctuating soil moisture conditions remain poorly understood. This study investigated root and shoot responses of upland New Rice for Africa (NERICA) varieties to episodic drought and re-watering during growth. We examined root and shoot growth of NERICA 1 and NERICA 4 compared with those of IR72, an improved lowland variety, and Dular, a traditional drought-tolerant variety, in terms of soil moisture fluctuations with different levels of nitrogen fertilization under field conditions that impeded deep root development. During soil moisture fluctuation, all varieties reduced shoot dry weight compared with well-watered plants, regardless of nitrogen fertilization levels. However, total root length for the three upland varieties was enhanced by soil moisture fluctuations at moderate and high nitrogen fertilization, while that of the lowland variety was reduced. Comparing root development during water fluctuations revealed that NERICA 1 had a greater root system than NERICA 4, which was attributed to lateral root development. Furthermore, we found that NERICA varieties increase lateral root mass during soil desiccation under adequate nitrogen fertilization, while Dular and IR72 reduced their root growth rate during drought and increased it after re-watering. Both root growth patterns developed, from around maximum tillering to heading. The analysis of regression between root elongation and shoot growth with fluctuating soil moisture indicated that an enhanced root system during drought, on adequate nitrogen fertilization, can contribute to shoot growth when sufficient water becomes available, specifically around the maximum tillering to the heading growth stage of rice. 相似文献
59.
60.
Robert A. McCleery Roel R. Lopez Nova J. Silvy William E. Grant 《Biological conservation》2005,124(1):27-33
We evaluated the effectiveness of supplemental stockings being proposed in the recovery of the federally endangered Key Largo woodrat (KLWR, Neotoma floridana smalli) using a stage-based, stochastic model. Supplemental stockings were evaluated with a population model using current trapping and telemetry data along with published and unpublished KLWR data. Model simulations predicted the KLWR had >70% probability of terminal extinction over the next 10 years even with the use of supplemental annual stockings. Supplemental stockings of KLWRs (?20 females) appear to delay the extinction of the species, but negative population trajectories accelerated after stockings cease. Model results illustrated the importance of determining limiting factors on the population prior to the use of supplemental stockings as a recovery option for this endangered woodrat population. 相似文献