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61.
江西珍稀濒危植物优先保护定量研究 总被引:14,自引:1,他引:13
以江西省50种珍稀濒危植物为定量研究对象,采用以濒危系数、遗传价值系数、物种价值系数和生物学特征系数4个指标构成的珍稀濒危植物等级综合评价值的方法对上述植物优先保护顺序进行了定量研究。对50种珍稀植物进行排序的结果基本符合《中国珍稀濒危植物》和《中国植物红皮书》第1册的分析,但也有不同:属一级保护的有长柄双花木、天目木姜子和长序榆等共10种,占研究物种总数的20.00%,其中有浙江楠和华东黄杉等2渐危种;二级保护的有胡豆莲、连香树、伯乐树、银钟花等共26种,占52.00%,其中胡豆莲属于濒危种;三级的有小花木兰、观光木等12种,占24.00%,其中有4种属稀有种,8种属渐危种;此外,八角莲、野大豆等在江西可以暂不列入保护,这两者均属渐危种,占4.00%。 相似文献
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63.
Yu-Min Song Jun-Peng Xu Qian Hou Zao-Long Zhu 《Journal of inorganic biochemistry》2009,103(3):396-400
Three new solid complexes have been synthesized by the reaction of rare earth(III) nitrate with the first ligand curcumin (HL) and the second ligand 1,10-phenanthroline-5,6-dione (L′) in alcohol solution (pH = 6.5-7.0). The composition of the complexes has been characterized by elemental analysis, molar conductivity, thermogravimetric analysis, IR, UV-vis methods. The results reveal that β-diketone group of the first ligand to coordinates with rare earth ions in bidentate mode after deprotonated. But the second ligand uses its two N atoms coordinates with rare earth ions in bidentate mode. The general formula of the complexes is REL3L′ (RE = Sm, Eu, Dy). The results of antibacterial activity indicated that the complexes have excellent antibacterial ability for the testing bacterium than that of curcumin. The result of agarose gel electrophoresis suggested that the complex of SmL3L′ can cleave the plasmid DNA at physiological pH and temperature. And it was found that the cleavage process of plasmid DNA was sensitive to pH, however, adding radical scavengers almost had no effect on the DNA cleavage reaction, therefore, the cleavage of DNA by SmL3L′ does not produce diffusible hydroxyl radicals via the Fenton reaction. 相似文献
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65.
Anna-Mária Cserg? Szilárd Nemes Dan Gafta László Demeter Sámuel Jakab 《Plant Ecology》2009,203(2):229-242
We modelled the effect of habitat heterogeneity on the abundance of the submediterranean Saponaria bellidifolia, a red list species in Romania. The study was designed at two scales: 100 and 0.5 m2. At larger scale, generalized additive models and canonical correspondence analysis were used to model the density of ramets,
whereas at microscale, binomial logistic regression was employed to model the species’ occurrence. S. bellidifolia abundance responded sensitively to habitat type (classified as “grassy”, “rocky” and “scree”), rather than to microclimatic
variables. At both scales, habitat type was the best predictor of ramet abundance, followed by slope and vegetation cover.
At 0.5 m2, soil depth was also a good predictor of species occurrence. The data revealed that screes are the most suitable habitats
for hosting relatively large populations of this rare species, because of occasional natural disturbances and presumably lower
interspecific competition. 相似文献
66.
Background: Habitat management for reproductively challenged rare species is a problem when there is insufficient knowledge of their autecology. This study investigated reproductive failure in the rare grass Calamagrostis porteri ssp. insperata (Swallen) C. Greene (Reed bentgrass). Does the management recommendation of high light stimulate clonal growth, flowering, and seed production? Location: Shawnee National Forest, IL, USA, and in a greenhouse and an experimental garden at Southern Illinois University, Carbondale, IL, USA. Methods: Clones obtained from the three known Illinois populations were grown in a glasshouse under experimental light and soil moisture treatments. After 3 years, plants from the high light treatment were planted outside in an experimental garden where the light treatments were maintained for two more years. In the field, vegetative and flowering tiller density, canopy cover, and associated biotic and abiotic variables including abundance of co‐occurring plant species were monitored for 5 years. The overhead tree canopy was cleared over a portion of one population. Results: In the glasshouse, plants increased in size under high light and moist soil, and there were size differences among populations. Sixty‐six per cent (20 of 30) of the genets flowered when planted outdoors under full sunlight but did not produce seed. In the field, flowering only occurred in Calamagrostis growing in the cleared area, but no seed were produced. The plants in the flowering population were smaller than plants in the other two populations. The herbaceous community associated with Calamagrostis in the open diverged from the communities remaining under the shade. Conclusions: This study highlights the difficulty of managing reproductively challenged rare species. Calamagrostis populations can be managed to enhance clonal growth, but establishment of new populations would require translocation of vegetative material as it is highly unlikely that seed can be obtained. 相似文献
67.
The Bankoualé Palm, Livistona carinensis is the only known species of Livistona occurring in Africa and is currently classified as vulnerable (IUCN 2004). This extreme outlier species of the genus is restricted to Yemen, Somalia and Djibouti, where all populations are in rapid
decline. In Djibouti the palm is confined to three valley systems within the upland plateau of the Goda Massif. This study
used microsatellite markers to investigate the genetic diversity and relationships within the species. At the species level
L. carinensis contained very low genetic diversity. Most variation was due to the variation between the samples from Yemen and Somalia
compared with those in Djibouti. The Djibouti populations were almost monomorphic across the nine loci tested. Interestingly,
and despite the small sample sizes, the individuals from botanic gardens collections of the Yemen and Somalia populations
were more genetically diverse than the Djibouti populations. This study indicates that the populations in Yemen and Somalia
are highly significant for the conservation of the species genetic diversity. Given the lack of genetic diversity both within
and among L. carinensis populations in Djibouti, plants could be cultivated for in-situ population enhancement from any seed that is available from
within Djibouti with no significant genetic impacts of provenance mismatch. Clearly the populations from Djibouti, Somalia
and Yemen are different genetic provenances raising some issues for the conservation and recovery of L. carinensis. 相似文献
68.
The chlamydiae are important human and animal pathogens which form a phylogentically distinct lineage within the Bacteria.
There is evidence that some genes in these obligate intracellular parasites have undergone lateral exchange with other free-living
organisms. In the present work, we describe two interesting cases of lateral gene transfer between chlamydiae and actinobacteria,
which have been identified based on the shared presence of conserved inserts in two important proteins. In the enzyme serine
hydroxymethyltransferase (SHMT or GlyA protein), which links amino acid and nucleotide metabolisms by generating the key intermediate
for one-carbon transfer reactions, two conserved inserts of 3 and 31 amino acids (aa) are uniquely present in various chlamydiae
species as well as in a subset of Actinobacteria and in the Treponema species. Similarly, in the enzyme UDP-N-acetylglucosamine enolpyruvyl transferase (MurA), which is involved in the synthesis of cell wall peptidoglycan, a 16-aa
conserved insert is specifically present in various sequenced chlamydiae and a subset of actinobacteria (i.e., Streptomyces, Actinomyces, Tropheryma, Bifidobacterium, Leifsonia, Arthrobacter, and Brevibacterium). To determine the phylogenetic depths of the GlyA and MurA inserts, the fragments of these genes from two chlamydiae-like
species, Simkania negevensis and Waddlia chondrophila, were PCR amplified and sequenced. The presence of the corresponding inserts in both these species strongly indicates that
these inserts are distinctive characteristics of the Chlamydiales order. In phylogenetic trees based on GlyA and MurA protein
sequences, the chlamydiae species (and also the Treponema species in the case of GlyA) branched with a high affinity with various insert-containing actinobacteria within a clade of
other actinobacteria. These results provide strong evidence that the shared presence of these indels in these bacteria is
very likely a consequence of ancient lateral gene transfers from actinobacteria to chlamydiae. Pairwise sequence identity
and the branching pattern of the GlyA homologues in the phylogenetic tree indicates that the glyA gene was initially transferred from an actinobacteria to an ancestor of the Treponema genus and from there it was acquired by the common ancestor of the Chlamydiales.
[Reviewing Editor: Dr. Siv Andersson] 相似文献
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70.
The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) was investigated by using various rare earth metal trifluoromethanesulfonates, that is, Yb(OTf)3, Sc(OTf)3, Ho(OTf)3, Sm(OTf)3, Nd(OTf)3 as catalysts in DMSO. It is found that the catalytic activity increases with decreasing ionic radius of rare earth metal cations. Among the examined catalysts, Sc(OTf)3 exhibits the highest catalytic activity. Fructose conversion of 100% and a HMF yield of 83.3% are obtained at 120 °C after 2 h by using Sc(OTf)3 as the catalyst. Moreover, the catalytic dehydration of fructose was also carried out in different solvents, for example, DMA, 1,4-dioxane, and a mixture of PEG-400 and water. The results show that among the solvents DMSO is the most efficient in promoting the dehydration of fructose to HMF, and no rehydration byproducts such as levulinic acid and formic acid are detected. 相似文献