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71.
[目的]对基于CO Ⅱ全基因的差翅亚目昆虫的分子系统学进行研究。[方法]设计蜻蜓目昆虫CO Ⅱ全基因的非特异性引物,获得差翅亚目5科6属8种共8条CO Ⅱ全序列。采用CluxtalX1.8、ContigExpress、MEGA2.1、PHYLIP3.6a以及MrBayes V3.0等生物学软件及简约法和最大似然法对其进行分析并构建分子系统树。[结果]CO Ⅱ的A+T含量较低(68.6%),说明蜻蜓目是一比较原始的类群;每条序列均含有2个半胱氨酸,这一点有别于其他类群昆虫;不支持将大蜻亚科上升为科的观点;支持将大蜓科和蜓科归入蜓总科,而将春蜓科上升为总科的观点;差翅亚目5科之间的进化关系由慢到快依次为:春蜓科→大蜓科→蜓科→伪蜻科→蜻科。[结论]为蜻蜓目分子系统学研究提供相关依据。 相似文献
72.
N. Gosman† Srinivasachary A. Steed E. Chandler M. Thomsett P. Nicholson 《Plant pathology》2010,59(1):147-157
A series of experiments was conducted to determine whether type I resistance (resistance to initial infection) to fusarium head blight (FHB) in wheat could be assessed using fungal species/isolates that do not produce deoxynivalenol (DON), a mycotoxin critical to the spread of Fusarium graminearum in the wheat spike. It was shown that, while the non-toxin-producing species Microdochium nivale and M. majus could infect following spray inoculation of wheat spikes, they were unable to spread within the spike following point inoculation. However, although these species might reveal type I resistance, they are not highly pathogenic towards wheat. A nivalenol (NIV)-producing isolate of F. graminearum caused high levels of disease following spray inoculation, but spread only very slowly within the spike and rarely induced bleaching above the point of inoculation. It is proposed that spray inoculation with an appropriate, aggressive, non-DON-producing FHB pathogen may be used to characterize type I resistance to complement point inoculation with a DON-producing isolate to assess type II resistance (resistance to spread within the spike). 相似文献
73.
Li. Li Xi. Chen Daoyong Zhang Xiangliang Pan 《Pesticide biochemistry and physiology》2010,98(2):300-304
Effects of insecticide acetamiprid on photosystem II (PSII) activity of Synechocystis sp. were investigated by a variety of in vivo chlorophyll fluorescence tests. Acetamiprid exposure increased the proportion of inactivated PSII reactive centers (PSIIX) and led to loss of active centers (PSIIA). High concentration (1.0 mM) acetamiprid decreased amplitude of the fast phase and increased the slow phase of fluorescence decay during reoxidation. The electron transport after QA was hindered by high concentration acetamiprid and more QA had to be reoxidized through S2(QAQB)− charge recombination. Acetamiprid decreased the density of the active reaction centers, electron transport flux per cross section and the performance of PSII activity but had little effect on dissipated energy flux per reaction center, antenna size and the maximum quantum yield for primary photochemistry (Fv/Fm). The target site of acetamiprid toxicity to the PSII of Synechocystis sp. was electron transfer on the acceptor side. 相似文献
74.
75.
Kerry McLaughlin Julian Seago Lucy Robinson Charles Kelly Bryan Charleston 《Veterinary research》2010,41(3)
Foot-and-mouth disease virus (FMDV) is the causative agent of a highly contagious acute vesicular disease affecting cloven-hoofed animals, including cattle, sheep and pigs. The current vaccine induces a rapid humoral response, but the duration of the protective antibody response is variable, possibly associated with a variable specific CD4+ T cell response. We investigated the use of heat shock protein 70 (Hsp70) as a molecular chaperone to target viral antigen to the Major Histocompatibility Complex (MHC) class II pathway of antigen presenting cells and generate enhanced MHC II-restricted CD4+ T cell responses in cattle. Monocytes and CD4+ T cells from FMDV vaccinated cattle were stimulated in vitro with complexes of Hsp70 and FMDV peptide, or peptide alone. Hsp70 was found to consistently improve the presentation of a 25-mer FMDV peptide to CD4+ T cells, as measured by T cell proliferation. Complex formation was required for the enhanced effects and Hsp70 alone did not stimulate proliferation. This study provides further evidence that Hsp70:peptide complexes can enhance antigen-specific CD4+ T cell responses in vitro for an important pathogen of livestock. 相似文献
76.
Kristine L. Vernon Laura Riggs Josie Coverdale Ashbey Budd Bodine John Gibbons 《Journal of Equine Veterinary Science》2010
Excessive exercise may induce osteoarthritis, which is a leading cause of lameness and decreased use in horses. The purpose of this study was to utilize a sheep model to determine the effects of circular and linear exercise on biochemical markers in serum and synovial fluid (SF). Twenty lambs (5 months) were assigned to three groups: circular exercise (C, 8.5 m diameter; n = 8), straight-line exercise (S, treadmill; n = 8) and nonexercised control (CON, n = 4). Lambs (C and S) were exercised up to 8 weeks at 1.3 m/s for up to 30 minutes, 6 days per week. Serum and SF from a metacarpophalangeal (MCP) joint was collected. Serum total protein (P = .66), Collagen Type II cleavage [3/4] fragments concentrations (P = .44) and lysyl oxidase (LOX) (P = .15) activity were not different among treatment groups throughout the study. There was a polynomial response to serum LOX over time (R2 = 0.7464). There were no differences in SF total protein (P = .94, right MCP; P = .68, left MCP) or SF LOX specific activities (P = .9, right MCP; P = .93, left MCP) among groups throughout the study. However, SF LOX specific activity did increase over time (P = .001) for all treatment groups. These results indicated that the biochemical markers utilized in this study were unable to detect differences between groups with respect to exercise protocols. However, the LOX activity did increase over time possibly as a result of growth. 相似文献
77.
78.
研究了一类具HollingII型功能性反应的捕食者一食饵系统非平凡周期解的存在性,其中捕食者种群具有密度制约,食饵种群服从Hallam增长,得到了存在正周期解的充分性条件. 相似文献
79.
硒对低温胁迫下番茄幼苗叶片光合特性与叶绿素荧光参数的影响 总被引:3,自引:1,他引:2
以加工番茄‘里格尔87-5’幼苗为试材,对其外施0.3、0.6、0.9、1.2mgSe? kg-1Na2SeO3的溶液,并进行昼(12±1)℃/夜(8±1)℃的低温胁迫处理。研究硒对低温胁迫下加工番茄幼苗叶片光合作用及叶绿素荧光参数的影响。结果表明:随着低温胁迫时间的延长,番茄幼苗叶片净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)和胞间CO2浓度(Ci)减小;叶片初始荧光(Fo)、非光化学荧光猝灭系数(qN)上升;最大荧光(Fm)、PSⅡ最大光化学效率(Fv/Fm)、PSⅡ潜在活性(Fv/Fo)、光化学猝灭系数(qP)表现下降。不同浓度的硒溶液可以缓解低温胁迫对番茄幼苗光合作用和叶绿素荧光参数的影响,并且以0.9mgSe?kg-1Na2SeO3 的作用效果最好。 相似文献
80.
This study describes a successful method of somatic embryogenesis and genetic transformation using immature cotyledons of Prunus mume. Immature cotyledons from four different developmental stages of eight different P. mume cultivars were used for the experiments to optimize somatic embryogenesis and genetic transformation protocols. Somatic embryogenesis was induced when the explants were cultured on somatic embryo inducing medium consisting of MS basic medium supplemented with 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 1 μM 6-benzyladenine (BA). They were cultured for 30 days and then transferred to somatic embryo propagation medium containing 0.1 μM α-naphthaleneacetic acid (NAA) and 5 μM BA. It appeared that the developmental stage of the immature cotyledons used as explants was the most important factor for somatic embryogenesis; higher frequencies of somatic embryogenesis were observed when the immature cotyledons were less than 5 mm in length regardless of cultivars. For genetic transformation, the immature cotyledons were inoculated with Agrobacterium tumefaciens EHA101 harbouring a binary plasmid vector with neomycin phosphotransferase II and an intron-interrupted β-glucuronidase gene under the control of cauliflower mosaic virus 35S promoter, and three transgenic plant lines were obtained from inoculated “Sirakaga” immature cotyledons. Transgenic somatic embryos and shoots were selected using 25 mg l−1 kanamycin. Integration of transgenes in the genome of GUS-positive putative transgenic shoots was confirmed by PCR and Southern blot analyses. 相似文献