全文获取类型
收费全文 | 2316篇 |
免费 | 192篇 |
专业分类
2508篇 |
出版年
2023年 | 7篇 |
2022年 | 20篇 |
2021年 | 42篇 |
2020年 | 27篇 |
2019年 | 30篇 |
2018年 | 34篇 |
2017年 | 31篇 |
2016年 | 74篇 |
2015年 | 107篇 |
2014年 | 142篇 |
2013年 | 157篇 |
2012年 | 201篇 |
2011年 | 198篇 |
2010年 | 137篇 |
2009年 | 102篇 |
2008年 | 175篇 |
2007年 | 142篇 |
2006年 | 144篇 |
2005年 | 116篇 |
2004年 | 102篇 |
2003年 | 96篇 |
2002年 | 99篇 |
2001年 | 24篇 |
2000年 | 19篇 |
1999年 | 22篇 |
1998年 | 30篇 |
1997年 | 25篇 |
1996年 | 22篇 |
1995年 | 16篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 7篇 |
1968年 | 3篇 |
排序方式: 共有2508条查询结果,搜索用时 0 毫秒
141.
Cord Dr?gemüller Jens Tetens Snaevar Sigurdsson Arcangelo Gentile Stefania Testoni Kerstin Lindblad-Toh Tosso Leeb 《PLoS genetics》2010,6(8)
Arachnomelia is a monogenic recessive defect of skeletal development in cattle. The causative mutation was previously mapped to a ∼7 Mb interval on chromosome 5. Here we show that array-based sequence capture and massively parallel sequencing technology, combined with the typical family structure in livestock populations, facilitates the identification of the causative mutation. We re-sequenced the entire critical interval in a healthy partially inbred cow carrying one copy of the critical chromosome segment in its ancestral state and one copy of the same segment with the arachnomelia mutation, and we detected a single heterozygous position. The genetic makeup of several partially inbred cattle provides extremely strong support for the causality of this mutation. The mutation represents a single base insertion leading to a premature stop codon in the coding sequence of the SUOX gene and is perfectly associated with the arachnomelia phenotype. Our findings suggest an important role for sulfite oxidase in bone development. 相似文献
142.
Khakpay R Polster D Köles L Skorinkin A Szabo B Wirkner K Illes P 《Purinergic signalling》2010,6(3):349-359
Locus coeruleus (LC) neurons in a rat brain slice preparation were superfused with a Mg2+-free and bicuculline-containing external medium. Under these conditions, glutamatergic spontaneous excitatory postsynaptic
currents (sEPSCs) were recorded by means of the whole-cell patch-clamp method. ATP, as well as its structural analogue 2-methylthio
ATP (2-MeSATP), both caused transient inward currents, which were outlasted by an increase in the frequency but not the amplitude
of the sEPSCs. PPADS, but not suramin or reactive blue 2 counteracted both effects of 2-MeSATP. By contrast, α,β-methylene
ATP (α,β-meATP), UTP and BzATP did not cause an inward current response. Of these latter agonists, only BzATP slightly facilitated
the sEPSC amplitude and strongly potentiated its frequency. PPADS and Brilliant Blue G, as well as fluorocitric acid and aminoadipic
acid prevented the activity of BzATP. Furthermore, BzATP caused a similar facilitation of the miniature (m)EPSC (recorded
in the presence of tetrodotoxin) and sEPSC frequencies (recorded in its absence). Eventually, capsaicin augmented the frequency
of the sEPSCs in a capsazepine-, but not PPADS-antagonizable, manner. In conclusion, the stimulation of astrocytic P2X7 receptors
appears to lead to the outflow of a signalling molecule, which presynaptically increases the spontaneous release of glutamate
onto LC neurons from their afferent fibre tracts. It is suggested, that the two algogenic compounds ATP and capsaicin utilise
separate receptor systems to potentiate the release of glutamate and in consequence to increase the excitability of LC neurons. 相似文献
143.
144.
Here we present the use of three fluorescent proteins in Staphylococcus aureus, Cerulean, PA-GFP, and mRFPmars. All molecules have an improved codon adaptation for expression in the A + T rich organisms and extend the fluorescent protein portfolio in staphylococcal research. 相似文献
145.
Kerstin Dreblow 《Biochemical and biophysical research communications》2010,395(4):490-288
During movement along microtubules, kinesin usually follows a track parallel to the axis of a single protofilament. The question arises what happens when kinesin encounters blockages. The present study describes the movement of kinesin labeled by 20-nm gold beads along immobilized microtubules artificially decorated with blocking proteins. To guarantee that exactly the kinesin-binding sites were occupied and to avoid steric effects exerted by large molecules, the KIF5A motor domain was used for blocking. After binding, the blockages were irreversibly cross-linked to the microtubules to make them non-exchangeable. Under such conditions, kinesin movement became a non-continuous one. As a rule, after temporary stopping the kinesin moved on without being released from the microtubule. The results strongly suggest a bypassing mechanism based on the postulation that kinesin changes to and continues movement along a neighbouring protofilament. Bypassing is considered to ensure an efficient long-distance transport of cellular cargoes by kinesins. 相似文献
146.
Transport of protons and solutes across mitochondrial membranes is essential for many physiological processes. However, neither the proton-pumping respiratory chain complexes nor the mitochondrial secondary active solute transport proteins have been characterized electrophysiologically in their native environment. In this study, solid-supported membrane (SSM) technology was applied for electrical measurements of respiratory chain complexes CI, CII, CIII, and CIV, the F(O)F(1)-ATPase/synthase (CV), and the adenine nucleotide translocase (ANT) in inner membranes of pig heart mitochondria. Specific substrates and inhibitors were used to validate the different assays, and the corresponding K(0.5) and IC(50) values were in good agreement with previously published results obtained with other methods. In combined measurements of CI-CV, it was possible to detect oxidative phosphorylation (OXPHOS), to measure differential effects of the uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) on the respective protein activities, and to determine the corresponding IC(50) values. Moreover, the measurements revealed a tight functional coupling of CI and CIII. Coenzyme Q (CoQ) analogues decylubiquinone (DBQ) and idebenone (Ide) stimulated the CII- and CIII-specific electrical currents but had inverse effects on CI-CIII activity. In summary, the results describe the electrophysiological and pharmacological properties of respiratory chain complexes, OXPHOS, and ANT in native mitochondrial membranes and demonstrate that SSM-based electrophysiology provides new insights into a complex molecular mechanism of the respiratory chain and the associated transport proteins. Besides, the SSM-based approach is suited for highly sensitive and specific testing of diverse respiratory chain modulators such as inhibitors, CoQ analogues, and uncoupling agents. 相似文献
147.
Manfred Türke Eric Heinze Kerstin Andreas Sarah M. Svendsen Martin M. Gossner Wolfgang W. Weisser 《Oecologia》2010,163(3):681-693
In beech-dominated forests in Central Europe, many spring geophytes show adaptations to seed dispersal by ants (myrmecochory). Ants, however, can be rare in such moist forests. Motivated by observations of slug feeding on seeds we investigated the seed consumption of two plant species, Anemone nemorosa and Asarum europaeum, by slugs, in a series of experiments. In a seed predation experiment in a beech forest, we found that seed removal was strongly reduced when gastropods were excluded from the seed depots. The contribution of insects, including ants, and rodents to seed removal was relatively less but differed between May and July. In the laboratory, slug species, in particular Arion sp., consumed seeds of both plant species. Slugs either consumed the elaiosomes of seeds or swallowed seeds intact. Swallowed seeds were defecated undamaged and germinated as well as control seeds when buried overwinter, indicating the potential for seed dispersal by slugs. We also recovered seeds of myrmecochores in the faeces of several slugs caught in forests. In a slug release experiment in the forest, slugs moved up to 14.6 m (mean 4.4 m) in 15 h, which is the median gut passage time of seeds based on measurements made in the laboratory. We also found that when slug-defecated seeds were offered to rodents, these were less attractive than control seeds, suggesting that passage through the slug gut reduces seed predation risk. Our results demonstrate that slugs are significant consumers of elaiosomes or entire seeds of ant-dispersed plants and that they can function as seed dispersers of these plants. 相似文献
148.
Anna-Lena Forslund Emelie Näslund Salomonsson Igor Golovliov Kerstin Kuoppa Stephen Michell Richard Titball Petra Oyston Laila Noppa Anders Sjöstedt Åke Forsberg 《BMC microbiology》2010,10(1):227
Background
All four Francisella tularensis subspecies possess gene clusters with potential to express type IV pili (Tfp). These clusters include putative pilin genes, as well as pilB, pilC and pilQ, required for secretion and assembly of Tfp. A hallmark of Tfp is the ability to retract the pilus upon surface contact, a property mediated by the ATPase PilT. Interestingly, out of the two major human pathogenic subspecies only the highly virulent type A strains have a functional pilT gene. 相似文献149.
Kerstin Huss-Danell 《Plant and Soil》1986,91(1):43-49
Summary A pot experiment withAlnus incana (L.) Moench growing in sand was set up to compare the amounts of nitrogen released from plants shoot litter with that released below ground as root litter and/or root exudation. No nitrogen fixation by free-living microorganisms was found in the sand and the increased nitrogen content of the plant + soil system was therefore due to nitrogen fixation byFrankia in the alder root-nodules. Most of the nitrogen released from the plants was in the nitrogen-rich leaf and other shoot litter. Only small amounts of nitrogen were found in the drainage water from the pots and were recorded as increased nitrogen content of the sand. 相似文献
150.
Stuiver M Lainez S Will C Terryn S Günzel D Debaix H Sommer K Kopplin K Thumfart J Kampik NB Querfeld U Willnow TE Němec V Wagner CA Hoenderop JG Devuyst O Knoers NV Bindels RJ Meij IC Müller D 《American journal of human genetics》2011,88(3):333-343
Familial hypomagnesemia is a rare human disorder caused by renal or intestinal magnesium (Mg(2+)) wasting, which may lead to symptoms of Mg(2+) depletion such as tetany, seizures, and cardiac arrhythmias. Our knowledge of the physiology of Mg(2+) (re)absorption, particularly the luminal uptake of Mg(2+) along the nephron, has benefitted from positional cloning approaches in families with Mg(2+) reabsorption disorders; however, basolateral Mg(2+) transport and its regulation are still poorly understood. Here, by using a candidate screening approach, we identified CNNM2 as a gene involved in renal Mg(2+) handling in patients of two unrelated families with unexplained dominant hypomagnesemia. In the kidney, CNNM2 was predominantly found along the basolateral membrane of distal tubular segments involved in Mg(2+) reabsorption. The basolateral localization of endogenous and recombinant CNNM2 was confirmed in epithelial kidney cell lines. Electrophysiological analysis showed that CNNM2 mediated Mg(2+)-sensitive Na(+) currents that were significantly diminished in mutant protein and were blocked by increased extracellular Mg(2+) concentrations. Our data support the findings of a recent genome-wide association study showing the CNNM2 locus to be associated with serum Mg(2+) concentrations. The mutations found in CNNM2, its observed sensitivity to extracellular Mg(2+), and its basolateral localization signify a critical role for CNNM2 in epithelial Mg(2+) transport. 相似文献