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951.
LCAccess is a U.S. Environmental Protection Agency sponsored web-site intended to promote the use of Life Cycle Assessments in business decision-making by facilitating access to data sources useful in developing a life cycle inventory (LCI). While LCAccess will not itself contain data, it will be a searchable global directory to potential data sources. In additional to directing users to relevant data sources, LCAccess will also serve as central source for LCA information. Development is currently being completed on LCAccess with an expected operational date of winter 2000/2001 for some features of the web-site. The LCI Global Directory is expected be fully functional by the summer of 2001. To find the LCAccess web-site in 2001 go to: www.epa.gov/LCAccess. LCAccess is currently soliciting organizations that have completed LCI/LCA studies to provide their data sources for reference in LCAccess. Inquiries should be directed to the development manager, Mr. Tim Skone (US 703/318-4745) and/or the EPA Sponsor, Ms. Mary Ann Curran (513/569-7782).  相似文献   
952.
Applications of biotechnology in eggplant   总被引:10,自引:0,他引:10  
Collonnier  C.  Fock  I.  Kashyap  V.  Rotino  G.L.  Daunay  M.C.  Lian  Y.  Mariska  I.K.  Rajam  M.V.  Servaes  A.  Ducreux  G.  Sihachakr  D. 《Plant Cell, Tissue and Organ Culture》2001,65(2):91-107
Eggplant (Solanum melongena L.), an economically important vegetable crop in many countries in Asia and Africa, often has insufficient levels of resistance to biotic and abiotic stresses. Genetic resources of eggplant have been assessed for resistance against its most serious diseases and pests (bacterial and fungal wilts, nematodes and shoot and fruit borer). Attempts at crossing eggplant with its wild relatives resulted in limited success due to sexual incompatibilities. However, the ability of eggplant to respond well in tissue culture, notably plant regeneration, has allowed the application of biotechnology, particularly the exploitation of somaclonal variation, haploidisation, somatic hybridisation and genetic transformation for gene transfer. Somaclonal variation has been used to obtain lines with increased resistance to salt and little leaf disease. Traits of resistance against bacterial and fungal wilts have successfully been introduced into the cultivated eggplant through somatic hybridisation. However, most somatic hybrids were sterile when the parental lines were distantly related. In contrast, the use of close relatives as fusion partners or highly asymmetric fusion resulted in the production of fertile hybrids with resistance traits and a morphology close to the cultivated eggplant, thus avoiding the series of backcrosses necessary for introgression of desired traits into eggplant. As far as molecular markers and genetic engineering are concerned, the information available for eggplant is very scanty. Two genetic linkage maps have been established by using RAPD and RFLP markers. In order to analyse the genetic relationships between eggplant and its relatives, some studies based on AFLP and ctDNA analyses have also been conducted. So far only resistance against insects, and parthenocarpic fruit development have successfully been developed in eggplant using Agrobacterium tumefasciens transformation. However, some work on genetic engineering of eggplant for other biotic and abiotic stresses has recently been initiated. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   
953.
果树核心种质研究进展   总被引:6,自引:0,他引:6  
近年来,继果树种质资源收集保存和鉴定评价等重大项目相继开展之后,利用现有基本信息、鉴定评价数据构建果树核心种质已成为种质资源领域又一新的研究热点和发展方向。根据核心种质的内涵和果树自身特点,提出了果树核心种质研究的主要特性,阐述了其主要研究内容、方法和步骤等研究现状,并通过分析果树核心种质构建的特殊性,指出存在的主要问题,探讨了果树核心种质研究的重点和发展方向。  相似文献   
954.
经过多年来的采集及最近集中考察,收集南岳山自然保护区大型真菌173种,分别隶属于15目、37科、83属,充分体现了种类方面的多样性.在生态特征方面,分布于常绿阔叶林、针阔叶混交林、竹林、常绿或落叶灌丛、针叶林、高山草甸等环境;其中腐生类型为主,有共生类型和寄生类型.在经济价值方面,有食用菌77种,药用菌43种,毒菌24种,木材腐朽菌93种,树木共生菌32种.另有省内新记录种18种.最后提出了保护和利用南岳山自然保护区大型真菌资源的建议.  相似文献   
955.
云南紫胶虫与粗纹举腹蚁之间的互利关系   总被引:2,自引:0,他引:2  
为了明确云南紫胶虫Kerria yunnanensis和粗纹举腹蚁Crematogaster macaoensis之间的相互作用关系, 于2009年4月至2010年10月, 在云南省墨江县雅邑乡紫胶种植园, 结合野外调查和室内试验对比研究了粗纹举腹蚁取食人工食物、 云南紫胶虫排泄的蜜露和无食物的3种处理下粗纹举腹蚁个体体重和存活率的变化, 以及在粗纹举腹蚁垄断蜜露、 自然条件下和无蚂蚁照顾的3种处理下云南紫胶虫个体怀卵量、 虫体大小、 死亡率和生活史周期的变化。结果显示: 云南紫胶虫排泄的蜜露是一种高质量的食物资源, 能够稳定增加粗纹举腹蚁工蚁的体重百分比[人工食物(44.55%)>蜜露(25.81%)>无食物(-4.13%)] (F(2,54)=18.81; P<0.01), 并提高其存活率[人工食物(85.78%)>蜜露(82.48%)>无食物(78.74%)] (F(2,55)=7.31; P<0.01)。粗纹举腹蚁取食蜜露的同时, 有利于增加单位面积上云南紫胶虫的雌虫数量[蚂蚁垄断蜜露(80.81%)>自然状态(75.55%)>无蚂蚁照顾(75.33%)] (F(2,143)=54.08; P<0.01), 提高云南紫胶虫的个体怀卵量[蚂蚁垄断蜜露(401.85粒)>自然状态(395.73粒)>无蚂蚁照顾(353.34粒)] (F(2,144)=4.82; P<0.01), 降低云南紫胶虫的死亡率[蚂蚁垄断蜜露(89.42%)<自然状态(89.78%)<无蚂蚁照顾(90.82%)] (F(2,146)=3.45; P<0.05); 云南紫胶虫虫体有变小的趋势[蚂蚁垄断蜜露(12.92 mm2)<自然状态(13.04 mm2)<无蚂蚁照顾(14.90 mm2)] (F(2,147)=10.88; P<0.01), 生活史周期变长[蚂蚁垄断蜜露(203.96 d)>无蚂蚁照顾(202.85 d)>自然状态(200.00 d)] (F(2,71)=19.77; P<0.01), 提示粗纹举腹蚁取食蜜露增加了云南紫胶虫的代谢压力。结果说明, 以蜜露为纽带的粗纹举腹蚁和云南紫胶虫之间的相互作用关系是兼性互利的。  相似文献   
956.
综述了中国的主要根茎型禾草的资源状况,其利用价值和与生产特性相关的研究概况,并对其研究和利用前景进行了展望与探讨。  相似文献   
957.
Amplified fragment length polymorphism (AFLP) and inter-simple sequence repeat markers were employed to characterize a genetic resource collection of Miscanthus, a grass under trial in Europe as a biomass crop. The 26 polymorphic markers produced by two ISSR fingerprinting primers were able to discriminate taxa and identify putative clones. AFLP fingerprints were fully reproducible and produced a larger number of markers for the three primer pairs tested, of which 998 were polymorphic (representing 79.3% of all bands). AFLP markers distinguished species, infra-specific taxa (varieties and cultivars) and putatively clonal material. They were also used to assess the inter-relationships of the taxa, to investigate the origin of important hybrid plants and to estimate the overall level of genetic variation in the collection. They were useful for assessing the species status of certain taxa such as M. transmorrisonensis, an endemic from Taiwan that was clearly distinct from M. sinensis; whereas other taxa of disputed species status, such as M. condensatus and M. yakushimanum were not genetically distinct from M. sinensis. The AFLP markers detected a high degree of infra-specific variation and allowed subdivisions of the genetic resource collection to be made, particularly within M. sinensis.  相似文献   
958.
The availability of the draft sequence of the chicken genome will undoubtedly propel an already important vertebrate research model, the domestic chicken, to a new level. This review describes aspects of chicken natural history and cross-disciplinary biological value. The diversity of extant genetic variants available to researchers is reviewed along with institutional stock locations for North America. An overview of the problem of lack of long-term stability for these resources is presented.  相似文献   
959.
公立医院规划布局是卫生资源配置极为最重要的一个环节。公立医院的合理配置、优化布局有助于提高医疗资源运行效率,使居民获得最大健康产出。从系统角度出发,要更好地配置公立医院资源,必须更好地发挥公立医院与社区卫生服务机构的协同作用,建立有序的分级诊疗模式。因此,文章结合全民健康覆盖的四个条件,对上海市黄浦区社区卫生服务作绩效评估与SWOT分析,为社区卫生服务的进一步发展提供建议,也为更好地配置公立医院资源提供参考。  相似文献   
960.
The aim of this paper is the study of the long-term behavior of population communities described by piecewise smooth models (known as Filippov systems). Models of this kind are often used to describe populations with selective switching between alternative habitats or diets or to mimic the evolution of an exploited resource where harvesting is forbidden when the resource is below a prescribed threshold. The analysis is carried out by performing the bifurcation analysis of the model with respect to two parameters. A relatively simple method, called the puzzle method, is proposed to construct the complete bifurcation diagram step-by-step. The method is illustrated through four examples concerning the exploitation and protection of interacting populations.  相似文献   
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