全文获取类型
收费全文 | 2765篇 |
免费 | 205篇 |
国内免费 | 9篇 |
出版年
2022年 | 17篇 |
2021年 | 56篇 |
2020年 | 28篇 |
2019年 | 35篇 |
2018年 | 49篇 |
2017年 | 36篇 |
2016年 | 64篇 |
2015年 | 90篇 |
2014年 | 120篇 |
2013年 | 167篇 |
2012年 | 209篇 |
2011年 | 192篇 |
2010年 | 129篇 |
2009年 | 109篇 |
2008年 | 138篇 |
2007年 | 134篇 |
2006年 | 124篇 |
2005年 | 107篇 |
2004年 | 122篇 |
2003年 | 122篇 |
2002年 | 93篇 |
2001年 | 29篇 |
2000年 | 33篇 |
1999年 | 32篇 |
1998年 | 34篇 |
1997年 | 31篇 |
1996年 | 24篇 |
1995年 | 25篇 |
1994年 | 25篇 |
1993年 | 32篇 |
1992年 | 39篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 22篇 |
1987年 | 22篇 |
1986年 | 14篇 |
1985年 | 19篇 |
1984年 | 12篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 12篇 |
1980年 | 15篇 |
1979年 | 13篇 |
1978年 | 13篇 |
1977年 | 15篇 |
1976年 | 14篇 |
1975年 | 12篇 |
1973年 | 14篇 |
1972年 | 15篇 |
1970年 | 21篇 |
排序方式: 共有2979条查询结果,搜索用时 31 毫秒
131.
132.
Comparative proteome profiling and functional analysis of chronic myelogenous leukemia cell lines 总被引:1,自引:0,他引:1
Fontana S Alessandro R Barranca M Giordano M Corrado C Zanella-Cleon I Becchi M Kohn EC De Leo G 《Journal of proteome research》2007,6(11):4330-4342
The aim of the present study was the molecular profiling of different Ph+ chronic myelogenous leukemia (CML) cell lines (LAMA84, K562, and KCL22) by a proteomic approach. By employing two-dimensional gel electrophoresis combined with mass spectrometry analysis, we have identified 191 protein spots corresponding to 142 different proteins. Among these, 63% were cancer-related proteins and 74% were described for the first time in leukemia cells. Multivariate analysis highlighted significant differences in the global proteomic profile of the three CML cell lines. In particular, the detailed analysis of 35 differentially expressed proteins revealed that LAMA84 cells preferentially expressed proteins associated with an invasive behavior, while K562 and KCL22 cells preferentially expressed proteins involved in drug resistance. These data demonstrate that these CML cell lines, although representing the same pathological phenotype, show characteristics in their protein expression profile that suggest different phenotypic leukemia subclasses. These data contribute a new potential characterization of the CML phenotype and may help to understand interpatient variability in the progression of disease and in the efficacy of a treatment. 相似文献
133.
Dong A Xu X Edwards AM;Midwest Center for Structural Genomics;Structural Genomics Consortium Chang C Chruszcz M Cuff M Cymborowski M Di Leo R Egorova O Evdokimova E Filippova E Gu J Guthrie J Ignatchenko A Joachimiak A Klostermann N Kim Y Korniyenko Y Minor W Que Q Savchenko A Skarina T Tan K Yakunin A Yee A Yim V Zhang R Zheng H Akutsu M Arrowsmith C Avvakumov GV Bochkarev A Dahlgren LG Dhe-Paganon S Dimov S Dombrovski L Finerty P Flodin S Flores A Gräslund S Hammerström M Herman MD Hong BS 《Nature methods》2007,4(12):1019-1021
We tested the general applicability of in situ proteolysis to form protein crystals suitable for structure determination by adding a protease (chymotrypsin or trypsin) digestion step to crystallization trials of 55 bacterial and 14 human proteins that had proven recalcitrant to our best efforts at crystallization or structure determination. This is a work in progress; so far we determined structures of 9 bacterial proteins and the human aminoimidazole ribonucleotide synthetase (AIRS) domain. 相似文献
134.
Removal of apex predators can drive ecological regime shifts owing to compensatory positive and negative population level responses by organisms at lower trophic levels. Despite evidence that apex predators can influence ecosystems though multiple ecological pathways, most studies investigating apex predators’ effects on ecosystems have considered just one pathway in isolation. Here, we provide evidence that lethal control of an apex predator, the dingo Canis dingo, drives shifts in the structure of Australia's tropical‐savannah ecosystems. We compared mammal assemblages and understorey structure at seven paired‐sites. Each site comprised an area where people poisoned dingoes and an area without dingo control. The effects of dingo control on mammals scaled with body size. Where dingoes were poisoned, we found greater activity of herbivorous macropods and feral cats, a mesopredator, but sparser understorey vegetation and lower abundances of native rodents. Our study suggests that ecological cascades arising from apex predators’ suppressive effects on herbivores and mesopredators occur simultaneously. Concordant effects of dingo removal across tropical‐savannah, forest and desert biomes suggest that dingoes once exerted ubiquitous top–down effects across Australia and provides support for calls that top–down forcing should be considered a fundamental process governing ecosystem structure. 相似文献
135.
Panagiota Koskinioti Erica Ras Antonios A. Augustinos George Tsiamis Leo W. Beukeboom Carlos Caceres Kostas Bourtzis 《Entomologia Experimentalis et Applicata》2019,167(3):197-208
The olive fruit fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae), is the major insect pest of olive orchards (Olea europaea L.), causing extensive damages on cultivated olive crops worldwide. Due to its economic importance, it has been the target species for a variety of population control approaches including the sterile insect technique (SIT). However, the inefficiency of the current mass‐rearing techniques impedes the successful application of area‐wide integrated pest management programs with an SIT component. It has been shown that insect mass rearing and quality of sterile insects can be improved by the manipulation of the insect gut microbiota and probiotic applications. In order to exploit the gut bacteria, it is important to investigate the structure of the gut microbial community. In the current study, we characterized the gut bacterial profile of two wild olive fruit fly populations introduced in laboratory conditions using next generation sequencing of two regions of the 16S rRNA gene. We compared the microbiota profiles regarding the geographic origin of the samples. Additionally, we investigated potential changes in the gut bacteria community before and after the first exposure of the wild adult flies to artificial adult diet with and without antibiotics. Various genera – such as Erwinia, Providencia, Enterobacter, and Klebsiella – were detected for the first time in B. oleae. The most dominant species was Candidatus Erwinia dacicola Capuzzo et al. and it was not affected by the antibiotics in the artificial adult diet used in the first generation of laboratory rearing. Geographic origin affected the overall structure of the gut community of the olive fruit fly, but antibiotic treatment in the first generation did not significantly alter the gut microbiota community. 相似文献
136.
137.
138.
Mariana Ilha Ketlen da Silveira Moraes Francieli Rohden Leo Anderson Meira Martins Radovan Borojevic Guido Lenz Florencia Barbé-Tuana Fátima Costa Rodrigues Guma 《Journal of cellular biochemistry》2019,120(11):19031-19043
Caveolin-1 (Cav-1) expression is increased in hepatic stellate cells (HSC) upon liver cirrhosis and it functions as an integral membrane protein of lipid rafts and caveolae that regulates and integrates multiple signals as a platform. This study aimed to evaluate the role of Cav-1 in HSC. Thus, the effects of exogenous expression of Cav-1 in GRX cells, a model of activated HSC, were determined. Here, we demonstrated through evaluating well-known HSC activation markers – such as α-smooth muscle actin, collagen I, and glial fibrillary acidic protein – that up regulation of Cav-1 induced GRX to a more activated phenotype. GRXEGFP-Cav1 presented an increased migration, an altered adhesion pattern, a reorganization f-actin cytoskeleton, an arrested cell cycle, a modified cellular ultrastructure, and a raised endocytic flux. Based on this, GRX EGFP-Cav1 represents a new cellular model that can be an important tool for understanding of events related to HSC activation. Furthermore, our results reinforce the role of Cav-1 as a molecular marker of HSC activation. 相似文献
139.
140.
Anabaena variabilis cells have been cultivated in the presence of diphenylamine (12 mg/l) which inhibits the biosynthesis of β-carotene, echinenone and zeasanthin. The content of chlorophyll a is also reduced by diphenylamine. The biosynthesis of myxoxanthophyll is, however, stimulated by this reagent.
The membrane fragments prepared from Anabaena cells grown in the presence of diphenylamine have the activities of both Photosystem 1 (NADP+ reduction with DCIP-ascorbate as electron donor) and Photosystem 2 (DCIP reduction with 1,5-diphenylcarbazide as electron donor).
The fluroescence spectra of these cells at 77°K show peaks at 696 and 731 nm and a shoulder around 687 nm. The fluorescence intensity at 687 and 696 nm is higher in these cells than in normal-Anabaena cells. 相似文献