全文获取类型
收费全文 | 1835篇 |
免费 | 135篇 |
专业分类
1970篇 |
出版年
2024年 | 5篇 |
2023年 | 14篇 |
2022年 | 35篇 |
2021年 | 66篇 |
2020年 | 45篇 |
2019年 | 64篇 |
2018年 | 75篇 |
2017年 | 75篇 |
2016年 | 98篇 |
2015年 | 103篇 |
2014年 | 120篇 |
2013年 | 138篇 |
2012年 | 136篇 |
2011年 | 128篇 |
2010年 | 90篇 |
2009年 | 66篇 |
2008年 | 105篇 |
2007年 | 94篇 |
2006年 | 82篇 |
2005年 | 58篇 |
2004年 | 50篇 |
2003年 | 42篇 |
2002年 | 40篇 |
2001年 | 32篇 |
2000年 | 20篇 |
1999年 | 25篇 |
1998年 | 9篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 6篇 |
1982年 | 8篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1974年 | 3篇 |
1970年 | 4篇 |
1968年 | 8篇 |
1967年 | 2篇 |
1965年 | 4篇 |
1964年 | 2篇 |
排序方式: 共有1970条查询结果,搜索用时 11 毫秒
1.
F F Dias M K Shaikh Y B Bhatt D C Modi V R Subramanyam 《The Journal of applied bacteriology》1986,60(4):271-275
Mutants of Bacillus amyloliquefaciens resistant to at least 10 micrograms/ml of tunicamycin were isolated and shown to be pleiotropic. The mutants were more resistant to streptomycin, chloramphenicol, kanamycin and neomycin than was the parent strain but less resistant to penicillin G and tetracycline. They were more autolytic, presumably due to an altered cell wall. The mutants produced reduced levels of amylase, penicillinase and both metal and serine protease besides having an enhanced sporulation frequency and being more motile. 相似文献
2.
Coelho-Rocha Nina Dias de Jesus Luís Cláudio Lima Barroso Fernanda Alvarenga Lima da Silva Tales Fernando Ferreira Enio Gonçalves José Eduardo dos Santos Martins Flaviano de Oliveira Carvalho Rodrigo Dias Barh Debmalya Azevedo Vasco Ariston de Carvalho 《Probiotics and antimicrobial proteins》2023,15(1):160-174
Probiotics and Antimicrobial Proteins - Beneficial effects of Lactiplantibacillus plantarum strains have been widely reported. Knowing that the effects of probiotic bacteria are strain-dependent,... 相似文献
3.
40 pelvic preparations of rabbits (oryctolagus cuniculus) were bilaterally studied by dissection under the stereomicroscope and angiography. The arterial pattern of the pelvis, i.e. origin and branching of the umbilical, urogenital and internal pudendal arteries (visceral branches), is described. The main characteristics observed are as follows: (1) The umbilical artery is permeable in adults and gives origin to the cranial vesical artery and a caudal branch that irrigates the pelvic urogenital organs and, eventually, the rectum, with six patterns of branching in both sexes. (2) Usually, the urogenital artery is the continuation of the visceral branch of the internal iliac artery. In 1 animal, unilaterally, it arises from the median sacral artery. In 12 animals (6 bilaterally and 6 unilaterally) the urogenital artery is absent. When present, it forms two branches, a cranial and a caudal one, that irrigate of the urogenital organs in both sexes. (3) The internal pudendal artery is the direct continuation of the internal iliac artery and gives to rise to some visceral branches that irrigate the penis, bulbourethral gland and rectum (with six patterns of branching) in males, and the vagina, clitoris and rectum (with three patterns of branching) in females. 相似文献
4.
Coffee genes associated with systemic acquired resistance (SAR) and incompatible reaction against coffee leaf rust inoculation were identified by suppression subtractive hybridization. Analysis of 384 clones of each of the subtracted cDNA libraries identified genes involved in oxidative burst/apoptosis/hypersensitive response, synthesis of antimicrobial proteins, synthesis and transport of antimicrobial metabolites, signal perception and transduction, metabolism of lipids, regulated protein degradation and cell maintenance and development. Induction of distinct sets of genes in the two resistance responses was observed. A wide range of genes involved in defence responses described in other plant species was also found in coffee plants. Semi-quantitative and quantitative RT-PCR analysis of seven selected genes showed differences in their expression profile within 72 h after treatment. Full-length cDNA sequences of two β-1,3-glucanases, one induced during SAR and the other in the incompatible reaction, were obtained by 5' and 3' RACE and the sequence data suggest different properties and cellular localization of the encoded proteins. 相似文献
5.
6.
This work aimed to study the effects of commercial doses of the fungicide, Mancozeb, on the photosynthetic apparatus of lettuce young leaves (YL) and expanded leaves (EL). Seven days after Mancozeb application, chlorophyll a fluorescence, pigment contents, lipid peroxidation, and proline content were evaluated. Independently of leaf age, Mancozeb treatment reduced the efficiency of photosystem II photochemistry, increased the nonphotochemical quenching and proline content, decreased pigment contents, and induced lipid peroxidation. Moreover, EL showed a more stable photosynthetic apparatus, less prone to oxidative damages compared with YL. The parameters measured proved to be good markers for the rapid and preliminary diagnosis of fungicide toxicity. 相似文献
7.
Julio Cesar Madureira de-Freitas-Junior Sandra Carvalho Ana M. Dias Patrícia Oliveira Joana Cabral Raquel Seruca Carla Oliveira José Andrés Morgado-Díaz Celso A. Reis Salomé S. Pinho 《PloS one》2013,8(11)
Changes in glycosylation are considered a hallmark of cancer, and one of the key targets of glycosylation modifications is E-cadherin. We and others have previously demonstrated that E-cadherin has a role in the regulation of bisecting GlcNAc N-glycans expression, remaining to be determined the E-cadherin-dependent signaling pathway involved in this N-glycans expression regulation. In this study, we analysed the impact of E-cadherin expression in the activation profile of receptor tyrosine kinases such as insulin receptor (IR) and IGF-I receptor (IGF-IR). We demonstrated that exogenous E-cadherin expression inhibits IR, IGF-IR and ERK 1/2 phosphorylation. Stimulation with insulin and IGF-I in MDA-MD-435 cancer cells overexpressing E-cadherin induces a decrease of bisecting GlcNAc N-glycans that was accompanied with alterations on E-cadherin cellular localization. Concomitantly, IR/IGF-IR signaling activation induced a mesenchymal-like phenotype of cancer cells together with an increased tumor cell invasion capability. Altogether, these results demonstrate an interplay between E-cadherin and IR/IGF-IR signaling as major networking players in the regulation of bisecting N-glycans expression, with important effects in the modulation of epithelial characteristics and tumor cell invasion. Here we provide new insights into the role that Insulin/IGF-I signaling play during cancer progression through glycosylation modifications. 相似文献
8.
Melo MS Guimarães AG Santana MF Siqueira RS De Lima Ado C Dias AS Santos MR Onofre AS Quintans JS De Sousa DP Almeida JR Estevam CS Araujo BS Quintans-Júnior LJ 《Biological research》2011,44(4):363-368
The anti-inflammatory and redox protective effects of the citronellal (CT) were evaluated using in vivo and in vitro tests. Intraperitoneal (i.p.) administration of CT (50, 100, and 200 mg/kg) inhibited (p < 0.05) the carrageenan-induced leukocyte migration to the peritoneal cavity. Additionally, the carrageenan- and arachidonic acid-induced rat hind paw edema was significantly inhibited (p < 0.05) by i.p. administration of 100 and 200 mg/kg of the compound. When the redox activity was evaluated, CT (200 mg/kg) significantly reduced hepatic lipoperoxidation (p < 0.001), as well as oxidation of plasmatic (p < 0.05) and hepatic (p < 0.01) proteins. The results of the present study support the hypothesis that CT possesses anti-inflammatory and redox protective activities. It is suggested that its effects are associated with the inhibition of the enzymes in the arachidonic acid pathway, which prevent cell migration by inhibiting leukotriene production, edema formation and the increase of reactive oxygen species in tissues. Therefore, CT is of potential benefit to manage inflammatory disorders and correlated damages caused by oxidant agents. 相似文献
9.
Lanzarotti E Pellizza L Bercovich A Foti M Coria SH Vazquez SC Ruberto L Hernández EA Dias RL Mac Cormack WP Cicero DO Smal C Nicolas MF Vasconcelos AT Marti MA Turjanski AG 《Journal of bacteriology》2011,193(23):6797-6798
A psychrotolerant marine bacterial strain, designated JUB59(T), was isolated from Antarctic surface seawater and classified as a new species of the genus Bizionia. Here, we present the first draft genome sequence for this genus, which suggests interesting features such as UV resistance, hydrolytic exoenzymes, and nitrogen metabolism. 相似文献
10.
Marcos Fernando Basso Karoline Estefani Duarte Thais Ribeiro Santiago Wagner Rodrigo de Souza Bruno de Oliveira Garcia Brbara Dias Brito da Cunha Adilson Kenji Kobayashi Hugo Bruno Correa Molinari 《Plant Biotechnology》2021,38(2):227
The CRISPR/Cas9 system has been used for genome editing in several organisms, including higher plants. This system induces site-specific mutations in the genome based on the nucleotide sequence of engineered guide RNAs. The complex genomes of C4 grasses makes genome editing a challenge in key grass crops like maize (Zea mays), sorghum (Sorghum bicolor), Brachiaria spp., switchgrass (Panicum virgatum), and sugarcane (Saccharum spp.). Setaria viridis is a diploid C4 grass widely used as a model for these C4 crop plants. Here, an optimized CRISPR/Cas9 binary vector that exploits the non-homologous end joining (NHEJ) system was used to knockout a green fluorescent protein (gfp) transgene in S. viridis accession A10.1. Transformation of embryogenic callus by A. tumefaciens generated ten glufosinate-ammonium resistant transgenic events. In the T0 generation, 60% of the events were biallelic mutants in the gfp transgene with no detectable accumulation of GFP protein and without insertions or deletions in predicted off-target sites. The gfp mutations generated by CRISPR/Cas9 were stable and displayed Mendelian segregation in the T1 generation. Altogether, the system described here is a highly efficient genome editing system for S. viridis, an important model plant for functional genomics studies in C4 grasses. Also, this system is a potential tool for improvement of agronomic traits in C4 crop plants with complex genomes. 相似文献