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排序方式: 共有645条查询结果,搜索用时 250 毫秒
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The aim of this study was to investigate possible involvement of annexin XI in the insulin secretory machinery. In fluorescence immunocytochemistry, annexin XI was found in the cytoplasm of pancreatic endocrine cells and a pancreatic beta-cell line, MIN6, in a granular pattern. MIN6 cells also possessed weak and diffused annexin XI immunoreactivity in the cytoplasm. Immunoelectron microscopy revealed annexin XI in the insulin granules. Insulin secretion from streptolysin-O-permeabilized MIN6 cells was inhibited by anti-annexin XI antibody, when the release was stimulated by either Ca2+ or GTP-gammaS, but not by a protein kinase C-activating phorbol ester. Inhibition of insulin release by anti-annexin XI antibody was reproduced in permeabilized rat islets. These findings suggest that annexin XI may be involved in the regulation of insulin secretion from the pancreatic beta-cells. 相似文献
64.
We examined gametogenesis and the periodicity of planula release in the brooding coral Acropora (Isopora) brueggemanni (Brook, 1893) on Akajima Island, Okinawa, Japan. We captured the moment when A. brueggemanni would be in the process of self-fertilization. Whole colonies of this species were cultured separately or together with other colonies in plastic containers. We observed no apparent periodicity of planula release in the collected colonies. A few planulae were released intermittently during the observation period, regardless of whether the colonies were cultured individually or with other colonies. Serial paraffin sections of A. brueggemanni showed follicle-like cells surrounding the oocyte during vitellogenesis. In September and October, some spermaries looked half-broken and some ova were surrounded by sperm or spermaries instead of follicle-like cells. Such ova were heart-shaped and may have been cells at the first cleavage stage. These observations suggest that the migration of spermaries and/or oocytes resulted in the close proximity of oocytes and sperm, which would allow self-fertilization. This possibility, together with the production of planula larvae by isolated colonies, suggests that this brooding coral engages in self-fertilization. 相似文献
65.
Ami E Nakahara K Sato A Nguyen JT Hidaka K Hamada Y Nakatani S Kimura T Hayashi Y Kiso Y 《Bioorganic & medicinal chemistry letters》2007,17(15):4213-4217
We designed several HIV protease inhibitors with various d-cysteine derivatives as P(2)/P(3) moieties based on the structure of clinical drug candidate, KNI-764. Herein, we report their synthesis, HIV protease inhibitory activity, HIV IIIB cell inhibitory activity, cellular toxicity, and inhibitory activity against drug-resistant HIV strains. KNI-1931 showed distinct selectivity against HIV proteases and high potency against drug-resistant strains, surpassing those of Ritonavir and Nelfinavir. 相似文献
66.
Hidaka M Su GN Chen JK Mukaisho K Hattori T Yamamoto G 《In vitro cellular & developmental biology. Animal》2007,43(2):49-58
Bone is a complex, highly structured, mechanically active, three-dimensional (3-D) tissue composed of cellular and matrix
elements. We previously published a report on in situ collagen gelation using a rotary 3-D culture system (CG–RC system) for
the construction of large tissue specimens. The objective of the current study was to evaluate the feasibility of bone tissue
engineering using our CG–RC system. Osteoblasts from the calvaria of newborn Wistar rats were cultured in the CG–RC system
for up to 3 wk. The engineered 3-D tissues were implanted into the backs of nude mice and calvarial round bone defects in
Wistar rats. Cell metabolic activity, mineralization, and bone-related proteins were measured in vitro in the engineered 3-D
tissues. Also, the in vivo histological features of the transplanted, engineered 3-D tissues were evaluated in the animal
models. We found that metabolic activity increased in the engineered 3-D tissues during cultivation, and that sufficient mineralization
occurred during the 3 wk in the CG–RC system in vitro. One mo posttransplantation, the transplants to nude mice remained mineralized
and were well invaded by host vasculature. Of particular interest, 2 mo posttransplantation, the transplants into the calvarial
bone defects of rats were replaced by new mature bone. Thus, this study shows that large 3-D osseous tissue could be produced
in vitro and that the engineered 3-D tissue had in vivo osteoinductive potential when transplanted into ectopic locations
and into bone defects. Therefore, this system should be a useful model for bone tissue engineering. 相似文献
67.
Hidaka A Hamaji Y Sasaki T Taniguchi S Fujimori M 《Bioscience, biotechnology, and biochemistry》2007,71(12):2921-2926
Bifidobacteria are nonpathogenic, anaerobic domestic bacteria with health-promoting properties for the host. In our previous study, Bifidobacterium longum (B. longum) were found to be localized selectively and to proliferate within solid tumors after systemic application. Additionally, B. longum transformed by shuttle-plasmid including the cytosine deaminase (CD) gene expressed active CD, converted the prodrug 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU). We also demonstrated antitumor efficacy with a transformant of B. longum in rats. In this study, we found that Bifidobacterium breve (B. breve), the smallest species of human-derived bifidobacterium, expressed the exogenous transgene (CD), that CD enzymatic activity in the transformant of B. breve was much higher, and that the segregational stability of the plasmid was greater than that of B. longum. Thus, numerous transformants of B. breve were detected solely in the tumors after systemic administration. We consider the transformant of B. breve to be more beneficial in our enzyme/prodrug therapy. 相似文献
68.
Ryu Tashiro Masahiro Iwamoto Hironobu Morinaga Tomoko Emura Kumi Hidaka Masayuki Endo Hiroshi Sugiyama 《Nucleic acids research》2015,43(14):6692-6700
DNA has recently emerged as a promising material for the construction of nanosized architectures. Chemically modified DNA has been suggested to be an important component of such architectural building blocks. We have designed and synthesized a novel H-shaped DNA oligonucleotide dimer that is cross-linked with a structurally rigid linker composed of phenylene and ethynylene groups. A rotatable DNA unit was constructed through the self-assembly of this H-shaped DNA component and two complementary DNA oligonucleotides. In addition to the rotatable unit, a locked DNA unit containing two H-shaped DNA components was also constructed. As an example of an extended locked structure, a hexagonal DNA origami dimer and oligomer were constructed by using H-shaped DNA as linkers. 相似文献
69.
Yamazaki Y Kido Y Hidaka K Yasui H Kiso Y Yakushiji F Hayashi Y 《Bioorganic & medicinal chemistry》2011,19(1):595-602
A new bioactive photoaffinity probe KPU-252-B1 (4) possessing a biotin tag on the oxazole ring of a potent plinabulin derivative KPU-244 (2) was synthesized via the CuI-catalyzed Huisgen’s cycloaddition reaction to understand the precise binding mode of the diketopiperazine-based anti-microtubule agent plinabulin on tubulin. Probe 4 showed significant binding affinity toward tubulin and cytotoxicity against an HT-29 cells. A photoaffinity labeling study suggested that probe 4 specifically recognizes tubulin at a binding site that binds plinabulin or colchicine, most likely near or at the colchicine binding site, which is located at the interfacial region formed by ??-and ??-tubulin association. The results also demonstrated that probe 4 may serve as a useful plinabulin chemical probe to investigate the molecular mechanism by which anti-microtubule diketopiperazine derivatives operate. 相似文献
70.
Tagad HD Hamada Y Nguyen JT Hidaka K Hamada T Sohma Y Kimura T Kiso Y 《Bioorganic & medicinal chemistry》2011,19(17):5238-5246
Previously, we reported potent pentapeptidic BACE1 inhibitors with the hydroxymethylcarbonyl isostere as a substrate transition-state mimic. To improve the in vitro potency, we further reported pentapeptidic inhibitors with carboxylic acid bioisosteres at the P(4) and P1' positions. In the current study, we screened new P1' position 1-phenylcycloalkylamine analogs to find non-acidic inhibitors that possess double-digit nanomolar range IC(50) values. An extensive structure-activity relationship study was performed with various amine derivatives at the P1' position. The most potent inhibitor of this pentapeptide series, KMI-1830, possessing 1-phenylcyclopentylamine at the P1' position had an IC(50) value of 11.6 nM against BACE1 in vitro enzymatic assay. 相似文献