全文获取类型
收费全文 | 6806篇 |
免费 | 549篇 |
国内免费 | 2篇 |
出版年
2023年 | 30篇 |
2022年 | 27篇 |
2021年 | 163篇 |
2020年 | 110篇 |
2019年 | 135篇 |
2018年 | 175篇 |
2017年 | 154篇 |
2016年 | 239篇 |
2015年 | 346篇 |
2014年 | 361篇 |
2013年 | 587篇 |
2012年 | 599篇 |
2011年 | 536篇 |
2010年 | 359篇 |
2009年 | 270篇 |
2008年 | 435篇 |
2007年 | 421篇 |
2006年 | 388篇 |
2005年 | 291篇 |
2004年 | 296篇 |
2003年 | 285篇 |
2002年 | 257篇 |
2001年 | 68篇 |
2000年 | 52篇 |
1999年 | 70篇 |
1998年 | 65篇 |
1997年 | 59篇 |
1996年 | 49篇 |
1995年 | 34篇 |
1994年 | 42篇 |
1993年 | 45篇 |
1992年 | 37篇 |
1991年 | 27篇 |
1990年 | 30篇 |
1989年 | 19篇 |
1988年 | 16篇 |
1987年 | 19篇 |
1986年 | 23篇 |
1985年 | 11篇 |
1984年 | 28篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 20篇 |
1980年 | 9篇 |
1978年 | 17篇 |
1977年 | 9篇 |
1974年 | 11篇 |
1973年 | 11篇 |
1972年 | 9篇 |
1938年 | 12篇 |
排序方式: 共有7357条查询结果,搜索用时 17 毫秒
1.
Patrizia Vaccino Heinz-Albert Becker Andrea Brandolini Francesco Salamini Benjamin Kilian 《Molecular genetics and genomics : MGG》2009,281(3):289-300
The celiac disease (CD) is an inflammatory condition characterized by injury to the lining of the small-intestine on exposure
to the gluten of wheat, barley and rye. The involvement of gluten in the CD syndrome has been studied in detail in bread wheat,
where a set of “toxic” and “immunogenic” peptides has been defined. For wheat diploid species, information on CD epitopes
is poor. In the present paper, we have adopted a genomic approach in order to understand the potential CD danger represented
by storage proteins in diploid wheat and sequenced a sufficiently large number of cDNA clones related to storage protein genes
of Triticum monococcum. Four bona fide toxic peptides and 13 immunogenic peptides were found. All the classes of storage proteins were shown to contain harmful
sequences. The major conclusion is that einkorn has the full potential to induce the CD syndrome, as already evident for polyploid
wheats. In addition, a complete overview of the storage protein gene arsenal in T. monococcum is provided, including a full-length HMW x-type sequence and two partial HMW y-type sequences.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
2.
3.
4.
R. Shainkin-Kestenbaum C. Caruso G. M. Berlyne 《Biological trace element research》1991,28(3):213-221
The effect of nickel on superoxide dismutase activity (SOD), as well as on rate of hydroxydopamine oxidation, was studied in vitro since lipid peroxidation has been implicated in cell damage by nickel, whose toxicity and carcinogenicity are well established. Nickel strongly inhibits SOD activity. The degree of inhibition is directly proportion to the nickel concentration (tested range 0.066 to 0.33 microgram/mL in the reaction mixture); to the substrate concentration (tested range 0.4 x 10 4M to 1.1 x 10 4M 6-hydroxydopamine); and to reaction mixture. Autoxidation of 6-hydroxydopamine was increased by nickel concentrations higher than 15 micrograms/mL. The combination of excessive oxygen free radical production and inhibition of their elimination by inhibition of SOD activity may contribute to the nickel toxicity that has been reported in industrial accidents, as well as to the high incidence of cancer occurring in nickel workers. It may also contribute to many complications in uremic patients, in whom increased serum nickel levels were reported to be in a similar range to those inhibiting SOD. 相似文献
5.
6.
7.
Natural antibodies to interferon-gamma 总被引:3,自引:0,他引:3
Natural antibodies to interferon (IFN)-γ were detected in the serum of virus-infected patients and also, at a low titre, in
the serum of healthy subjects. The increased titre of antibodies to IFN-γ in the sera of virus-infected patients, and its
decrease with clinical resolution, indicate that these antibodies are related to viral infection and probably reflect IFN-γ
production as a result of antigenic stimulationin vivo. Natural antibodies to IFN-γ were affinity purified and studied for their capability to interferein vitro with the multiple activities of the lymphokine. Data obtained show that these human anti-IFN-γ antibodies have no inhibitory
effect on the antiviral and antiproliferative activity of IFN-γ and do not interfere with the binding of the lymphokine to
its specific cell receptor. Instead, they can inhibit the expression of HLA-DR antigens induced by IFN-γ on U937 cells and
interfere, in mixed lymphocyte culture, with the proliferation of lymphocytes and the generation of cytotoxic lymphocytes.
Experiments in animal models suggest that natural antibodies to IFN-γ may have a role in the immunoregulatory process limiting
the intensity and/or duration of immune response. As they can interfere only with the immunomodulating activities of IFN-γ,
these antibodies might open up new therapeutic approaches to diseases with evidence of activated cell-mediated immunity. 相似文献
8.
Paolo d’Errico Marina Boido Antonio Piras Valeria Valsecchi Elena De Amicis Denise Locatelli Silvia Capra Francesco Vagni Alessandro Vercelli Giorgio Battaglia 《PloS one》2013,8(12)
Loss of the survival motor neuron gene (SMN1) is responsible for spinal muscular atrophy (SMA), the most common inherited cause of infant mortality. Even though the SMA phenotype is traditionally considered as related to spinal motor neuron loss, it remains debated whether the specific targeting of motor neurons could represent the best therapeutic option for the disease. We here investigated, using stereological quantification methods, the spinal cord and cerebral motor cortex of ∆7 SMA mice during development, to verify extent and selectivity of motor neuron loss. We found progressive post-natal loss of spinal motor neurons, already at pre-symptomatic stages, and a higher vulnerability of motor neurons innervating proximal and axial muscles. Larger motor neurons decreased in the course of disease, either for selective loss or specific developmental impairment. We also found a selective reduction of layer V pyramidal neurons associated with layer V gliosis in the cerebral motor cortex. Our data indicate that in the ∆7 SMA model SMN loss is critical for the spinal cord, particularly for specific motor neuron pools. Neuronal loss, however, is not selective for lower motor neurons. These data further suggest that SMA pathogenesis is likely more complex than previously anticipated. The better knowledge of SMA models might be instrumental in shaping better therapeutic options for affected patients. 相似文献
9.
Effect of cytochalasins on cytosolic-free calcium concentration and phosphoinositide metabolism in leukocytes 总被引:3,自引:0,他引:3
Susan Treves Francesco Di Virgilio Giorgina M. Vaselli Tullio Pozzan 《Experimental cell research》1987,168(2):285-298
Cytochalasins are routinely used to stimulate a variety of functions in eukaryotic cells even though their precise mode of action remains to be elucidated. In the present work we used the fluorescent Ca2+ indicator quin2 to study the effect of various cytochalasins, cytochalasins A, B, C, D, E (CA, CB, CC, CD, CE) and dihydrocytochalasin B (dhCB) on the intracellular Ca2+ concentration ([Ca2+]i) in various types of leukocytes, viz, neutrophils and lymphocytes. In human neutrophils, cytochalasins increase [Ca2+]i mainly by releasing Ca2+ from membrane-bound, intracellular stores. Thus, in order to readily appreciate the effect of cytochalasins on [Ca2+ )i, these cells must be loaded with low intracellular quin2 concentrations. On the other hand, in peripheral blood lymphocytes, splenocytes and thymocytes, the increase in [Ca2+]i is predominantly due to an increased Ca2+ influx from the extracellular medium. In addition, we found that in neutrophils these drugs prolong the increase in [Ca2+]i induced by chemotactic peptides, probably by increasing the cell permeability to Ca2+. Finally, in thymocytes, cytochalasins potentiate the production of inositol phosphates induced by the polyclonal mitogen concanavalin A (conA). 相似文献
10.