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71.
GIS支持下安徽省近35 a参考作物蒸散量的时空变化 总被引:8,自引:4,他引:4
参考作物蒸散量是重要的水分资源分量。为了研究气候变化条件下安徽省参考作物蒸散量的变化,采用联合国粮农组织(FAO)1998年推荐的Penman-Monteith法,利用安徽省79个台站1971-2005年的气象观测资料,计算站点参考作物蒸散量。在此基础上采用克里格插值方法,生成基于GIS的安徽省参考作物蒸散量分布图。分析结果表明:安徽省近35a平均参考作物蒸散量空间分布特征为,平原大、山区小;由北向南逐渐递减,受气候、地形等因素的影响,具有较明显的地域性差异;从时间尺度上看,自1971年以来,参考作物蒸散量总体上呈随年代波动下降趋势,但存在地区差异;年内季节变化为夏季>春季>秋季>冬季;逐月变化呈单峰变化趋势,峰值出现在7月,5-8月份较多,11月至翌年2月最低,且不同区域之间存在着明显的差别。 相似文献
72.
掺砂对土壤水分入渗和蒸发影响的室内试验 总被引:7,自引:5,他引:2
通过掺砂调控农田土壤水分入渗和蒸发,对新疆干旱绿洲农田抑盐、保水及合理的掺砂制度制定具有重要意义。该研究以不同的掺砂率为影响因子进行土柱模拟试验,设置了4个掺砂率水平,分别是0(对照)、25%、50%、75%。结果表明:不同掺砂率条件下湿润锋和累积入渗量与入渗历时有显著地乘幂关系,影响顺序为75%>50%>25%>0,且在掺砂率≥25%影响幅度较大;不同掺砂处理对土壤水分蒸发过程同样也有显著地影响,随着掺砂率的增加,土壤蒸发显著减弱,随着掺砂率的增加,抑制土壤蒸发越强,且在掺砂率≥75%时有较大幅度影响。土壤在连续20 d蒸发过程中,各个处理的土壤累积蒸发量随时间的关系和Rose经验公式拟合度高; 不同掺砂处理能显著提高土壤掺砂层以下的土壤含水率,随着掺砂率的增加而增加,其中掺砂75%时最高。 相似文献
73.
采用PCR-SSCP和聚丙烯酰胺凝胶电泳(PAGE)技术检测类固醇21-羟化酶基因(steroid 21-hydroxylase,CYP21)10个外显子在山羊(Capra hircus)低繁殖力品种(安哥拉山羊和内蒙古绒山羊)、中等繁殖力品种(波尔山羊)和高繁殖力品种(济宁青山羊)中的碱基变异,同时研究该基因对济宁青山羊高繁殖力的影响.结果表明,10对引物中仅引物P10扩增片段存在多态性.对于P10扩增产物,在内蒙古绒山羊、波尔山羊和济宁青山羊中检测到AA、AB和BB基因型,在安哥拉山羊中检测到AA和AB基因型;测序分析发现,BB与AA基因型相比发生了A2789C、C2791A、G2818A、G2851C、G2852T和G2854A的突变,在第2821与2 822位发生了两个碱基CG的缺失突变,导致426~448位共有19个氨基酸发生改变;济宁青山羊BB和AB基因型产羔数最小二乘均值分别比AA基因型的多0.81只(P<0.05)和0.47只(P<0.05),BB和AB基因型之间差异不显著(P<0.05).研究结果初步表明CYP21基因的B等位基因是提高山羊产羔数的一个潜在有效的DNA标记. 相似文献
74.
Steven Alan Wakelin Guixin Chu Richard Lardner Yongchao Liang Mike McLaughlin 《Pedobiologia》2010,53(2):149-68
Long-term diversity-disturbance responses of soil bacterial communities to copper were determined from field-soils (Spalding; South Australia) exposed to Cu in doses ranging from 0 through to 4012 mg Cu kg−1 soil. Nearly 6 years after application of Cu, the structure of the total bacterial community showed change over the Cu gradient (PCR-DGGE profiling). 16S rRNA clone libraries, generated from unexposed and exposed (1003 mg Cu added kg−1 soil) treatments, had significantly different taxa composition. In particular, Acidobacteria were abundant in unexposed soil but were nearly absent from the Cu-exposed sample (P<0.05), which was dominated by Firmicute bacteria (P<0.05). Analysis of community profiles of Acidobacteria, Bacillus, Pseudomonas and Sphingomonas showed significant changes in structural composition with increasing soil Cu. The diversity (Simpsons index) of the Acidobacteria community was more sensitive to increasing concentrations of CaCl-extractable soil Cu (CuExt) than other groups, with decline in diversity occurring at 0.13 CuExt mg kg−1 soil. In contrast, diversity in the Bacillus community increased until 10.4 CuExt mg kg−1 soil, showing that this group was 2 orders of magnitude more resistant to Cu than Acidobacteria. Sphingomonas was the most resistant to Cu; however, this group along with Pseudomonas represented only a small percentage of total soil bacteria. Changes in bacterial community structure, but not diversity, were concomitant with a decrease in catabolic function (BioLog). Reduction in function followed a dose-response pattern with CuExt levels (R2=0.86). The EC50 for functional loss was 0.21 CuExt mg kg−1 soil, which coincided with loss of Acidobacteria diversity. The microbial responses were confirmed as being due to Cu and not shifts in soil pH (from use of CuSO4) as parallel Zn-based field plots (ZnSO4) were dissimilar. Changes in the diversity of most bacterial groups with soil Cu followed a unimodal response - i.e. diversity initially increased with Cu addition until a critical value was reached, whereupon it sharply decreased. These responses are indicative of the intermediate-disturbance-hypothesis, a macroecological theory that has not been widely tested in environmental microbial ecosystems. 相似文献
75.
Two new A-type trimeric proanthocyanidins with two doubly bonded interflavanoid linkages, litchitannin A1 [epicatechin-(2β→O→7,4β→6)-epicatechin-(2β→O→7,4β→8)-catechin] (1) and litchitannin A2 [epicatechin-(2β→O→7,4β→6)-epicatechin-(2β→O→7,4β→6)-epicatechin] (2), were isolated from lychee (Litchi chinensis Sonn. cv. Heiye) seeds together with aesculitannin A (3), epicatechin-(2β→O→7,4β→8)-epiafzelechin-(4α→8)-epicatechin (4), proanthocyanidin A1 (5), proanthocyanidin A2 (6), proanthocyanidin A6 (7), epicatechin-(7,8-bc)-4β-(4-hydroxyphenyl)-dihydro-2(3H)-pyranone (8), and epicatechin (9). Their structures were elucidated on the basis of spectroscopic and chemical evidence. It is the first time that compounds 1-4, 7, and 8 have been reported in this species. Compounds 1-9 showed more potent antioxidant activity than L-ascorbic acid with ferric reducing antioxidant power (FRAP) values of 3.71-24.18 mmol/g and IC50 values of 5.25-20.07 μM toward DPPH radicals. Moreover, litchitannin A2 (2) was found to exhibit in vitro antiviral activity against coxsackie virus B3 (CVB3) and compounds 3 and 6 displayed antiherpes simplex virus 1 (HSV-1) activity. 相似文献
76.
Organic residues provide the fundamental energy supply supporting soil fungal communities. Provision of adequate energy is required for soil microbial communities to adapt and function in the presence of ecological stress, such as copper (Cu) contamination. However, contamination can also lead to decreased ecological fitness of microorganisms, limiting their ability to access substrates. Thus, complex interactions exist between substrates, metals, energy supply/accessibility, fungal communities and their processes, and these have implications for ecosystem processes. We investigated the interaction between energy resources and Cu tolerance on soil fungal communities, including Fusarium and Trichoderma (model disease causing and beneficial genera). Using quantitative PCR and DGGE fingerprinting, the effects of increasing soil Cu levels (0 to >3000 mg Cu kg−1 soil) on size and structure of soil fungal communities were tested under basal and plant-residue (medic; Medicago trunculata) added conditions. The interaction between increasing soil Cu levels and the addition of plant resources on fungal community structure was tested using multivariate analysis. The relative size (DNA copies per unit of soil DNA) of soil fungal communities, including Trichoderma and Fusarium, significantly (P < 0.05) increased (94% and 32% respectively) with addition of medic to soil. In medic-applied samples, the bacterial to fungal ratio decreased, demonstrating the selective influence of the cellulose-rich substrate on the fungal community. Under the high nutrient conditions fungal DNA increased as a fraction of the total soil DNA, demonstrating the tolerance of fungi to Cu (relative to other microbiota) given adequate energy resources. Copper had no impact on the abundance of Fusarium or Trichoderma, but significantly affected community structure (PERMANOVA; P < 0.05). With increasing Cu, species selection and replacement could be observed, particularly in soils where medic had been included. Plant residue addition itself was a highly selective factor affecting the structure of communities of Trichoderma and Fusarium (P < 0.05). The effects of increasing Cu could be seen in both medic and basal soils for Trichoderma, but only in the basal treatments for soil Fusarium. This was due to very low dispersion in Fusarium community structure in the medic-added treatment (PERMDISP; P < 0.05). The results show the interactive influence of organic matter inputs and heavy metal contamination on size and structure of soil fungal communities. The data show that species selection and replacement is an important mechanism for community adaptation to increasing levels of soil Cu, and this mechanism can be influenced by addition of resources to the soil. 相似文献
77.
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79.
25 ̄35年生兴安落叶松母树林丰产结构是密度为300株/hm^2,Ⅰ级木占75%、Ⅱ级木占25%;偏雌,中间型,偏雄母树比例为6:0:4,其球果产量为203kg/hm^2,种子品质也较好。在促进开花结实措施中,以环状砍皮方法效果较好,结实率为90%,单株产量提高60%;施肥中磷肥的效果显著,其施肥量为60g/m^2。 相似文献
80.
玫红百合为亲本育成百合种间杂种 总被引:49,自引:4,他引:45
玫红百合(Lilium amoenum Wilson ex Sealy)是起源于中国的珍稀百合。本试验以王百合和麝香百合为母本与玫红百合进行了种间杂交。以花柱内授粉和幼胚离体培养法得到了王百合×玫红百合杂种F_1和麝香百合×玫红百合杂种F_1。通过染色体组型分析确认了杂种的真实性。杂种王百合×玫红百合杂种F_1花朵为粉红色、株矮,可供盆栽,花粉不育。麝香百合×玫红百合杂种F_1花色淡粉红,诱导成多倍体后花粉可育,可作为进一步杂交的亲本。 相似文献