全文获取类型
收费全文 | 686篇 |
免费 | 57篇 |
专业分类
743篇 |
出版年
2022年 | 14篇 |
2021年 | 28篇 |
2020年 | 14篇 |
2019年 | 11篇 |
2018年 | 24篇 |
2017年 | 17篇 |
2016年 | 32篇 |
2015年 | 29篇 |
2014年 | 35篇 |
2013年 | 53篇 |
2012年 | 56篇 |
2011年 | 44篇 |
2010年 | 33篇 |
2009年 | 27篇 |
2008年 | 29篇 |
2007年 | 39篇 |
2006年 | 32篇 |
2005年 | 29篇 |
2004年 | 26篇 |
2003年 | 23篇 |
2002年 | 27篇 |
2001年 | 3篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1981年 | 4篇 |
1979年 | 8篇 |
1978年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1968年 | 2篇 |
1967年 | 2篇 |
1965年 | 3篇 |
排序方式: 共有743条查询结果,搜索用时 15 毫秒
1.
In this study we investigated whether alpha-tocopherol can be spared by ubiquinol-3 during autoxidation of multilamellar liposome. A lipophilic azocompound, 2,2'-azobis-(2,4-dimethyl-valeronitrile), was chosen to initiate liposome autoxidation. The effect of either alpha-tocopherol, ubiquinol-3, or a mixture of them was compared. Rates of conjugated diene formation and concomitant disappearance of the two antioxidants was measured. Since the inhibition rate constant for the scavenging of peroxyl radical for alpha-tocopherol was higher than that for quinol-3, it was concluded that alpha-tocopherol is regenerated by ubiquinol-3. 相似文献
2.
The experience of the Toronto General Hospital in the use of nonspecific stimulation of the immune system with bacille Calmette-Guérin (BCG) for the treatment of cancer of the gastrointestinal tract, malignant melanoma and breast cancer is described. The results are presented in terms of survival curves. The use of BCG administered intraperitoneally in a randomized study of patients with gastric, pancreatic and colorectal cancer proved of no benefit. On the other hand, when BCG was given orally in a randomized study of patients with resectable cancer of the colon and in nonrandomized consecutive studies of patients with malignant melanoma and stage IV carcinoma of the breast survival was increased. In a group of patients with advanced gastrointestinal cancer selective stimulation of the immune system with NED 137 produced a significant increase in survival when compared with the survival of historical controls (the patients given BCG intraperitoneally along with 5-fluorouracil for gastrointestinal cancer). The results of these studies suggest the need for a more rational approach in manipulating the immune response that would combine chemotherapy with selective stimulation of the immune system. 相似文献
3.
Bruna Tadolini Diana Fiorentini Laura Landi Luciana Cabrini 《Free radical research》1989,5(4):245-252
To find experimental conditions to selectively study the propagation phase of lipoperoxidation we studied the lipoperoxidation, catalyzed by FeCl2, of liposomes in a buffering condition where Fe2+ autoxidation and oxygen active species generation does not occur. Liposomes from egg yolk phosphatidylcholine. prepared by vortex mixing, do not oxidize Fe2+: on the contrary they oxidize Fe2+ when prepared by ultrasonic irradiation. Dimyristoyl phosphatidylcholine liposomes prepared by ultrasonic irradiation do not oxidize Fe2+. During sonication polyunsaturated fatty acid residues autoxidize and lipid hydroperoxides (LOOH) are generated. Only when LOOH are present in the liposimes Fe2+ oxidizes and its rate of oxidation depends on the amount of LOOH in the assay. The reaction results in the generation of both LOOH and thiobarbituric acid reactive material (TBAR): it is inhibited by butylated hydroxytoluene and has a acidic pH optimum; it is not inhibited by catalase and OH' scavengers. The reaction studied. thus, appears to be the chain branching and propagation phase of lipoperoxidation. When we studied the dependence of Fe2+ oxidation, LOOH and TBAR generation on FeCl2 concentration, we observed that at high FeCl2 concentrations the termination phase of lipoperoxidation was prevalent. Thus. by selecting the appropriate FeCl2 concentration the proposed experimental system allows study of either the propagation or the termination phase of lipoperoxidation. 相似文献
4.
M. Sari-Gorla S. Ferrario E. Frascaroli C. Frova P. Landi M. Villa 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(6-7):812-817
In order to assess the efficiency of male gametophytic selection (MGS) for crop improvement, pollen selection for tolerance to herbicide was applied in maize. The experiment was designed to test the parallel reactivity to Alachlor of pollen and plants grown in controlled conditions or in the field, the response to pollen selection in the sporophytic progeny, the response to a second cycle of MGS, and the transmission of the selected trait to the following generations. The results demonstrated that pollen assay can be used to predict Alachlor tolerance under field conditions and to monitor the response to selection. A positive response to selection applied to pollen in the sporophytic progeny was obtained in diverse genetic backgrounds, indicating that the technique can be generally included in standard breeding programs; the analysis of the data produced in a second selection cycle indicated that the selected trait is maintained in the next generation. 相似文献
5.
P. Pasquali L. Landi L. Cabrini G. Lenaz 《Journal of bioenergetics and biomembranes》1981,13(3-4):141-148
Extraction of endogenous ubiquinone with different methods does not influence ubiquinol oxidase activity in lyophilized mitochondria in terms ofK
M, although a decrease ofV
max is sometimes observed. Experiments with submitochondrial particles from a UQ-deficient mutant ofS. cerevisiae confirm the results with UQ-depleted mitochondria and support the idea that endogenous ubiquinone is not required for the oxidation of exogenous ubiquinols by complex III. 相似文献
6.
Juan Morales-Magaa Ivonne Maciel Arciniega-Martínez Maria Elisa Drago-Serrano Aldo Arturo Resndiz-Albor Rosa Adriana Jarillo-Luna Andrea Cruz-Baquero Modesto Gmez-Lpez Fabiola Guzmn-Mejía Judith Pacheco-Ypez 《Current issues in molecular biology》2022,44(6):2542
Cholecystokinin 8 (CCK8) is an entero-octapeptide that participates in crosstalk with components of intestinal immunity via the CCK receptor (CCKR), but its role in modulation of the IgA response is not fully known under physiological conditions. Male eight-week-old BALB/c mice each were intraperitoneally injected once during 7 days with CCK8, devazapide (CCKR1 antagonist), L365,260 (CCKR2 antagonist) or vehicle (sham group). In intestinal lavages, total and secretory IgA (SIgA) were determined by ELISA; in lamina propria, IgA+ B lymphocytes and IgA+ plasma cells were analyzed by flow cytometry; mRNA levels of polymeric immunoglobulin receptor (pIgR) in epithelial cells and α chain, interleukins (ILs) in lamina propria cells were assessed by qRTPCR. Regarding the sham conditions, IgA+ plasma-cell percentage and IL-2, IL-5, IL-10 and transforming growth factor-β (TGF-β) mRNA levels were either increased by CCK8 or decreased by both CCKR antagonists. For IgA/SIgA responses, IL-4/IL-6 mRNA levels were decreased by all drugs and pIgR mRNA was increased by CCK8 and reduced by L365,260. IgA+ B cell percentage and α chain mRNA levels were elicited by CCK8 and L365,260. Data suggested a presumable differential role of CCK/CCKR on the IgA-response; outcome of L365,260 on the elicitation of IgA+ B cells and α chain mRNA needs further examination. 相似文献
7.
8.
9.
Fabiola Marín‐Aguilar Ana V. Lechuga‐Vieco Elísabet Alcocer‐Gmez Beatriz Castejn‐Vega Javier Lucas Carlos Garrido Alejandro Peralta‐Garcia Antonio J. Prez‐Pulido Alfonso Varela‐Lpez Jos L. Quiles Bernhard Ryffel Ignacio Flores Pedro Bulln Jesús Ruiz‐Cabello Mario D. Cordero 《Aging cell》2020,19(1)
While NLRP3‐inflammasome has been implicated in cardiovascular diseases, its role in physiological cardiac aging is largely unknown. During aging, many alterations occur in the organism, which are associated with progressive impairment of metabolic pathways related to insulin resistance, autophagy dysfunction, and inflammation. Here, we investigated the molecular mechanisms through which NLRP3 inhibition may attenuate cardiac aging. Ablation of NLRP3‐inflammasome protected mice from age‐related increased insulin sensitivity, reduced IGF‐1 and leptin/adiponectin ratio levels, and reduced cardiac damage with protection of the prolongation of the age‐dependent PR interval, which is associated with atrial fibrillation by cardiovascular aging and reduced telomere shortening. Furthermore, old NLRP3 KO mice showed an inhibition of the PI3K/AKT/mTOR pathway and autophagy improvement, compared with old wild mice and preserved Nampt‐mediated NAD+ levels with increased SIRT1 protein expression. These findings suggest that suppression of NLRP3 prevented many age‐associated changes in the heart, preserved cardiac function of aged mice and increased lifespan. 相似文献
10.
Irene Pichler Fabiola Del Greco M. Martin G?gele Christina M. Lill Lars Bertram Chuong B. Do Nicholas Eriksson Tatiana Foroud Richard H. Myers PD GWAS Consortium Michael Nalls Margaux F. Keller International Parkinson's Disease Genomics Consortium Wellcome Trust Case Control Consortium Beben Benyamin John B. Whitfield Genetics of Iron Status Consortium Peter P. Pramstaller Andrew A. Hicks John R. Thompson Cosetta Minelli 《PLoS medicine》2013,10(6)