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991.
以波兰引进花楸嫩茎为试验材料,利用组织培养技术,筛选出诱导分化、继代增殖和生根的最佳培养基。结果表明:芽继代增殖培养基为:wpm+6-BA 1.0mg/L+NAA 0.1mg/L+2%蔗糖,pH=5.8;最佳壮苗培养基为wpm+6-BA 0.2mg/L+NAA 0.5mg/L;生根适宜培养基为wpm+NAA 0.5mg/L,生根率达98%。  相似文献   
992.
以棉花秸秆为原料,采用KOH活化法制备活性炭样品,探讨了炭化、活化及后处理过程中各实验条件对活性炭样品性能的影响。综合考虑活性炭样品的性能及得率,得出较优的实验条件为:炭化温度450~500℃、碱炭比值1.0、活化温度800℃、活化时间120 min;在较优条件下制得活性炭的比表面积2 312 m2/g,碘吸附值1 936 mg/g,亚甲基蓝吸附值392 mg/g;孔径分布以微孔为主;表面含有羟基(—OH)、活泼氢(—H)等基团。  相似文献   
993.
不同竹种竹醋液组分分析   总被引:2,自引:0,他引:2  
利用气-质联用仪和ICP-OES型等离子发射仪对雷竹(Phyllostachyspraecox)、白夹竹(Phyllostachys nidularia)、斑竹(Phyllostachys bambusoidesf)、赤竹(Sasa longiligula McClure)4种竹醋液的组分含量、微量元素进行了测定与分析。结果表明:(1)4种竹醋液组分含量、有机物种类各不相同。斑竹含有81种有机物,白夹竹75种,赤竹76种,雷竹61种,主要包括有机酸类、酚类、酮类、醇类、醛类、酯类及少量其它物质。(2)从K、Ca、Na、Mg元素的含量来看,雷竹的含量最高,斑竹含量最低;重金属Hg、Cd、Se基本没有,重金属As、Pb、Cr、Co等含量各不同。(3)不同竹种的竹醋液化学组分、含量和微量元素各不同,应根据不同的用途进行合理选择竹醋液。  相似文献   
994.
Tree-ring width chronologies of Larix chinensis were developed from the northern and southern slopes of the Qinling Mountains in Shaanxi Province,and climatic factors affecting the tree-ring widths of L.chinensis were examined.Correlation analysis showed that similar correlations between tree-ring width chronologies and climatic factors demonstrated that radial growth responded to climate change on both slopes.The radial growth of L.chinensis was mainly limited by temperature,especially the growing season.In contrast,both chronologies were negatively correlated with precipitation in May of the previous year and April of the current year.Spatial climate-correlation analyses with gridded land-surface climate data revealed that our tree-ring width chronologies contained a strong regional temperature signal over much of northcentral and eastern China.Spatial correlation with seasurface temperature fields highlights the influence of the Pacific Ocean,Indian Ocean,and North Atlantic Ocean.Wavelet coherence analysis indicated the existence of some decadal and interannual cycles in the two tree-ring width chronologies.This may suggest the influences of El Nin˜o-Southern Oscillation and solar activity on tree growth in the Qinling Mountains.These findings will help us understand the growth response of L.chinensis to climate change in the Qinling region,and they provide critical information for future climate reconstructions based on this species in semi-humid regions.  相似文献   
995.
自20世纪80年代始,衢州市各县(市、区)逐渐推广毛竹低产林改造技术,为竹林增产增效打下了基础。但是,由于改制后的毛竹林地被挖锄,天敌资源锐减,竹林中年年有笋,立竹上终年披叶,使竹子害虫食物条件改善,致使竹子害虫种类、数量增加,危害逐年加重。通过害虫种群变动分析,可以为开展竹林病虫害综合防治提供有效的应对措施。  相似文献   
996.
Molecular genetic strategies for species identification   总被引:2,自引:0,他引:2  
This paper probes into the molecular genetic mechanism of the formation of species, subspecies and variety in evolving progression, and brings forward 5 criteria of an ideal strategy in species identification: stating the specific characteristics at species, subspecies and variety level without any interference of too high polymorphism at individual or population level; keys should be distributed as 0 or 1, e. g. yes or no; satisfying repeatability and simple operation; high veracity and reliability; adaptability to widely various specimen. Respectively, this paper reviews two strategies focusing on detecting the fragment length polymorphism and base replacement and lays out some detail methods under above strategies. It demonstrates that it is not possible to solve all species problems by pursuing identification with only a single gene or DNA fragment. Only based on thorough consideration of all strategies, a method or combined several methods could bring satisfying reliability. For advanced focuses, it requires not only development and optimization of methods under above strategies, but also new originality of creative strategies.  相似文献   
997.
杜松赤枯病病原菌的研究   总被引:2,自引:0,他引:2  
阐述了杜松赤枯病病原菌的研究结果 ,研究表明交链孢 (Alternariasp )和茎点霉 (Phomasp )是杜松赤枯病的主要致病真菌 ;两种病原菌均喜偏酸性的条件 ,菌丝生长发育的适宜pH值是 5~ 7;菌丝生长的适宜温度是 2 0~ 30℃ ,孢子萌发的适宜温度是 15~ 2 5℃ ,2 0℃时萌发率最高 ;Al ternariasp 在相对湿度 90 %以上能较好萌发 ,Phomasp 在湿度 10 0 %时才能萌发 ,在水滴中萌发率最高 ;两种病原菌对云杉和丹东桧的嫩枝叶也有较强的致病性  相似文献   
998.
The forage quality of pasture species is spatially heterogeneous. In this study, we evaluated the dynamics and spatial structure of forage quality and attempted to relate the observed variation to differences in light availability and soil properties. We compared grass forage quality in open grasslands with forest edge environments and established plots in open Japanese grasslands surrounded by secondary forests. We sampled Anthoxanthum odoratum L. and soil from each plot in May and September. These samples were analyzed to determine the crude protein (CP), neutral detergent fiber, and mineral concentrations. We calculated Moran’s I coefficients across discrete lag distance classes to construct autocorrelograms. The CP model showed a non-random pattern in May at a lag distance of 40 m, but a clustered pattern in September at a small scale. The mineral models produced similar clustered spatial patterns. We found no strong correlation between aboveground (plant) and belowground (soil) mineral contents. CP and some mineral element concentrations in the plants collected in September were significantly greater at the forest edge than in open grasslands. The forest edge therefore appears to be a valuable place to provide grazing animals with adequate protein and mineral intake during the later part of the growing season.  相似文献   
999.
蓝莓是具有较高经济价值和广阔开发前景的新兴果树树种,发展蓝莓产业是富民兴市的好项目。对伊春市蓝莓产业的发展现状进行了分析,提出了今后一个时期发展蓝莓产业的建议。  相似文献   
1000.
To improve its overall performance, fast-growing poplar was modified using the vacuum-pressure-vacuum impregnation method with a urea-formaldehyde resin-sodium montmorillonite intercalation as the modification solution. The results showed that considerable amounts of urea-formaldehyde resin and montmorillonites entered the poplar tracheid, and some entered the microporous wood. These substances formed bonds with the active groups in timber, causing reduced crystallinity in the amorphous region of the poplar, a decreased level of free hydroxyl, and an enhanced association with hydroxyl and ether bonds. The density, dimensional stability, and mechanical properties of poplar were markedly improved. The best results were obtained with 14% sodium montmorillonite and 20% ureaformaldehyde resin: the bending resistance, compressive resistance, and elastic modulus increased by 19.37%, 30.24%, and 50.06%, respectively. With elevated levels of sodium montmorillonite, the impact toughness and wear rate decreased.  相似文献   
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