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191.
Shin-ichi Morita Sota Takanezawa Michio Hiroshima Toshiyuki Mitsui Yukihiro Ozaki Yasushi Sako 《Biophysical journal》2014,107(10):2221-2229
Cellular differentiation proceeds along complicated pathways, even when it is induced by extracellular signaling molecules. One of the major reasons for this complexity is the highly multidimensional internal dynamics of cells, which sometimes causes apparently stochastic responses in individual cells to extracellular stimuli. Therefore, to understand cell differentiation, it is necessary to monitor the internal dynamics of cells at single-cell resolution. Here, we used a Raman and autofluorescence spectrum analysis of single cells to detect dynamic changes in intracellular molecular components. MCF-7 cells are a human cancer-derived cell line that can be induced to differentiate into mammary-gland-like cells with the addition of heregulin (HRG) to the culture medium. We measured the spectra in the cytoplasm of MCF-7 cells during 12 days of HRG stimulation. The Raman scattering spectrum, which was the major component of the signal, changed with time. A multicomponent analysis of the Raman spectrum revealed that the dynamics of the major components of the intracellular molecules, including proteins and lipids, changed cyclically along the differentiation pathway. The background autofluorescence signals of Raman scattering also provided information about the differentiation process. Using the total information from the Raman and autofluorescence spectra, we were able to visualize the pathway of cell differentiation in the multicomponent phase space. 相似文献
192.
Masatomo So Yuto Kimura Keiichi Yamaguchi Toshihiko Sugiki Toshimichi Fujiwara Cesar Aguirre Kensuke Ikenaka Hideki Mochizuki Yasushi Kawata Yuji Goto 《Protein science : a publication of the Protein Society》2021,30(8):1701
Amyloid fibril formation is associated with various amyloidoses, including neurodegenerative diseases such as Alzheimer''s and Parkinson''s diseases. Amyloid fibrils form above the solubility of amyloidogenic proteins or peptides upon breaking supersaturation, followed by a nucleation and elongation mechanism, which is similar to the crystallization of solutes. Many additives, including salts, detergents, and natural compounds, promote or inhibit amyloid formation. However, the underlying mechanisms of the opposing effects are unclear. We examined the effects of two polyphenols, that is, epigallocatechin gallate (EGCG) and kaempferol‐7─O─glycoside (KG), with high and low solubilities, respectively, on the amyloid formation of α‐synuclein (αSN). EGCG and KG inhibited and promoted amyloid formation of αSN, respectively, when monitored by thioflavin T (ThT) fluorescence or transmission electron microscopy (TEM). Nuclear magnetic resonance (NMR) analysis revealed that, although interactions of αSN with soluble EGCG increased the solubility of αSN, thus inhibiting amyloid formation, interactions of αSN with insoluble KG reduced the solubility of αSN, thereby promoting amyloid formation. Our study suggests that opposing effects of polyphenols on amyloid formation of proteins and peptides can be interpreted based on the solubility of polyphenols. 相似文献
193.
Tsubasa Fukue Motohide Tamura Ryo Kandori Nobuhiko Kusakabe James H. Hough Jeremy Bailey Douglas C. B. Whittet Philip W. Lucas Yasushi Nakajima Jun Hashimoto 《Origins of life and evolution of the biosphere》2010,40(3):335-346
We present a wide-field (∼6′ × 6′) and deep near-infrared (K
s
band: 2.14 μm) circular polarization image in the Orion nebula, where massive stars and many low-mass stars are forming.
Our results reveal that a high circular polarization region is spatially extended (∼0.4 pc) around the massive star-forming
region, the BN/KL nebula. However, other regions, including the linearly polarized Orion bar, show no significant circular
polarization. Most of the low-mass young stars do not show detectable extended structure in either linear or circular polarization,
in contrast to the BN/KL nebula. If our solar system formed in a massive star-forming region and was irradiated by net circularly
polarized radiation, then enantiomeric excesses could have been induced, through asymmetric photochemistry, in the parent
bodies of the meteorites and subsequently delivered to Earth. These could then have played a role in the development of biological
homochirality on Earth. 相似文献
194.
Shigero Tamba Rieko Yodoi Kazushi Morimoto Tomoaki Inazumi Mamiko Sukeno Eri Segi-Nishida Yasushi Okuno Gozoh Tsujimoto Shuh Narumiya Yukihiko Sugimoto 《Biochimie》2010
To understand the role of prostaglandin (PG) receptor EP2 (Ptger2) signaling in ovulation and fertilization, we investigated time-dependent expression profiles in wild-type (WT) and Ptger2−/− cumuli before and after ovulation by using microarrays. We prepared cumulus cells from mice just before and 3, 9 and 14 h after human chorionic gonadotropin injection. Key genes including cAMP-related and epidermal growth factor (EGF) genes, as well as extracellular matrix- (ECM-) related and chemokine genes were up-regulated in WT cumuli at 3 h and 14 h, respectively. Ptger2 deficiency differently affected the expression of many of the key genes at 3 h and 14 h. These results indicate that the gene expression profile of cumulus cells greatly differs before and after ovulation, and in each situation, PGE2-EP2 signaling plays a critical role in cAMP-regulated gene expression in the cumulus cells under physiological conditions. 相似文献
195.
Hideo Mukai Tetsuya Kimoto Yasushi Hojo Suguru Kawato Gen Murakami Shimpei Higo Yusuke Hatanaka Mari Ogiue-Ikeda 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
The hippocampus is a center for learning and memory as well as a target of Alzheimer's disease in aged humans. Synaptic modulation by estrogen is essential to understand the molecular mechanisms of estrogen replacement therapy. Because the local synthesis of estrogen occurs in the hippocampus of both sexes, in addition to the estrogen supply from the gonads, its functions are attracting much attention. 相似文献
196.
Yusuke Ohnishi Yasushi Totoki Atsushi Toyoda Toshiaki Watanabe Yasuhiro Yamamoto Katsushi Tokunaga Yoshiyuki Sakaki Hiroyuki Sasaki Hirohiko Hohjoh 《Nucleic acids research》2010,38(15):5141-5151
Recent studies showed that small interfering RNAs (siRNAs) and Piwi-interacting RNA (piRNA) in mammalian germ cells play important roles in retrotransposon silencing and gametogenesis. However, subsequent contribution of those small RNAs to early mammalian development remains poorly understood. We investigated the expression profiles of small RNAs in mouse metaphase II oocytes, 8–16-cell stage embryos, blastocysts and the pluripotent inner cell mass (ICM) using high-throughput pyrosequencing. Here, we show that during pre-implantation development a major small RNA class changes from retrotransposon-derived small RNAs containing siRNAs and piRNAs to zygotically synthesized microRNAs (miRNAs). Some siRNAs and piRNAs are transiently upregulated and directed against specific retrotransposon classes. We also identified miRNAs expression profiles characteristic of the ICM and trophectoderm (TE) cells. Taken together, our current study reveals a major reprogramming of functional small RNAs during early mouse development from oocyte to blastocyst. 相似文献
197.
Ogata M Obara T Chuma Y Murata T Park EY Usui T 《Bioscience, biotechnology, and biochemistry》2010,74(11):2287-2292
A series of dansyl-labeled glycosides with di-, tetra-, and hexasaccharides carrying the terminal N-acetyllactosamine (LacNAc) sequence were synthesized as acceptor substrates for α2,6- and α2,3-sialyltransferases. As an alternative design, dansyl-labeled LacNAc glycoside carrying a long-spacer linked glycan was engineered by replacement of the LacNAc or lactose units with an alkyl chain. In addition, we designed a dansyl-labeled bi-antennary LacNAc glycoside as an N-linked oligosaccharide mimetic, such as asialo-α(1)-acid glycoprotein. The kinetic parameters for the transfer reaction of synthesized dansyl-labeled glycosides by sialyltransferases were determined by the fluorescent HPLC method. The catalytic efficiencies (V(max)/K(m)) of acceptor substrates carrying the terminal LacNAc sequence with various length glycans in the array for α2,6- and α2,3-sialyltransferases decreased in a glycan length-dependent manner. Furthermore, of the acceptor substrates tested, dansyl-labeled bi-antennary LacNAc glycoside displayed the most favorable K(m) value for α2,6- and α2,3-sialyltransferases. 相似文献
198.
Nahoko Shikata Yukihiro Maki Masahiko Nakatsui Masato Mori Yasushi Noguchi Shintaro Yoshida Michio Takahashi Nobuo Kondo Masahiro Okamoto 《Amino acids》2010,38(1):179-187
The changes in the concentrations of plasma amino acids do not always follow the flow-based metabolic pathway network. We
have previously shown that there is a control-based network structure among plasma amino acids besides the metabolic pathway
map. Based on this network structure, in this study, we performed dynamic analysis using time-course data of the plasma samples
of rats fed single essential amino acid deficient diet. Using S-system model (conceptual mathematical model represented by
power-law formalism), we inferred the dynamic network structure which reproduces the actual time-courses within the error
allowance of 13.17%. By performing sensitivity analysis, three of the most dominant relations in this network were selected;
the control paths from leucine to valine, from methionine to threonine, and from leucine to isoleucine. This result is in
good agreement with the biological knowledge regarding branched-chain amino acids, and suggests the biological importance
of the effect from methionine to threonine. 相似文献
199.
Yasushi Todoroki Kumi Naiki Hikaru Aoyama Minaho Shirakura Kotomi Ueno Masaharu Mizutani Nobuhiro Hirai 《Bioorganic & medicinal chemistry letters》2010,20(18):5506-5509
The plant growth-retardant uniconazole (UNI), a triazole inhibitor of gibberellin biosynthetic enzyme (CYP701A), inhibits multiple P450 enzymes including ABA 8′-hydroxylase (CYP707A), a key enzyme in ABA catabolism. Azole P450 inhibitors bind to a P450 active site by both coordinating to the heme-iron atom via sp2 nitrogen and interacting with surrounding protein residues through a lipophilic region. We hypothesized that poor selectivity of UNI may result from adopting a distinct conformation and orientation for different active sites. Based on this hypothesis, we designed and synthesized novel UNI analogs with a disubstituted azole ring (DSI). These analogs were expected to have higher selectivity than UNI because the added functional group may interact with the active site to restrict orientation of the molecule in the active site. DSI-505ME and DSI-505MZ, which have an imidazolyl group with a methyl 5-acrylate, strongly inhibited recombinant CYP707A3, with no growth-retardant effect. 相似文献
200.
Yoshimi Tokuzawa Ken Yagi Yzumi Yamashita Yutaka Nakachi Itoshi Nikaido Hidemasa Bono Yuichi Ninomiya Yukiko Kanesaki-Yatsuka Masumi Akita Hiromi Motegi Shigeharu Wakana Tetsuo Noda Fred Sablitzky Shigeki Arai Riki Kurokawa Toru Fukuda Takenobu Katagiri Christian Sch?nbach Tatsuo Suda Yosuke Mizuno Yasushi Okazaki 《PLoS genetics》2010,6(7)