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131.
Hammond AL 《Science (New York, N.Y.)》1974,183(4125):644-646
132.
This study investigated possible associations between soil types, land use and badger numbers in an area of the Irish Midlands where badger removal had been conducted during 1989–1994. For this purpose, the area was divided into approximately 2500 geo-referenced square grids of 0.5°km per side. For the outcomes (setts per grid, badgers per grid and tuberculous badgers per grid), Poisson models of land use, of soil type, and a combination of these two were developed. Influential grids were removed and the models adjusted for over-dispersion in the badger outcomes. Mineral-based soils, dry and very-dry peat soils supported increased numbers of setts and badgers. High-quality pasture was the major land use (pastures often are found on mineral-based soils) and supported increased numbers of setts, badgers, and tuberculous badgers. “Natural” areas also supported more setts and broad-leaf forested areas were associated with increased tuberculous badger numbers. Discontinuous urban areas tended to decrease sett numbers per grid. Hedgerow length was not an important predictor given the information on soil type and land use.
Spatial correlations existed for badger setts in 1°km grids, for badger numbers in 1.5°km grids, and for tuberculous badgers in 2°km grids. The latter two grids have approximately the same area as the territory size used by a social group of badgers. There were no spatial correlations at the smallest (0.5 km) grid size. 相似文献
133.
Alvarez P Spicer LJ Chase CC Payton ME Hamilton TD Stewart RE Hammond AC Olson TA Wettemann RP 《Journal of animal science》2000,78(5):1291-1302
To determine breed differences in ovarian function and endocrine secretion, daily rectal ultrasonography was conducted on multiparous lactating Angus (temperate Bos taurus; n = 12), Brahman (tropical Bos indicus; n = 12), and Senepol (tropical Bos taurus; n = 12) cows during an estrous cycle in summer. Blood was collected daily to quantify plasma concentrations of FSH, LH, progesterone, estradiol, GH, insulin-like growth factor (IGF)-I, IGF-II, IGF binding proteins (IGFBP), insulin, glucose, and plasma urea nitrogen (PUN). Numbers of small (2 to 5 mm), medium (6 to 8 mm), and large follicles (> or = 9 mm) were greater (P < .05) in Brahman than in Angus and(or) Senepol cows. Length of the estrous cycle (SEM = .6 d) was similar (P > .10) among Senepol (20.4 d), Angus (19.5 d), and Brahman (19.7 d) cows. Senepol cows had greater (P < .05) diameters of the corpus luteum (CL) and a delayed regression of the CL as compared with Angus cows. The secondary surge of FSH (between d 1 and 2; d 0 = estrus) was greater in Angus than Brahman or Senepol cows (breed x day, P < .05). Between d 2 and 14 of the estrous cycle, concentrations of progesterone, LH, IGF-II, and binding activities of IGFBP-3, IGFBP-2, and the 27- to 29-kDa IGFBP in plasma did not differ (P > .10) among breeds. Concentrations of GH, IGF-I, insulin, and PUN were greater (P < .001) and binding activities of the 22-kDa and 20-kDa IGFBP tended (P < .10) to be greater in plasma of Brahman than in Angus or Senepol cows. Plasma glucose concentrations were greater (P < .05) in Senepol than in Brahman or Angus cows. In conclusion, Brahman (Bos indicus) and Senepol cows (tropical Bos taurus) had greater numbers of follicles in all size categories and greater diameter of CL than Angus (temperate Bos taurus) cows. These ovarian differences may be due to changes in the pattern of secretion of FSH, insulin, IGF-I, and GH but not LH, IGF-II, or IGFBP-2 or -3. 相似文献
134.
Hammond PR 《Science (New York, N.Y.)》1963,142(3591):502
This exceptionally reactive compound 1,4-benzoquinone tetracarboxylic acid dianhydride is one of the strongest vr-acids yet described. 相似文献
135.
Neuronal properties of clonal hybrid cell lines derived from central cholinergic neurons 总被引:5,自引:0,他引:5
Clonal cell lines derived from specific types of central neurons can be used to identify and characterize properties specific to those neurons. With somatic cell fusion techniques, nine clonal hybrid cell lines have been developed from the septal region of the mouse basal forebrain. Two lines express characteristics typical of cholinergic neurons--choline acetyltransferase activity and immunoreactivity, neurite formation with neurofilament protein immunoreactivity, and aggregation in rotation-mediated cell culture. These cell lines may be useful for studying the trophic interactions that support the development and maintenance of central cholinergic connections. 相似文献
136.
137.
Hammond AL 《Science (New York, N.Y.)》1973,182(4107):43-44
138.
Hammond N 《Science (New York, N.Y.)》1984,224(4650):741-743
139.
Hammond N 《Science (New York, N.Y.)》1972,178(4065):1092-1093
Obsidian from two sources in highland Guatemala has been found at 23 sites of the Classic Mayan civilization, mainly in the nonvolcanic lowlands to the north. The distribution, together with trade routes suggested by topography and documentary sources, suggests efficient waterborne transport and competition between sources for the lowland market. 相似文献
140.
Hammond AL 《Science (New York, N.Y.)》1977,195(4278):566-567