全文获取类型
收费全文 | 5090篇 |
免费 | 314篇 |
国内免费 | 2篇 |
出版年
2022年 | 22篇 |
2021年 | 50篇 |
2020年 | 22篇 |
2019年 | 50篇 |
2018年 | 34篇 |
2017年 | 49篇 |
2016年 | 79篇 |
2015年 | 118篇 |
2014年 | 156篇 |
2013年 | 374篇 |
2012年 | 241篇 |
2011年 | 262篇 |
2010年 | 155篇 |
2009年 | 170篇 |
2008年 | 272篇 |
2007年 | 265篇 |
2006年 | 243篇 |
2005年 | 250篇 |
2004年 | 243篇 |
2003年 | 238篇 |
2002年 | 213篇 |
2001年 | 160篇 |
2000年 | 148篇 |
1999年 | 119篇 |
1998年 | 76篇 |
1997年 | 54篇 |
1996年 | 74篇 |
1995年 | 64篇 |
1994年 | 47篇 |
1993年 | 55篇 |
1992年 | 103篇 |
1991年 | 97篇 |
1990年 | 97篇 |
1989年 | 74篇 |
1988年 | 64篇 |
1987年 | 62篇 |
1986年 | 50篇 |
1985年 | 35篇 |
1984年 | 61篇 |
1983年 | 41篇 |
1982年 | 48篇 |
1981年 | 38篇 |
1980年 | 30篇 |
1979年 | 34篇 |
1978年 | 31篇 |
1977年 | 31篇 |
1976年 | 31篇 |
1974年 | 31篇 |
1973年 | 21篇 |
1972年 | 22篇 |
排序方式: 共有5406条查询结果,搜索用时 31 毫秒
101.
Tadao Hashimoto Yukuo Yoshida Kunio Tagawa 《Journal of bioenergetics and biomembranes》1990,22(1):27-38
An intrinsic ATPase inhibitor inhibits the ATP-hydrolyzing activity of mitochondrial F1F0-ATPase and is released from its binding site on the enzyme upon energization of mitochondrial membranes to allow phosphorylation of ADP. The mitochondrial activity to synthesize ATP is not influenced by the absence of the inhibitor protein. The enzyme activity to hydrolyze ATP is induced by dissipation of the membrane potential in the absence of the inhibitor. Thus, the inhibitor is not responsible for oxidative phosphorylation, but acts only to inhibit ATP hydrolysis by F1F0-ATPase upon deenergization of mitochondrial membranes. The inhibitor protein forms a regulatory complex with two stabilizing factors, 9K and 15K proteins, which facilitate the binding of the inhibitor to F1F0-ATPase and stabilize the resultant inactivated enzyme. The 9K protein, having a sequence very similar to the inhibitor, binds directly to F1 in a manner similar to the inhibitor. The 15K protein binds to the F0 part and holds the inhibitor and the 9K protein on F1F0-ATPase even when one of them is detached from the F1 part. 相似文献
102.
103.
Severe combined immune deficiency (scid) mice are assumed to have two types of abnormalities: one is high radiosensitivity and the other is abnormal recombination
in immunoglobulin and T-cell receptor genes. The human chromosome 8 q1.1 region has an ability to complement the scid aberrations. Moreover, the localization of the subunit DNA-dependent protein kinase [DNA-PKcs] participating in DNA double-strand break repair in the same locus was clarified. In scid mouse cells, the number of DNA-PKcs products and extent of DNA-PK activity remarkably decrease. These observations gave rise to the assumption that DNA-PKcs is the scid factor itself. In order to determine whether the DNA-PK
cs
gene is the scid gene, we isolated the mouse DNA-PK
cs
gene and investigated its chromosomal locus by fluorescence in situ hybridization (FISH). Consequently, it became clear that
the mouse DNA-PK
cs
gene existed in the centromeric region of mouse chromosome 16, determined by cross-genetic study, as a scid locus. This finding strongly suggests that mouse DNA-PK
cs
is the scid gene.
Received: 22 March 1996 相似文献
104.
Ping Z. Ding Kunio Kawamura James P. Ferris 《Origins of life and evolution of the biosphere》1996,26(2):151-171
The 5-phosphorimidazolide of uridine reacts on Na+-montmorillonite 22A in aqueous solution to give oligomers as long as 7 mers. The maximum chain length increases to 9 mers and the overall oligomer yield increases when 9:1 ImpU, A5 ppA mixtures react under the same conditions. The oligomer yield and maximum chain length decreases with the structure of the added pyrophosphate in the order A5 ppA>A5 ppU>U5 ppU. Structure analysis of individual oligomer fractions was performed by selective enzymatic hydrolyses followed by HPLC analysis of the products. The regioselectivity for 3,5-bond formation is 80–90% in the 9:1 ImpU, A5 ppA reaction, a percentage comparable to that observed in the 9:1 ImpA, A5 ppA reaction. Oligomerization of ImpU is inhibited by addition of dA5 ppdA, and MeppA. No oligomers containing A5 ppU were products of the 9:1 ImpU, A5 ppA reaction, a finding consistent with the simple addition of the ImpU to the A5 ppA and not the rearrangement of an ImpU-A5 ppA adduct. Concentrations of lysine or arginine which were close to that of the ImpU did not inhibit oligomer formation. Treatment of Na+-montmorillonite with 1 M arginine yielded arginine-montmorillonite, an amino acid-mineral adduct which did not catalyze ImpU oligomerization. Neither the 4–9 mers formed in the 9:1 ImpU, A5 ppA reaction nor the 4–9 mers formed by the base hydrolysis of poly(U) served as templates for the formation of oligo(A)s. 相似文献
105.
Phosphorylation of a Protein (pp56) is Related to the Regeneration of Rice Cultured Suspension Cells 总被引:3,自引:0,他引:3
Short-term cultured suspension cells of rice (Oryza sativa L.)are capable of regeneration, but not in long-term culture. Forclarification of the mechanism of regeneration, protein phosphorylationin short-term and long-term cultured suspension cells was comparedby two dimensional- polyacrylamide gel electrophoresis. A 56kDa protein having an isoelectric point of 4.5 was phosphorylatedin vitro in short-term cultured suspension cells, but was notphosphorylated after regeneration. This protein in longtermcultured suspension cells remained phosphorylated after transferto the regeneration medium. However, using an antibody raisedagainst this protein from short-term cultured suspension cells,it was always detected in long-term and short-term culturedsuspension cells after transfer to the regeneration medium.The partial amino acid sequence of the HPLC-purified proteinshowed homology to a calcium-binding protein from maize. Thephosphorylation of the 56 kDa protein (pp56) appears to be associatedwith the regeneration of cultured rice cells. (Received December 11, 1995; Accepted June 3, 1996) 相似文献
106.
Shinichiro Nakamura Wijit Kiatipattanasakul Hiroyuki Nakayama Fumiko Ono Ippei Sakakibara Yasuhiro Yoshikawa Naoaki Goto Kunio Doi 《Journal of medical primatology》1996,25(4):294-300
Abstract: In this study, we immunohistochemically examined the several constituents of senile plaques (SPs) and cerebral amyloid angiopathy (CAA) in aged cynomolgus monkeys. Apolipoprotein E (apoE) deposited in all mature plaques and CAA, and in half of the diffuse plaques. Alpha-1-antichymotripsin (αACT) deposited in half of the mature plaques and in one third of the CAA. Amyloid precursor protein (APP), ubiquitin (Ub), and microtubule-associated protein-2 (MAP-2) accumulated in the swollen neurites of mature plaques. Glial fibrillary acidic protein (GFAP) was detected in the astrocytes and their processes surrounding the mature plaques. Tau was detected in neither the SPs nor CAA. Therefore, mature plaques involved extracellular Aβ, apoE, and αACT, and also astrocytes and swollen neurites. However, diffuse plaques involved only extracellular Aβ and apoE. Since these features, except for tau, were consistent with those in humans, this animal model will be useful for studying the pathogenesis of cerebral amyloid deposition. 相似文献
107.
Satoshi Muraki Masahiro Yamasaki Yoshito Ehara Kunio Kikuchi Kunihiro Seki 《European journal of applied physiology and occupational physiology》1996,74(5):481-483
The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed
lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed
graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC)
were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subject's mean peak oxygen
uptake and peak heart rate was 1.41 ± 0.22 1·min−1 and 171.6 ± 19.2 beats·min−1, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest.
These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE. 相似文献
108.
Purification of a novel UV-damaged-DNA binding protein highly specific for (6-4) photoproduct. 下载免费PDF全文
UV damage-specific binding proteins are considered to play important roles in early responses of cells irradiated with UV, including damage recognition in the DNA repair process. We have surveyed nuclear and cytoplasmic proteins which bind selectively to UV-irradiated DNA using an electrophoretic mobility shift assay. We detected four distinct binding activities with different mobilities in fractions separated from HeLa cells by heparin chromatography. Three of them were found in nuclear extracts and one in cytoplasmic extracts. We purified one of the binding factors from nuclear extracts to homogeneity, which was designated NF-10 (the 10th fraction of nuclear extract on heparin chromatography). It migrated as a 40 kDa polypeptide in SDS-PAGE, and bound to UV-irradiated double- stranded DNA but not to unirradiated DNA. The binding pattern of the NF-10 protein to DNA irradiated with UV corresponded to the induction kinetics of (6-4) photoproduct. Removal of (6-4) photoproducts from UV- irradiated DNA by (6-4) photoproduct-specific photolyase diminished the binding of NF-10 protein. These results suggest that the NF-10 protein binds to UV-damaged DNA through (6-4) photoproduct. Immunoblot analysis using a monoclonal antibody revealed that the NF-10 protein was expressed in cell lines from all complementation groups of xeroderma pigmentosum, indicating that the NF-10 protein is a novel UV-damaged-DNA binding protein. 相似文献
109.
Y. Sakai T. Abe Y. Ohbayashi K. Isaka K. Yamamoto Y. Tani N. Kato 《Applied microbiology》1996,62(7):2669-2672
When 7-aminocephalosporanic acid (7-ACA) was used as a single carbon source in the enrichment culture medium for screening 7-ACA-degrading microorganisms, pink yeast colonies appeared frequently, and these were identified as Rhodotorula glutinis. These intact R. glutinis cells converted (i) 7-ACA to deacetyl-7-ACA (7-ADACA) and (ii) monochloroacetyl-7-ACA to monochloroacetyl-7-ADACA at sufficiently high levels to be of commercial interest. Acetylation of 7-ADACA to 7-ACA, the reverse reaction of hydrolysis in an organic medium with methyl acetate as an acetyl donor, was also demonstrated. 相似文献
110.
Indoor climate was assessed in an apartment in Isehara City, Kanagawa Prefecture, Japan, by use of a fungal index. The index represents the environmental (climate) capacity to allow fungal growth; it is determined by measuring the growth rate of a biosensor fungus, Eurotium herbariorum J-183. Differences in climate among various parts of the apartment (microclimate) and its changes could be clarified by using the index. The index in the entire apartment was high in summer, low in winter, and intermediate in spring and autumn. According to the part of the apartment, the index was high in water-associated areas and cool areas. This high fungal index in cool areas was caused by the air at the same absolute humidity showing an increase in the relative humidity with a decrease in temperature. Fungal contamination rapidly progressed in areas with a high fungal index in this apartment. A correlation was observed between the fungal index and fungal contamination. Therefore, areas susceptible to fungal contamination can be estimated by use of the fungal index. 相似文献