全文获取类型
收费全文 | 781篇 |
免费 | 49篇 |
专业分类
830篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 15篇 |
2016年 | 20篇 |
2015年 | 32篇 |
2014年 | 36篇 |
2013年 | 48篇 |
2012年 | 51篇 |
2011年 | 46篇 |
2010年 | 36篇 |
2009年 | 24篇 |
2008年 | 42篇 |
2007年 | 52篇 |
2006年 | 54篇 |
2005年 | 35篇 |
2004年 | 46篇 |
2003年 | 44篇 |
2002年 | 34篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 5篇 |
1997年 | 12篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1973年 | 4篇 |
排序方式: 共有830条查询结果,搜索用时 15 毫秒
21.
22.
Annalisa Cossu Anna Maria Posadino Roberta Giordo Costanza Emanueli Anna Maria Sanguinetti Amalia Piscopo Marco Poiana Giampiero Capobianco Antonio Piga Gianfranco Pintus 《PloS one》2012,7(11)
The cardiovascular benefits associated with diets rich in fruit and vegetables are thought to be due to phytochemicals contained in fresh plant material. However, whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed apricots were isolated and their presence confirmed by colorimetric analysis and browning index. Oxidative injury of endothelial cells (ECs) is the key step for the onset and progression of cardiovascular diseases (CVD), therefore the potential protective effect of apricot melanoidins on hydrogen peroxide-induced oxidative mitochondrial damage and cell death was explored in human ECs. The redox state of cytoplasmic and mitochondrial compartments was detected by using the redox-sensitive, fluorescent protein (roGFP), while the mitochondrial membrane potential (MMP) was assessed with the fluorescent dye, JC-1. ECs exposure to hydrogen peroxide, dose-dependently induced mitochondrial and cytoplasmic oxidation. Additionally detected hydrogen peroxide-induced phenomena were MMP dissipation and ECs death. Pretreatment of ECs with apricot melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide-induced intracellular oxidation, mitochondrial depolarization and cell death. In this regard, our current results clearly indicate that melanoidins derived from heat-processed apricots, protect human ECs against oxidative stress. 相似文献
23.
24.
Giovanni Benelli Santosh Revadi Adriano Carpita Giulia Giunti Alfio Raspi Gianfranco Anfora Angelo Canale 《Biological Control》2013,64(2):116-124
Psyttalia concolor (Szépligeti) is a koinobiont larval-pupal endoparasitoid of many Tephritidae of great economic importance, such as the medfly, Ceratitis capitata (Wiedemann). In several species of parasitoids it has been demonstrated that the mated females are strongly attracted by specific volatiles from insect-damaged plants. Yet the role of olfactory cues deriving from C. capitata-infested fruits on the female’s decision during the P. concolor host location was poorly investigated. In the present study, the responses of P. concolor females to either healthy or C. capitata-infested fruits was studied through behavioral assays. Volatiles emitted by healthy and infested fruits were SPME-sampled and analyzed by gas chromatography–mass spectrometry (GC–MS). The attractiveness of the identified volatiles was assessed and their electrophysiological activity was analyzed through gas-chromatography coupled with electroantennography (GC-EAD). P. concolor preferred infested peaches and apples over healthy ones, either when visual and olfactory or only olfactory cues were given. Nine compounds were found as exclusive of infested peaches, with respect to healthy ones, and seven of them evoked electrophysiological responses. In apples only quantitative changes in volatile emissions were observed after the medfly infestation. The emissions of 1-butyl butylate, 1-hexyl acetate and 1-butyl esanoate increased in infested apples, whereas 1-hexyl (E)-2-methyl butenoate decreased significantly. Among apple volatiles, 1-butyl butylate, 2-methyl-1-butyl acetate, 1-hexyl acetate, 2-methyl-1-butyl 2-methylbutanoate, 1-butyl hexanoate and 1-hexyl (E)-2-methyl butenoate elicited responses in female antennae. Synthetic blends reproducing the odors emitted by infested peaches and apples elicited strong attraction towards P. concolor females. For both fruits, the blend attractiveness was mainly due to some specific electrophysiological active chemicals: ethyl octanoate, decanal and 4-decanolide for peach, and 1-butyl butylate and 1-butyl hexanoate for apple. The responses induced by the identified fruit volatiles to P. concolor females allow us to suppose that they play a role as short-range attractants during host location. 相似文献
25.
Abstract Morphological and ecological observations on four fleshy crustose algae collected in the eulittoral and upper sublittoral zone of the Island of Gorgona: Myrionema liechtenstenii Hauck, Hildenbrandia canariensis B?rgesen, Peyssonnelia armorica (P. et H. Crouan) Weber-van Bosse in B?rgesen and Cruoria cruoriaeformis (P. et H. Crouan) Denizot are reported. For each species, information on some aspects of their ecology, geographical distribution and notes on their vegetative and reproductive morphology are given. 相似文献
26.
Giuseppe Giaccone Blasco Scammacca Francesco Cinelli Gianfranco Sartoni Giovanni Furnari 《Plant biosystems》2013,147(4):211-229
Abstract Preliminary studies on the marine phythobenthic communities in the Straits of Sicily and adjacent islands. — The results of algological researches carried out by the Gruppo di Algologia of the S.B.I. in the Straits of Sicily and adjacent islands are reported. 288 species have been collected, 275 of which have been identified: 160 were Rhodophyta, 62 Phaeophyta, 32 Chlorophyta, 16 Cyanophyta and 2 Angiospermae. The vegetational research leads to the following conclusions: 1 - the harbour areas (Pantelleria, Malta: loc. 1 and 11) show a nitrophile vegetation, particulary near La Valletta where an almost pure population of Pterocladia pinnata is found; 2 - there are important biogeographical differences between Pelagie islands (Lampedusa, Linosa) and Pantelleria. In fact the former ones have an algal flora composed mostly of eastern mediterranean species, whilst the latter shows strong affinities with the north-african basin, as is demonstrated by the rich well developed belt of Cystoseira sedoides; 3 - several species of atlantic origin, such as Callophyllis laciniata, Peyssonnelia coriacea, P. inamoena and Castagnea chordariaeformis, have been found on the banks (loc. 3, 6, 7). 相似文献
27.
Alfredo Vizzini Angela Lantieri Gianfranco Medardi Enrico Ercole Gabriele Cacialli 《Mycological Progress》2016,15(8):883-901
This study was focused on species of Peziza belonging to the “P. ammophila” complex, using both morphological and molecular approaches. Molecular and morphological analyses showed that several taxa are hidden under the name “ammophila” and, as a consequence, two additional species and one form are established: P. hellenica sp. nov., P. oceanica sp. nov. and P. ammophila f. megaspora f. nov. On the basis of the data that we have, these taxa seem to be related to some geographical areas; P. ammophila appears to be prevalent in northern, central and southern Europe, its f. megaspora is distributed in France and in the Netherlands, P. hellenica comes from Greece and P. oceanica from New Zealand. A cryptic species, not yet circumscribed satisfactorily, is described as P. deceptiva ad int. Moreover, the problem concerning the identification of P. ammophila is raised, the species is epitypified with a sequenced collection from Sicily (Italy) and a key to the species of the complex is provided. 相似文献
28.
On‐chip assessment of human primary cardiac fibroblasts proliferative responses to uniaxial cyclic mechanical strain 下载免费PDF全文
29.
30.
Rachna Aneja Antonella Grigoletto Aakansha Nangarlia Adel A. Rashad Steven Wrenn Jeffrey M. Jacobson Gianfranco Pasut Irwin Chaiken 《Journal of peptide science》2019,25(4)
Previously, we reported the discovery of macrocyclic peptide triazoles (cPTs) that bind to HIV‐1 Env gp120, inhibit virus cell infection with nanomolar potencies, and cause irreversible virion inactivation. Given the appealing virus‐killing activity of cPTs and resistance to protease cleavage observed in vitro, we here investigated in vivo pharmacokinetics of the cPT AAR029b. AAR029b was investigated both alone and encapsulated in a PEGylated liposome formulation that was designed to slowly release inhibitor. Pharmacokinetic analysis in rats showed that the half‐life of FITC‐AAR029b was substantial both alone and liposome‐encapsulated, 2.92 and 8.87 hours, respectively. Importantly, liposome‐encapsulated FITC‐AAR029b exhibited a 15‐fold reduced clearance rate from serum compared with the free FITC‐cPT. This work thus demonstrated both the in vivo stability of cPT alone and the extent of pharmacokinetic enhancement via liposome encapsulation. The results obtained open the way to further develop cPTs as long‐acting HIV‐1 inactivators against HIV‐1 infection. 相似文献