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141.
A photosystem other than PS370 also mediates the negative phototaxis of Halobacterium halobium 总被引:2,自引:0,他引:2
Tetsuo Takahashi Hiroaki Tomioka Naoki Kamo Yonosuke Kobatake 《FEMS microbiology letters》1985,28(2):161-164
Abstract It was found that a photorepellent system other than photosystem 370 (PS370) also controls the behavior of Halobacterium halobium . Both the dependence of background illumination and wavelength where the response showed maximum action distinguished that photosystem from PS370 whose photoreceptor pigment is thought to be an intermediate of s-rhodopsin (sR). A mutant strain that has no detectable activity in PS370 and in photoattractant response was isolated. This mutant strain showed the repellent response due to the new photosystem. 相似文献
142.
143.
Ibayashi S Nagao T Kitazono T Ooboshi H Kitayama J Sadoshima S Fujishima M 《Neurochemical research》2000,25(3):349-355
The present study was designed to examine the effect of a calcium antagonist isradipine (PN200-110: PN) on local cerebral blood flow and brain tissue metabolism after 1-hour supratentorial ischemia induced by bilateral carotid artery ligation (BCL) in spontaneously hypertensive rats (SHR). PN, dissolved in ethanol plus polyethylene glycol 400, diluted with saline to make the final concentration of 0.25mg/ml and 2.5mg/ml, was administered subcutaneously either 30 min prior to BCL or just after the induction of incomplete cerebral ischemia (n = 7 in each group). Vehicle injection was served as a control group (n = 7). Cerebral blood flow in the parietal cortex (CBF) and the cerebellar cortex (CeBF) was measured by hydrogen clearance technique, and the supra- and infratentorial metabolites of the brain frozen in situ were determined by the enzymatic method. Blood pressure was lowered, but CBF was increased by PN administration in pre-BCL treatment study. After 1 hour of BCL, CBF decreased to around 10% or less of the resting value, being insignificant among the groups. Brain adenosine triphosphate was better preserved in PN-administered groups. The increase in lactate level tended to reduce dose dependently by PN treatment. PN also reduced the metabolic alterations in brain tissue with significance, even when administered just after the induction of forebrain ischemia. It is considered that pre- as well as post-BCL administration of PN is beneficial to attenuate the metabolic alterations in incomplete forebrain ischemia in SHR. 相似文献
144.
Hiroaki Kataoka Kazuki Nabeshima Naoto Komada Masashi Koono 《Virchows Archiv. B, Cell pathology including molecular pathology》1989,57(1):157-165
Two new human cell lines, RCM-1 and CoCM-1, have been established from primary colorectal adenocarcinomas. Both cell lines
were unique in that the cultures secreted trypsin inhibitors in vitro. The activities of these inhibitors were accumulated
in serum-free media of both cell lines over a period of several days. Two inhibitors (PI-1 and PI-2) were isolated from serum-free
conditioned medium in which RCM-1 was grown by anion-exchange and gel filtration high-performance liquid chromatography. PI-1
inhibited trypsin and chymotrypsin strongly, and pancreatic elastase weakly. Its molecular weight was about 57 kilodaltons
(Kd) as determined by gel filtration chromatography. It cross-reacted with the antiserum elicited against human α1-antitrypsin in double immunodiffusion. PI-1 corresponding to α1
- antitrypsin was also demonstrated immunohistochemically in both cell lines. PI-2 inhibited trypsin strongly, and chymotrypsin,
kallikrein and plasmin weakly. It had higher molecular weight (200–300 Kd) than that of PI-1, and did not crossreact with
antisera against human α1-antitrypsin, α2-macroglobulin, α1-antichymotrypsin, α2-plasmin inhibitor, inter-α-trypsin inhibitor and urinary trypsin inhibitor. RCM-1 and CoCM-1 are the first colorectal adenocarcinoma
cell lines that secrete functionally active trypsin inhibitors, including α1-antitrypsin in vitro, and are useful for the study of tumor-cell derived proteinase inhibitors. 相似文献
145.
Nuki Y Uchinokura S Miyata S Fukushima T Hamasuna R Nakano S Wakisaka S Akiyama Y Itoh H Kataoka H 《Human cell》2004,17(3):145-150
A cell line designated NYGM was established from a human cerebral glioblastoma multiforme (GBM) obtained from a 75-year-old Japanese woman. The cell line has grown slowly without interruption and has been propagated continuously by serial passages (more than 80 passage) during the past 3 years. The cultured cells were fusiform or polyhedral in shape. The population doubling time was 24 hours. The chromosomal number varied between 77 and 88, with modal chromosomal number of 84. NYGM cells concomitantly expressed MET receptor tyrosine kinase (a product of c-met protooncogene) and its ligand HGF/SF (hepatocyte growth factor/scatter factor), as well as HGF activator and HGF activator inhibitors. The cells might be useful for the study of pericellular regulation of HGF/SF-MET signaling and HGF activation of GBM cells. 相似文献
146.
Jochen Schulze Sebastian Seitz Hiroaki Saito Michael Schneebauer Robert P. Marshall Anke Baranowsky Bjoern Busse Arndt F. Schilling Felix W. Friedrich Joachim Albers Alexander S. Spiro Jozef Zustin Thomas Streichert Kristina Ellwanger Christof Niehrs Michael Amling Roland Baron Thorsten Schinke 《PloS one》2010,5(4)
Wnt signalling is a key pathway controlling bone formation in mice and humans. One of the regulators of this pathway is Dkk1, which antagonizes Wnt signalling through the formation of a ternary complex with the transmembrane receptors Krm1/2 and Lrp5/6, thereby blocking the induction of Wnt signalling by the latter ones. Here we show that Kremen-2 (Krm2) is predominantly expressed in bone, and that its osteoblast-specific over-expression in transgenic mice (Col1a1-Krm2) results in severe osteoporosis. Histomorphometric analysis revealed that osteoblast maturation and bone formation are disturbed in Col1a1-Krm2 mice, whereas bone resorption is increased. In line with these findings, primary osteoblasts derived from Col1a1-Krm2 mice display a cell-autonomous differentiation defect, impaired canonical Wnt signalling and decreased production of the osteoclast inhibitory factor Opg. To determine whether the observed effects of Krm2 on bone remodeling are physiologically relevant, we analyzed the skeletal phenotype of 24 weeks old Krm2-deficient mice and observed high bone mass caused by a more than three-fold increase in bone formation. Taken together, these data identify Krm2 as a regulator of bone remodeling and raise the possibility that antagonizing KRM2 might prove beneficial in patients with bone loss disorders. 相似文献
147.
Sumio Ishijima Zenpei Shigemi Hiroaki Adachi Nana Makinouchi Ikuko Sagami 《生物化学与生物物理学报:生物膜》2012,1818(9):2202-2208
Magnesium (Mg2+) plays critical role in many physiological processes. The mechanism of Mg2+ transport has been well documented in bacteria; however, less is known about Mg2+ transporters in eukaryotes. The AtMRS2 family, which consists of 10 Arabidopsis genes, belongs to a eukaryotic subset of the CorA superfamily proteins. Proteins in this superfamily have been identified by a universally conserved GlyMetAsn motif and have been characterized as Mg2+ transporters. Some members of the AtMRS2 family, including AtMRS2-10, may complement bacterial mutants or yeast mutants that lack Mg2+ transport capabilities. Here, we report the purification and functional reconstitution of AtMRS2-10 into liposomes. AtMRS2-10, which contains an N-terminal His-tag, was expressed in Escherichia coli and solubilized with sarcosyl. The purified AtMRS2-10 protein was reconstituted into liposomes. AtMRS2-10 was inserted into liposomes in a unidirectional orientation. Direct measurement of Mg2+ uptake into proteoliposomes revealed that reconstituted AtMRS2-10 transported Mg2+ without any accessory proteins. Mutation in the GMN motif, M400 to I, inactivated Mg2+ uptake. The AtMRS2-10-mediated Mg2+ influx was blocked by Co(III)hexamine, and was independent of the external pH from 5 to 9. The activity of AtMRS2-10 was inhibited by Co2+ and Ni2+; however, it was not inhibited by Ca2+, Fe2+, or Fe3+. While these results indicate that AtMRS2-10 has similar properties to the bacterial CorA proteins, unlike bacterial CorA proteins, AtMRS2-10 was potently inhibited by Al3+. These studies demonstrate the functional capability of the AtMRS2 proteins in proteoliposomes to study structure–function relationships. 相似文献
148.
Munehiro Uda Hiroaki Kawasaki Ayako Shigenaga Takeshi Baba Fumiyuki Yamakura 《Bioscience reports》2012,32(6):521-530
Nitration of tryptophan residues is a novel post-translational modification. In the present
study, we examined whether NO2Trp (nitrotryptophan)-containing proteins are produced in
the hippocampus and cerebellum of the adult rat under physiological conditions in
vivo. Using Western blot analysis with anti-6-NO2Trp-specific antibody, we found
many similar immunoreactive spots in the protein extracts from both regions. These spots were
subsequently subjected to trypsin digestion and LC-ESI-MS/MS (LC-electrospray ionization-tandem MS)
analysis. We identified several cytoskeletal proteins and glycolytic enzymes as
NO2Trp-containing proteins and determined the position of nitrated tryptophan residues
with significant ion score levels (P<0.05) in several proteins in both
regions. We also observed that the total amount of NO2Trp-containing proteins in the
cerebellum was significantly greater than that in the hippocampus (P<0.05).
Moreover, IP (immunoprecipitation) assays using anti-aldolase C antibody showed that the relative
intensity of immunostaining for NO2Trp over aldolase C was much higher in cerebellum than
in hippocampus. The amounts of nNOS (neuronal nitric oxide synthase) and eNOS (endothelial nitric
oxide synthase) were much greater in cerebellum than in hippocampus. This is the first evidence of
several specific sites of nitrated tryptophan in proteins under physiological conditions in
vivo. 相似文献
149.
Kimura H Kwan KM Zhang Z Deng JM Darnay BG Behringer RR Nakamura T de Crombrugghe B Akiyama H 《PloS one》2008,3(9):e3174
Background
Bone mass is maintained by continuous remodeling through repeated cycles of bone resorption by osteoclasts and bone formation by osteoblasts. This remodeling process is regulated by many systemic and local factors.Methodology/Principal Findings
We identified collagen triple helix repeat containing-1 (Cthrc1) as a downstream target of bone morphogenetic protein-2 (BMP2) in osteochondroprogenitor-like cells by PCR-based suppression subtractive hybridization followed by differential hybridization, and found that Cthrc1 was expressed in bone tissues in vivo. To investigate the role of Cthrc1 in bone, we generated Cthrc1-null mice and transgenic mice which overexpress Cthrc1 in osteoblasts (Cthrc1 transgenic mice). Microcomputed tomography (micro-CT) and bone histomorphometry analyses showed that Cthrc1-null mice displayed low bone mass as a result of decreased osteoblastic bone formation, whereas Cthrc1 transgenic mice displayed high bone mass by increase in osteoblastic bone formation. Osteoblast number was decreased in Cthrc1-null mice, and increased in Cthrc1 transgenic mice, respectively, while osteoclast number had no change in both mutant mice. In vitro, colony-forming unit (CFU) assays in bone marrow cells harvested from Cthrc1-null mice or Cthrc1 transgenic mice revealed that Cthrc1 stimulated differentiation and mineralization of osteoprogenitor cells. Expression levels of osteoblast specific genes, ALP, Col1a1, and Osteocalcin, in primary osteoblasts were decreased in Cthrc1-null mice and increased in Cthrc1 transgenic mice, respectively. Furthermore, BrdU incorporation assays showed that Cthrc1 accelerated osteoblast proliferation in vitro and in vivo. In addition, overexpression of Cthrc1 in the transgenic mice attenuated ovariectomy-induced bone loss.Conclusions/Significance
Our results indicate that Cthrc1 increases bone mass as a positive regulator of osteoblastic bone formation and offers an anabolic approach for the treatment of osteoporosis. 相似文献150.
Masaki Wakasugi Hiroaki Gouda Tomoyasu Hirose Akihiro Sugawara Tsuyoshi Yamamoto Kazuro Shiomi Toshiaki Sunazuka Satoshi Ōmura Shuichi Hirono 《Bioorganic & medicinal chemistry》2013,21(11):3214-3220
Human acidic mammalian chitinase (hAMCase) was recently shown to be involved in the development of asthma, suggesting a possible application for hAMCase inhibitors as novel therapeutic agents for asthma. We therefore initiated drug discovery research into hAMCase using a combination of in silico methodologies and a hAMCase assay system. We first selected 23 candidate hAMCase inhibitors from a database of four million compounds using a multistep screening system combining Tripos Topomer Search technology, a docking calculation and two-dimensional molecular similarity analysis. We then measured hAMCase inhibitory activity of the selected compounds and identified seven compounds with IC50 values ?100 μM. A model describing the binding modes of these hit compounds to hAMCase was constructed, and we discuss the structure–activity relationships of the compounds we identified, suggested by the model and the actual inhibitory activities of the compounds. 相似文献