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61.
The present investigation was undertaken to verify whether mitochondria play a significant role in aluminium (Al) toxicity, using the mitochondria isolated from tobacco cells (Nicotiana tabacum, non-chlorophyllic cell line SL) under Al stress. An inhibition of respiration was observed in terms of state-III, state-IV, succinate-dependent, alternative oxidase (AOX)-pathway capacity and cytochrome (CYT)-pathway capacity, respectively, in the mitochondria isolated from tobacco cells subjected to Al stress for 18 h. In accordance with the respiratory inhibition, the mitochondrial ATP content showed a significant decrease under Al treatment. An enhancement of reactive oxygen species (ROS) production under state-III respiration was observed in the mitochondria isolated from Al-treated cells, which would create an oxidative stress situation. The opening of mitochondrial permeability transition pore (MPTP) was seen more extensively in mitochondria isolated from Al-treated cells than in those isolated from control cells. This was Ca(2+) dependent and well modulated by dithioerythritol (DTE) and Pi, but insensitive to cyclosporine A (CsA). The collapse of inner mitochondrial membrane potential (DeltaPsi(m)) was also observed with a release of cytochrome c from mitochondria. A great decrease in the ATP content was also seen under Al stress. Transmission electron microscopy analysis of Al-treated cells also corroborated our biochemical data with distortion in membrane architecture in mitochondria. TUNEL-positive nuclei in Al-treated cells strongly indicated the occurrence of nuclear fragmentation. From the above study, it was concluded that Al toxicity affects severely the mitochondrial respiratory functions and alters the redox status studied in vitro and also the internal structure, which seems to cause finally cell death in tobacco cells. 相似文献
62.
In adipocytes, lipid droplet (LD) size reflects a balance of triglyceride synthesis (lipogenesis) and hydrolysis (lipolysis). Perilipin A (Peri A) is the most abundant phosphoprotein on the surface of adipocyte LDs and has a crucial role in lipid storage and lipolysis. Adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) are the major rate-determining enzymes for lipolysis in adipocytes. Each of these proteins (Peri A, ATGL, and HSL) has been demonstrated to regulate lipid storage and release in the adipocyte. However, in the absence of protein kinase A (PKA) stimulation (basal state), the lipases (ATGL and HSL) are located mainly in the cytoplasm, and their contribution to basal rates of lipolysis and influence on LD size are poorly understood. In this study, we utilize an adenoviral system to knockdown or overexpress ATGL and HSL in an engineered model system of adipocytes in the presence or absence of Peri A. We are able to demonstrate in our experimental model system that in the basal state, LD size, triglyceride storage, and fatty acid release are mainly influenced by the expression of ATGL. These results demonstrate for the first time the relative contributions of ATGL, HSL, and Peri A on determination of LD size in the absence of PKA stimulation. 相似文献
63.
Hajime Yoshida Keizo Hanada Hisakazu Ohsawa Hidehiko Kumagai Hideaki Yamada 《Bioscience, biotechnology, and biochemistry》2013,77(4):1035-1042
Biosynthetic threonine deaminase was purified to an apparent homogeneous state from the cell extract of Proteus morganii, with an overall yield of 7.5%. The enzyme had a s020,w of 10.0 S, and the molecular weight was calculated to be approximately, 228,000. The molecular weight of a subunit of the enzyme was estimated to be 58,000 by sodium dodecyl sulfate gel electrophoresis. The enzyme seemed to have a tetrameric structure consisting of identical subunits. The enzyme had a marked yellow color with an absorption maximum at 415 nm and contained 2 mol of pyridoxal 5′-phosphate per mol. The threonine deaminase catalyzed the deamination of l-threonine, l-serine, l-cysteine and β-chloro-l-alanine. Km values for l-threonine and l-serine were 3.2 and 7.1 mm, respectively. The enzyme was not activated by AMP, ADP and ATP, but was inhibited by l-isoleucine. The Ki for l-isoleucine was 1.17 mm, and the inhibition was not recovered by l-valine. Treatment with mercuric chloride effectively protected the enzyme from inhibition by l-isoleucine. 相似文献
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66.
A lignan glycoside [(+)-cycloolivil 4'-O-beta-d-glucopyranoside], a phenolic glycoside [3,4-dimethoxyphenyl 1-O-beta-d-xylopyranosyl-(1-->6)-beta-d-glucopyranoside] and a iridoid glycoside (stereospermoside) were isolated from the leaves and branches of Stereospermum cylindricum, together with (+)-cycloolivil, (+)-cycloolivil 6-O-beta-d-glucopyranoside, (-)-olivil, (-)-olivil 4-O-beta-d-glucopyranoside, (-)-olivil 4'-O-beta-d-glucopyranoside, vanilloloside, decaffeoyl-verbascoside, isoverbascoside, 3,4,5-trimethoxyphenyl 1-O-beta-d-xylopyranosyl-(1-->6)-beta-d-glucopyranoside, ajugol, verminoside, and specioside. The structure elucidations were based on spectroscopic evidence. 相似文献
67.
Astrocytes with previous chronic exposure to amyloid β‐peptide fragment 1–40 suppress excitatory synaptic transmission 下载免费PDF全文
Hiroyuki Kawano Kohei Oyabu Hideaki Yamamoto Kei Eto Yuna Adaniya Kaori Kubota Takuya Watanabe Ayumi Hirano‐Iwata Junichi Nabekura Shutaro Katsurabayashi Katsunori Iwasaki 《Journal of neurochemistry》2017,143(6):624-634
68.
Takeda Y Masuda T Morikawa H Ayabe H Hirata E Shinzato T Aramoto M Otsuka H 《Phytochemistry》2005,66(6):727-732
From the aerial parts of Crepidiastrum lanceolatum, six guaiane-type sesquiterpene glucosides, lanceocripidiasides A-F were isolated together with five known sesquiterpene glucosides, ixerin Y, crepidialanceosides A and B, and youngiasides A and D, two known megastigmane glucosides, icariside B1 and corchoionoside A, and benzyl 6'-O-beta-D-apiofuranosyl-beta-D-glucopyranoside. Structures were elucidated by spectroscopic analyses. 相似文献
69.
A human T-cell lymphotropic virus type 1 enhancer of Myc transforming potential stabilizes Myc-TIP60 transcriptional interactions 下载免费PDF全文
70.
Variation and association of fibronectin‐binding protein genes fnbA and fnbB in Staphylococcus aureus Japanese isolates 下载免费PDF全文
Miyo Murai Hideaki Moriyama Eiji Hata Junko Amemura‐Maekawa 《Microbiology and immunology》2016,60(5):312-325
Fibronectin‐binding proteins A and B (FnBPA and FnBPB) mediate adhesion of Staphylococcus aureus to fibrinogen, elastin and fibronectin. FnBPA and FnBPB are encoded by two closely linked genes, fnbA and fnbB, respectively. With the exception of the N‐terminal regions, the amino acid sequences of FnBPA and FnBPB are highly conserved. To investigate the genetics and evolution of fnbA and fnbB, the most variable regions, which code for the 67th amino acids of the A through B regions (A67–B) of fnbA and fnbB, were focused upon. Eighty isolates of S. aureus in Japan were sequenced and 19 and 18 types in fnbA and fnbB, respectively, identified. Although the phylogeny of fnbA and fnbB were found to be quite different, each fnbA type connected with a specific fnbB type, indicating that fnbA and fnbB mutate independently, whereas the combination of both genes after recombination is stable. Hence those fnbA–fnbB combinations were defined as FnBP sequence types (FnSTs). Representative isolates of each FnST were assigned distinct STs by multilocus sequence typing, suggesting correspondence of FnST with genome lineage. Linkage disequilibrium (LD) analysis of the A67–B region revealed that subdomains N2, N3 and FnBR1 form a LD block in fnbA, whereas N2 and N3 form two independent LD blocks in fnbB. N2–N3 three‐dimensional structural models indicated that not only the variable amino acid residues, but also well‐conserved amino acid residues between FnBPA and FnBPB, are located on the surface of the protein. These results highlight a molecular process of the FnBP that has evolved by mingled mutation and recombination with retention of functions. 相似文献