全文获取类型
收费全文 | 6150篇 |
免费 | 427篇 |
出版年
2023年 | 35篇 |
2022年 | 63篇 |
2021年 | 118篇 |
2020年 | 67篇 |
2019年 | 89篇 |
2018年 | 104篇 |
2017年 | 110篇 |
2016年 | 177篇 |
2015年 | 235篇 |
2014年 | 248篇 |
2013年 | 398篇 |
2012年 | 389篇 |
2011年 | 428篇 |
2010年 | 218篇 |
2009年 | 211篇 |
2008年 | 334篇 |
2007年 | 305篇 |
2006年 | 287篇 |
2005年 | 226篇 |
2004年 | 276篇 |
2003年 | 217篇 |
2002年 | 243篇 |
2001年 | 125篇 |
2000年 | 132篇 |
1999年 | 114篇 |
1998年 | 55篇 |
1997年 | 52篇 |
1996年 | 54篇 |
1995年 | 44篇 |
1994年 | 37篇 |
1993年 | 47篇 |
1992年 | 103篇 |
1991年 | 102篇 |
1990年 | 79篇 |
1989年 | 85篇 |
1988年 | 83篇 |
1987年 | 54篇 |
1986年 | 48篇 |
1985年 | 51篇 |
1984年 | 47篇 |
1983年 | 35篇 |
1982年 | 38篇 |
1981年 | 35篇 |
1980年 | 26篇 |
1979年 | 59篇 |
1978年 | 30篇 |
1977年 | 36篇 |
1975年 | 31篇 |
1974年 | 34篇 |
1972年 | 25篇 |
排序方式: 共有6577条查询结果,搜索用时 46 毫秒
91.
Lentinan, a -1,6;1,3-glucan, is tumor-specific for transplantable mouse solid-type tumors and it also stimulates the production of acute phase proteins (APPs). The APP response to lentinan is of the delayed type (DT-APR) and differs from that to lipopolysaccharide, which is acute. We found that the responses were genetically controlled in mice and that low responsiveness is dominant (Maeda et al. 1991). Using 123 segregants of crosses between SWR/J (a high responder) andMus spretus (a low responder), we analyzed the linkage between DT-APR responsiveness and the DNA polymerase chain reaction-simple sequence lenght polymorphism (PCR-SSLP) phenotype using 80 chromosome-specific microsatellite markers. We identified two loci (ltn1.1 andltn1.2) responsible for DT-APR.ltn1.1 is closely linked toD3Mit11 on chromosome 3 andltn1.2 toD11Nds9 on chromosome 11 (P<0.001). The linkage analysis also suggested thatltn1.2 is the major determinant for DT-APR. Correlation between lentinan-specific IL-6 mRNA expression (the late expression) controlled recessively and DT-APR induction suggests that theltn1 loci control some process(es) of IL-6 expression in the regulation step before NF-IL6. 相似文献
92.
Hideki Fukuda Yuji Turugida Takahiro Nakajima Eiji Nomura Akihiko Kondo 《Biotechnology letters》1996,18(8):951-956
Summary Production of phospholipase D (PLD) by Streptoverticillium cinnamoneum immobilized within porous particles was investigated in repeated batch fermentation. The enzyme productivity in repeated batch fermentation was 2.2-fold that obtained in batch fermentation without immobilization, since many of the immobilized cells could be utilized as seed cells for each subsequent batch cycle. 相似文献
93.
Effects of 1,1-dimethyl-4-(phenylsulfonyl)semicarbazide (DPSS) on carnation flower longevity 总被引:2,自引:0,他引:2
Naoki Midoh Yuki Saijou Kuniomi Matsumoto Michiaki Iwata 《Plant Growth Regulation》1996,20(3):195-199
The effects of a novel preservative for cut carnation flowers, 1,1-dimethyl-4-(phenylsulfonyl)semicarbazide (DPSS), were investigated. DPSS extended the vase life of cut carnation flowers not only by continuous treatment but pulse treatment as well. This inhibition of senescence by DPSS appeared to depend on that of ethylene production in carnation flowers. DPSS provided no protection from the action of ethylene nor did it inhibit 1-aminocyclopropane-1-carboxylic acid (ACC) synthase. It did inhibit ACC-dependent ethylene production in carnation petal discs, suggesting possible potential for inhibiting ACC oxidase. 相似文献
94.
K. ARIHARA, S. OGIHARA, T. MUKAI, M. ITOH AND Y. KONDO. 1996. Fifteen of 353 environmental isolates of lactic acid bacteria consistently showed activity against Listeria monocytogenes, Streptococcus mutans, Actinomyces viscosus , and/or Propionibacterium acnes . Strain T140, isolated from the surface of Japanese pampas grass leaves and identified as Lactobacillus salivarius subsp. salicinius , also had activity against several Lactobacillus species, Staphylococcus aureus and Yersinia enterocolitica . Since the antagonistic factor(s) produced by T140 was sensitive to a proteolytic enzyme, it was concluded that a bacteriocin (named salivacin 140) was involved in the inhibition activity. Strain T140 required a high initial pH (7.5–8.5) in agar plates for bacteriocin production. 相似文献
95.
Bae Gong Young; Nakajima Nobuyoshi; Ishizuka Kozo; Kondo Noriaki 《Plant & cell physiology》1996,37(2):129-134
The rate of evolution of ethylene by tomato plants was rapidlyincreased by O3 fumigation. The time course of the increasein 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activitywas the same as that in the rate of evolution of ethylene, suggestingthat ACC synthase activity might be a rate-limiting step inthe evolution of ethylene that is caused by O3 fumigation. Therate of the O3-induced evolution of ethylene was increased bythe application of ACC to tomato plants, suggesting the involvementof ACC oxidase in the O3-induced evolution of ethylene. Treatmentof plants with tiron inhibited the evolution of ethane, butnot of ethylene. These results indicated that evolution of ethylenein O3-treated tomato plants might result from enzymatic reactionscatalyzed by both ACC synthase and ACC oxidase, but not fromstimulation by O3 of the peroxidation of lipids mediated byfree radicals. Pretreatment of leaves with aminoethoxyvinylglycine (AVG), aninhibitor of ACC synthase, significantly inhibited the evolutionof ethylene that was induced by O3 and concomitantly reducedthe extent of O3-induced visible damage to leaves. Treatmentwith 2,5-norbonadiene, an inhibitor of the action of ethylene,strongly reduced the extent of visible damage caused by O3,even though it did not suppress the evloution of ethylene. Theseresults indicate that ethylene acts on certain metabolic processesto cause visible damage. (Received September 7, 1995; Accepted December 18, 1995) 相似文献
96.
Takeuchi Yuichi; Murakami Mina; Nakajima Nobuyoshi; Kondo Noriaki; Nikaido Osamu 《Plant & cell physiology》1996,37(2):181-187
Photoinduced lesions in DNA, namely, cyclobutane pyrimidinedimers (CPDs) and pyrimidine-(6-4)-pyrimidone photoproducts[(6-4)photoproducts], in cucumber cotyledons that had been irradiatedwith naturally occurring levels of UV-B (290320 nm) werequantitated by enzyme-linked immunosorbent assays with monoclonalantibodies specific to each type of photolesion. Induction ofthese photolesions was dependent on temperature and their extentwas reduced by simultaneous irradiation with white light. Thedark repair of both types of photolesion was undetectable. Light-dependentremoval of (6-4)photoproducts was very slow, with 50% removalin 4 h. By contrast, 50% of initial CPDs were removed within15 min. Both photorepair processes were dependent on the intensityof white light and were sensitive to temperature. These resultsindicate that high photolyase activity is present in cucumbercotyledons and that repair activities in cucumber cotyledonsare different from those reported in Arabidopsis, in which (6-4)photoproductsare photorepaired more rapidly than CPDs. (Received October 13, 1995; Accepted December 28, 1995) 相似文献
97.
Yuriko Osakabe Kazuya Nanto Hiroko Kitamura Shinya Kawai Yuki Kondo Tomoyuki Fujii Keiji Takabe Yoshihiro Katayama Noriyuki Morohoshi 《Planta》1996,200(1):13-19
The polypeptide encoded by the partial fragment of cDNA of phenylalanine ammonia-lyase (PAL; EC 4.3.1.5), PALcDNAl (Osakabe et al., 1995, Plant Sci. 105: 217–226), isolated from Populus kitakamiensis (P. sieboldii x P. grandidentata), was expressed in Escherichia coli cells. The polypeptide was purified and an antiserum raised against it. The antiserum recognized a protein of 77 kDa on nitrocellulose blots after sodium dodecyl sulfate-poly-acrylamide gel electrophoresis of total protein and the partially purified PAL protein from P. kitakamiensis. Moreover,the antiserum recognized a protein on the blot after non-denaturing polyacrylamide gel electrophoresis of P. kitakamiensis proteins and this protein had PAL activity. Furthermore, the antibody inhibited PAL activity of extracts from stem tissues. These results showed that the antiserum against the partial PAL peptide recognized only the PAL subunits in extracts of P. kitakamiensis. Immunolocalization studies of P. kitakamiensis tissues revealed that the PAL protein was specifically localized in the xylem and the phloem fibers and no immunogold signal was found in the epidermis, the cortex, the pith, or the cambium of either stems or leaves.Abbreviations IgG
immunoglobulin G
- IPTG
isopropylthio--d-galactoside
- PAL
phenylalanine ammonia-lyase
The authors thank Dr. Kunio Hata of Nippon Paper Industries Co., Ltd. (Japan) for supplying P. kitakamiensis. This work was supported in part by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (No. 07406008). 相似文献
98.
S. Fukuda N. Shimozawa Y. Suzuki Z. Zhang S. Tomatsu T. Tsukamoto N. Hashiguchi T. Osumi M. Masuno K. Imaizumi Y. Kuroki Y. Fujiki T. Orii N. Kondo 《American journal of human genetics》1996,59(6):1210-1220
Peroxisome-biogenesis disorders (PBD) are genetically heterogeneous and can be classified into at least ten complementation groups. We recently isolated the cDNA for rat peroxisome assembly factor-2 (PAF-2) by functional complementation using the peroxisome-deficient Chinese-hamster-ovary cell mutant, ZP92. To clarify the novel pathogenic gene of PBD, we cloned the full-length human PAF-2 cDNA that morphologically and biochemically restores peroxisomes of group C Zellweger fibroblasts (the same as group 4 in the Kennedy-Krieger Institute) and identified two pathogenic mutations in the PAF-2 gene in two patients with group C Zellweger syndrome. The 2,940-bp open reading frame of the human PAF-2 cDNA encodes a 980-amino-acid protein that shows 87.1% identity with rat PAF-2 and also restored the peroxisome assembly after gene transfer to fibroblasts of group C patients. Direct sequencing of the PAF-2 gene revealed a homozygous 1-bp insertion at nucleotide 511 (511 insT) in one patient with group C Zellweger syndrome (ZS), which introduces a premature termination codon in the PAF-2 gene, and, in the second patient, revealed a splice-site mutation in intron 3 (IVS3+1G-->A), which skipped exon 3, an event that leads to peroxisome deficiency. Chromosome mapping utilizing FISH indicates that PAF-2 is located on chromosome 6p21.1. These results confirm that human PAF-2 cDNA restores peroxisome of group C cells and that defects in the PAF-2 produce peroxisome deficiency of group C PBD. 相似文献
99.
Kenji Kondo Susumu Terabayashi Minoru Okada Changqi Yuan Shanan He 《Journal of plant research》1996,109(1):21-27
Cnidium officinale Makino is important medicinally and economically, but its origin is uncertain. The phylogenetic relationship ofC. officinale is provided from the analyses based on the ribulose-1,5-bisphosphate carboxylase/oxgenase gene (rbcL) sequences of 41 species which represent the 34 genera of Aplaceae, the four genera of Araliaceae, and one genus each of
Pittosporaceae, Cornaceae, and Caprifoliaceae. The strict consensus tree obtained supports a close relationship ofC. officinale to the Chinese members ofLigusticum, especially toL. chuanxiong. Additionally, the tree shows (1) polyphyly of the genusLigusticum and (2) monophyly of the subfamily Apioideae. Within Apioideae, we recognized some groups in our phylogenetic tree. The grouping
is discordant in several respects with the traditional tribal divisions based mainly on fruit morphology. 相似文献
100.