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101.
A feasibility study of neural transplantation in adult rhesus monkey was undertaken. Fresh and preserved neocortex containing multiplying and maturing neurons obtained from 55–70 gestation days were transplanted into the striatum, cerebellum and cerebral cortex of adult monkeys. Tissues were preserved for 4 days either at subzero temperature in the freezer compartment of the ordinary refrigerator in Ringer lactate or incubated in culture medium. While 2 monkeys out of 5 injected with preserved tissue had successful transplants after 4 months, all the 10 monkeys injected with fresh tissue had no transplants. The size of the two surviving transplants was small. The neurons in the transplants were mainly in clusters. Many of the cells were immature and some showed early degenerative changes. Neuronal processes were restricted to the transplants and thus showed lack of morphological integration with the host tissue. Further studies are in progress to define the nature of the embryonic tissue of primate which can grow and survive and also the role of neural grafts in functional recovery following experimental lesions of the brain regions.  相似文献   
102.
JC virus, JCV, is a human neurotropic polyomavirus whose replication in glial cells causes the fatal demyelinating disease progressive multifocal leukoencephalopathy (PML). In addition, JCV possesses oncogenic activity and expression of its transforming protein, large T-antigen (T-Ag), in several experimental animals induces tumors of neural origin. Further, the presence of JCV DNA and T-Ag have been repeatedly observed in several human malignant tissues including primitive neuroectodermal tumors and glioblastomas. Earlier studies have demonstrated that Bag3, a member of the Bcl-2-associated athanogene (Bag) family of proteins, which is implicated in autophagy and apoptosis, is downregulated upon JCV infection of glial cells and that JCV T-Ag is responsible for suppressing the activity of the BAG3 promoter. Here, we investigated the possible impact of Bag3 on T-Ag expression in JCV-infected human primary glial cells as well as in cells derived from T-Ag-induced medulloblastoma in transgenic animals. Results from these studies revealed that overexpression of Bag3 drastically decreases the level of T-Ag expression by inducing the autophagic degradation of the viral protein. Interestingly, this event leads to the inhibition of JCV infection of glial cells, suggesting that the reduced levels of T-antigen seen upon the overexpression of Bag3 has a biological impact on the viral lytic cycle. Results from protein-protein interaction studies showed that T-Ag and Bag3 physically interact with each other through the zinc-finger of T-Ag and the proline rich domains of Bag3, and this interaction is important for the autophagic degradation of T-Ag. Our observations open a new avenue of research for better understanding of virus-host interaction by investigating the interplay between T-Ag and Bag3, and their impact on the development of JCV-associated diseases.  相似文献   
103.
A map has been developed of nuclease-hypersensitive sites of P-rr , the standard allele of the P -locus of Zea mays L. Using a traditional DNase I assay, eight such sites have been found that are specific for the expressing tissue and span a region of more than 25 kb of the P -locus, making it one of the largest plant genes yet described. The maps of the standard allele have also been compared with the recently described moderately stable P-pr allele, which arose from epimutation. Six of the eight sites exhibit the same tissue-specificity in P-pr plants, while two stay repressed as in non-expressing tissues of plants with the standard allele. Interestingly, the two repressed sites coincide with two hypermethylated restriction sites that have previously been correlated with the expression potential of the P-pr allele. On the other hand, four of the DNase I sites, coinciding with CpG islands that were not hypermethylated by the epimutation, also showed no differences in their sensitivity to DNase I between the standard allele and the P-pr allele. This suggests that the epimutation affects both site-specific methylation changes and a specific local chromatin structure of the P gene involved in its regulation.  相似文献   
104.
105.
Prem P. Jauhar 《Genetica》1968,39(1):360-370
Meiosis in the interspecific hybrid betweenPennisetum typhoides (2n=14; genomeAA) andP. purpureum (2n=28; genomesA′A′BB) has been studied with particular reference to allosyndetic and autosyndetic pairing of chromosomes. Although up to nine bivalents occurred in the hybrid, never more than five were observed to be (heteromorphic)AA′ bivalents (range 1–5). It has been concluded thatA andA′ genomes are onlypartially homologous. It has further been inferred that the two genomes are evolutionarily related and could have arisen from a common progenitor withx=5 chromosomes or from related species withx=5 chromosomes. Autosyndetic pairing of chromosomes within thetyphoides complement (A genome) and within theA′ genome ofpurpureum have been reported here for the first time. Intra-haploid pairing to a probable maximum of two bivalents within each of the three genomes of the hybrid, viz.,A, A′ andB, further suggestsx=5 as the phyletically basic number in the genusPennisetum. It has been inferred thatx=7 is a secondarily basic number, having been derived fromx=5. The occurrence of a species withn=5 inPennisetum, viz.,P. ramosum, substantiates this view. Further support in favour of this conclusion comes from the secondary association of bivalents in dipoidP. typhoides. Thus, the apparently diploid species,Pennisetum typhoides with2n=14 chromosomes is considered to be a “secondary diploid” having a secondarily balanced number ofx=7. On the basis of the results obtained by the author is conjunction with the available evidence from the literature, it is suggested thatx=5 may be the original basic number for the entire grass family and seven, the most preponderant number in it, and other higher numbers derived from it subsequently during the course of evolution.  相似文献   
106.
 Cell wall-bound invertase (CWI) is spatially and temporally the first enzyme which metabolizes the incoming sucrose in developing seed of maize (Zea mays). Our previous studies have shown that the cell wall-bound invertase-2 (INCW2) isozyme encoded by the wild-type gene of the Miniature1 (Mn1) seed locus plays a critical role in seed development. Null mutations of the gene, such as the mn1 seed mutant which lacks invertase activity, are associated with a loss of ∼70–80% of the normal seed weight. We show here that under in vitro kernel culture conditions the hexose-based medium was similar to the sucrose-based medium in promoting the normal development of kernels of the Mn1, but not of the mutant mn1, genotype. Anatomical, biochemical, and immunohistological data showed that the mn1 kernels retain their mutant phenotype regardless of the presence of sucrose or hexoses in the culture media. The most drastic changes in the mn1 seed mutant were associated with a significant reduction in the size of the endosperm, but not in the pattern or the level of starch localization. Because Mn1 expression was temporally coincident with the endosperm cell divisions, INCW2 must play a critical role in providing hexose sugars for mitotic division, and only a minor role in generating carbon skeletal substrates for starch biosynthesis in the early stages of endosperm development. Furthermore, a lack of the wild-type seed phenotype of the mn1 mutant in hexose media suggests that a metabolic release of hexoses catalyzed by INCW2, rather than an exogenous source, is critical for both generating appropriate sugar-sensing signals for gene expression and for normal endosperm development. Received: 8 April 1998 / Accepted: 14 August 1998  相似文献   
107.
Various concentrations of salt (NaCI) were shown to have an influence on the differentiation of tissues in the root and stem ofBacopa monniera (L) Wettst. Higher concentrations induced drastic changes in roots grown on salt-supplemented media; epidermal and cortical cells experienced changes in shape, size, and orientation and/or were got disintegrated. A low concentration of salt induced a profuse development of root hairs which gradually disappeared at higher concentrations. Air spaces in the stem cortex were enlarged and xylem cell walls in the vascular ring were thickened.  相似文献   
108.
109.
In this communication we report a serendipitously discovered hybrid molecule 1, combining fragment of 3 (an in vivo active antileishmanial molecule) with H2S donor moiety (known for bimodal behavior of cytoprotection and apoptosis), as antileishmanial agent. Compound 1 suppresses 99.82% parasitemia of L. donovani infected macrophages at 12.5 μg/ml without even deforming them (CC50 > 100 μg/ml). This compound appears cytotoxic for intracellular amastigotes while cytoprotective to host macrophages. The concept can be utilized to develop high therapeutic index NCE (New Chemical Entities) for other macrophage mediated diseases like tuberculosis and cancer.  相似文献   
110.
Sex determination in domestic animals is of potential value to livestock breeding programs. The aim of this study was to develop a simple and accurate PCR-based sex determination protocol, which can be applicable to 6 major domesticated species of the family Bovidae,viz. Bos frontalis, B. grunniens, B. indicus, Bubalus bubalis, Capra hircus, andOvis aries. In silico analysis was done to identify conserved DNA sequence in the HMG box region of the sex-determining region of the Y-chromosome (SRY gene) across the bovids. Duplex PCR assay, including theSRY gene and theGAPDH housekeeping gene, was optimized by using genomic DNA extracted from blood samples of known sex. It was possible to identify the sex of animals by amplifying both gender-specific (SRY) and autosomal (GAPDH) genes simultaneously in the duplex reaction, with the male yielding two bands and the female one band. The protocol was subjected to a blind test that showed a 100 percent specificity and accuracy, thus it can be used in sex determination in livestock breeding programs.  相似文献   
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