全文获取类型
收费全文 | 55608篇 |
免费 | 20099篇 |
国内免费 | 19292篇 |
出版年
2024年 | 381篇 |
2023年 | 1138篇 |
2022年 | 1896篇 |
2021年 | 2405篇 |
2020年 | 4034篇 |
2019年 | 5790篇 |
2018年 | 5215篇 |
2017年 | 5455篇 |
2016年 | 5471篇 |
2015年 | 5956篇 |
2014年 | 6415篇 |
2013年 | 6431篇 |
2012年 | 5106篇 |
2011年 | 4736篇 |
2010年 | 5759篇 |
2009年 | 4644篇 |
2008年 | 3769篇 |
2007年 | 3235篇 |
2006年 | 3050篇 |
2005年 | 2584篇 |
2004年 | 2027篇 |
2003年 | 1716篇 |
2002年 | 1598篇 |
2001年 | 1561篇 |
2000年 | 1431篇 |
1999年 | 882篇 |
1998年 | 413篇 |
1997年 | 220篇 |
1996年 | 200篇 |
1995年 | 156篇 |
1994年 | 155篇 |
1993年 | 110篇 |
1992年 | 97篇 |
1991年 | 98篇 |
1990年 | 84篇 |
1989年 | 85篇 |
1988年 | 78篇 |
1987年 | 58篇 |
1986年 | 52篇 |
1985年 | 68篇 |
1984年 | 38篇 |
1983年 | 46篇 |
1982年 | 59篇 |
1981年 | 31篇 |
1958年 | 23篇 |
1957年 | 23篇 |
1956年 | 15篇 |
1955年 | 17篇 |
1954年 | 20篇 |
1950年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
Carolina Mazo‐Molina Samantha Mainiero Benjamin J. Haefner Ryland Bednarek Jing Zhang Ari Feder Kai Shi Susan R. Strickler Gregory B. Martin 《The Plant journal : for cell and molecular biology》2020,103(4):1433-1445
The Ptr1 (Pseudomonas tomato race 1) locus in Solanum lycopersicoides confers resistance to strains of Pseudomonas syringae pv. tomato expressing AvrRpt2 and Ralstonia pseudosolanacearum expressing RipBN. Here we describe the identification and phylogenetic analysis of the Ptr1 gene. A single recombinant among 585 F2 plants segregating for the Ptr1 locus was discovered that narrowed the Ptr1 candidates to eight nucleotide‐binding leucine‐rich repeat protein (NLR)‐encoding genes. From analysis of the gene models in the S. lycopersicoides genome sequence and RNA‐Seq data, two of the eight genes emerged as the strongest candidates for Ptr1. One of these two candidates was found to encode Ptr1 based on its ability to mediate recognition of AvrRpt2 and RipBN when it was transiently expressed with these effectors in leaves of Nicotiana glutinosa. The ortholog of Ptr1 in tomato and in Solanum pennellii is a pseudogene. However, a functional Ptr1 ortholog exists in Nicotiana benthamiana and potato, and both mediate recognition of AvrRpt2 and RipBN. In apple and Arabidopsis, recognition of AvrRpt2 is mediated by the Mr5 and RPS2 proteins, respectively. Phylogenetic analysis places Ptr1 in a distinct clade compared with Mr5 and RPS2, and it therefore appears to have arisen by convergent evolution for recognition of AvrRpt2. 相似文献
994.
995.
Beatriz Fernndez‐Marín Javier Gulías Carlos M. Figueroa Concepcin Iiguez María J. Clemente‐Moreno Adriano Nunes‐Nesi Alisdair R. Fernie Lohengrin A. Cavieres Len A. Bravo Jos I. García‐Plazaola Jorge Gago 《The Plant journal : for cell and molecular biology》2020,101(4):979-1000
In this work, we review the physiological and molecular mechanisms that allow vascular plants to perform photosynthesis in extreme environments, such as deserts, polar and alpine ecosystems. Specifically, we discuss the morpho/anatomical, photochemical and metabolic adaptive processes that enable a positive carbon balance in photosynthetic tissues under extreme temperatures and/or severe water‐limiting conditions in C3 species. Nevertheless, only a few studies have described the in situ functioning of photoprotection in plants from extreme environments, given the intrinsic difficulties of fieldwork in remote places. However, they cover a substantial geographical and functional range, which allowed us to describe some general trends. In general, photoprotection relies on the same mechanisms as those operating in the remaining plant species, ranging from enhanced morphological photoprotection to increased scavenging of oxidative products such as reactive oxygen species. Much less information is available about the main physiological and biochemical drivers of photosynthesis: stomatal conductance (gs), mesophyll conductance (gm) and carbon fixation, mostly driven by RuBisCO carboxylation. Extreme environments shape adaptations in structures, such as cell wall and membrane composition, the concentration and activation state of Calvin–Benson cycle enzymes, and RuBisCO evolution, optimizing kinetic traits to ensure functionality. Altogether, these species display a combination of rearrangements, from the whole‐plant level to the molecular scale, to sustain a positive carbon balance in some of the most hostile environments on Earth. 相似文献
996.
997.
Jrme Bartholom Andr Mabiala Rgis Burlett Didier Bert Jean‐Charles Lepl Christophe Plomion Jean‐Marc Gion 《The Plant journal : for cell and molecular biology》2020,103(1):338-356
The pulse of the tree (diurnal cycle of stem radius fluctuations) has been widely studied as a way of analyzing tree responses to the environment, including the phenotypic plasticity of tree–water relationships in particular. However, the genetic basis of this daily phenotype and its interplay with the environment remain largely unexplored. We characterized the genetic and environmental determinants of this response, by monitoring daily stem radius fluctuation (dSRF) on 210 trees from a Eucalyptus urophylla × E. grandis full‐sib family over 2 years. The dSRF signal was broken down into hydraulic capacitance, assessed as the daily amplitude of shrinkage (DA), and net growth, estimated as the change in maximum radius between two consecutive days (ΔR). The environmental determinants of these two traits were clearly different: DA was positively correlated with atmospheric variables relating to water demand, while ΔR was associated with soil water content. The heritability for these two traits ranged from low to moderate over time, revealing a time‐dependent or environment‐dependent complex genetic determinism. We identified 686 and 384 daily quantitative trait loci (QTL) representing 32 and 31 QTL regions for DA and ΔR, respectively. The identification of gene networks underlying the 27 major genomics regions for both traits generated additional hypotheses concerning the biological mechanisms involved in response to water demand and supply. This study highlights that environmentally induced changes in daily stem radius fluctuation are genetically controlled in trees and suggests that these daily responses integrated over time shape the genetic architecture of mature traits. 相似文献
998.
999.
Minmin Du Ke Zhou Yuanyuan Liu Lei Deng Xiaoyue Zhang Lihao Lin Ming Zhou Wei Zhao Changlong Wen Jiayi Xing Chang‐Bao Li Chuanyou Li 《The Plant journal : for cell and molecular biology》2020,102(5):1090-1100
Incorporating male sterility into hybrid seed production reduces its cost and ensures high varietal purity. Despite these advantages, male‐sterile lines have not been widely used to produce tomato (Solanum lycopersicum) hybrid seeds. We describe the development of a biotechnology‐based breeding platform that utilized genic male sterility to produce hybrid seeds. In this platform, we generated a novel male‐sterile tomato line by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9)‐mediated mutagenesis of a stamen‐specific gene SlSTR1 and devised a transgenic maintainer by transforming male‐sterile plants with a fertility‐restoration gene linked to a seedling‐colour gene. Offspring of crosses between a hemizygous maintainer and the homozygous male‐sterile plant segregated into 50% non‐transgenic male‐sterile plants and 50% male‐fertile maintainer plants, which could be easily distinguished by seedling colour. This system has great practical potential for hybrid seed breeding and production as it overcomes the problems intrinsic to other male‐sterility systems and can be easily adapted for a range of tomato cultivars and diverse vegetable crops. 相似文献