全文获取类型
收费全文 | 3316篇 |
免费 | 214篇 |
出版年
2023年 | 15篇 |
2022年 | 32篇 |
2021年 | 54篇 |
2020年 | 40篇 |
2019年 | 59篇 |
2018年 | 83篇 |
2017年 | 59篇 |
2016年 | 85篇 |
2015年 | 134篇 |
2014年 | 148篇 |
2013年 | 238篇 |
2012年 | 252篇 |
2011年 | 257篇 |
2010年 | 156篇 |
2009年 | 128篇 |
2008年 | 221篇 |
2007年 | 226篇 |
2006年 | 184篇 |
2005年 | 154篇 |
2004年 | 150篇 |
2003年 | 162篇 |
2002年 | 162篇 |
2001年 | 29篇 |
2000年 | 18篇 |
1999年 | 27篇 |
1998年 | 26篇 |
1997年 | 33篇 |
1996年 | 21篇 |
1995年 | 29篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 28篇 |
1991年 | 25篇 |
1990年 | 29篇 |
1989年 | 11篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 11篇 |
1985年 | 13篇 |
1984年 | 16篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 18篇 |
1980年 | 12篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 13篇 |
1975年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有3530条查询结果,搜索用时 15 毫秒
101.
102.
103.
Stefania Galdiero Annarita Falanga Rossella Tarallo Luigi Russo Emilia Galdiero Marco Cantisani Giancarlo Morelli Massimiliano Galdiero 《Journal of peptide science》2013,19(3):148-158
Herpes simplex virus (HSV) is a significant human pathogen causing mucocutaneous lesions primarily in the oral or genital mucosa. Although acyclovir (ACV) and related nucleoside analogs provide successful treatment, HSV remains highly prevalent worldwide and is a major cofactor for the spread of human immunodeficiency virus. Encephalitis, meningitis, and blinding keratitis are among the most severe diseases caused by HSV. ACV resistance poses an important problem for immunocompromised patients and highlights the need for new safe and effective agents; therefore, the development of novel strategies to eradicate HSV is a global public health priority. Despite the continued global epidemic of HSV and extensive research, there have been few major breakthroughs in the treatment or prevention of the virus since the introduction of ACV in the 1980s. A therapeutic strategy at the moment not fully addressed is the use of small peptide molecules. These can be either modeled on viral proteins or derived from antimicrobial peptides. Any peptide that interrupts protein–protein or viral protein–host cell membrane interactions is potentially a novel antiviral drug and may be a useful tool for elucidating the mechanisms of viral entry. This review summarizes current knowledge and strategies in the development of synthetic and natural peptides to inhibit HSV infectivity. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
104.
Milena Merlo Pich Alida Castagnoli Annalisa Biondi Andrea Bernacchia Pier Luigi Tazzari Marilena D'Aurelio 《Free radical research》2013,47(4):429-436
The conditions under which Coenzyme Q (CoQ) may protect platelet mitochondrial function of transfusional buffy coats from aging and from induced oxidative stress were investigated. The Pasteur effect, i.e. the enhancement of lactate production after inhibition of mitochondrial respiratory chain, was exploited as a marker of mitochondrial function as it allows to calculate the ratio of mitochondrial ATP to glycolytic ATP. Reduced CoQ 10 improves platelet mitochondrial function of transfusional buffy coats and protects the cells from induced oxidative stress. Oxidized CoQ is usually less effective, despite the presence, shown for the first time in this study, of quinone reductase activities in the platelet plasma membranes. The addition of a CoQ reducing system to platelets is effective in enhancing the protection of platelet mitochondrial function from the oxidative stress. The results support on one hand a possibility of protection of mitochondrial function in aging by exogenous CoQ intake, on the other a possible application in protection of transfusional buffy coats from storage conditions and oxidative deterioration. 相似文献
105.
Prof. Luigi Desole 《Plant biosystems》2013,147(2-3):256-273
Summary The Author has studied the embryological development of Centaurea horrida Bad., pure pliocenic endemisms of Sardinia and has established that: 1°) the cromosomic number of the species is: 2n = 18. 2°) the genesis of microspores is of simultaneous type; 3°) The archesporium is constituted of one cell only seldom accompanied by a basal cell; 4°) the development of the female gamethophyte is of normal type; 5°) even showing cases of degenerated antipodal cells, the species has a marked tendency to the polyantipody, sometimes also characterized by a strong hypertrophy of its cells; 6°) in the species the contemporary germination of some megaspores in the same ovule is enough frequent; 7°) there are also some cases of coesistence of some gamethophytes in their different stages of development; 8°) the phenomenon of «multiple oospheres» and of «multiple synergidae» may happen; 9°) in some ovules, near the egg-apparatus, cells of two or four nuclei may be found. For these last ascertainments (8° and 9°) the Author makes the hypothesis that it may be probably an anomalous prolification of micropylar nuclei, or asynchronous development, for delayed germination of some micropylar megaspores producing primary stages of gamethophyte. Moreover the Author has the opportunity to bring into evidence: 10°) a case of ovular teratology represented by the extraovular development of an adult gamethophyte very similar to those previously found by the Author himself in Petasites fragrans; 11°) frequent cases of regretion of female sexuality, founding that about the 10% of the flowers examined were functionally male. The Author has fronted the possibility of the existence, in Asteraceae, also of the type of inflorescence where «flowers are all tubulated: the marginal ones neuter, the others or hermaphrodite or hermaphrodite and male». 相似文献
106.
Luke C. Pilling William Henley Dena G. Hernandez Andrew B. Singleton Stefania Bandinelli Jack M. Guralnik Luigi Ferrucci Lorna W. Harries 《Aging cell》2013,12(2):324-326
We have previously described a statistical model capable of distinguishing young (age <65 years) from old (age ≥75 years) individuals. Here we studied the performance of a modified model in three populations and determined whether individuals predicted to be biologically younger than their chronological age had biochemical and functional measures consistent with a younger biological age. Those with ‘younger’ gene expression patterns demonstrated higher muscle strength and serum albumin, and lower interleukin‐6 and blood urea concentrations relative to ‘biologically older’ individuals (odds ratios 2.09, 1.64, 0.74, 0.74; P = 2.4 × 10?2, 3.5 × 10?4, 1.8 × 10?2, 1.5 × 10?2, respectively). We conclude that our expression signature of age is robust across three populations and may have utility for estimation of biological age. 相似文献
107.
Alessandra Vacca Roberta Montisci Pietro Garau Paolo Siotto Matteo Piga Alberto Cauli Massimo Ruscazio Luigi Meloni Sabino Iliceto Alessandro Mathieu 《Arthritis research & therapy》2013,15(1):R8
Introduction
Microcirculation dysfunction is a typical feature of systemic sclerosis (SSc) and represents the earliest abnormality of primary myocardial involvement. We assessed coronary microcirculation status by combining two functional tests in SSc patients and estimating its impact on disease outcome.Methods
Forty-one SSc patients, asymptomatic for coronary artery disease, were tested for coronary flow velocity reserve (CFR) by transthoracic-echo-Doppler with adenosine infusion (A-TTE) and for left ventricular wall motion abnormalities (WMA) by dobutamine stress echocardiography (DSE). Myocardial multi-detector computed tomography (MDCT) enabled the presence of epicardial stenosis, which could interfere with the accuracy of the tests, to be excluded. Patient survival rate was assessed over a 6.7- ± 3.5-year follow-up.Results
Nineteen out of 41 (46%) SSc patients had a reduced CFR (≤2.5) and in 16/41 (39%) a WMA was observed during DSE. Furthermore, 13/41 (32%) patients showed pathological CFR and WMA. An inverse correlation between wall motion score index (WMSI) during DSE and CFR value (r = -0.57, P <0.0001) was observed; in addition, CFR was significantly reduced (2.21 ± 0.38) in patients with WMA as compared to those without (2.94 ± 0.60) (P <0.0001). In 12 patients with abnormal DSE, MDCT was used to exclude macrovasculopathy. During a 6.7- ± 3.5-year follow-up seven patients with abnormal coronary functional tests died of disease-related causes, compared to only one patient with normal tests.Conclusions
A-TTE and DSE tests are useful tools to detect non-invasively pre-clinical microcirculation abnormalities in SSc patients; moreover, abnormal CFR and WMA might be related to a worse disease outcome suggesting a prognostic value of these tests, similar to other myocardial diseases. 相似文献108.
Luigi Agrofoglio Roger Condom Roger Guedj S. Richard Challand John Selway 《Nucleosides, nucleotides & nucleic acids》2013,32(5):1147-1160
Abstract The 1-hydroxymethyl-3-cyclopentene (4) was converted, after epoxidation, to two new exocyclic amino carbocyclic nucleosides (1, 2), and a new cyclopentane nucleoside analogue (3), with potential biological activities. The regioselectivity of the epoxidation (4), which is the key step, is governed by steric control using aryl and silyl hydroxyl protecting groups. 相似文献
109.
Stefano Pavan Adalgisa Schiavulli Michela Appiano Cecilia Miacola Richard G. F. Visser Yuling Bai Concetta Lotti Luigi Ricciardi 《Molecular breeding : new strategies in plant improvement》2013,31(1):247-253
Powdery mildew is the most widespread disease of pea (Pisum sativum L.) and causes severe economic losses worldwide. Recessively inherited er1 powdery mildew resistance, successfully used for decades in pea breeding programs, has recently been shown to originate from the loss of function of the PsMLO1 gene. Five er1 alleles, each corresponding to a different PsMLO1 null mutation, have been characterized to date in pea germplasm. In order to aid er1 selection, we aimed to identify functional markers which target PsMLO1 polymorphisms directly responsible for the resistant phenotype. Highly informative cleaved amplified polymorphic sequence (CAPS), derived cleaved amplified polymorphic sequence (dCAPS), sequence tagged site (STS) and high-resolution melting (HRM) markers were developed which enable the selection of each of the five er1 alleles. Taken together, the results described here provide a powerful tool for breeders, overcoming limitations of previously reported er1-linked markers due to the occurrence of recombination with the resistance locus and/or the lack of polymorphism between parental genotypes. The HRM marker er1-5/HRM54 reported here, targeting a mutagenesis-induced er1 allele recently described by us, does not require manual processing after PCR amplification, and is therefore suitable for large-scale breeding programs based on high-throughput automated screening. 相似文献
110.
Luigi Di Luigi Mariangela Sottili Cristina Antinozzi Gabriella Barbara Vannelli Francesco Romanelli Valeria Riccieri Guido Valesini Andrea Lenzi Clara Crescioli 《PloS one》2013,8(10)