全文获取类型
收费全文 | 606篇 |
免费 | 27篇 |
专业分类
633篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 10篇 |
2017年 | 7篇 |
2016年 | 16篇 |
2015年 | 34篇 |
2014年 | 25篇 |
2013年 | 47篇 |
2012年 | 55篇 |
2011年 | 61篇 |
2010年 | 35篇 |
2009年 | 24篇 |
2008年 | 56篇 |
2007年 | 46篇 |
2006年 | 40篇 |
2005年 | 26篇 |
2004年 | 32篇 |
2003年 | 19篇 |
2002年 | 28篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 6篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有633条查询结果,搜索用时 0 毫秒
51.
52.
Panagiotis D Velentzas Athanassios D Velentzas Vassiliki E Mpakou Issidora S Papassideri Dimitrios J Stravopodis Lukas H Margaritis 《Cell biology international》2011,35(1):15-27
Ubiquitin/proteasome‐mediated degradation of eukaryotic proteins is critically implicated in a number of signalling pathways and cellular processes. To specifically impair proteasome activities, in vitro developing Drosophila melanogaster egg chambers were exposed to the MG132 or epoxomicin proteasome inhibitors, while a GAL4/UAS binary genetic system was employed to generate double transgenic flies overexpressing β2 and β6 conditional mutant proteasome subunits in a cell type‐specific manner. MG132 and epoxomicin administration resulted in severe deregulation of in vitro developing egg chambers, which was tightly associated with precocious induction of nurse cell‐specific apoptotic and autophagic death programmes, featured by actin cytoskeleton disorganization, nuclear chromatin condensation, DRICE caspase activation and autophagosome accumulation. In vivo targeted overexpression of β2 and β6 conditional mutants, specifically in the nurse cell compartment, led to a notable up‐regulation of sporadic apoptosis potency during early and mid‐oogenesis ‘checkpoints’, thus reasonably justifying the observed reduction in eclosion efficiency. Furthermore, in response to the intracellular abundance of β2 and β6 conditional mutant forms, specifically in numerous tissues of third instar larval stage, the developmental course was arrested, and lethal phenotypes were obtained at this particular embryonic period, with the double transgenic heterozygote embryos being unable to further proceed to complete maturation to adult flies. Our data demonstrate that physiological proteasome function is required to ensure normal oogenesis and embryogenesis in D. melanogaster, since targeted and cell type‐dependent proteasome inactivation initiates developmentally deregulated apoptotic and autophagic mechanisms. 相似文献
53.
From research to implementation: Nature conservation in the Eastern Rhodopes mountains (Greece and Bulgaria), European Green Belt 总被引:2,自引:0,他引:2
Stefan Schindler Nuno Curado Stoyan C. Nikolov Elzbieta Kret Beatriz Cárcamo Giorgos Catsadorakis Kostas Poirazidis Thomas Wrbka Vassiliki Kati 《Journal for Nature Conservation》2011,19(4):193-201
Nature conservation should ideally build on the scientific recommendations that are concluded from applied conservation research, as well as on monitoring schemes that evaluate the effectiveness of recommendations. We considered as a case study a system of six protected areas located in the Eastern Rhodopes mountains in the southern part of the European Green Belt (EGB). To investigate nature conservation effectiveness, we reviewed 196 articles from scientific journals and books, eight doctoral and master theses, and 39 scientific reports regarding the Greek (one protected area, 428 km2) and the Bulgarian (five protected areas, 904 km2) part of the study area. We extracted 743 conservation recommendations, and through questionnaires completed by 10 local experts, we found that 74% of the recommendations were familiar for the experts. In the Greek (GR) and the Bulgarian part (BG) only 52% and 16%, respectively, of the recommendations were implemented, and only 15% (GR) and 3.1% (BG) were implemented and evaluated regarding their effectiveness. According to the experts, the main reasons for non-implementation and non-evaluation were absence or incompetence of the responsible authorities. Some recommendations obtained a remarkable low rate of implementation, such as those regarding agriculture and livestock rearing practices (GR: 29%, BG: 16%) or mammal conservation (GR: 0%, BG: 16%). Some other recommendations obtained rather high rates at least for Greece, such as tourism and environmental education (GR: 57%, BG: 42%) and bird conservation (GR: 57%, BG: 11%). We found that researchers and conservation managers at both sides of the Greek-Bulgarian border face similar implementation problems, related often to the lack of political will for nature conservation and establishment of competent authorities. The role of the EGB is crucial in enhancing the established cross-border collaborations between stakeholders involved in nature conservation. 相似文献
54.
Kotoula V Lambaki S Televantou D Kalogera-Fountzila A Nikolaou A Markou K Misailidou D Syrigos KN Fountzilas G 《Translational oncology》2011,4(1):47-58
The anti-epidermal growth factor receptor antibody cetuximab (Erbitux, CTX) is currently used for the treatment of locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN), as yet with modest effectiveness, prompting for the identification of response predictors to this treatment and for the targeting of additional pathways implicated in this disease. Within this scope, we investigated the effect of SRC/STAT pathway components on LA-SCCHN patient outcome. SRC, STAT1, STAT3, STAT5A, STAT5B, ANXA1, CAV1, IGFBP2, EPHA2, EPHB2, and MSN relative gene expression, as well as Stat protein activation, were assessed on LA-SCCHN tumor tissues from 35 patients treated with combined radiotherapy (RT) and CTX-based regimens. Stat1, Stat3, and Stat5 proteins were usually found activated in neoplastic nuclei (70.4%, 85.7%, and 70.8%, respectively). Activated Stat3 and Stat5 were associated with each other (P = .017) and with a CAV1(high)/MSN(high)/IGFBP2(low) profile. All patients with tumors expressing high STAT5A/EPHA2 experienced a complete response on RT-CTX-based treatments (12/15 complete responders, P < .0001) and a longer progression-free survival (P = .024). Few tumors expressed high ANXA1/CAV1/EPHA2 and low IGFBP2, a putative dasatinib response-related profile, whereas high ANXA1 was associated with shorter overall survival (P = .003). In conclusion, Stat activation is common in LA-SCCHN, where overexpression of STAT5A and EPHA2 may predict for response to RT-CTX treatments. The STAT5A/EPHA2 profile seems of particular interest for validation in larger cohorts and in multiple tumor types because markers for the positive selection of patients to benefit from CTX-containing treatments are currently lacking. 相似文献
55.
56.
The study objective was to analyze the integration of psychomotor coordination into other dimensions evaluated. Four morphologic variables (stature, body mass, forearm circumference and triceps skinfold) and 7 motor variables (hand tapping, standing jump, sit-ups, forward bow, bent arm hang, 3-min run and polygon backward) were assessed in a sample of 2205 male children (subdivided into 4 groups) aged 7-11 years, elementary school first- to fourth-graders from the Primorje - Gorski Kotar County, Republic of Croatia. Relations between the set of morphologic-motor variables and the coordination variable (of backward polygon) as a criterion were analyzed Data were processed by use of regression analysis. Study results clearly indicated the values of the criterion variable (coordination) to rise and the criterion prediction using the set of variables to improve with age. Explosive strength, movement frequency and static strength were the best positive criterion predictors, whereas body weight at age 7-10, and skeletal longitudinality and subcutaneous adipose tissue at age 10-11 were the best negative criterion predictors. Also, developmental characteristics of coordination were found to be a major determinant on programming the work in kinesiologic education of elementary school children. 相似文献
57.
Brd2/RING3 interacts with a chromatin-binding domain in the Kaposi's Sarcoma-associated herpesvirus latency-associated nuclear antigen 1 (LANA-1) that is required for multiple functions of LANA-1 下载免费PDF全文
Viejo-Borbolla A Ottinger M Brüning E Bürger A König R Kati E Sheldon JA Schulz TF 《Journal of virology》2005,79(21):13618-13629
58.
Wang GT Wang S Gentles R Sowin T Maring CJ Kempf DJ Kati WM Stoll V Stewart KD Laver G 《Bioorganic & medicinal chemistry letters》2005,15(1):125-128
(+/-)-(2R,3R,5R)-[2-(1'-S-acetamido-3'-methyl)butyl-3-methoxycarbonyl]tetrahydrofuran-5-carboxylic acid (9) and (+/-)-(2R,3R,5R)-[2-(1'-S-acetamido-3'-methyl)butyl-3-(4'-imidazolyl)]tetrahydrofuran 5-carboxylic acid (14) were synthesized as inhibitors of influenza neuraminidase (NA). Both compounds 9 and 14 inhibit influenza NA A with an IC(50) of about 0.5 microM and NA B with an IC(50) of 1.0 microM. 相似文献
59.
Dysregulated psychophysiological responses have been observed in patients with fibromyalgia syndrome (FMS), although the results
are inconsistent. Surface electromyographic (EMG), systolic and diastolic blood pressure, heart rate (HR), and skin conductance
levels (SCLs) were continuously recorded at baseline, and during a series of stress and relaxation tasks in 90 FMS patients
and 30 age and sex matched healthy controls (HCs). The patient sample demonstrated lower baseline EMG levels compared to the
HCs on all tasks. In contrast, the patients displayed elevated HR and SCL (sympathetic vasomotor and sudomotor indices, respectively)
during both stress tasks. A cluster analysis identified four psychophysiological response patterns: 63.3% of HCs showed increased
muscle tension and stable cardiovascular responses; 34.8% of FMS patients showed a pattern of increased sympathetic vasomotor
reactivity with stable sudomotor and reduced muscular response; 12.2% of FMS patients showed a pattern of increased sympathetic
sudomotor reactivity connected with increased sympathetic vasomotor response and reduced muscular response; and, in contrast,
46.7% of FMS patients showed a pattern of parasympathetic vasomotor reactivity and reduced sudomotor as well as muscular response.
The identification of low baseline muscle tension in FMS is discrepant with other chronic pain syndromes and suggests that
unique psychophysiological features may be associated with FMS. The different psychophysiological response patterns within
the patient sample support the heterogeneity of FMS. 相似文献
60.
Saccharomyces paradoxus is the closest known relative of the well-known S. cerevisiae and an attractive model organism for population genetic and genomic studies. Here we characterize a set of 28 wild isolates from a 10-km(2) sampling area in southern England. All 28 isolates are homothallic (capable of mating-type switching) and wild type with respect to nutrient requirements. Nine wild isolates and two lab strains of S. paradoxus were surveyed for sequence variation at six loci totaling 7 kb, and all 28 wild isolates were then genotyped at seven polymorphic loci. These data were used to calculate nucleotide diversity and number of segregating sites in S. paradoxus and to investigate geographic differentiation, population structure, and linkage disequilibrium. Synonymous site diversity is approximately 0.3%. Extensive incompatibilities between gene genealogies indicate frequent recombination between unlinked loci, but there is no evidence of recombination within genes. Some localized clonal growth is apparent. The frequency of outcrossing relative to inbreeding is estimated at 1.1% on the basis of heterozygosity. Thus, all three modes of reproduction known in the lab (clonal replication, inbreeding, and outcrossing) have been important in molding genetic variation in this species. 相似文献