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961.
962.
963.
优选了人凝血因子Ⅷ(FⅧ)制剂的冻干工艺。通过电阻法测定共晶点,再采用正交试验法,对预冻温度、主要干燥温度、主干燥时间、解析温度与真空压力等进行研究以优选冻干工艺,得到最佳的冻干工艺:-40℃预冻1.5 h;主要干燥温度从-40℃升温至-33℃,再从-33℃升温至0℃,总耗时36 h,真空压力为30 Pa;解析温度维持在35℃,真空压力为5 Pa,于终点测试压力无变化时结束。由于该工艺冻干出的人凝血因子Ⅷ制剂符合《中国药典》3部该项下的质量要求,经验证该冻干工艺能够应用于人凝血因子Ⅷ制剂的大规模生产。 相似文献
964.
《Basic and Applied Ecology》2014,15(1):59-65
Several studies in temperate forests have demonstrated effects of litter addition on decomposers and predators. However, adding litter does not allow separating the effects of food availability and habitat space. We investigated the response of decomposers and predators to increased food resources and space in forests of the southern Mata Atlântica of Brazil. In two forest ecosystems representing an early successional stage of secondary forests and old-growth forest, we added nutrient-rich organic material, artificial litter of no nutritional value, or a combination of both to the soil surface of 120 plots to separate the effects of habitat space and food on soil food webs. We sampled litter- and soil-dwelling arthropods after three months using pitfall traps, soil sample extraction, and sticky traps just above the soil. Adding artificial litter had no positive effect on any of the 17 analyzed arthropod groups. Combining all sampled arthropods the effect was even significantly negative. Adding food had a positive effect on the abundance of decomposers, but not predators. We found no interactions between added artificial litter and added organic material. Our results suggest that the soil fauna in tropical forests is food limited. The lack of a bottom-up effect on predators suggests that they are not predominantly regulated by the abundance of epigeic prey but rather by competition or predation. 相似文献
965.
Masaharu Kitano Kazuki Urayama Yoshinobu Sakata Yasutaka Sonoda Kenji Ebihara Yuki Sago Hisashi Yoshikoshi Takuya Araki Daisuke Yasutake Hiroyuki Cho Tetsuo Kobayashi 《Biologia》2009,64(3):474-477
Water deficit and salt accumulation in soil presents serious problems to crop production in semi-arid regions. These problems
depend on the active transpiration stream and the selective absorption of ions by crop roots. In this study, a large sized
soil column system was used to examine the dynamics of water and ion transport and salt accumulation in soil layers. Special
reference was placed on the effects of the active and selective absorption by roots of different crops (i.e., corn plants,
sunflower plants and no plants). The column system was equipped with on-line systems for the control of groundwater level.
Soil water content sensors enabled time-course evaluations of the volumetric water content and hence upward flux of the groundwater
in the soils at different depths. Furthermore, the distribution and accumulation of ions in soil layers, plant organs and
xylem sap were analyzed using ion chromatography. In this column experiment, diurnal and longer term changes in water movement
and ion accumulation in soil, affected by root absorption characteristics of plants, were evaluated quantitatively. The results
demonstrated that the column system was applicable for the quantitative analysis of the effects of root absorption by different
crops on water deficit and salinization in soils. 相似文献
966.
Wu-Jie Su Bing Li Wei-De Shen Yan Wu Shan-Ying Zhu Ying Sun Wen-Bing Wang 《Biologia》2009,64(2):383-387
Bombyx mori nucleopolyhedrovirus (BmNPV) orf4 has been shown to be expressed at very early stage of Bm-NPV infection cycle. In this study, using transient expression experiment,
we demonstrated for the first time that orf4 promoter is an immediate early promoter, indicating that orf4 may play a role in the immediate-early stage of BmNPV infection. Moreover, with the recently developed Bac-to-Bac/BmNPV baculovirus
expression system and a modified pFast-Bac1 whose polyhedrin promoter was replaced with orf4 promoter, a recombinant bacmid baculovirus expressing enhanced green fluorescent protein (EGFP) under the control of orf4 promoter in Bombyx mori (Bm) cells was successfully constructed. The result not only showed that the polyhedrin promoter can be replaced easily with
other promoters to direct the expression of foreign genes by using this novel system but also laid the foundation for the
rescue experiment of orf4 deletion mutant. 相似文献
967.
We studied the demography of Viola elatior, V. pumila, and V. stagnina, three rare and endangered Central European floodplain species, to (i) analyse variation in life-cycles among congeners and
between regions (Dyje-Morava floodplains, Czech Republic; Upper Rhine, Germany), (ii) to define sensitive stages in the life-cycles,
and (iii) to identify possible threats for population viability and species conservation.
Matrix models were based on the fate of marked individuals from a total of 27 populations over two years. We analysed population
growth rate (λ), stage distribution, net reproductive rate (R
0), generation time, age at first reproduction, and elasticity and calculated a life table response experiment (LTRE).
Most populations were declining and λ did not differ between species or regions during the observed interval. Despite higher probabilities for survival and flowering
in the Dyje populations, R
0 was higher in the Rhine populations. Also other demographic traits showed consistent differences between regions and/or species.
Complex life-cycles and large variation in λ precluded unequivocal identification of sensitive stages or vital rates for conservation. Variation between regions may be
a consequence of differences in habitat quality.
Our results suggest that deterministic processes such as reduced management, succession, habitat destruction, and lack of
disturbance through reduced or eliminated flooding present the strongest threat for the viability and persistence of populations
of the three floodplain violets as compared with stochastic processes. However, the persistent seed bank of the species may
buffer populations against environmental variation and represents a reservoir for recovery after resumption of suitable land-use
management. 相似文献
968.
Contrasting impacts of invasive engineers on freshwater ecosystems: an experiment and meta-analysis 总被引:1,自引:0,他引:1
Invasion by common carp (Cyprinus carpio) and red swamp crayfish (Procambarus clarkii) in shallow lakes have been followed by stable-state changes from a macrophyte-dominated clear water state to a phytoplankton-dominated
turbid water state. Both invasive carp and crayfish are, therefore, possible drivers for catastrophic regime shifts. Despite
these two species having been introduced into ecosystems world-wide, their relative significance on regime shifts remains
largely unexplored. We compared the ecological impacts of carp and crayfish on submerged macrophytes, water quality, phytoplankton,
nutrient dynamics, zooplankton and benthic macroinvertebrates by combining an enclosure experiment and a meta-analysis. The
experiment was designed to examine how water quality and biological variables responded to increasing carp or crayfish biomass.
We found that even at a low biomass, carp had large and positive impacts on suspended solids, phytoplankton and nutrients
and negative impacts on benthic macroinvertebrates. In contrast, crayfish had a strong negative impact on submerged macrophytes.
The impacts of crayfish on macrophytes were significantly greater than those of carp. The meta-analysis showed that both carp
and crayfish have significant effects on submerged macrophytes, phytoplankton, nutrient dynamics and benthic macroinvertebrates,
while zooplankton are affected by carp but not crayfish. It also indicated that crayfish have significantly greater impacts
on macrophytes relative to carp. Overall, the meta-analysis largely supported the results of the experiment. Taken as a whole,
our results show that both carp and crayfish have profound effects on community composition and ecosystem processes through
combined consequences of bioturbation, excretion, consumption and non-consumptive destruction. However, key variables (e.g.
macrophytes) relating to stable-state changes responded differently to increasing carp or crayfish biomass, indicating that
they have differential ecosystem impacts. 相似文献
969.
CHRISTIAN A. HAGEN BRETT K. SANDERCOCK JAMES C. PITMAN ROBERT J. ROBEL ROGER D. APPLEGATE 《The Journal of wildlife management》2009,73(8):1325-1332
ABSTRACT The lesser prairie-chicken (Tympanuchus pallidicinctus) is currently considered a candidate for protection under the Endangered Species Act. To identify potential limiting factors for lesser prairie-chicken populations, we developed an age-based matrix model of lesser prairie-chicken population dynamics to compare the relative importance of components of reproduction and survival, and determine if various management alternatives stabilize or increase rates of population change. We based our analyses on an intensive 6-year population study from which demographic rates were estimated for each age class in Kansas. We used deterministic models and elasticity values to identify parameters predicted to have the greatest effect on the rate of population change (λ) at 2 study sites. Last, we used life-stage simulation analysis to simulate various management alternatives. Lambda was <1 for both populations (site 1: λ = 0.54, site 2: λ = 0.74). However, we found differences in sensitivity to nest success and chick survival between populations. The results of the simulated management scenarios complemented the lower-level elasticity analysis and indicated the relative importance of female survival during the breeding season compared with winter. If management practices are only capable of targeting a single demographic rate, changes to either nest success or chick survival had the greatest impact on λ at site 1 and 2, respectively. Management that simultaneously manipulated both nest success and chick survival was predicted to have a greater effect on λ than changes in survival of adult females. In practice, our demographic analyses indicate that effective management should be based on habitat conservation measures to increase components of fecundity. 相似文献
970.
Anthropogenic climate change is predicted to cause widespread biodiversity loss due to shifts in species' distributions, but these predictions rarely incorporate ecological associations such as zonation. Here, we predict the decline of a diverse assemblage of mid-latitude salt marsh plants, based on an ecosystem warming experiment. In New England salt marshes, a guild of halophytic forbs occupies stressful, waterlogged pannes. At three sites, experimental warming of < 4 °C led to diversity declines in pannes and rapid takeover by a competitive dominant, Spartina patens . In Rhode Island, near their southern range limit, pannes were more sensitive to warming than farther north, and panne area also declined in control plots over the three-season experiment. These results suggest that warming will rapidly reduce plant diversity in New England salt marshes by eliminating a high diversity zone. Biodiversity in zoned ecosystems may be more affected by climate-driven shifts in zonation than by individual species' distribution shifts. 相似文献