全文获取类型
收费全文 | 72篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
林业 | 1篇 |
11篇 | |
综合类 | 22篇 |
农作物 | 5篇 |
水产渔业 | 8篇 |
畜牧兽医 | 34篇 |
植物保护 | 4篇 |
出版年
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 1篇 |
2008年 | 6篇 |
2007年 | 3篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1947年 | 1篇 |
1938年 | 1篇 |
1933年 | 1篇 |
1932年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有85条查询结果,搜索用时 31 毫秒
1.
PB Fernandes KO Marques FR de Araujo Neto DP de Oliveira NA Hurtado‐Lugo RR Aspilcueta‐Borquis H Tonhati 《Reproduction in domestic animals》2016,51(3):428-434
Because of the importance of reproduction in stock breeding systems, it is necessary to find selection criteria that increase reproductive efficiency. The aim of this study was to estimate genetic parameters for the probability of conception on first service (PROB) in Murrah heifers, and its association with other traits of economic interest [age at first calving (AFC), service period, calving interval and milk yield at 270 days], with the purpose of evaluating their use as selection criteria. Reproductive information and first lactation records of 1200 Murrah heifers were used to perform two‐trait analyses between PROB and the other characteristics. Bayesian inference was used to estimate the variance components, considering PROB as threshold and the other as linear factors. The results demonstrate that this trait has heritability of 0.15, indicating the possibility of a genetic gain by using it for selection. With respect to the genetic correlation estimates, the only high‐magnitude association was with AFC (?0.899), which is the current criterion indicating sexual precocity of females. In the light of the parameters estimated, the first‐service pregnancy rate is an alternative for indication of sexual precocity, although presenting a smaller genetic gain than the current standard AFC. Nevertheless, additional research should be conducted regarding this trait to assess the economic importance of its use in dairy buffalo production systems. 相似文献
2.
Petra FRÝDLOVÁ Jan HNÍZDO Lenka CHYLÍKOVÁ Olga ŠIMKOVÁ Veronika CIKÁNOVÁ Petr VELENSKÝ Daniel FRYNTA 《Integrative zoology》2013,8(Z1):39-45
Blood cell morphology and count are not uniform across species. Recently, between‐species comparisons revealed that the size of red blood cells is associated with body size in some lizard taxa, and this finding was interpreted in the context of the metabolic theory. In the present study, we examined the numbers and the size of blood cells in 2 species of monitor lizards, the mangrove‐dwelling monitor (Varanus indicus) and the savannah monitor (V. exanthematicus), and we compared these traits in individuals of different body size. The results revealed that during the course of ontogeny, the size of red blood cells increases with body mass. Because the mass‐specific metabolic rate decreases with body size and the cell volume‐to‐surface ratio decreases with the cell size, changes in the erythrocyte size might be the result of oxygen transport adjustment. 相似文献
3.
Krueger AP 《Science (New York, N.Y.)》1930,72(1872):507-508
4.
G E Martin H W Krueger J M Burggraff 《Journal of the Association of Official Analytical Chemists》1985,68(3):440-443
Specific 14C-activities, percent of modern 14C-activity, and calculated percent of fermentation CO2 are presented for CO2 contained in commercial sparkling wines, labeled as champagne or produced by the bulk (charmat) process. These data are given for the production years 1976-1982. The survey encompassed effervescent wines produced in Spain, Italy, West Germany, California, and New York. Addition of synthetic CO2 to approximately 40 samples represented as sparkling wines was indicated by low 14C-activities of CO2 in these wines. Data for 14C-activity were also presented for the ethanol distilled from sparkling wines for the years 1977-1980. In all cases, the 14C-activity of ethanol was appropriate to the year of vintage. 相似文献
5.
Sighting of el chichon sulfur dioxide clouds with the nimbus 7 total ozone mapping spectrometer 总被引:1,自引:0,他引:1
Krueger AJ 《Science (New York, N.Y.)》1983,220(4604):1377-1379
The eruptions of El Chichón volcano on 28 March and 3 and 4 April 1982 were observed by the Nimbus 7 total ozone mapping spectrometer due to strong absorption by volcanic gases at the shortest wavelengths of the spectrometer (312.5 and 317.5 nanometers). These ultraviolet pictures permit a measurement of the volume, dispersion, and drift of volcanic gas clouds. The tropospheric clouds were rapidly dispersed in westerly winds while persistent stratospheric clouds drifted in easterly winds at speeds up to 13 meters per second. The spectral reflectance is consistent with sulfur dioxide absorption and rules out carbon disulfide as a major constituent. A preliminary estimate of the mass of sulfur dioxide deposited in the stratosphere by the large eruptions on 3 and 4 April is 3.3 x 10(6) tons. Prior estimates of volcanic cloud volume were based on extrapolation of locally measured sulfur dioxide concentrations. 相似文献
6.
Large-scale reductions in the ozone content of the middle and upper stratosphere over the polar cap regions were associated with the major solar proton event of 4 August 1972. This reduction, which was determined from measurements with the backscattered ultraviolet experiment on the Nimbus 4 satellite, is interpreted as being due to the catalytic destruction of ozone by odd-nitrogen compounds (NO(x)) produced by the event. 相似文献
7.
8.
Ashraf?M.?El-Assar Robert?R.?Krueger Pachanoor?S.?Devanand Chih-Cheng?T.?ChaoEmail author 《Genetic Resources and Crop Evolution》2005,52(5):601-607
Forty-seven samples of date palm (Phoenix dactylifera L.) collected from eight locations in Egypt were studied using four sets of amplified fragment length polymorphism (AFLP)
markers with near infrared fluorescence labeled primers. These samples belonged to 21 named accessions and 9 of unknown pedigrees.
A total of 350 bands were scored and 233 (66.6%) were polymorphic. Twenty-seven Egyptian accessions and ‘Medjool’and ‘Deglet
Noor’accessions from California could beclassified into the major cluster. This major cluster may represent a major group
of date palm germplasm in North Africa. There were four other clusters, each containing one or two accessions. The variety
‘Halawy’and one accession of unknown provenance were most likely from hybridization between two clusters. Six groups of accessions
of which had the same names, revealed similar but not identical AFLP profiles suggesting these accessions might derive from
seedlings rather thanthrough clonal offshoot propagation. 相似文献
9.
Junt T Schulze H Chen Z Massberg S Goerge T Krueger A Wagner DD Graf T Italiano JE Shivdasani RA von Andrian UH 《Science (New York, N.Y.)》2007,317(5845):1767-1770
Platelets are generated from megakaryocytes (MKs) in mammalian bone marrow (BM) by mechanisms that remain poorly understood. Here we describe the use of multiphoton intravital microscopy in intact BM to visualize platelet generation in mice. MKs were observed as sessile cells that extended dynamic proplatelet-like protrusions into microvessels. These intravascular extensions appeared to be sheared from their transendothelial stems by flowing blood, resulting in the appearance of proplatelets in peripheral blood. In vitro, proplatelet production from differentiating MKs was enhanced by fluid shear. These results confirm the concept of proplatelet formation in vivo and are consistent with the possibility that blood flow-induced hydrodynamic shear stress is a biophysical determinant of thrombopoiesis. 相似文献
10.
H.R. Krueger 《Pesticide biochemistry and physiology》1977,7(2):154-160
Soybean root homogenates were found to oxidize aldicarb to aldicarb sulfoxide. Fractionation of soybean root homogenate indicates that the enzyme(s) which oxidize aldicarb to the sulfoxide are largely (63%) in the 25,000g supernatant. In vitro studies of the 25,000g supernatant showed a linear reaction rate at 24 and 34°C for periods of up to 2 and 1 hr, respectively, at the pH optimum of 5.5. Bean and soybean root 25,000g supernatants were the most active on a per milligram of protein basis followed by corn, sorghum, barley, and tomato (8–27 nmol/mg of protein/hr). A 140-fold purification of soybean root aldicarb sulfoxidase was achieved. In vitro studies indicated that methomyl, methiocarb, phorate, Counter, fensulfothion, fenthion, Nemacur, EPTC, vernolate, carboxin, dl-methionine, l-cysteine, l-methionyl-l-serine, thiodiglycolic acid, lipoic acid, thiourea, and thioacetic acid when present at a 10:1 ratio with aldicarb significantly inhibited soybean root aldicarb sulfoxidation. 相似文献