全文获取类型
收费全文 | 9235篇 |
免费 | 811篇 |
国内免费 | 12篇 |
出版年
2023年 | 33篇 |
2022年 | 105篇 |
2021年 | 197篇 |
2020年 | 103篇 |
2019年 | 141篇 |
2018年 | 188篇 |
2017年 | 185篇 |
2016年 | 265篇 |
2015年 | 460篇 |
2014年 | 502篇 |
2013年 | 645篇 |
2012年 | 794篇 |
2011年 | 765篇 |
2010年 | 500篇 |
2009年 | 422篇 |
2008年 | 644篇 |
2007年 | 593篇 |
2006年 | 554篇 |
2005年 | 532篇 |
2004年 | 483篇 |
2003年 | 435篇 |
2002年 | 430篇 |
2001年 | 90篇 |
2000年 | 53篇 |
1999年 | 80篇 |
1998年 | 110篇 |
1997年 | 67篇 |
1996年 | 55篇 |
1995年 | 34篇 |
1994年 | 50篇 |
1993年 | 40篇 |
1992年 | 30篇 |
1991年 | 31篇 |
1990年 | 36篇 |
1989年 | 25篇 |
1988年 | 27篇 |
1987年 | 28篇 |
1986年 | 27篇 |
1985年 | 18篇 |
1984年 | 27篇 |
1983年 | 14篇 |
1982年 | 30篇 |
1981年 | 26篇 |
1980年 | 25篇 |
1979年 | 26篇 |
1978年 | 17篇 |
1977年 | 16篇 |
1974年 | 21篇 |
1972年 | 16篇 |
1971年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
281.
Barcoding,population structure,and demographic history of Prodiplosis longifila associated with the Andes
下载免费PDF全文
![点击此处可从《Entomologia Experimentalis et Applicata》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Sandra M. Velasco‐Cuervo Lizethe L. Espinosa Diana N. Duque‐Gamboa Maria F. Castillo‐Cárdenas Luis M. Hernández Yoan C. Guzmán Maria R. Manzano Nelson Toro‐Perea 《Entomologia Experimentalis et Applicata》2016,158(2):217-227
Prodiplosis longifila Gagné (Diptera: Cecidomyiidae) is an insect pest that attacks various types of crops, including tomato, Solanum lycopersicum L. (Solanaceae), a vegetable with substantial economic significance worldwide. Prodiplosis longifila is a widely distributed pest in Colombia, Ecuador, and Peru, countries characterized by the presence of significant geographic barriers like the Andes Mountains. It has been reported that geographic barriers affect the dynamics and genetic differentiation of insect populations. Therefore, the aim of this study was to assess the diversity, genetic structure, and demographic history of P. longifila through the analysis of sequences within the mitochondrial region of cytochrome oxidase I (COI) and rDNA‐ITS2 in 27 populations located in Colombia and Ecuador. Analyses were performed on populations distributed in three geographic groups separated by the presence of the Andes Mountains. A total of 11 haplotypes were identified with the COI gene and only one haplotype in the rDNA‐ITS2 was found. Analyses of population structure and demographic history revealed that there is a structure associated with the Andes, which is reflected in an uneven distribution of the haplotype frequencies between regions, but even so, gene flow between populations was detected which produces low genetic differentiation. Because P. longifila has a short‐range dispersion that determines its territorial nature, it would be expected that other factors are producing the genetic exchange between populations. We suggest that the anthropogenic effect produced by farming practices, such as the use of seedlings as seed, which may carry P. longifila larvae, cause passive dispersal of pest throughout the Andes, particularly in Colombia. 相似文献
282.
Alexis R. Sullivan Sandra A. Owusu Jaime A. Weber Andrew L. Hipp Oliver Gailing 《Botanical journal of the Linnean Society. Linnean Society of London》2016,181(1):99-114
Oaks (Quercus: Fagaceae) commonly interbreed yet retain their morphological, genetic and ecological distinctiveness. Post‐zygotic isolation mechanisms, such as ecologically dependent selection on adaptive loci, may therefore limit introgression. To test this hypothesis, we quantified hybridization and genetic divergence across the contact zone of four red oaks (Quercus section Lobatae) in the Great Lakes region of North America using a suite of 259 amplified fragment length polymorphisms and 27 genic and genomic microsatellite markers. First, we identified hybrids using genetic structure analysis and confirmed the reliability of our assignments via simulations. Then, we identified candidate loci for species maintenance with three complementary tests for selection and obtained partial gene sequences linked to an outlier locus and three other loci. We detected evidence of recent hybridization among all species and considerable gene flow between Q. ellipsoidalis and Q. velutina. Overall, c. 20% of Q. velutina had recent ancestry from Q. ellipsoidalis, whereas nearly 30% of Q. ellipsoidalis had a Q. velutina ancestor. Most loci were negligibly to weakly differentiated among species, but two gene‐linked microsatellites deviated significantly from neutral expectations in multiple, complementary outlier tests. Both outlier loci were located in the same 15‐cM bin on an existing Q. robur linkage map, a region under divergent selection in other oak species. Adaptive loci in this highly differentiated genomic region may contribute to ecological divergence among species and limit introgression. 相似文献
283.
284.
285.
Erinaldo Ubirajara Damasceno dos Santos Géssica Dayane Cordeiro de Lima Micheline de Lucena Oliveira Sandra de Andrade Heráclio Hildson Dornelas Angelo da Silva Sergio Crovella Maria de Mascena Diniz Maia Paulo Roberto Eleutério de Souza/ 《Memórias do Instituto Oswaldo Cruz》2016,111(3):174-180
Polymorphisms in chemokine receptors play an important role in the progression of
cervical intraepithelial neoplasia (CIN) to cervical cancer (CC). Our study examined
the association of CCR2-64I (rs1799864) andCCR5-Δ32
(rs333) polymorphisms with susceptibility to develop cervical lesion (CIN and CC) in
a Brazilian population. The genotyping of 139 women with cervical lesions and 151
women without cervical lesions for the CCR2-64I and
CCR5-Δ32 polymorphisms were performed using polymerase chain
reaction-restriction fragment length polymorphism. The individuals carrying
heterozygous or homozygous genotypes (GA+AA) for CCR2-64I
polymorphisms seem to be at lower risk for cervical lesion [odds ratio (OR) = 0.37, p
= 0.0008)]. The same was observed for the A allele (OR = 0.39, p = 0.0002), while no
association was detected (p > 0.05) with CCR5-Δ32 polymorphism.
Regarding the human papillomavirus (HPV) type, patients carrying the
CCR2-64Ipolymorphism were protected against infection by HPV type
16 (OR = 0.35, p = 0.0184). In summary, our study showed a protective effect
ofCCR2-64I rs1799864 polymorphism against the development of
cervical lesions (CIN and CC) and in the susceptibility of HPV 16 infection. 相似文献
286.
Manuel J. Steinbauer Richard Field John‐Arvid Grytnes Panayiotis Trigas Claudine Ah‐Peng Fabio Attorre H. John B. Birks Paulo A. V. Borges Pedro Cardoso Chang‐Hung Chou Michele De Sanctis Miguel M. de Sequeira Maria C. Duarte Rui B. Elias José María Fernández‐Palacios Rosalina Gabriel Roy E. Gereau Rosemary G. Gillespie Josef Greimler David E. V. Harter Tsurng‐Juhn Huang Severin D. H. Irl Daniel Jeanmonod Anke Jentsch Alistair S. Jump Christoph Kueffer Sandra Nogué Rüdiger Otto Jonathan Price Maria M. Romeiras Dominique Strasberg Tod Stuessy Jens‐Christian Svenning Ole R. Vetaas Carl Beierkuhnlein 《Global Ecology and Biogeography》2016,25(9):1097-1107
287.
288.
Matthias M. Falk Cheryl L. Bell Rachael M. Kells Andrews Sandra A. Murray 《BMC cell biology》2016,17(Z1):S22
Internalization of gap junction plaques results in the formation of annular gap junction vesicles. The factors that regulate the coordinated internalization of the gap junction plaques to form annular gap junction vesicles, and the subsequent events involved in annular gap junction processing have only relatively recently been investigated in detail. However it is becoming clear that while annular gap junction vesicles have been demonstrated to be degraded by autophagosomal and endo-lysosomal pathways, they undergo a number of additional processing events. Here, we characterize the morphology of the annular gap junction vesicle and review the current knowledge of the processes involved in their formation, fission, fusion, and degradation. In addition, we address the possibility for connexin protein recycling back to the plasma membrane to contribute to gap junction formation and intercellular communication. Information on gap junction plaque removal from the plasma membrane and the subsequent processing of annular gap junction vesicles is critical to our understanding of cell-cell communication as it relates to events regulating development, cell homeostasis, unstable proliferation of cancer cells, wound healing, changes in the ischemic heart, and many other physiological and pathological cellular phenomena. 相似文献
289.
Enilson B. Silva Felipe G. Fonseca Luís R. F. Alleoni Sandra S. Nascimento Paulo H. Grazziotti Bárbara O. Nardis 《International journal of phytoremediation》2016,18(9):847-852
It is important to know the mechanisms for forage development, especially those related to the tolerance of potentially toxic elements, when considering their use in phytoremediation in heavy metal contaminated areas. In this study, we evaluated plant growth, concentration, and the availability of cadmium (Cd) for forage grasses (Panicum maximum Jacq. cv. Aruana and cv. Tanzânia; Brachiaria decumbens cv. Basilisk; Brachiaria brizantha cv. Xaraés and cv. Marandu) cultivated in Cd contaminated soils. The experiments were performed under greenhouse conditions over a 90-day evaluation period, and the Cd rates were 2, 4, and 12 mg/kg of soil. The relative growth rate of the forage grasses decreased as Cd rates increased, and the following descending order of susceptibility was observed: Marandu > Xaraés > Aruana > Tanzânia > Basilisk, with regard to phytotoxicity in these plants. The forage Cd concentration increased in line with increases in the Cd rates. Cd contents extracted by Mehlich-1 and by diethylenetriaminepentaacetic acid presented high positive correlation with forage relative growth. The forage plants did not block Cd entry into the food chain because they were not capable of limiting Cd absorption. 相似文献
290.
Thomas Simonson Shixin Ye‐Lehmann Zoltan Palmai Najette Amara Sandra Wydau‐Dematteis Erwan Bigan Karen Druart Clara Moch Pierre Plateau 《Proteins》2016,84(2):240-253
d ‐Amino acids are largely excluded from protein synthesis, yet they are of great interest in biotechnology. Unnatural amino acids have been introduced into proteins using engineered aminoacyl‐tRNA synthetases (aaRSs), and this strategy might be applicable to d ‐amino acids. Several aaRSs can aminoacylate their tRNA with a d ‐amino acid; of these, tyrosyl‐tRNA synthetase (TyrRS) has the weakest stereospecificity. We use computational protein design to suggest active site mutations in Escherichia coli TyrRS that could increase its d ‐Tyr binding further, relative to l ‐Tyr. The mutations selected all modify one or more sidechain charges in the Tyr binding pocket. We test their effect by probing the aminoacyl‐adenylation reaction through pyrophosphate exchange experiments. We also perform extensive alchemical free energy simulations to obtain l ‐Tyr/d ‐Tyr binding free energy differences. Agreement with experiment is good, validating the structural models and detailed thermodynamic predictions the simulations provide. The TyrRS stereospecificity proves hard to engineer through charge‐altering mutations in the first and second coordination shells of the Tyr ammonium group. Of six mutants tested, two are active towards d ‐Tyr; one of these has an inverted stereospecificity, with a large preference for d ‐Tyr. However, its activity is low. Evidently, the TyrRS stereospecificity is robust towards charge rearrangements near the ligand. Future design may have to consider more distant and/or electrically neutral target mutations, and possibly design for binding of the transition state, whose structure however can only be modeled. Proteins 2016; 84:240–253. © 2015 Wiley Periodicals, Inc. 相似文献