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41.
Tropical forests store vast amounts of carbon and are the most biodiverse terrestrial habitats, yet they are being converted and degraded at alarming rates. Given global shortfalls in the budgets required to prevent carbon and biodiversity loss, we need to seek solutions that simultaneously address both issues. Of particular interest are carbon‐based payments under the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism to also conserve biodiversity at no additional cost. One potential is for REDD+ to protect forest fragments, especially within biomes where contiguous forest cover has diminished dramatically, but we require empirical tests of the strength of any carbon and biodiversity cobenefits in such fragmented systems. Using the globally threatened Atlantic Forest landscape, we measured above‐ground carbon stocks within forest fragments spanning 13 to 23 442 ha in area and with different degrees of isolation. We related these stocks to tree community structure and to the richness and abundance of endemic and IUCN Red‐listed species. We found that increasing fragment size has a positive relationship with above‐ground carbon stock and with abundance of IUCN Red‐listed species and tree community structure. We also found negative relationships between distance from large forest block and tree community structure, endemic species richness and abundance, and IUCN Red‐listed species abundance. These resulted in positive congruence between carbon stocks and Red‐listed species, and the abundance and richness of endemic species, demonstrating vital cobenefits. As such, protecting forest fragments in hotspots of biodiversity, particularly larger fragments and those closest to sources, offers important carbon and biodiversity cobenefits. More generally, our results suggest that macroscale models of cobenefits under REDD+ have likely overlooked key benefits at small scales, indicating the necessity to apply models that include finer‐grained assessments in fragmented landscapes rather than using averaged coarse‐grained cells.  相似文献   
42.
Rocha FB  Barreto RW  Bezerra JL  Neto JA 《Mycologia》2010,102(6):1240-1252
We studied the foliicolous mycobiota associated with Coussapoa floccosa. This is a tree belonging to the Cecropiaceae, endemic to the Brazilian tropical seasonal semideciduous montane forest. It is listed as an endangered species because of habitat destruction. Until now no fungus has been recorded in association with this plant species. This paper describes six foliicolous fungi associated with this plant that were collected during a survey of the mycobiota occurring in a locality where a small population of C. floccosa was discovered. All fungi described here are new to science, namely Dennisiella coussapoae, Mycosphaerella coussapoae, Pseudoallosoma nervisequens (which also represents a newly proposed genus), Pseudocercospora coussapoae, Pseudocercospora atrofuliginosa and Tripospermum acrobaticum. The high proportion of taxonomic novelties revealed in this study reflects the general lack of mycological information for forest ecosystems in Brazil and also indicates that vulnerable plant species such as C. floccosa may harbor unique mycobiota. Such mycobiota may depend on their nearly extinct hosts and consequently can be equally endangered with extinction and therefore also deserve consideration for in situ and ex situ conservation.  相似文献   
43.
44.
In cattle and mares, free insulin-like growth factor 1 (IGF-1) is higher in the future dominant follicle (F1) than in the future largest subordinate follicle (F2) before deviation in diameter or selection is manifested between the two follicles. The effect of IGF-1 on other follicular-fluid factors and on the destiny of F2 were studied in two experiments in each species, using a total of 40 heifers and 42 mares. An injection of IGF-1 was made into F2 at the expected beginning of deviation (heifers, F1 >or= 8.5 mm; mares, F1 >or= 20.0 mm; Hour 0). In heifers, follicular fluid was taken from F2 at Hours 3, 6, 12, or 24; each heifer was sampled only once. In mares, sequential F2 samples were taken from each mare at Hours 0, 6, and 24 or at Hours 12 and 24. Transvaginal ultrasound guidance was used for treatment and sample collection. In heifers, IGF-1 treatment of F2 stimulated the secretion of estradiol (P < 0.05) between Hours 3 and 6 and androstenedione (P < 0.05) between Hours 3 and 12. In F2 of control heifers, estradiol decreased (P < 0.05) and androstenedione did not change significantly. In mares, IGF-1 treatment of F2 did not affect the concentrations of estradiol during the 24-h posttreatment period; androstenedione decreased (P < 0.04) in the IGF-1 group and increased (P < 0.006) in the controls. Compared with control mares, the IGF-1 group had higher (P < 0.04) activin-A at Hours 12 and 24 and higher (P < 0.0006) inhibin-A at Hour 24. After ablating F1 at Hour 24 in mares, F2 became dominant and ovulated in more mares (P < 0.0002) in the IGF-1 group (12/14) than in the control group (2/14). These results are consistent with reported temporal relationships among follicular factors during deviation in both species and indicate that IGF-1 plays a key role in controlling the temporal relationships; however, no indication was found that IGF-1 stimulated estradiol production in mares during the 24 h after treatment.  相似文献   
45.
In rats, CL-Brener clone caused high mortality, severe acute myocarditis, and myositis that subsided completely in surviving animals. Accordingly, no parasite kDNA could be amplified in several organs after 4 months. The monoclonal JG strain caused null mortality, acute predominantly focal myocarditis, discrete and focal myositis, and a chronic phase with sparse inflammatory foci. Double infection with both Trypanosoma cruzi populations turned mortality very low or null. At the end of the acute phase, the heart exhibited only JG strain kDNA (LSSP-PCR), while skeletal muscles and rectum exhibited only CL-Brener kDNA. Molecular and histopathological findings were accordant. In double infection chronic phase, JG strain remains in heart and appeared in organs previously parasitized by CL-Brener clone. Understanding the virulence and histotropism shifts now described could be important to clarify the variable clinical course and epidemiological peculiarities of Chagas' disease.  相似文献   
46.
Acclimation of the halotolerant alga Dunaliella salina to low temperature induced the accumulation of a 12.4 kDa protein (DsGRP-1) and reduction of a 13.1 kDa protein (DsGRP-2). DsGRP-1 and DsGRP-2 are boiling-stable proteins that are localised in the cytoplasm, as revealed by sub-cellular fractionation and by immuno-localisation. The proteins were partially purified and their corresponding genes were cloned. The predicted sequences are homologous to Glycine-Rich RNA-binding Proteins (GRPs) from plants and cyanobacteria. The nucleotide sequences of grp1 and grp2 differ in a short insert encoding 9 amino acids in the glycine-rich domain of DsGRP-2. grp2 contains a single intron at position 179 indicating that DsGRP-1 and DsGRP-2 are not derived from alternative splicing of a common gene. The level of grp mRNA increased at 7 degrees C and was rapidly depressed at 24 degrees C. Analysis of binding to ribonucleotide homopolymers revealed that DsGRP-1 and DsGRP-2 bind preferentially to poly-G and to poly-U indicating that they are RNA-binding proteins. It is proposed that DsGRP-1 and DsGRP-2 are encoded by distinct genes which are differentially regulated by temperature.  相似文献   
47.
Follicle diameters and concentrations of follicular fluid factors were studied in the two largest follicles (F1 and F2) using F1 diameters in increments of 0.2 mm (equivalent to 4 h intervals) and extending from 7.4 to 8.4 mm (12 heifers in each of 6 groups). Changes were compared between follicles using the F2 associated with each F1-diameter group. Diameter deviation began in the 8.2-mm group as indicated by a greater (P < 0.05) diameter difference between F1 and F2 in the 8.4-mm group than in the 8.2-mm group. In the 8.0-mm group, estradiol concentrations began to increase (P < 0.05) differentially in F1 versus F2, and free insulin-like growth factor-1 (IGF-1) began to decrease differentially in F2 (P < 0.06). Combined for F1 and the associated F2, activin-A concentrations increased (P < 0.05) between the 7.6- and 8.2-mm groups and then decreased (P < 0.05). Results supported the hypothesis that estradiol and free IGF-1 concentrations simultaneously become higher in F1 than in the associated F2 by the beginning of diameter deviation. Results did not support the hypothesis that a transient elevation in activin-A is present in F1 but not in the associated F2 at the beginning of the estradiol and IGF-1 changes; instead, a mean transient elevation in activin-A occurred at this time only when data for the two follicles were combined. Comparisons between F1 and F2 also were made by independently grouping F2 and using diameter groups at 0.2-mm increments for F2 as well as for F1. In the diameter groups common to F1 and F2 (7.4, 7.6, 7.8, and 8.0 mm) there was a group effect (P < 0.003) for estradiol involving an increase (P < 0.05) beginning at the 7.6-mm group averaged over F1 and F2. For free IGF-1 concentrations, a fluctuation (a significant increase followed by a significant decrease) occurred independently in F1 between the 7.4- to 7.8-mm groups and independently in F2 between the 7.0- to 7.4-mm groups.  相似文献   
48.
A highly significant association between a COMT haplotype and schizophrenia   总被引:35,自引:0,他引:35  
Several lines of evidence have placed the catechol-O-methyltransferase (COMT) gene in the limelight as a candidate gene for schizophrenia. One of these is its biochemical function in metabolism of catecholamine neurotransmitters; another is the microdeletion, on chromosome 22q11, that includes the COMT gene and causes velocardiofacial syndrome, a syndrome associated with a high rate of psychosis, particularly schizophrenia. The interest in the COMT gene as a candidate risk factor for schizophrenia has led to numerous linkage and association analyses. These, however, have failed to produce any conclusive result. Here we report an efficient approach to gene discovery. The approach consists of (i) a large sample size-to our knowledge, the present study is the largest case-control study performed to date in schizophrenia; (ii) the use of Ashkenazi Jews, a well defined homogeneous population; and (iii) a stepwise procedure in which several single nucleotide polymorphisms (SNPs) are scanned in DNA pools, followed by individual genotyping and haplotype analysis of the relevant SNPs. We found a highly significant association between schizophrenia and a COMT haplotype (P=9.5x10-8). The approach presented can be widely implemented for the genetic dissection of other common diseases.  相似文献   
49.
The natural propagation rate of bulb forming Amaryllidaceae including Nerine is low. Conventional micropropagation techniques are labor intensive and therefore expensive. Liquid cultures facilitate: scaling up, automation and cost reduction of micropropagation. Inflorescence-derived explants of Nerine were cultured on 2,4-dichlorophenoxyacetic acid (2,4-d) and 6-benzyladenine (BA) supplemented Murashige & Skoog (MS) medium. Callus-like tissue interspersed with nodular tissue, as well as direct organogenesis developed at the junction between flower pedicel and peduncle. Subculture of nodular tissue to 1-naphthalene acetic acid (NAA), BA and paclobutrazol (PAC) supplemented liquid medium in Erlenmeyer flasks or bubble bioreactors resulted in proliferation of rounded, compact, easily crumbled meristematic clusters. Growth and proliferation in bioreactors were higher than in shaken flasks and were affected differently by the inoculum to medium ratio in the two types of culture vessel. Nerine cultures showed low sensitivity to high aeration rates in bubble bioreactors despite the accumulation of debris. It was therefore possible to increase aeration rates without reducing the proliferation rate or damaging the quality of the meristematic aggregates. The conditions in semi-continuous culture in flasks and bioreactors were more favorable and increased the growth value by 100% and 140%, respectively. The total protein content increased by 180% in flasks and 90% in bioreactors. Although the presence of PAC throughout the culture period decreased growth and proliferation, it was a promotive bioregulator for meristernatic cluster formation. Proembryogenic clusters developed upon the removal of PAC. The use of meristematic clusters for micropropagation in scaled-up liquid cultures is discussed.  相似文献   
50.
The ontogeny of somatic embryos was followed in liquid cultured Nerine tissue. Proliferating, nodular meristematic clusters were maintained in bubble bioreactors in a medium supplemented with 0.25 M 1-naphthalene acetic acid (NAA), 10 M 6-benzyladenine (BA) and 8.7 M Paclobutrazol (PAC). Regeneration of plantlets from this tissue was limited. Omission of PAC from the medium induced proembryogenic clusters. Embryo development and maturation were enhanced in flask cultures by substituting N6-(isopentenyl) adenine (2iP) for BA and elevating the sucrose concentration in the medium to 6%. High rates of embryo germination occurred in a growth regulator-free, low (3%) sucrose medium. Bulblet-bearing plantlets developed on agar-solidified, auxin-supplemented media. Recurrent embryogenesis occurred in long term growth regulator-free, or high sucrose media. The potential of using the somatic embryogenesis pathway for micropropagation of Nerines is described.  相似文献   
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