全文获取类型
收费全文 | 744篇 |
免费 | 105篇 |
出版年
2021年 | 9篇 |
2019年 | 9篇 |
2017年 | 8篇 |
2016年 | 10篇 |
2015年 | 18篇 |
2014年 | 18篇 |
2013年 | 23篇 |
2012年 | 41篇 |
2011年 | 34篇 |
2010年 | 22篇 |
2009年 | 15篇 |
2008年 | 41篇 |
2007年 | 38篇 |
2006年 | 40篇 |
2005年 | 59篇 |
2004年 | 23篇 |
2003年 | 30篇 |
2002年 | 40篇 |
2001年 | 15篇 |
2000年 | 14篇 |
1999年 | 8篇 |
1998年 | 17篇 |
1997年 | 7篇 |
1995年 | 9篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 15篇 |
1991年 | 6篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 12篇 |
1984年 | 11篇 |
1983年 | 10篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1977年 | 11篇 |
1974年 | 12篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 8篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1968年 | 12篇 |
1967年 | 5篇 |
1965年 | 6篇 |
1961年 | 5篇 |
排序方式: 共有849条查询结果,搜索用时 15 毫秒
31.
John H. Collins Bliss Forbush Lois K. Lane Eleanor Ling Arnold Schwartz Anita Zot 《生物化学与生物物理学报:生物膜》1982,686(1):7-12
Highly purified lamb kidney (Na++K+)-ATPase was photoaffinity labeled with the tritiated 2-nitro-5-azidobenzoyl derivative of ouabain (NAB-ouabain). The labeled (Na++K+)-ATPase was mixed with unlabeled carrier enzyme. Two proteolipid (γ1 and γ2) fractions were then isolated by chromatography on columns of Sepharose CL-6B and Sephadex LH-60. The two fractions were interchangeable when rechromatographed on the LH-60 column, suggesting that γ1 is an aggregated form of γ2. The total yield was 0.8–1.5 mol of γ component per mol of catalytic subunit recovered. This indicates that the γ component is present in stoichiometric amounts in the (Na++K+)-ATPase. The proteolipids that were labeled with NAB-ouabain copurified with the unlabeled proteolipids. 相似文献
32.
33.
The possibility of cultivation of fungi on sugar cane waste (leaves and stalk tops) was tested. Having been crushed, macerated
and heated, this material becomes a suitable substrate for cultivation of oyster mushrooms. Selected hybrids ofPleurotus ostreatus × P. ostreatus form Florida rapidly colonized the substrate and, in the first phase, yielded more than 10% of fresh fruiting bodies per
initial mass of the wet substrate, which is considered, to be the efficiency limit of this technology. The growth cycle in
Cuba is shorter than in Europe. Under the tested temperature and light conditions in Cuba, all strains formed white fruiting
bodies, as compared to a multicolored variety developed in Czechoslovakia. Some of the newly obtained hybrids were found to
have better properties than the original production strains. Hybrids of Cuban origin should be prepared. Besides common, well-known
pests, several species of ants damage the cultures of oyster mushrooms.
Translated by Č. Novotny 相似文献
34.
35.
Mazhar N. Malik Laurie A. Meyers Khalid Iqbal Ashfaq M. Sheikh Lois Scotto Henryk M. Wisniewski 《Life sciences》1981,29(8):795-802
A Ca2+ activated protease(s) capable of hydrolyzing several polypeptides at neutral pH including cytoskeletal proteins, actin, myosin, tubulin and neurofilament triplet was identified in calf brain cortex. The enzyme activity precipitates at 75 mM KCl, pH 6.5 – 7.0 and is inhibited by the sulfhydryl inhibitors, N-ethylmaleimide and para-chloromercuribenzoate and the protease inhibitors, antipain, pepstatin and leupeptin, leupeptin being the most effective. 相似文献
36.
Avian Retroviruses That Cause Carcinoma and Leukemia: Identification of Nucleotide Sequences Associated with Pathogenicity 总被引:11,自引:7,他引:4
下载免费PDF全文
![点击此处可从《Journal of virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Diana Sheiness Klaus Bister Carlo Moscovici Lois Fanshier Thomas Gonda J. Michael Bishop 《Journal of virology》1980,33(3):962-968
Avian myelocytomatosis virus (MC29V) is a retrovirus that transforms both fibroblasts and macrophages in culture and induces myelocytomatosis, carcinomas, and sarcomas in birds. Previous work identified a sequence of about 1,500 nucleotides (here denoted oncMCV) that apparently derived from a normal cellular sequence and that may encode the oncogenic capacity of MC29V. In an effort to further implicate oncMCV in tumorigenesis, we used molecular hybridization to examine the distribution of nucleotide sequences related to oncMCV among the genomes of various avian retroviruses. In addition, we characterized further the genetic composition of the remainder of the MC29V genome. Our work exploited the availability of radioactive DNAs (cDNA's) complementary to oncMCV (cDNAMCV) or to specific portions of the genome of avian sarcoma virus (ASV). We showed that genomic RNAs of avian erythroblastosis virus (AEV) and avian myeloblastosis virus (AMV) could not hybridize appreciably with cDNAMCV. By contrast, cDNAMCV hybridized extensively (about 75%) and with essentially complete fidelity to the genome of Mill Hill 2 virus (MH2V), whose pathogenicity is very similar to that of MC29V, but different from that of AEV or AMV. Hybridization with the ASV cDNA's demonstrated that the MC29V genome includes about half of the ASV envelope protein gene and that the remainder of the MC29V genome is closely related to nucleotide sequences that are shared among the genomes of many avian leukosis and sarcoma viruses. We conclude that oncMCV probably specifies the unique set of pathogenicities displayed by MC29V and MH2V, whereas the oncogenic potentials of AEV and AMV are presumably encoded by a distinct nucleotide sequence unrelated to oncMCV. The genomes of ASV, MC29V, and other avian oncoviruses thus share a set of common sequences, but apparently owe their various oncogenic potentials to unrelated transforming genes. 相似文献
37.
38.
Lois T. Hunt Margaret O. Dayhoff 《Biochemical and biophysical research communications》1980,95(2):864-871
A distant relationship between chicken ovalbumin and two human plasma protease inhibitors was revealed by computer analyses. We propose a new protein superfamily containing at least three families: ovalbumin (and probably gene X and gene Y proteins), antithrombin-III, and alpha1-proteinase inhibitor. Although these families may have diverged from a common ancestor more than 500 million years ago, they may still share similarity in gene structure as well as in protein sequence. 相似文献
39.
Previous studies have shown that cells from subjects with trisomy 21 have enhanced sensitivity to the antiviral effects of interferon, presumably because of the location of the gene, IfRec, coding for the species-specific response to interferon on chromosome 21. Interferon is also known to have many other effects including the ability to inhibit the proliferation of many types of cells. To determine whether proliferating trisomic lymphocytes are more sensitive to the antiproliferative effect of interferon we have investigated, using healthy noninstitutionalized subjects with trisomy 21, the ability of interferon to inhibit the proliferation of lymphocytes stimulated with phytohemagglutinin P(PHA), concanavalin A (Con A), and tetanus toxoid. The trisomic subjects had normal numbers of peripheral blood leukocytes, and normal numbers and proportions of T and B lymphocytes. The production of interferon by PHA-stimulated trisomic T lymphocytes was normal. Trisomic lymphocytes also had normal proliferative responses to PHA and Con A. There were no differences between the inhibitory effects of interferon on the proliferation of PHA-stimulated trisomic and normal lymphocytes. However, trisomic lymphocytes stimulated with low doses of Con A did display significantly enhanced sensitivity to the antiproliferative effects of interferon. In contrast to normal lymphocytes, trisomic lymphocytes were not stimulated to proliferate by tetanus toxoid, and exposure to interferon resulted in enhancement, rather than inhibition, of DNA synthesis. 相似文献
40.
Lois K. Miller Scott G. Franzblau Hugh W. Homan Leslie P. Kish 《Journal of invertebrate pathology》1980,36(2):159-165
A variant of the baculovirus, Autographa californica nuclear polyhedrosis virus, has been isolated in Idaho during an epizootic disease in a field population of A. californica. Genotypic characterization indicates that the virus is distinct from variants previously characterized. Analysis of five clones, derived by plaque purification in cell culture, indicates relative homogeneity of the original virus isolate. Further exploration of the factors involved in natural genetic variability of baculoviruses is appropriate. 相似文献