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Spontaneous DNA breakage in single living Escherichia coli cells 总被引:3,自引:0,他引:3
Spontaneous DNA breakage is predicted to be a frequent, inevitable consequence of DNA replication and is thought to underlie much of the genomic change that fuels cancer and evolution. Despite its importance, there has been little direct measurement of the amounts, types, sources and fates of spontaneous DNA lesions in living cells. We present a direct, sensitive flow cytometric assay in single living Escherichia coli cells for DNA lesions capable of inducing the SOS DNA damage response, and we report its use in quantification of spontaneous DNA double-strand breaks (DSBs). We report efficient detection of single chromosomal DSBs and rates of spontaneous breakage approximately 20- to 100-fold lower than predicted. In addition, we implicate DNA replication in the origin of spontaneous DSBs with the finding of fewer spontaneous DSBs in a mutant with altered DNA polymerase III. The data imply that spontaneous DSBs induce genomic changes and instability 20-100 times more potently than previously appreciated. Finally, FACS demonstrated two main cell fates after spontaneous DNA damage: viability with or without resumption of proliferation. 相似文献
23.
Prickett TD Wei X Cardenas-Navia I Teer JK Lin JC Walia V Gartner J Jiang J Cherukuri PF Molinolo A Davies MA Gershenwald JE Stemke-Hale K Rosenberg SA Margulies EH Samuels Y 《Nature genetics》2011,43(11):1119-1126
G protein-coupled receptors (GPCRs), the largest human gene family, are important regulators of signaling pathways. However, knowledge of their genetic alterations is limited. In this study, we used exon capture and massively parallel sequencing methods to analyze the mutational status of 734 GPCRs in melanoma. This investigation revealed that one family member, GRM3, was frequently mutated and that one of its mutations clustered within one position. Biochemical analysis of GRM3 alterations revealed that mutant GRM3 selectively regulated the phosphorylation of MEK, leading to increased anchorage-independent growth and migration. Melanoma cells expressing mutant GRM3 had reduced cell growth and cellular migration after short hairpin RNA-mediated knockdown of GRM3 or treatment with a selective MEK inhibitor, AZD-6244, which is currently being used in phase 2 clinical trials. Our study yields the most comprehensive map of genetic alterations in the GPCR gene family. 相似文献
24.
Double helix at atomic resolution 总被引:15,自引:0,他引:15
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J. Rosenberg 《Cellular and molecular life sciences : CMLS》1973,29(6):690-691
Summary A hitherto unknown endocrine gland in the head ofScutigera coleoptrata is described. It is attached to a small blood vessel. Its cells are typical podocytes. Between the pedicells and along the lateral cell membranes, there are many intercellulary spaces. The fine structure of the gland is very similar to that of the collar gland in the diplopodPolyxenus lagurus. 相似文献
27.
In this and the accompanying paper we demonstrate that certain prokaryotic mRNAs, when modified at their 5'-termini with a cap structure, are translated in a eukaryotic cell-free protein synthesising system as efficiently as, or more efficiently than, eukaryotic mRNAs. Apparently, the prokaryotic mRNA contains all the information necessary for efficient recognition and initiation by eukaryotic translational components, except for the cap structure. 相似文献
28.
P. Rosenberg 《Cellular and molecular life sciences : CMLS》1975,31(12):1401-1403
Summary Following 1 h exposure, the level of phospholipase A2 penetration into the axoplasm of the squid giant axon was 107 to 350% of that in the external media; corresponding values for phospholipase C were 18 to 31%. Phospholipases can therefore be used to study phospholipid function in axons since they can penetrate through connective tissue and Schwann cell to reach the axolemma.I thank Dr.Toshio Narahashi for allowing me to use his laboratory facilities at the Marine Biological Laboratory, Woods Hole, Mass. for the dissection of squid axons. Expert technical assistance in these studies were provided by Mr.Steven Trudel and Mr.Stuart Owen Rosenberg. This work was supported in part by a grant from the University of Connecticut Research Foundation. 相似文献
29.
Progress in human tumour immunology and immunotherapy 总被引:72,自引:0,他引:72
Rosenberg SA 《Nature》2001,411(6835):380-384
Studies of the administration of interleukin-2 to patients with metastatic melanoma or kidney cancer have shown that immunological manipulations can mediate the durable regression of metastatic cancer. The molecular identification of cancer antigens has opened new possibilities for the development of effective immunotherapies for patients with cancer. Clinical studies using immunization with peptides derived from cancer antigens have shown that high levels of lymphocytes with anti-tumour activity can be raised in cancer-bearing patients. Highly avid anti-tumour lymphocytes can be isolated from immunized patients and grown in vitro for use in cell-transfer therapies. Current studies are aimed at understanding the mechanisms that enable the cancer to escape from immune attack. 相似文献
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Burrowing Owls ( Athene cunicularia ) occupy intensively managed agricultural areas within the Imperial Valley of California, where they occur at high densities relative to other areas in the state, and yet reproductive rates are often low. Understanding diet and food-niche breadth may lead to insights into factors contributing to their poor reproductive performance. We tested the relative contribution of sex, year, and season on diet composition and food-niche breadth from analyses of stomach contents of adult Burrowing Owls ( n = 53). Orthoptera dominated the diet; it accounted for 58.9% of the total number of prey items in all stomachs and was found in 98.2% of all samples. Rodents, a source of potentially limiting dietary calcium, were found in only 2 stomachs. We detected yearly and seasonal effects on estimated food-niche breadth. Mean food niche for the breeding season was broader (antilog of Shannons index: 2.38 ± 0.15) and more even (Pielous index: 0.67 ± 0.06) than for the nonbreeding season (1.83 ± 0.13, 0.49 ± 0.07, respectively) partially because of a greater frequency of Araneida, Isopoda, Lepidoptera, and Solpugida in the diet during the breeding season. Mean food-niche breadth for 1997 (2.25 ± 0.23) was broader than during 1994, 1995, and 1996 (2.07 ± 0.23, 1.98 ± 0.20, and 1.82 ± 0.40, respectively) because of a greater frequency of Araneida, Dermaptera, Isopoda, Lepidoptera, and Solpugida. These results, and auxiliary diet information, suggest rodents were infrequent in the diet of Burrowing Owls in the Imperial Valley and may help explain their lower reproductive success relative to other areas of California. 相似文献