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981.
Michele Lorusso Tiziana Cocco Michele Minuto Nazzareno Capitanio Sergio Papa 《Journal of bioenergetics and biomembranes》1995,27(1):101-108
The effect of pH and transmembrane pH on the efficiency of the proton pump of the mitochondrialbc
1 complex bothin situ and in the reconstituted state was studied. In both cases the H+/e
– ratio for vectorial proton translocation by thebc
1 complex respiring at the steady state, under conditions in which the transmembrane pH difference (pH) represents the only component of the proton motive force (p), was significantly lower than that measured under level flow conditions. The latter amounts, at neutral pH, to 1 (2 including the scalar H+ release). In the reconstituted system steady-state pH was modulated by changing the intravesicular buffer as well as the intra/extra-liposomal pH. Under these conditions the H+/e– ratio varied inversely with the pH. The data presented show that pH exerts a critical control on the proton pump of thebc
1 complex. Increasing the external pH above neutrality caused a decrease of the level flowH
+/e
– ratio. This effect is explained in terms of proton/electron linkage inb cytochromes. 相似文献
982.
Satu Kuokkanen Michele Gschwend John D. Rioux Mark J. Daly Joseph D. Terwilliger Pentti J. Tienari Juhani Wikström Jorma Palo Lincoln D. Stein Thomas J. Hudson Eric S. Lander Leena Peltonen 《American journal of human genetics》1997,61(6):1379-1387
Multiple sclerosis (MS) is a neurological, demyelinating disorder with a putative autoimmune etiology. It is thought to be a multifactorial disease with a complex mode of inheritance. Here we report the results of a two-stage genomewide scan for loci predisposing to MS. The first stage of the screen, with a low-resolution map, was performed in a selection of 16 pedigrees collected from an isolated Finnish population. Multipoint, non-parametric linkage analysis of the 328 markers did not reveal statistically significant results. However, 10 slightly interesting regions (P = .1-.15) emerged, including our previous findings of the HLA complex on 6p21 and a putative locus on 5p14-p12. Eight of these novel regions were further analyzed by use of denser marker maps, in the second stage of the scan. For the chromosomal regions 4cen, 11tel, and 17q, the statistical significance increased, but not conclusively; for 2q32 and 10q21, the statistical significance did not change. Accordingly, genotyping of the high-density markers in these regions was performed, and the data were analyzed by use of two-point, parametric linkage analysis using the complete pedigree information of the 21 Finnish multiplex families. We detected suggestive evidence for a predisposing locus on chromosomal region 17q22-q24. Several markers on 17q22-q24 yielded positive LOD scores, with the maximum LOD score (Zmax) occurring with D17S807 (Zmax = 2.8, theta = .04; dominant model). Interestingly, a suggestive linkage between MS and the markers on 17q22-q24 was also revealed by a recent genomewide scan in MS families from the United Kingdom. 相似文献
983.
984.
985.
Michele Rubini Atsushi Hongo Consuelo D'Ambrosio Renato Baserga 《Experimental cell research》1997,230(2):284
The type 1 receptor for insulin-like growth factors (IGF-IR) plays an important role in the growth and transformation of several types of cells. We have investigated the role of IGF-IR number in IGF-I-mediated mitogenesis and transformation of mouse embryo fibroblasts. We have used R−cells (3T3-like cells originating from mouse embryos with a targeted disruption of the IGF-IR genes) transfected with a plasmid expressing the human IGF-IR cDNA to generate clones with receptor numbers ranging from zero to 106receptors per cell. In this model, between 15,000 and 22,000 receptors per cell are sufficient to render mouse embryo cells competent to grow in serum-free medium supplemented solely with IGF-I. For growth in soft agar, 30,000 receptors per cell seem to be the minimum requirement. These experiments indicate that a small increment in the number of receptors per cell, well within the physiological range, can modulate the mitogenic and transforming activities of the IGF-IR in 3T3-like cells. 相似文献
986.
Bush Michele L.; Asplund Patrick T.; Miles Kristen A.; Ben-Jebria Abdellaziz; Ultman James S. 《Journal of applied physiology》1996,81(4):1651-1657
Bush, Michele L., Patrick T. Asplund, Kristen A. Miles,Abdellaziz Ben-Jebria, and James S. Ultman. Longitudinaldistribution of O3 absorption inthe lung: gender differences and intersubject variability.J. Appl. Physiol. 81(4):1651-1657, 1996.Because the National Ambient Air QualityStandard for ozone (O3) isintended to protect the most sensitive individuals in the generalpopulation, it is necessary to identify sources of intersubjectvariation in the exposure-dose-response cascade. We hypothesize thatdifferences in lung anatomy can modulate exposure-dose relationshipsbetween individuals, and this results in differences between theirresponsiveness to O3 at a fixedexposure condition. During quiet breathing, the conducting airwaysremove the majority of inhaled O3,so the volume of this region should have an important impact onO3 dose distribution. Employingthe bolus inhalation method, we measured the distribution ofO3 absorption with respect topenetration volume (VP), and using the Fowler single-breath N2washout method, we determined the dead space volume(VD) in the lungs of 10 menand 10 women at a fixed respiratory flow of 250 ml/s. On average, thewomen absorbed O3 at smallerVP than the men, and the women hadsmaller VD than the men. Whenexpressed in terms ofVP/ VD,the absorption distribution of the men and women was indistinguishable.Moreover, an interpretation of theO3 distribution in terms of anintrinsic mass transfer parameter(Ka) indicated that differencesbetween the O3 dosimetry in allsubjects, whether men or women, could be explained by a uniquecorrelation with anatomic dead space: Ka (ins1) = 610 VD1.05(in ml). Application of this result to measurements ofO3 exposure response indicatedthat previously reported gender differences may be due to a failure inproperly accounting for tissue surface within the conducting airways. 相似文献
987.
A first linkage map of Cichorium intybus L. using a one-way pseudo-testcross and PCR-derived markers
De Simone Matteo Morgante Michele Lucchin Margherita Parrini Paolo Marocco Adriano 《Molecular breeding : new strategies in plant improvement》1997,3(6):415-425
We have used a one-way pseudo-testcross mapping strategy in combination with different types of PCR-based markers (RAPD, AFLP, SAMPL) to construct a first linkage map for variegated chicory (Cichorium intybus L. var. silvestre Biskoff, n=9), a self-incompatible vegetable species. The success of such a strategy depends on the presence of sufficiently high levels of heterozygosity in the individual plant which is being mapped and on the informativeness of the marker system that is used. A total of 371 markers, comprising 16 RAPDs, 72 SAMPLs and 283 AFLPs, were scored in 46 F1 individuals obtained from an interspecific cross between a C. intybus outbred individual and a C. endivia inbred line. Grouping of the markers at a LOD score of 4.0 resulted in 13 linkage groups covering 1330 cM. A framework map covering 1201.4 cM was assembled by using all markers that could be ordered with a LOD greater than 2.0. We estimate the total genome size of chicory to be ca. 1405 cM, thus considerably smaller than that estimated for lettuce (1950 cM). The usefulness of the different marker systems that were applied is analysed in terms of level of heterozygosity and marker index, i.e. number of different genetic loci that may be simultaneously analysed per experiment. Out of the 371 markers, 50 of them showed segregation distortion which is discussed in terms of the hybrid origin of the variegated chicory. 相似文献
988.
Luigina Cellini Emanuela Di Campli Michele Masulli Soraya Di Bartolomeo Nerino Allocati 《FEMS immunology and medical microbiology》1996,13(4):273-277
Abstract The antibacterial effect of aqueous garlic extract (AGE) was investigated against Helicobacter pylori . Sixteen clinical isolates and three reference strains of H. pylori were studied. Two different varieties of garlic were used. The concentration of AGE required to inhibit the bacterial growth was between 2–5 mg ml−1 . The concentration, for both AGE types, to inhibit 90% (MIC90 ) of isolates was 5 mg ml−1 . The minimum bactericidal concentration (MBC) was usually equal to, or two-fold higher than, minimum inhibitory concentration (MIC). Heat treatment of extracts reduced the inhibitory or bactericidal activity against H. pylori ; the boiled garlic extract showed a loss of efficacy from two-to four-fold the values of MIC and the MBC obtained with fresh AGR. The antibacterial activity of garlic was also studied after combination with a proton pump-inhibitor (omeprazole) in a ratio of 250:1. A synergistic effect was found in 47% of strains studied; an antagonistic effect was not observed. 相似文献
989.
Optically pure protected L -[3,4-(1,4,7,10,13-pentaoxatridecamethylene) phenyl] alanine, its dipeptide, diketopiperazine and homopolymer, protected L -[3,4-(1,4,7,10,13,16-hexaoxahexadecamethylene) phenyl] alanine and its polymer have been synthesized and characterized. These crown ether derivatives complex the potassium and ammonium cations as well as protonated leucine and glycine in tetrahydrofuran and methanol. They are also phase-transfer agents. The cooperativity of the crown units was studied in detail for the dimeric ligands. 相似文献
990.
Antonio Giordano Andrea Frontini Incoronata Murano Cristina Tonello M Antonella Marino Michele O Carruba Enzo Nisoli Saverio Cinti 《The journal of histochemistry and cytochemistry》2005,53(6):679-687
White adipose tissue (WAT) is innervated by the sympathetic nervous system. A role for WAT sympathetic noradrenergic nerves in lipid mobilization has been suggested. To gain insight into the involvement of nerve activity in the delipidation process, WAT nerves were investigated in rat retroperitoneal and epididymal depots after prolonged fasting. A significant increase in tyrosine hydroxylase (TH) content was found in epididymal and, especially, retroperitoneal WAT by Western blotting. Accordingly, an increased immunoreactivity for TH was detected by immunohistochemistry in epididymal and, especially, retroperitoneal vascular and parenchymal noradrenergic nerves. Neuropeptide Y (NPY)-containing nerves were found around arteries and in the parenchyma. Double-staining experiments and confocal microscopy showed that most perivascular and some parenchymal noradrenergic nerves also contained NPY. Detection of protein gene product (PGP) 9.5, a general marker of peripheral nerves, by Western blotting and PGP 9.5-TH by double-staining experiments showed significantly increased noradrenergic nerve density in fasted retroperitoneal, but not epididymal depots, suggesting that formation of new nerves takes place in retroperitoneal WAT in fasting conditions. On the whole, these data confirm the important role of sympathetic noradrenergic nerves in WAT lipid mobilization during fasting but also raise questions about the physiological role of regional-dependent nerve adjustments and their functional significance in relation to white adipocyte secretory products. 相似文献