全文获取类型
收费全文 | 1114篇 |
免费 | 43篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 16篇 |
2017年 | 21篇 |
2016年 | 27篇 |
2015年 | 38篇 |
2014年 | 65篇 |
2013年 | 61篇 |
2012年 | 93篇 |
2011年 | 96篇 |
2010年 | 54篇 |
2009年 | 38篇 |
2008年 | 80篇 |
2007年 | 87篇 |
2006年 | 103篇 |
2005年 | 53篇 |
2004年 | 67篇 |
2003年 | 62篇 |
2002年 | 59篇 |
2001年 | 12篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1157条查询结果,搜索用时 31 毫秒
1.
The hypothesis being tested was that the exposure of female workers to the electromagnetic field (EMF) emitted by an induction hob (IHb) meeting public exposure limitations (evaluated according to EN/IEC 62233) is also compliant with European Directive 2013/35/EU on workers’ protection. The electric field induced in three female models in a realistic ergonomically comfortable posture near IHb was evaluated using numerical models of 25 kHz EMF sources (IHb covered by cooking vessels). It was found that, in analyzed ergonomically comfortable exposure situations, the electric field induced in the user's body may exceed public and workers’ limits when the vessels do not match the dimensions of IHb's heating zone. This can even be the case when IHb complies with Conformité Européenne labeling requirements (i.e. EMF exposure falls below public limits 30 cm away from IHb edge). In the 36 exposure scenarios analyzed, statistically significant differences were found when the distances from IHb and vessel dimension, and the height and body mass index of models in exposure scenarios varied, but not between the use of models of pregnant and nonpregnant women. The use of IHb complying with European requirements on general public protection does not ensure that EMF exposure to workers complies with the relevant limits. Adequate protection measures need to address these occupational environmental hazards. © 2020 Bioelectromagnetics Society. 相似文献
2.
Anna Oczkowska Wojciech Kozubski Margarita Lianeri Jolanta Dorszewska 《Current Genomics》2013,14(8):502-517
Although Parkinson’s disease (PD) was first described almost 200 years ago, it remains an incurable disease
with a cause that is not fully understood. Nowadays it is known that disturbances in the structure of pathological proteins
in PD can be caused by more than environmental and genetic factors. Despite numerous debates and controversies in the
literature about the role of mutations in the SNCA and PRKN genes in the pathogenesis of PD, it is evident that these
genes play a key role in maintaining dopamine (DA) neuronal homeostasis and that the dysfunction of this homeostasis is
relevant to both familial (FPD) and sporadic (SPD) PD with different onset. In recent years, the importance of alphasynuclein
(ASN) in the process of neurodegeneration and neuroprotective function of the Parkin is becoming better understood.
Moreover, there have been an increasing number of recent reports indicating the importance of the interaction between
these proteins and their encoding genes. Among others interactions, it is suggested that even heterozygous substitution
in the PRKN gene in the presence of the variants +2/+2 or +2/+3 of NACP-Rep1 in the SNCA promoter, may increase
the risk of PD manifestation, which is probably due to ineffective elimination of over-expressed ASN by the mutated
Parkin protein. Finally, it seems that genetic testing may be an important part of diagnostics in patients with PD and may
improve the prognostic process in the course of PD. However, only full knowledge of the mechanism of the interaction
between the genes associated with the pathogenesis of PD is likely to help explain the currently unknown pathways of selective
damage to dopaminergic neurons in the course of PD. 相似文献
3.
4.
Jolanta J. Adamczyk 《Ecological Research》2011,26(3):547-554
Macrofungal communities were investigated in four associations of xerothermic swards: Festucetum pallentis, Origano-Brachypodietum, Adonido-Brachypodietum pinnati and Diantho-Armerietum elongatae in a Jurassic area of the Częstochowa Upland (southern Poland). A total of 47 species were recorded. The self-organising
map (SOM)—an unsupervised algorithm for artificial neural networks—was used to recognise patterns in the macrofungal communities
of diverse xerothermic swards. Only two associations were mycologically similar: Origano-Brachypodietum and Adonido-Brachypodietum pinnati. Species with high and significant IndVal (the species indicator value) for each investigated phytocoenoses are presented.
The presence of macrofungal species and the participation of indicator species were connected with habitat factors of plant
associations, as documented by the IndVal application. In the least fertile phytocoenoses, macrofungal communities were poor
with few indicator species. The more fertile phytocoenoses had richer and more varied communities of macrofungi with higher
numbers of indicator species. The ordering methods applied in this study were very effective for analyzing the macrofungal
communities existing in plant associations. 相似文献
5.
6.
Jolanta Krudysz-Amblo Mark E. Jennings II Tyler Knight Dwight E. Matthews Kenneth G. Mann Saulius Butenas 《Biochimica et Biophysica Acta (BBA)/General Subjects》2013
Background
Tissue factor (TF), an in vivo initiator of blood coagulation, is a transmembrane protein and has two disulfides in the extracellular domain. The integrity of one cysteine pair, Cys186–Cys209, has been hypothesized to be essential for an allosteric “decryption” phenomenon, presumably regulating TF procoagulant function, which has been the subject of a lengthy debate. The conclusions of published studies on this subject are based on indirect evidences obtained by the use of reagents with potentially oxidizing/reducing properties.Methods
The status of disulfides in recombinant TF1–263 and natural placental TF in their non-reduced native and reduced forms was determined by mass-spectrometry. Functional assays were performed to assess TF cofactor function.Results
In native proteins, all four cysteines of the extracellular domain of TF are oxidized. Reduced TF retains factor VIIa binding capacity but completely loses the cofactor function.Conclusion
The reduction of TF disulfides (with or without alkylation) eliminates TF regulation of factor VIIa catalytic function in both membrane dependent FX activation and membrane independent synthetic substrate hydrolysis.General significance
Results of this study advance our knowledge on TF structure/function relationships. 相似文献7.
Katarzyna Ginda Martyna Bezulska Małgorzata Ziółkiewicz Jarosław Dziadek Jolanta Zakrzewska‐Czerwińska Dagmara Jakimowicz 《Molecular microbiology》2013,87(5):998-1012
Mycobacteria are among the clinically most important pathogens, but still not much is known about the mechanisms of their cell cycle control. Previous studies suggested that the genes encoding ParA and ParB (ATPase and DNA binding protein, respectively, required for active chromosome segregation) may be essential in Mycobacterium tuberculosis. Further research has demonstrated that a Mycobacterium smegmatis parB deletion mutant was viable but exhibited a chromosome segregation defect. Here, we address the question if ParA is required for the growth of M. smegmatis, and which cell cycle processes it affects. Our data show that parA may be deleted, but its deletion leads to growth inhibition and severe disturbances of chromosome segregation and septum positioning. Similar defects are also caused by ParA overproduction. EGFP–ParA localizes as pole‐associated complexes connected with a patch of fluorescence accompanying two ParB complexes. Observed aberrations in the number and positioning of ParB complexes in the parA deletion mutant indicate that ParA is required for the proper localization of the ParB complexes. Furthermore, it is shown that ParA colocalizes and interacts with the polar growth determinant Wag31 (DivIVA homologue). Our results demonstrate that mycobacterial ParA mediates chromosome segregation and co‐ordinates it with cell division and elongation. 相似文献
8.
Jolanta Patamsytė Vytautas Rančelis Tatjana Čėsnienė Violeta Kleizaitė Virginija Tunaitienė Donatas Naugžemys Virginija Vaitkūnienė Donatas Žvingila 《Central European Journal of Biology》2013,8(9):898-911
The alien species Erigeron annuus (L.) Pers. is in an intensive spreading phase in Lithuania. Random amplified polymorphic DNA (RAPDs) and inter-simple sequence repeats (ISSRs) assays were used to study the genetic structure of old and new invasive populations and to determine the most spread genotypes of this species in Lithuania. Pairwise genetic distances between populations established using RAPD and ISSR markers significantly correlated (r=0.91, P<0.05). Our study indicates that there are two genetically different types of E. annuus populations. The first type is represented by a widely spread main clone and related monomorphic populations. The second type is represented by polymorphic populations, some of them present at sites where E. annuus has not been previously observed. Main clone predominates in nine populations and is from the region where this species was first described in natural ecosystems of Lithuania. UPGMA cluster analysis revealed genetic relationships between the main clone and accessions from old cemeteries where E. annuus has been grown as an ornamental plant. We found high genetic differentiation among populations (G ST=0.58 for RAPDs, G ST=0.64 for ISSRs). Taken together, our results will contribute to the monitoring of E. annuus spread in Lithuania. 相似文献
9.
Regina Vyšniauskienė Vida Rančelienė Jolanta Patamsytė Donatas Žvingila 《Central European Journal of Biology》2013,8(5):480-491
Alfalfa (Medicago sativa; =M. sativa ssp. sativa) in Lithuania is sown as albuminous forage for cattle due to favourable climatic condition. Over many generations, alfalfa plants have escaped from cultivation fields into natural ecosystems and established wild populations. We collected and analyzed individuals from seventeen wild populations of M. sativa. Using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analyses, 117 RAPD and 64 ISSR reproducible and highly polymorphic (90.8% for RAPD and 86.3% for ISSR) loci were established. AMOVA showed a high genetic differentiation of M. sativa populations for both types of DNA markers utilized. According to RAPD markers, the genetic variability among populations was 63.1% and 57.0% when ISSR markers were used. Taken together, these results demonstrate that wild populations of M. sativa possess a high potential of genetic variability, that could potentially result in colonization of natural ecosystems. The UPGMA cluster analysis also showed that the DNA markers discovered in this study can distinguish between M. sativa and M. falcata (=M. sativa ssp. falcata) populations and therefore may be used to study the genetic impact of M. sativa on the native populations of M. falcata. 相似文献
10.
Aleksandra Markiewicz Marzena We?nicka-Ja?kiewicz Jaros?aw Skokowski Janusz Ja?kiewicz Jolanta Szade Jacek Jassem Anna J. ?aczek 《PloS one》2013,8(8)