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171.
Danillo S Silva Susana SR Milhomem Julio C Pieczarka Cleusa Y Nagamachi 《BMC genetics》2009,10(1):1-8
Background
Previous studies suggested that multiple domestication events in South and South-East Asia (Yunnan and surrounding areas) and India have led to the genesis of modern domestic chickens. Ha Giang province is a northern Vietnamese region, where local chickens, such as the H'mong breed, and wild junglefowl coexist. The assumption was made that hybridisation between wild junglefowl and Ha Giang chickens may have occurred and led to the high genetic diversity previously observed. The objectives of this study were i) to clarify the genetic structure of the chicken population within the Ha Giang province and ii) to give evidence of admixture with G. gallus. A large survey of the molecular polymorphism for 18 microsatellite markers was conducted on 1082 chickens from 30 communes of the Ha Giang province (HG chickens). This dataset was combined with a previous dataset of Asian breeds, commercial lines and samples of Red junglefowl from Thailand and Vietnam (Ha Noï). Measurements of genetic diversity were estimated both within-population and between populations, and a step-by-step Bayesian approach was performed on the global data set.Results
The highest value for expected heterozygosity (> 0.60) was found in HG chickens and in the wild junglefowl populations from Thailand. HG chickens exhibited the highest allelic richness (mean A = 2.9). No significant genetic subdivisions of the chicken population within the Ha Giang province were found. As compared to other breeds, HG chickens clustered with wild populations. Furthermore, the neighbornet tree and the Bayesian clustering analysis showed that chickens from 4 communes were closely related to the wild ones and showed an admixture pattern.Conclusion
In the absence of any population structuring within the province, the H'mong chicken, identified from its black phenotype, shared a common gene pool with other chickens from the Ha Giang population. The large number of alleles shared exclusively between Ha Giang chickens and junglefowl, as well as the results of a Bayesian clustering analysis, suggest that gene flow has been taking place from junglefowl to Ha Giang chickens. 相似文献172.
Navendu V. Page Qamar Qureshi Gopal S. Rawat Cheppudira G. Kushalappa 《Plant Ecology》2010,206(2):237-250
The effect of fragmentation on different life forms within tropical forest plant communities is poorly understood. We studied
the effect of degree of fragmentation and surrounding matrix on trees, lianas, shrubs and epiphytes in tropical forest fragments
of Kodagu, Western Ghats, India. These fragments exist as sacred groves amidst a highly modified agricultural landscape, and
have been preserved by the religious sentiments of local communities. Plants were sampled at two sites in continuous forests
and 11 forest fragments. A total of 122 species of trees, 29 species of lianas, 60 species of shrubs and 66 species of epiphytes
were recorded. Trees exhibited a significant species–area relationship (R
2 = 0.74). Richness estimates after controlling for stem density (rarefaction) revealed that observed species–area relationship
was not an artefact of passive sampling. Variation in species richness of the other three groups was explained by stem density
and structural diversity. Linear distance from the reserve forest did not explain any variation in species richness. All life
forms exhibited significant nested pattern. Trees were nested along the area gradient while nestedness in the other three
groups showed evidence in support of habitat nestedness. The four life forms thus responded variably to degree of fragmentation.
Our study revealed that 74% of the regional diversity for trees was contributed by diversity among plots, highlighting the
importance of inter-patch habitat diversity in maintaining the total regional species pool. We conclude that trees alone cannot
serve as good indicator for taking appropriate conservation measures to mitigate species loss resulting from habitat fragmentation. 相似文献
173.
174.
Theta-defensins prevent HIV-1 Env-mediated fusion by binding gp41 and blocking 6-helix bundle formation 总被引:7,自引:0,他引:7
Gallo SA Wang W Rawat SS Jung G Waring AJ Cole AM Lu H Yan X Daly NL Craik DJ Jiang S Lehrer RI Blumenthal R 《The Journal of biological chemistry》2006,281(27):18787-18792
Retrocyclin-1, a -defensin, protects target cells from human immunodeficiency virus, type 1 (HIV-1) by preventing viral entry. To delineate its mechanism, we conducted fusion assays between susceptible target cells and effector cells that expressed HIV-1 Env. Retrocyclin-1 (4 microm) completely blocked fusion mediated by HIV-1 Envs that used CXCR4 or CCR5 but had little effect on cell fusion mediated by HIV-2 and simian immunodeficiency virus Envs. Retrocyclin-1 inhibited HIV-1 Env-mediated fusion without impairing the lateral mobility of CD4, and it inhibited the fusion of CD4-deficient cells with cells bearing CD4-independent HIV-1 Env. Thus, it could act without cross-linking membrane proteins or inhibiting gp120-CD4 interactions. Retrocyclin-1 acted late in the HIV-1 Env fusion cascade but prior to 6-helix bundle formation. Surface plasmon resonance experiments revealed that retrocyclin bound the ectodomain of gp41 with high affinity in a glycan-independent manner and that it bound selectively to the gp41 C-terminal heptad repeat. Native-PAGE, enzyme-linked immunosorbent assay, and CD spectroscopic analyses all revealed that retrocyclin-1 prevented 6-helix bundle formation. This mode of action, although novel for an innate effector molecule, resembles the mechanism of peptidic entry inhibitors based on portions of the gp41 sequence. 相似文献
175.
Harish Chandra Andola Kailash Singh Gaira Ranbeer Singh Rawal Mohan Singh Muniyari Rawat Indra Dutt Bhatt 《化学与生物多样性》2010,7(2):415-420
The variation of the berberine content in roots and stem bark of Berberis asiatica with altitude and edaphic conditions in the western Himalaya was estimated by HPLC. The comparative assessment revealed a significantly higher berberine content in roots than in stem barks. Moreover, the berberine content varied significantly with altitude and edaphic conditions both in root and stem bark samples. The populations growing at low altitude contained significantly more berberine than the ones growing at high altitude. Also the moisture and potassium (K) percentage of the soil significantly influenced the berberine content. 相似文献
176.
Synthetic amphiploids are the immortal sources for studies on crop evolution, genome dissection, and introgression of useful variability from related species. Cytological analysis of synthetic decaploid wheat (Triticum aestivum L.) - Aegilops kotschyi Boiss. amphiploids (AABBDDUkUkSkSk) showed some univalents from the C1 generation onward followed by chromosome elimination. Most of the univalents came to metaphase I plate after the reductional division of paired chromosomes and underwent equational division leading to their elimination through laggards and micronuclei. Substantial variation in the chromosome number of pollen mother cells from different tillers, spikelets, and anthers of some plants also indicated somatic chromosome elimination. Genomic in situ hybridization, fluorescence in situ hybridization, and simple sequence repeat markers analysis of two amphiploids with reduced chromosomes indicated random chromosome elimination of various genomes with higher sensitivity of D followed by the Sk and Uk genomes to elimination, whereas 1D chromosome was preferentially eliminated in both the amphiploids investigated. One of the partial amphiploids, C4 T. aestivum 'Chinese Spring' - Ae. kotschyi 396 (2n = 58), with 34 T. aestivum, 14 Uk, and 10 Sk had stable meiosis and high fertility. The partial amphiploids with white glumes, bold seeds, and tough rachis with high grain macro- and micronutrients and resistance to powdery mildew could be used for T. aestivum biofortification and transfer of powdery mildew resistance. 相似文献
177.
Santosh Kumar Sharma Deepika Rawat Shrawan Kumar Arun Kumar Suman Kumaria Rama Rao Satyawada 《Trees - Structure and Function》2010,24(5):855-864
Prosopis cineraria, an important multipurpose tree and vital component of the otherwise fragile ecosystem of arid and semiarid regions of India.
It is highly drought tolerant and sprouts profusely during the extreme dry summer months when most other trees are leafless.
P. cineraria is known to exhibit comparable genetic variations at intra-specific and inter-population levels reflected through morphological
and cytogenetical diversity in regions, where this plant grows naturally. In the present study, single primer amplification
reaction (SPAR) methods have been used for determination of diversity at DNA level in 30 accessions of P. cineraria collected from different districts of Rajasthan. The analyses include the use of six minisatellite core sequence primers
for direct amplification of minisatellite DNA (DAMD), eight inter simple sequence repeats (ISSR) and 20 arbitrary primed decamer
sequences for random amplification (RAPD) reactions. Upon analysis of the data generated, all the three SPAR methods, either
independently and/or in combination, revealed wide range of genetic variation among accessions. Comparison of matrix of individual
SPAR method using MxComp component of NTSYS-pc 2.02 K software proving that analysis of natural genetic variation using combination
of SPAR methods particularly ISSR and DAMD, rather than an isolated approach, is very effective. Such an approach also yields
better information and reflection of the relatedness and affinities at intra-species and inter-population levels. Therefore,
it is opined that in order to reveal the intrinsic intra-specific variation, SPAR approaches involving more than one DNA marker
may reveal more authentic genetic variation in tropical tree species like P. cineraria. 相似文献
178.
Allelopathic potential of sunflower (Helianthus annuus L.) fresh plant tissues aqueous extraction in bioassay, rhizosphere soil in pot experiment and phytotoxicity of decomposed sunflower plant biomass in bioassay against Vigna radiata, Pennisetum glaucum, Trianthema portulacastrum and Parthenium hysterophorum was investigated. In bioassay aqueous extracts of fresh sunflower plant tissue inhibited the germination, seedling growth (shoot and root) and dry matter accumulation of test plant species. In pot study sunflower rhizosphere soil inhibited growth attributes (plant height, population, number of branches) and yield attributes (grain yield, biomass yield) of selected crops and weeds. Phytotoxicity of decomposed sunflower biomass showed inhibitory effect on selected plant species. The fresh plant tissues was greatest inhibitory to test plants and followed by that of the decomposed biomass extracts in all bioassays. Significant reductions in the root and shoot growth were observed as the extract concentration was increased. The concentrations of extract fraction of fresh sunflower was determined, since nine compounds i.e. ferulic, p-coumaric, syringic, chlorogenic acid, isochlorogenic acid, neochlorogenic acid, vanillic acid, p-hydroxybenzoic acid, caffeoylquinic acid, found to be main growth inhibitors in sunflower plant tissue. These results suggested that sunflower plants may possess allelopathic potential, and the plant tissues may be potentially useful for weed management. 相似文献
179.
Monika Sharma Lokesh Kumar Ashish Jain Vikas Verma Vikas Sharma Bhavana Kushwaha Nand Lal Lalit Kumar Tara Rawat Anil K. Dwivedi Jagdamba P. Maikhuri Vishnu L. Sharma Gopal Gupta 《PloS one》2013,8(6)
Unlike somatic cells, sperm have several-fold more available-thiols that are susceptible to redox-active agents. The present study explains the mechanism behind the instant sperm-immobilizing and trichomonacidal activities of pyrrolidinium pyrrolidine-1-carbodithioate (PPC), a novel thiol agent rationally created for prophylactic contraception by minor chemical modifications of some known thiol drugs. PPC, and its three derivatives (with potential active-site blocked by alkylation), were synthesized and evaluated against live human sperm and metronidazole-susceptible and resistant Trichomonas vaginalis, in vitro. Sperm hexokinase activity was evaluated by coupled enzyme assay. PPC irreversibly immobilized 100% human sperm in ∼30 seconds and totally eliminated Trichomonas vaginalis more efficiently than nonoxynol-9 and metronidazole. It significantly inhibited (P<0.001) thiol-sensitive sperm hexokinase. However, the molecule completely lost all its biological activities once its thiol group was blocked by alkylation. PPC was subsequently formulated into a mucoadhesive vaginal film using GRaS excipients and evaluated for spermicidal and microbicidal activities (in vitro), and contraceptive efficacy in rabbits. PPC remained fully active in quick-dissolving, mucoadhesive vaginal-film formulation, and these PPC-films significantly reduced pregnancy and fertility rates in rabbits. The films released ∼90% of PPC in simulated vaginal fluid (pH 4.2) at 37°C in 5 minutes, in vitro. We have thus discovered a common target (reactive thiols) on chiefly-anaerobic, redox-sensitive cells like sperm and Trichomonas, which is susceptible to designed chemical interference for prophylactic contraception. The active thiol in PPC inactivates sperm and Trichomonas via interference with crucial sulfhydryl-disulfide based reactions, e.g. hexokinase activation in human sperm. In comparison to non-specific surfactant action of OTC spermicide nonoxynol-9, the action of thiol-active PPC is apparently much more specific, potent and safe. PPC presents a proof-of-concept for prophylactic contraception via manipulation of thiols in vagina for selective targeting of sperm and Trichomonas, and qualifies as a promising lead for the development of dually protective vaginal-contraceptive. 相似文献
180.
Priyanka Tripathi Garima Rawat Sweta Yadav R. K. Saxena 《Bioprocess and biosystems engineering》2013,36(11):1665-1673
Different physiological and nutritional parameters affect the fermentative production of shikimic acid. In our study, Citrobacter freundii initially produced 0.62 g/L of shikimic acid in 72 h. However, when process optimization was employed, 5.11 g/L of shikimic acid was produced in the production medium consisting of glucose (5.0 %), asparagine (4.5 %), CaCO3 (2.0 %), at pH 6.0, when inoculated with 6 % inoculum and incubated at 30 ± 1 °C, 200 rpm for 60 h. Preliminary fed-batch studies have resulted in the production of 9.11 g/L of shikimic acid on feeding the production medium by 20 g/L of glucose at 24 h of the fermentation run. Production of similar amount of shikimic acid was observed when the optimized conditions were employed in a 10-L bioreactor as obtained in shake flask conditions. A total of 9.11 g/L of shikimic acid was produced in 60 h. This is approximately 14.69-fold increase in shikimic acid production when compared to the initial un-optimized production conditions. This has also resulted in the reduction of the production time. The present study provides useful information to the industrialists seeking environmentally benign technology for the production of bulk biomolecules through manipulation of various chemical parameters. 相似文献