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141.
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花椒根腐病的成因分析 总被引:2,自引:0,他引:2
本文通过设立标准地定点调查,应用通径分析,揭示了影响花椒根腐病发生的 因素间的相互关系,其主导因素为土壤中病原菌的群体数量,并利用回归分析 建立了发病椒园花椒产量的预测模型。 相似文献
143.
AIM: To investigate the effects of puerarin on blood pressure in renovascular hypertensive rats, and to measure puerarin-induced changes of apelin-12, angiotensin II (Ang II) and nitric oxide(NO), the factors related to development of hypertension. METHODS: Sixty-five male Sprague-Dawley rats were used, of which 8 rats were randomly selected as sham operation group, and the remaining were used to make two-kidney, one-clip model. The rats that met the criterion for Goldblatt hypertensive rat model were randomly allocated into 5 groups: high-, middle- and low-dose puerarin groups, captopril group, and model group. The drugs were administered for 6 weeks. Blood pressure was measured every 2 weeks. Six weeks after treatment, all rats were sacrificed under deep anesthesia. Blood and kidney samples were collected. The level of apelin-12 in serum and kidneys was detected by ELISA. The level of Ang II in plasma and kidneys was measured by radioimmunoassay. NO level in serum was examined by nitrate reductase assay. RESULTS: Puerarin had an antihypertensive effect in a dose-dependent manner. Marked decreases in the level of serum apelin-12 in high- and middle-dose puerarin groups were observed(P<0.01). Puerarin at low dose did not cause obvious change in the content of apelin but still reached significant level (P<0.05). As the dose of puerarin went up, the level of apelin-12 in the kidneys was gradually decreased. Puerarin at high and middle doses obviously reduced the level of AngII in plasma, while purarin at low dose did not produce any significant effects. Puerarin at high and middle doses markedly increased the level of NO in serum, but puerarin at low dose did not induce any significant changes. CONCLUSION: Puerarin has an antihypertensive effect, and its mechanism may be related to inducing the changes of apelin, Ang II and NO, and regulating the balance among those factors. 相似文献
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猴头菌不同生长发育期粗蛋白、粗多糖含量及水溶性粗多糖体外免疫活性 总被引:2,自引:0,他引:2
测定猴头菌(Hericium erinaceus)华中猴头菌株不同生长发育期子实体中的粗蛋白、粗多糖和水溶性粗多糖中β-葡聚糖含量,并研究不同生长发育期子实体粗多糖体外刺激巨噬细胞产生NO的活性变化规律.结果表明,供试菌株不同生长发育期子实体的粗蛋白、粗多糖和β-葡聚糖含量以及粗多糖体外刺激巨噬细胞产生NO的活性均存在显著或极显著差异,随着生长发育的进行,猴头菌子实体中粗蛋白含量总体上呈下降的趋势(小菌剌期比前一时期有所增加),而多糖含量则总体呈上升趋势(小菌刺期比后一时期高),β-葡聚糖含量呈先快速上升后平稳的趋势;分裂期粗多糖在浓度500 μg/mL时对RAW264.7释放NO的促进作用较强. 相似文献
146.
The origin of carbonate accumulations in termite mounds is a controversial issue. This study is an attempt to elucidate the processes of carbonate precipitation in Macrotermes mounds built on Ferralsols in Upper Katanga, D.R. Congo, whereby a differentiation between pedogenic and inherited carbonates is considered. Carbonate features were investigated for a 9 m deep termite-mound profile, and for an 18 m wide cross-section through a termite mound and the adjacent soil, using field and laboratory techniques. Field evidence for a pedogenic origin includes morphological type (soft powdery materials, nodules, and coatings on ped surfaces) and distribution patterns of the carbonates. Thin-section studies reveal that the carbonates occur predominantly as impregnative orthic nodules and less commonly as coatings, both clearly pedogenic; calcareous pellets are interpreted as locally reworked pedogenic carbonates. X-ray diffraction (XRD), scanning electron microscopy/energy dispersive X-ray spectrometry (SEM-EDS) and stable isotope (δ13C) analyses show that all isolated carbonate features consist of high-Mg calcite (4.9-12.3 mol% MgCO3) with δ13C signatures ranging from − 13.2‰ to − 11.5‰. Weddellite (CaC2O4. 2H2O) is identified in a thin-section and by XRD analysis, and appears to be locally transformed into calcite. The stable isotope composition of carbon suggests that calcite precipitated in equilibrium with soil CO2 generated during decomposition of soil organic matter, and locally most likely during oxidation of oxalate. This study proves that carbonates which accumulated in Macrotermes mounds are pedogenic precipitates, whose deposition is partly related to microbial decay of organic matter, subsequently redistributed to some extent by abiotic dissolution-reprecipitation and termite activity. 相似文献
147.
Laccases of fungal origin have been intensively studied due to their importance in various biotechnological applications. There is a constant demand for new laccases with improved properties such as stability at higher temperatures or at an alkaline pH. Growing molecular evidence suggests that laccases may also be widespread in bacteria. While only a handful of bacterial laccases have been purified and characterized, several novel traits have already been discovered (e.g. pH-stability and 2-domain organization of the enzyme as opposed to the usual 3-domain structure of fungal laccases). The aim of this study was to examine the diversity of bacterial laccase-like genes in two types of high-organic peat soil using a cloning and sequencing approach. Gene libraries prepared of small fragments (150 base pairs) revealed an amazing diversity of bacterial laccases. The fragments clustered in 11 major lineages, and one third of the 241 sequences resembled laccase-like genes of Acidobacteria. Additionally, a new primer was used to retrieve several larger fragments of the putative bacterial laccase genes that spanned all four copper-binding sites. Both “conventional” 3-domain laccases and the recently described 2-domain small laccases have been obtained using this approach, demonstrating the potential of the primer. The present study thus contributes to the understanding of the diversity of bacterial laccases and provides a new tool for finding laccase-like sequences in bacterial strains and soil samples. 相似文献
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149.
通过免疫荧光获得雌激素α、β受体在体外星形胶质细胞(Acrocyte,AC)中表达的形态学证据;CCK-8法获得脂多糖(Lipopolysaccharide,LPS)激发AC的适宜浓度。在此基础上,研究了17β-雌二醇(17β-estradiol,E2)对AC的细胞活性、细胞周期和超微结构的影响。结果显示:E2作用AC 48h,10nmol/L E2可提高AC细胞活性和G2+S%(P〈0.05),而100,1 000nmol/L E2可降低AC细胞活性(P〈0.05),100nmol/L E2还可降低G2+S%(P〈0.05);100nmol/L E2作用AC 24,48,72h,均可降低AC细胞活性和G2+S%,以作用48h时抑制作用最强(P〈0.05);10nmol/L E2可引起AC线粒体数量增加,细胞核分裂增多,但线粒体、粗面内质网结构正常,而100nmol/L E2可导致AC线粒体肿胀或空泡化,粗面内质网扩张或断裂。结果表明,低浓度(10nmol/L)E2促进AC增殖;高浓度(100,1 000nmol/L)E2抑制AC增殖。 相似文献
150.