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1.
E. Nieman 《BioControl》1991,36(1):77-86
The mothMimorista pulchellalis was monitored over 2 years after liberation in a jointed cactus (Opuntia aurantiaca) infestation in South Africa. Moth and cactus densities were estimated using a system of randomly-assigned quadrats and the
impact of the moth on the cactus population quantified. Moths appeared adapted to survive on the etiolated form of jointed
cactus plants, killing approximately 1% of the increment in small plants annually. Large plants were also attacked but damage
was negligible. The moths occurred in low numbers throughout the study period and generally went through 3 generations in
a year.
Résumé La pyraleMimorista pulchellalis a été surveillée durant les deux années qui suivirent sa libération dans une infestation de figuier de Barbarie en Afrique du Sud. Les densités de pyrale et de cactus ont été estimées en utilisant un système de quadrats distribués au hasard et l'impact de la pyrale sur la population de cactus a été quantifiée. Les pyrales semblaient adaptées à survivre sur la forme étiolée des plants de cactus tuant approximativement 1% de l'accroissement annuel des petits plants. Les gros plants étaient aussi attaqués, mais les dégats étaient négligeables. La pyrale existait en faibles nombres durant toute la période d'étude et elle présentait généralement 3 générations par an.相似文献
2.
J. A. M. van Arendonk C. Smith B. W. Kennedy 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,78(5):735-740
Summary A Bayesian method to estimate genotype probabilities at a single locus using information on the individual and all its relatives and their mates has been developed. The method uses data over several generations, can deal with large numbers of individuals in large livestock families and allows for missing information. It can be extended to multiple alleles and can be used for autosomal or sex-linked loci. The allele frequencies and the form of expression (dominance, penetrance) must be specified. An algorithm using the method and involving an iterative procedure has been developed to calculate the genotype probabilities for practical use in livestock breeding. The method and algorithm were used to determine the accuracy of estimating genotype probabilities of sires for a female sex-limited trait, such as genetic variants of milk proteins. Data were similated and genotype probabilities estimated for 100 sires (20 replicates) with 3, 6 and 12 female offspring per sire, for different population frequencies, for additive and dominance gene action and for variable genotypic expression. Such simulation is useful in the design of testing systems for the use of information on specific genetic loci in selection.Prepared during a leave at Centre for Genetic Improvement of Livestock, Guelph, Canada 相似文献
3.
A simple procedure is described for the determination of the photosensitizing potency of drugs, using three leukemic cell lines, two of lymphocytic origin, L1210 and P388 and one of erythroid type, Friend-745. The procedure allows one to investigate several aspects of the photosensitization properties of tested compounds such as cellular localization and direct (trypan blue exclusion) or delayed (clonogenicity) photomediated toxicities.The method was assessed using crude hematoporphyrin derivative (HPD) as well as dihematoporphyrin ether (DHE) or commercially available Photofrin II. Results were compared to those obtained with normal cells, e.g spleen lymphocytes and erythropoietic stem cells (CFU-e), and discussed in the light of the relative response of normal versus transformed cells.Abbreviations DHE
Dihematoporphyrin Ether
- FCS
Fetal Calf Serum
- HPD
Hematoporphyrin Derivative
- PDT
Photodynamic Therapy 相似文献
4.
A firm, mobile, oblong mass was discovered as an incidental finding in the stomach of a chimpanzee (Pan troglodytes) during routine surgery. It was removed and determined to be a trichobezoar. 相似文献
5.
Patrick T. Curry Terry Ziemer Gerhard Van der Horst Warren Burgess Monte Straley Robert W. Atherton Robert M. Kitchin 《Molecular reproduction and development》1989,22(1):27-36
Ejaculated sperm from the domestic ferret (Mustela putorius furo) and the black-footed ferret (Mustela nigripes) were compared for differences in morphological abnormalities and argentophilic protein distribution. Thawed domestic ferret sperm was also compared to fresh sperm to determine whether there were any effects on cell morphology due to cryopreservation. There were statistically significant differences between the two species of ferret in two of the categories scored. The domestic ferret had a higher frequency of cells that were bent in the midpiece and in the principal piece, and a higher frequency of headless and tailless cells when compared to the black-footed ferret. There were no statistically significant differences in cell morphology between the fresh and cryopreserved ejaculates of the domestic ferret employing a standard egg yolk cryoextender. Silver nitrate staining distribution was different between the two species in both the head and tail region. 相似文献
6.
Fertilizers labelled with 32P were used to measure amounts of phosphorus, Ps and PF, taken up by Lolium perenne from available soil P and from P fertilizer respectively, when applied at a rate of 66 mg P·(kg soil–1) in greenhouse experiments. The quantity Ps of phosphorus taken up from soil in the presence of P fertilizer was compared to the quantity Po taken up from soil without P fertilizer. The quantity (Ps–Po) is positive for low Po values, i.e. in soils poor in available phosphorus, but is negative for high Po values indicating that an input of P fertilizer can induce a decrease in the utilization of available soil phosphorus. Moreover, for a given soil, the quantity (Ps–Po) depends on the chemical form of the fertilizer. The standard method of evaluation of P fertilizer efficiency is based on the assumption that Ps=Po, but Ps can differ from Po. This result can explain the contradictory data published from field experiments about the efficiency of the various P fertilizers. 相似文献
7.
Full and reduced models for yield trials 总被引:2,自引:0,他引:2
H. G. Gauch Jr. 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,80(2):153-160
Summary Empirical results routinely demonstrate that the reduced Additive Main effects and Multiplicative Interaction (AMMI) model achieves better predictive accuracy for yield trials than does the full treatment means model. It may seem mysterious that treatment means are not the most accurate estimates, but rather that the AMMI model is often more accurate than its data. The statistical explanation involves the Stein effect, whereby a small sacrifice in bias can produce a large gain in accuracy. The corresponding agricultural explanation is somewhat complex, beginning with a yield trial's design and ending with its research purposes and applications. In essence, AMMI selectively recovers pattern related to the treatment design in its model, while selectively relegating noise related to the experimental design in its discarded residual. For estimating the yield of a particular genotype in a particular environment, the AMMI model uses the entire yield trial, rather than only the several replications of this particular trial, as in the treatment means model. This use of more information is the source of AMMI's gain in accuracy.This research was supported by the Rhizobotany Project of the USDA-ARS 相似文献
8.
.熊治廷;.黄德世;.王徽勤;.孙祥钟 《武汉植物学研究》1990,8(1):47-52
用R聚类分析和主分量分析,定量研究了湖北菱科5种8变种37个形态和生态性状的变异及分类学价值。结果表明,植物体大小变异是形态演化的主要方向之一。形态演化的同时,也发生生态分化。除少数性状例外,形态演化与生态分化在相当程度上是独立的。 相似文献
9.
以往研究流域开发战略问题,多从流域内资源的开发利用方面考虑,而衡量其方案的优劣也多以经济效益的大小为准绳。现在,环境污染与生态危机已威胁着人类的生存与发展,因此在研究流域战略问题时,必须开拓思路, 相似文献
10.
腐霉属分类性状评价及其中国的种 总被引:1,自引:0,他引:1
本文对腐霉属Pythium Pringsheim的研究历史作了简单的回顾,对该属的分类性状和系统进行了论述和评价,最后对中国已发现的55种腐霉,以检索表的方式进行了分类、检索。 相似文献