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171.
Regulation of K+ current in human airway epithelial cells by exogenous and autocrine adenosine 总被引:4,自引:0,他引:4
Szkotak Artur J.; Ng Amy M. L.; Sawicka Jolanta; Baldwin Stephen A.; Man S. F. Paul; Cass Carol E.; Young James D.; Duszyk Marek 《American journal of physiology. Cell physiology》2001,281(6):C1991
The regulatory actions ofadenosine on ion channel function are mediated by four distinctmembrane receptors. The concentration of adenosine in the vicinity ofthese receptors is controlled, in part, by inwardly directed nucleosidetransport. The purpose of this study was to characterize the effects ofadenosine on ion channels in A549 cells and the role of nucleosidetransporters in this regulation. Ion replacement and pharmacologicalstudies showed that adenosine and an inhibitor of human equilibrative nucleoside transporter (hENT)-1, nitrobenzylthioinosine, activated K+ channels, most likely Ca2+-dependentintermediate-conductance K+ (IK)channels. A1 but not A2 receptor antagonistsblocked the effects of adenosine. RT-PCR studies showed that A549 cellsexpressed mRNA for IK-1 channels as well asA1, A2A, and A2B but notA3 receptors. Similarly, mRNA for equilibrative (hENT1 andhENT2) but not concentrative (hCNT1, hCNT2, and hCNT3) nucleosidetransporters was detected, a result confirmed in functional uptakestudies. These studies showed that adenosine controls the function ofK+ channels in A549 cells and that hENTs play a crucialrole in this process. 相似文献
172.
173.
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
174.
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
175.
Floral meristems of Lolium and Festuca grasses give a 5- to 19-fold enhancement in yield of extracted DNA in comparison with leaves. Meristems also provide highly
pure DNA samples. The method could be useful for applications in molecular genetics in many species of the Gramineae.
Received: 14 April 1998 / Revision received: 8 June 1998 / Accepted: 10 July 1998 相似文献
176.
177.
Hydrological and environmental variables outperform spatial factors in structuring species,trait composition,and beta diversity of pelagic algae 下载免费PDF全文
Naicheng Wu Yueming Qu Björn Guse Kristė Makarevičiūtė Szewing To Tenna Riis Nicola Fohrer 《Ecology and evolution》2018,8(5):2947-2961
There has been increasing interest in algae‐based bioassessment, particularly, trait‐based approaches are increasingly suggested. However, the main drivers, especially the contribution of hydrological variables, of species composition, trait composition, and beta diversity of algae communities are less studied. To link species and trait composition to multiple factors (i.e., hydrological variables, local environmental variables, and spatial factors) that potentially control species occurrence/abundance and to determine their relative roles in shaping species composition, trait composition, and beta diversities of pelagic algae communities, samples were collected from a German lowland catchment, where a well‐proven ecohydrological modeling enabled to predict long‐term discharges at each sampling site. Both trait and species composition showed significant correlations with hydrological, environmental, and spatial variables, and variation partitioning revealed that the hydrological and local environmental variables outperformed spatial variables. A higher variation of trait composition (57.0%) than species composition (37.5%) could be explained by abiotic factors. Mantel tests showed that both species and trait‐based beta diversities were mostly related to hydrological and environmental heterogeneity with hydrological contributing more than environmental variables, while purely spatial impact was less important. Our findings revealed the relative importance of hydrological variables in shaping pelagic algae community and their spatial patterns of beta diversities, emphasizing the need to include hydrological variables in long‐term biomonitoring campaigns and biodiversity conservation or restoration. A key implication for biodiversity conservation was that maintaining the instream flow regime and keeping various habitats among rivers are of vital importance. However, further investigations at multispatial and temporal scales are greatly needed. 相似文献
178.
179.
Partial biotinidase deficiency is usually due to the D444H mutation in the biotinidase gene 总被引:1,自引:0,他引:1
Katie L. Swango Mübeccel Demirkol Gülden Hüner E. Pronicka Jolanta Sykut-Cegielska Andreas Schulze B. Wolf 《Human genetics》1998,102(5):571-575
Newborn screening for biotinidase deficiency has identified children with profound biotinidase deficiency (<10% of mean normal
serum activity) and those with partial biotinidase deficiency (10%–30% of mean normal serum activity). Children with partial
biotinidase deficiency and who are not treated with biotin do not usually exhibit symptoms unless they are stressed (i.e.,
prolonged infection). We found that 18 of 19 randomly selected individuals with partial deficiency have the transversion missense
mutation G1330>C, which substitutes a histidine for aspartic acid444 (D444H) in one allele of the biotinidase gene. We have
previously estimated that the D444H mutation results in 48% of normal enzyme activity for that allele and occurs with an estimated
frequency of 0.039 in the general population. The D444H mutation in biotinidase deficiency is similar to the Duarte variant
in galactosemia. The D444H mutation in one allele in combination with a mutation for profound deficiency in the other allele
is the common cause of partial biotinidase deficiency.
Received: 8 December 1997 / Accepted: 22 January 1998 相似文献
180.
Witold Kozak Marianna Rajchert-Trzpil Jolanta Zajdel W?adys?aw T. Dobrzański 《Applied microbiology》1973,25(2):305-308
Eighty-seven strains of lactic streptococci (46 of Streptococcus lactis, 24 of S. diacetilactis, and 17 of S. cremoris) were tested for lysogeny; 12 S. lactis strains produced nisin. Lysogeny was found in five S. lactis strains (two of them were nisin producers) and in two S. diacetilactis strains. Four S. lactis and two S. diacetilactis lysogens liberated phages both spontaneously and after ultraviolet treatment, and one S. lactis strain liberated phages spontaneously only. No lysogens were found among the S. cremoris strains tested. An initial characterization of the lysogens and their phages was made. The lytic spectrum of some of the examined phages was very narrow (homospecific), whereas that of others was wide, including strains of the three investigated species. 相似文献