全文获取类型
收费全文 | 821篇 |
免费 | 41篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 27篇 |
2015年 | 29篇 |
2014年 | 34篇 |
2013年 | 52篇 |
2012年 | 54篇 |
2011年 | 60篇 |
2010年 | 45篇 |
2009年 | 30篇 |
2008年 | 57篇 |
2007年 | 54篇 |
2006年 | 51篇 |
2005年 | 48篇 |
2004年 | 39篇 |
2003年 | 46篇 |
2002年 | 44篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 9篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 19篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有862条查询结果,搜索用时 371 毫秒
851.
Relationships Between Bactericidal Effect and Inhibition of Ribonucleic Acid Nucleotidyl-transferase by Rifampicin in Escherichia coli K-12 总被引:5,自引:3,他引:2 下载免费PDF全文
The mechanism of action of rifampicin, an antibiotic which inhibits in vitro the polycondensation of ribonucleotides by ribonucleic acid (RNA) nucleotidyltransferase, was studied in vivo in Escherichia coli. It is argued that the inhibition of RNA nucleotidyltransferase represents the primary lesion and is responsible for the bactericidal effect. This conclusion is based on (i) the correlation between concentrations of the antibiotic which block in vivo incorporation of labeled uracil and the bactericidal concentrations, (ii) the evidence that the loss of viability of the cells immediately follows the block of RNA synthesis, and (iii) the observation that the reversal of the inhibition of RNA synthesis goes together with a reversal of the loss of viability. 相似文献
852.
Stefania Pagliari Vladimir Vinarsky Fabiana Martino Ana Rubina Perestrelo Jorge Oliver De La Cruz Guido Caluori Jan Vrbsky Pamela Mozetic Antonio Pompeiano Andrea Zancla Sri Ganji Ranjani Petr Skladal Dan Kytyr Zbynk Zdrhal Gabriele Grassi Maurilio Sampaolesi Alberto Rainer Giancarlo Forte 《Cell death and differentiation》2021,28(4):1193
853.
Alessandra Lamas Granero Lucchetti Giancarlo Lucchetti Frederico Camelo Leão Mario Fernando Prieto Peres Homero Vallada 《Culture, medicine and psychiatry》2016,40(3):404-421
The present study aims to describe the characteristics of the complementary religious treatment conducted by Spiritist centers in the city of São Paulo (Brazil), to understand how physical and mental health problems are addressed and how the directors of these centers differentiate between persons with spiritual experiences from those with psychiatric disorders. From 365 Spiritist centers, which received the questionnaire, 55 (15.1 %) were included in the final analysis. There were on average 261 people per week attending spiritual sessions in each center, totalizing approximately 15,000 attendees per week in all 55 centers. The most common treatment performed in these centers was disobsession (Spirit release therapy) (92.7 %); the least common was the ‘spiritual surgery’, present in only 5.5 %. The most frequent health problems reported by attendees were depression (45.1 %), cancer (43.1 %) and diseases in general (33.3 %). Concerning the directors’ awareness to differentiate between spiritual experiences and psychiatric disorders, we found some remarkable divergent opinions. In conclusion, the Spiritist centers are an important health related support system for the city of São Paulo, responsible for a significant share of the city’s total health consultations. The most common conditions the patients suffer from were depression and cancer. 相似文献
854.
Stefania De Luca Giovanni Bruno Roberto Fattorusso Carla Isernia Carlo Pedone Giancarlo Morelli 《Letters in Peptide Science》1998,5(4):269-276
New metal-tetraphenylporphyrins and Fmoc-lysine-metalloporphyrin derivatives have been used to prepare peptide-porphyrin and peptide-metalloporphyrin compounds via solid-phase peptide synthesis. A water-soluble peptide, covalently bound to a manganese(III)-porphyrin, has been used as a catalyst to promote the oxidation of ABTS by hydrogen peroxide or t-butylhydroperoxide. 相似文献
855.
The effect of black widow spider venom [crude gland extract (CGE), gland lumen venom (GLV), or from direct bite] on the cardiac activity of Periplaneta americana was assayed both in vivo and in vitro. It was shown that these different forms of venom in all cases blocked the cockroach heart-beat. Both CGE and GLV showed a selective activity on the heart function compared with their effect on the CNS. It is suggested that cardiac block is due to impairment of either the cardiac nerve ganglia function or the myocardial neuromuscular junctions, or of both of them. The mode of action of the toxic effects on the heart is discussed. Experiments with antiserum from CGE indicate that the antigenic fractions of CGE and GLV affecting the heart function, as well as those affecting the insect motor functions, are common to both toxic materials. 相似文献
856.
857.
858.
Dr. Dharam V. Ablashi Paul H. Levine Caterina De Vinci James E. Whitman Jr. Giancarlo Pizza Dimitri Viza 《Biotherapy》1996,9(1-3):81-86
Specific Human Herpes virus-6 (HHV-6) transfer factor (TF) preparation, administered to two chronic fatigue syndrome patients,
inhibited the HHV-6 infection. Prior to treatment, both patients exhibited an activated HHV-6 infection. TF treatment significantly
improved the clinical manifestations of CFS in one patient who resumed normal duties within weeks, whereas no clinical improvement
was observed in the second patient. It is concluded that HHV-6 specific TF may be of significant value in controlling HHV-6
infection and related illnesses. 相似文献
859.
Carlo Alberto Palmerini Michela Mazzoni Giancarlo Giovinazzo Giuseppe Arienti 《The Journal of membrane biology》2009,230(3):125-131
Antarctic fish live in very cold water and have adapted to this exceptional environment. Hemoglobin is absent or very low;
yet these fish still have erythrocytes, and from these we prepared ghost-like membranes. We studied for the first time the
lipid composition of ghost membranes and of plasma in Antarctic fish (C. hamatus and T. bernacchii) and compared our results with those obtained for temperate-water fish (C. auratus and A. anguilla taken from Lake Trasimeno, Perugia, Italy). The membranes of Antarctic fish were richer in glycerophospholipid (especially
phosphatidylethanolamine), whereas the membranes of temperate-water fish were richer in sphingomyelin. Unsaturated fatty acids
were particularly abundant in Antarctic fish: C. hamatus had long-chain unsaturated fatty acid (especially C22:6 ω-3), whereas T. bernacchii had shorter unsaturated fatty acyl chains (c16:1, ω-7). On the other hand, C. auratus and A. anguilla were particularly rich in C16:0, which constituted more than one-half of the total fatty acid. Plasma lipids (both phospholipid
and cholesterol) were much more abundant in temperate-water fish. The differences in phospholipid content were mainly due
to choline glycerolipids. Measures of membrane fluidity inferred from the fluorescence anisotropy of DPH indicated that the
membranes from Antarctic fish were more fluid at any measured temperature than those obtained from fish living in temperate
waters. The ability to live in a very cold environment has therefore been achieved by the two Antarctic species tested in
this paper by different strategies, but with the same results on fluidity. 相似文献
860.
Francesco Lagona Monia Ranalli Elisabetta Barbi 《Biometrical journal. Biometrische Zeitschrift》2020,62(6):1508-1524
Multivariate spatial count data are often segmented by unobserved space-varying factors that vary across space. In this setting, regression models that assume space-constant covariate effects could be too restrictive. Motivated by the analysis of cause-specific mortality data, we propose to estimate space-varying effects by exploiting a multivariate hidden Markov field. It models the data by a battery of Poisson regressions with spatially correlated regression coefficients, which are driven by an unobserved spatial multinomial process. It parsimoniously describes multivariate count data by means of a finite number of latent classes. Parameter estimation is carried out by composite likelihood methods, that we specifically develop for the proposed model. In a case study of cause-specific mortality data in Italy, the model was capable to capture the spatial variation of gender differences and age effects. 相似文献