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排序方式: 共有173条查询结果,搜索用时 31 毫秒
91.
Neuronal generation of singing in a cicada 总被引:1,自引:0,他引:1
P J Simmons 《Nature》1977,270(5634):243-245
92.
93.
外荷载作用下的软黏土电渗试验 总被引:4,自引:0,他引:4
为改善软土地基的固结排水效果,对联合使用电渗固结与预压排水技术进行了电渗试验。对于不同黏土试样,同时施加恒定的75 kPa外荷载和0~20V外电场,研究在耦合作用时的渗透出流变化。试验结果表明:与仅有外荷载作用相比,在耦合作用下表现为阳极渗透出流量减小、阴极渗透出流量增大、总渗透出流量增大;阳极渗透出流量的变化与电压大小无直接关系;耦合作用能提高饱和黏土的排水速率,特别是在外加电压较高时,电渗固结效果较为明显。 相似文献
94.
Davies WI Zheng L Hughes S Tamai TK Turton M Halford S Foster RG Whitmore D Hankins MW 《Cellular and molecular life sciences : CMLS》2011,68(24):4115-4132
Melanopsin (OPN4) is an opsin photopigment that, in mammals, confers photosensitivity to retinal ganglion cells and regulates
circadian entrainment and pupil constriction. In non-mammalian species, two forms of opn4 exist, and are classified into mammalian-like (m) and non-mammalian-like (x) clades. However, far less is understood of the function of this photopigment family. Here we identify in zebrafish five
melanopsins (opn4m-1, opn4m-2, opn4m-3, opn4x-1 and opn4x-2), each encoding a full-length opsin G protein. All five genes are expressed in the adult retina in a largely non-overlapping
pattern, as revealed by RNA in situ hybridisation and immunocytochemistry, with at least one melanopsin form present in all
neuronal cell types, including cone photoreceptors. This raises the possibility that the teleost retina is globally light
sensitive. Electrophysiological and spectrophotometric studies demonstrate that all five zebrafish melanopsins encode a functional
photopigment with peak spectral sensitivities that range from 470 to 484 nm, with opn4m-1 and opn4m-3 displaying invertebrate-like
bistability, where the retinal chromophore interchanges between cis- and trans-isomers in a light-dependent manner and remains within the opsin binding pocket. In contrast, opn4m-2, opn4x-1 and opn4x-2
are monostable and function more like classical vertebrate-like photopigments, where the chromophore is converted from 11-cis to all-trans retinal upon absorption of a photon, hydrolysed and exits from the binding pocket of the opsin. It is thought that all melanopsins
exhibit an invertebrate-like bistability biochemistry. Our novel findings, however, reveal the presence of both invertebrate-like
and vertebrate-like forms of melanopsin in the teleost retina, and indicate that photopigment bistability is not a universal
property of the melanopsin family. The functional diversity of these teleost melanopsins, together with their widespread expression
pattern within the retina, suggests that melanopsins confer global photosensitivity to the teleost retina and might allow
for direct “fine-tuning” of retinal circuitry and physiology in the dynamic light environments found in aquatic habitats. 相似文献
95.
Kornum BR Kawashima M Faraco J Lin L Rico TJ Hesselson S Axtell RC Kuipers H Weiner K Hamacher A Kassack MU Han F Knudsen S Li J Dong X Winkelmann J Plazzi G Nevsimalova S Hong SC Honda Y Honda M Högl B Ton TG Montplaisir J Bourgin P Kemlink D Huang YS Warby S Einen M Eshragh JL Miyagawa T Desautels A Ruppert E Hesla PE Poli F Pizza F Frauscher B Jeong JH Lee SP Strohl KP Longstreth WT Kvale M Dobrovolna M Ohayon MM Nepom GT Wichmann HE Rouleau GA Gieger C Levinson DF Gejman PV Meitinger T 《Nature genetics》2011,43(1):66-71
Growing evidence supports the hypothesis that narcolepsy with cataplexy is an autoimmune disease. We here report genome-wide association analyses for narcolepsy with replication and fine mapping across three ethnic groups (3,406 individuals of European ancestry, 2,414 Asians and 302 African Americans). We identify a SNP in the 3' untranslated region of P2RY11, the purinergic receptor subtype P2Y?? gene, which is associated with narcolepsy (rs2305795, combined P = 6.1 × 10?1?, odds ratio = 1.28, 95% CI 1.19-1.39, n = 5689). The disease-associated allele is correlated with reduced expression of P2RY11 in CD8(+) T lymphocytes (339% reduced, P = 0.003) and natural killer (NK) cells (P = 0.031), but not in other peripheral blood mononuclear cell types. The low expression variant is also associated with reduced P2RY11-mediated resistance to ATP-induced cell death in T lymphocytes (P = 0.0007) and natural killer cells (P = 0.001). These results identify P2RY11 as an important regulator of immune-cell survival, with possible implications in narcolepsy and other autoimmune diseases. 相似文献
96.
Mutations in CLCN5, which encodes the voltage-dependent Cl−/H+antiporter, CLC-5, cause Dent’s disease. This disorder is characterized by low molecularweight proteinuria, hypercalciuria,
nephrocalcinosis and nephrolithiasis. Using a collecting duct cell model (mIMCD-3) in which endogenous clc-5 is disrupted
by antisense clc-5 or overexpression of truncated clc-5, we demonstrate altered expression of the crystal adhesion molecule, annexin A2. Endogenously expressed annexin A2 is intracellular
with limited plasma membrane localization. Following clc-5 disruption, there is both a marked increase in plasma membrane
annexin A2 and an increase in cell surface crystal retention and agglomeration, which may be attenuated using pretreatment
with anti-annexin A2 antibodies or wheat germ agglutinin lectin but not by concanavalin A. We hypothesize that in Dent’s disease,
endocytic failure leads to an accumulation at the plasma membrane of crystal-binding molecules that include annexin A2 leading
to retention of calcium crystals and ultimately nephrocalcinosis and nephrolithiasis.
Received 22 October 2005; received after revision 26 November 2005; accepted 2 December 2005 相似文献
97.
Lee JE Silhavy JL Zaki MS Schroth J Bielas SL Marsh SE Olvera J Brancati F Iannicelli M Ikegami K Schlossman AM Merriman B Attié-Bitach T Logan CV Glass IA Cluckey A Louie CM Lee JH Raynes HR Rapin I Castroviejo IP Setou M Barbot C Boltshauser E Nelson SF Hildebrandt F Johnson CA Doherty DA Valente EM Gleeson JG 《Nature genetics》2012,44(2):193-199
Tubulin glutamylation is a post-translational modification that occurs predominantly in the ciliary axoneme and has been suggested to be important for ciliary function. However, its relationship to disorders of the primary cilium, termed ciliopathies, has not been explored. Here we mapped a new locus for Joubert syndrome (JBTS), which we have designated as JBTS15, and identified causative mutations in CEP41, which encodes a 41-kDa centrosomal protein. We show that CEP41 is localized to the basal body and primary cilia, and regulates ciliary entry of TTLL6, an evolutionarily conserved polyglutamylase enzyme. Depletion of CEP41 causes ciliopathy-related phenotypes in zebrafish and mice and results in glutamylation defects in the ciliary axoneme. Our data identify CEP41 mutations as a cause of JBTS and implicate tubulin post-translational modification in the pathogenesis of human ciliary dysfunction. 相似文献
98.
Christina M. Dobson Samuel J. Hempel Stephanie H. Stalnaker Ryan Stuart Lance Wells 《Cellular and molecular life sciences : CMLS》2013,70(16):2849-2857
Glycosylation of proteins is arguably the most prevalent co- and post-translational modification. It is responsible for increased heterogeneity and functional diversity of proteins. Here we discuss the importance of one type of glycosylation, specifically O-mannosylation and its relationship to a number of human diseases. The most widely studied O-mannose modified protein is alpha-dystroglycan (α-DG). Recent studies have focused intensely on α-DG due to the severity of diseases associated with its improper glycosylation. O-mannosylation of α-DG is involved in cancer metastasis, arenavirus entry, and multiple forms of congenital muscular dystrophy [1, 2]. In this review, we discuss the structural and functional characteristics of O-mannose-initiated glycan structures on α-DG, enzymes involved in the O-mannosylation pathway, and the diseases that are a direct result of disruptions within this pathway. 相似文献
99.
Kornak U Reynders E Dimopoulou A van Reeuwijk J Fischer B Rajab A Budde B Nürnberg P Foulquier F;ARCL Debré-type Study Group Lefeber D Urban Z Gruenewald S Annaert W Brunner HG van Bokhoven H Wevers R Morava E Matthijs G Van Maldergem L Mundlos S 《Nature genetics》2008,40(1):32-34
We identified loss-of-function mutations in ATP6V0A2, encoding the a2 subunit of the V-type H+ ATPase, in several families with autosomal recessive cutis laxa type II or wrinkly skin syndrome. The mutations result in abnormal glycosylation of serum proteins (CDG-II) and cause an impairment of Golgi trafficking in fibroblasts from affected individuals. These results indicate that the a2 subunit of the proton pump has an important role in Golgi function. 相似文献