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51.
Yuichi Mishima Chanika D. Jayasinghe Kai Lu Junji Otani Masahiro Shirakawa Toru Kawakami Hironobu Kimura Hironobu Hojo Peter Carlton Shoji Tajima Isao Suetake 《Nucleic acids research》2015,43(21):10200-10212
The α, β and γ isoforms of mammalian heterochromatin protein 1 (HP1) selectively bind to methylated lysine 9 of histone H3 via their chromodomains. Although the phenotypes of HP1-knockout mice are distinct for each isoform, the molecular mechanisms underlying HP1 isoform-specific function remain elusive. In the present study, we found that in contrast to HP1α, HP1γ could not bind tri-methylated H3 lysine 9 in a reconstituted tetra-nucleosomes when the nucleosomes were in an uncompacted state. The hinge region connecting HP1''s chromodomain and chromoshadow domain contributed to the distinct recognition of the nucleosomes by HP1α and HP1γ. HP1γ, but not HP1α, was strongly enhanced in selective binding to tri-methylated lysine 9 in histone H3 by the addition of Mg2+ or linker histone H1, which are known to induce compaction of nucleosomes. We propose that this novel property of HP1γ recognition of lysine 9 in the histone H3 tail in different nucleosome structures plays a role in reading the histone code. 相似文献
52.
Heather E Dwyer Marie Jasieniuk Miki Okada Arthur M Shapiro 《Ecology and evolution》2015,5(14):2865-2877
Gene flow and hybridization among species dramatically affect our understanding of the species as a biological unit, species relationships, and species adaptations. In North American Colias eurytheme and Colias eriphyle, there has been historical debate over the extent of hybridization occurring and the identity of phenotypically intermediate individuals as genetic hybrids. This study assesses the population structure of these two species to measure the extent of hybridization and the genetic identity of phenotypic intermediates as hybrids. Amplified fragment length polymorphism (AFLP) marker analysis was performed on 378 specimens collected from northern California and Nevada. Population structure was inferred using a Bayesian/Markov chain Monte Carlo method, which probabilistically assigns individuals to genetic clusters. Three genetic clusters provided the best fit for the data. C. eurytheme individuals were primarily assigned to two closely related clusters, and C. eriphyle individuals were mostly assigned to a third, more distantly related cluster. There appeared to be significant hybridization between the two species. Individuals of intermediate phenotype (putative hybrids) were found to be genetically indistinguishable from C. eriphyle, indicating that previous work based on the assumption that these intermediate forms are hybrids may warrant reconsideration. 相似文献
53.
The excitation polarization spectrum of epsilon-ADP bound to F-actin shows that two absorption dipoles at 260 nm and 340 nm are oriented in different directions relative to the emission dipole. On the other hand, the linear dichroism of F-actin-epsilon-ADP gives that the dichroic ratio of the bound epsilon-ADP is approximately constant (about-0.5) in the wavelength region form 250 to 350nm. Furthermore, the fluorescence polarization of epsilon-ADP bound to F-actin which is oriented in the field of flow shows that the emission dipole is nearly perpendicular to the long axis of F-actin. From these observations we conclude that the adenine plane of the bound nucleotide is almost perpendicular to the long axis of F-actin. 相似文献
54.
55.
Yuki Tsuchikane Miki Tsuchiya Yume Kokubun Jun Abe Hiroyuki Sekimoto 《Phycological Research》2011,59(1):74-82
Detailed conjugation processes in Penium, a unicellular conjugating green alga, are described for the first time. A homothallic strain of Penium margaritaceum (Ehrenb.) Bréb. (Designation, izu84‐10) was isolated from a rice paddy field in Japan. The species was identified based on its morphology, and a molecular phylogeny confirmed that izu84‐10 was closely related to another identified strain of this species. Using time‐lapse photography, the conjugation processes in P. margaritaceum were observed and then categorized into the following six stages: (1) cell division, resulting in the formation of two sister gametangial cells from one vegetative cell; (2) formation of a sexual pair between the two sister gametangial cells (or between gametangial cells of another nearby individual); (3) formation of conjugation papillae by elongation of the cell wall; (4) release of a gamete from one of the pair members; (5) release of a gamete from the other pair member; and (6) formation of the zygospore by gamete fusion. By alcian blue staining, possible involvement of mucilage to facilitate this cell adhesion and cell–cell communication was suggested. 相似文献
56.
Katsumi Mera Ryoji Nagai Kazuhiro Takeo Miyoko Izumi Toru Maruyama Masaki Otagiri 《Biochemical and biophysical research communications》2011,407(2):420
Advanced glycation end products (AGEs) are believed to play a significant role in the development of diabetic complications. In this study, we measured the levels of autoantibodies against several AGE structures in healthy human plasma and investigated the physiological role of the autoantibodies. A high titer of the autoantibody against Nε-(carboxyethyl)lysine (CEL) was detected in human plasma compared with other AGE structures such as CML and pentosidine. The purified human anti-CEL autoantibody reacted with CEL-modified human serum albumin (CEL-HSA), but not CML-HSA. A rabbit polyclonal anti-CEL antibody, used as a model autoantibody against CEL, accelerated the uptake of CEL-HSA by macrophages, but did not enhance the uptake of native HSA. Furthermore, when 125I-labeled CEL-HSA was injected into the tail vein of mice, accumulation of 125I-CEL-HSA in the liver was accelerated by co-injection of the rabbit anti-CEL antibody. These results demonstrate that the autoantibody against CEL in plasma may play a role in the macrophage uptake of CEL-modified proteins. 相似文献
57.
Toru Mizoguchi Yukari Arakawa Michie Kobayashi Masaki Fujishima 《Biochemical and biophysical research communications》2011,(1):121
We used the forced swimming test to investigate the influence of Chlorella powder intake during muscle stress training in mice. After day 14, swimming time was about 2-fold longer for Chlorella intake mice than for control swimming mice. Microarray analysis revealed that the global gene expression profile of muscle from the Chlorella intake mice was similar to that of muscle from the intact (non-swimming) mice, and the profile of these two groups differed from that of the control (swimming) mice. Gene ontology and pathway analyses of gene expression data showed that oxidoreductase activity and the leukotriene synthesis pathway were repressed in the Chlorella intake mice following the swimming test. In addition, measurements of free fatty acids, glucose, triglycerides, and lactic acid in the blood of Chlorella intake mice were higher than that of control mice. These findings suggest that metabolism in tissues is altered by Chlorella intake. 相似文献
58.
K. Saito Y. Kogawa M. Fukata K. Odashiro Toru Maruyama K. Akashi T. Fujino 《Journal of Biorheology》2011,25(1-2):18-26
Comprehensive research to quantify the deformability of erythrocytes in diabetic animals and humans has been lacking. The objective of this study was to compare the impairment of erythrocyte deformability in diabetic rats and patients by use of the same rheologic method. Deformability was investigated in streptozotocin-induced diabetic rats and diabetic patients, by using the highly sensitive and quantitative nickel-mesh-filtration technique. Erythrocyte filterability (whole-cell deformability) was defined as flow rate of hematocrit-adjusted erythrocyte suspension relative to that of saline (%). Hematological and biochemical data for diabetic rats did not differ from those for age-matched control rats except for hyperglycemia and malnutrition. Erythrocyte filterability for diabetic rats was significantly lower than that for control rats (69.4 ± 10.1%, n = 8, compared with 83.1 ± 4.2%, n = 8; p < 0.001). Likewise, erythrocyte filterability for diabetic patients was significantly impaired compared with that for controls (87.6 ± 3.4%, n = 174, compared with 88.6 ± 2.1%, n = 51; p = 0.046). Stepwise multiple regression analysis revealed that this impairment was mostly attributable to associated obesity (BMI, p = 0.029) and glycemic stress (HbA1c(JDS), p = 0.046). We therefore conclude that erythrocyte filterability is commonly impaired in diabetic rats and in humans. Moreover, metabolic risk accumulation further impairs erythrocyte filterability, resulting in derangement of the microcirculation. 相似文献
59.
No study has systematically studied the relevance of original Izumo strain of spontaneously hypertensive rats (SHR/Izm) as
a stroke model. Furthermore, both SHR/Izm and stroke-prone SHR/Izm (SHRSP/Izm) are commercially available, and recent progress
in genetic studies allowed us to use several congenic strains of rats constructed with SHR/Izm and SHRSP/Izm as the genetic
background strains. A total of 166 male SHR/Izm and 17 male SHRSP/Izm were subjected to photothrombotic middle cerebral artery
(MCA) occlusion with or without YAG laser-induced reperfusion. The pattern of distal MCA was recorded. Infarct volumes were
determined with 2,3,5-triphenyltetrazolium chloride. At 24 or 48 h after MCA occlusion, infarct volumes in the permanent occlusion
and 2-h occlusion groups (88 ± 22 [SD] and 87 ± 25 mm3, respectively) were significantly larger than that in the 1-h occlusion group (45 ± 14 mm3), indicating the presence of sizeable zone of penumbra. Infarct size in SHRSP/Izm determined at 24 h after MCA occlusion
was fairly large (124.0 ± 34.8 mm3, n = 10). Infarct volume in SHR/Izm with simple distal MCA was 76 ± 19 mm3, which was significantly smaller than 95 ± 22 mm3 in the other SHR/Izm with more branching MCA. These data suggest that this stroke model in SHR/Izm is useful in the preclinical
testing of stroke therapies and elucidating the pathophysiology of cerebral ischemia/reperfusion. 相似文献
60.
Hiraku Sasaki Hiroki Ishikawa Toru Sato Satoshi Sekiguchi Hiromi Amao Eiichi Kawamoto Tetsuya Matsumoto Kazuhiko Shirama 《BMC microbiology》2011,11(1):55