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排序方式: 共有225条查询结果,搜索用时 31 毫秒
1.
Iu P Popov B A Kolontarev A I Gudkov N I Matve?chuk P V Derkachev 《Biulleten' eksperimental'no? biologii i meditsiny》1990,110(10):358-360
The article gives experimental data proving the usage of the method of bloodless reduction of gastric secretion through endoscope in case of peptic ulcer. Pricking around the secretory zones of the stomach with hypertonic glucose solution conducted on 35 mongrel dogs led to a stable reduction of acid producing function of the stomach. Morphological changes of the stomach mucous membrane were mainly expressed in the atrophy of glands. The analysis of the test results gives opportunity to recommend the clinical introduction of the method in complex treatment of peptic ulcer. 相似文献
2.
Usdin K; Chevret P; Catzeflis FM; Verona R; Furano AV 《Molecular biology and evolution》1995,12(1):73-82
The single most difficult problem in phylogenetic analysis is deciding
whether a shared taxonomic character is due to common ancestry or one that
appeared independently due to convergence, parallelism, or reversion to an
ancestral state. Mammalian L1 retrotransposons undergo periodic
amplifications in which multiple copies of the elements are interspersed in
the genome. Because these elements apparently are transmitted only by
inheritance and are retained in the genome, a shared L1 amplification event
can only be an inherited ancestral character. We propose that L1
amplification events can be an excellent tool for analyzing mammalian
evolution and demonstrate here how we addressed several refractory problems
in rodent systematics using L1 DNA as a taxonomic character.
相似文献
3.
AV Shevchenko IG Budzanivska TP Shevchenko VP Polischuk D Spaar 《Archives Of Phytopathology And Plant Protection》2013,46(2):139-146
The work was focused on the investigation of possible dependencies between the development of viral infection in plants and the presence of high heavy metal concentrations in soil. Field experiments have been conducted in order to study the development of systemic tobacco mosaic virus (TMV) infection in Lycopersicon esculentum L. cv. Miliana plants under effect of separate salts of heavy metals Cu, Zn and Pb deposited in soil. As it is shown, simultaneous effect of viral infection and heavy metals in tenfold maximum permissible concentration leads to decrease of total chlorophyll content in experiment plants mainly due to the degradation of chlorophyll a. The reduction of chlorophyll concentration under the combined influence of both stress factors was more serious comparing to the separate effect of every single factor. Plants' treatment with toxic concentrations of lead and zinc leaded to slight delay in the development of systemic TMV infection together with more than twofold increase of virus content in plants that may be an evidence of synergism between these heavy metal's and virus' effects. Contrary, copper although decreased total chlorophyll content but showed protective properties and significantly reduced amount of virus in plants. 相似文献
4.
5.
Data are reviewed concerning the results of study of multidrug-resistant (MDR) tumor cells. MDR often develops in the course of chemotherapy or in vitro selection of tumor cells by vincristine, adriamycin, actinomycin D, colchicine, etc. MDR cells are resistant to all these drugs though their targets and mechanisms of toxic action are quite different. Resistance is due to the decreased accumulation by MDR cells of these compounds. The genetic basis for MDR is amplification of a large genomic region that contains a number of genes coding for products and functions that are under extensive study. Specific karyotype and amplified DNA alterations occur during the development of MDR imitating the processes of appearance and variability of multigene families. The obtained data demonstrate the ways of overcoming of tumor multidrug resistance in clinic. 相似文献
6.
A V Gudkov O B Chernova A R Kazarov B P Kopnin 《Molekuliarnaia genetika, mikrobiologiia i virusologiia》1987,(6):33-38
Six cloned DNA fragments representing different portions of the genomic region amplified in multidrug resistant Djungarian hamster cells were used to study amplicon variations in a large number of the resistant cell lines. Expressed correlation exists between the degree of 3 cloned sequences amplification and the level of multidrug resistance. Three other cloned regions amplify coordinately with the latter ones at the initial steps of selection. Later their amplification halts and they mao even eliminate from amplicons of highly resistant cells. The rates and order of elimination of these sequences vary among different independently derived series of multidrug resistant cell lines. 相似文献
7.
R Alan Harris Dorottya Nagy-Szakal Sabina AV Mir Eibe Frank Reka Szigeti Jess L Kaplan Jiri Bronsky Antone Opekun George D Ferry Harland Winter Richard Kellermayer 《Epigenetics》2014,9(8):1131-1137
Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P < 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD. 相似文献
8.
Elemental distribution in striated muscle and the effects of hypertonicity: Electron probe analysis of cryo sections 总被引:15,自引:4,他引:11 下载免费PDF全文
A method of rapid freezing in supercooled Freon 22 (monochlorodifluoromethane) followed by cryoultramicrotomy is described and shown to yield ultrathin sections in which both the cellular ultrastructure and the distribution of diffusible ions across the cell membrane are preserved and intracellular compartmentalization of diffusabler ions can be quantitated. Quantitative electron probe analysis (Shuman, H., A.V. Somlyo, and A.P. Somlyo. 1976. Ultramicros. 1:317-339.) of freeze-dried ultrathin cryto sections was found to provide a valid measure of the composition of cells and cellular organelles and was used to determine the ionic composition of the in situ terminal cisternae of the sarcoplasmic reticulum (SR), the distribution of CI in skeletal muscle, and the effects of hypertonic solutions on the subcellular composition if striated muscle. There was no evidence of sequestered CI in the terminal cisternae of resting muscles, although calcium (66mmol/kg dry wt +/- 4.6 SE) was detected. The values of [C1](i) determined with small (50-100 nm) diameter probes over cytoplasm excluding organelles over nuclei or terminal cisternae were not significantly different. Mitochondria partially excluded C1, with a cytoplasmic/ mitochondrial Ci ratio of 2.4 +/- 0.88 SD. The elemental concentrations (mmol/kg dry wt +/- SD) of muscle fibers measured with 0.5-9-μm diameter electron probes in normal frog striated muscle were: P, 302 +/- 4.3; S, 189 +/- 2.9;C1, 24 +/- 1.1;K, 404 +/- 4.3, and Mg, 39 +/- 2.1. It is concluded that: (a) in normal muscle the "excess CI" measured with previous bulk chemical analyses and flux studies is not compartmentalized in the SR or in other cellular organelles, and (b) the cytoplasmic C1 in low [K](0) solutions exceeds that predicted by a passive electrochemical distribution. Hypertonic 2.2 X NaCl, 2.5 X sucrose, or 2.2 X Na isethionate produced: (a) swollen vacuoles, frequently paired, adjacent to the Z lines and containing significantly higher than cytoplasmic concentrations of Na and Cl or S (isethionate), but no detectable Ca, and (b) granules of Ca, Mg, and P = approximately (6 Ca + 1 Mg)/6P in the longitudinal SR. It is concluded that hypertonicity produces compartmentalized domains of extracellular solutes within the muscle fibers and translocates Ca into the longitudinal tubules. 相似文献
9.
It was shown using the Ellman's reagent that chloride and bicarbonate anions are the heat-induced reducing agents of sea-water, and their combined action is more than additive. Sulfate anions do not exhibit these properties. The influence of sea-water anions on the heat-induced production of hydrogen peroxide was studied by enhanced chemiluminescence in a peroxidase-luminol-p-iodophenol system. In NaCl and NaHCO3 solutions, at concentration and pH values equal to those of sea-water, the production of H2O2 upon heating increased, as compared with water, whereas sulfate anions depressed its formation. By using coumarin-3-carboxylic acid as a fluorescent detector of OH radicals, a substantial increase in the production of radicals in the presence of chloride and bicarbonate anions upon heating was shown. The effect is due to the electron donor properties of these anions, which lead to the decomposition of H2O2 with the formation of OH radicals. The results obtained were considered from the viewpoint of the equivalence of heat and electromagnetic radiation of an absolutely black body. It is supposed that the high-energy quanta of its spectrum lead to the dissociation of anions with the formation of a hydrated electron and radicals. Then a recombination of radicals with the formation of various molecular products takes place. 相似文献
10.
Seven variants of Thermus thermophilus elongation factor G (EF-G) with mutations in loops of domain IV were constructed by PCR. Point mutations Arg504-->Thr, Pro554-->Thr, or Ile534-->Asp did not affect the GTPase and translocational activities of EF-G. Similar results were obtained for mutants with tetra- or hexapeptide inserts in two loops located at the tip and two loops at the base of domain IV. Insertion of tetrapeptide Gly-Ser-Gly-Thr into loop 501--504 at the tip of domain IV dramatically reduced the activity of EF-G in poly(U)-directed polyphenylalanine synthesis on ribosomes, and halved its translocational activity. The intact conformation of loop Thr501-Gly-Gly-Arg504 was assumed to be essential for sterically perfect, efficient interaction of EF-G with the ribosome. The structural and biochemical data on the 30S subunit and EF-G were analyzed to specify the position of EF-G relative to the 30S and 50S ribosomal subunits. 相似文献