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121.
B J Milner L A Allan K F Kelly D Cruickshank M Hall A Johnston H Kitchener D Parkin N Haites 《American journal of human genetics》1993,52(4):761-766
Genes on chromosomes 17q and 18q have been shown to code for putative tumor suppressors. By a combination of allele-loss studies on sporadic ovarian carcinomas and linkage analysis on a breast/ovarian cancer family, we have investigated the involvement of such genes in these diseases. Allele loss occurred in sporadic tumors from both chromosome 17p, in 18/26 (69%) cases, and chromosome 17q, in 15/22 (68%) cases. In the three familial tumors studied, allele loss also occurred on chromosome 17 (in 2/3 cases for 17p markers and in 2/2 cases for a 17q allele). Allele loss on chromosome 18q, at the DCC (deleted in colorectal carcinomas) locus, was not as common (6/16 cases [38%]) in sporadic ovarian tumors but had occurred in all three familial tumors. The results of linkage analysis on the breast/ovarian cancer family suggested linkage between the disease locus and 17q markers, with a maximum lod score of 1.507 obtained with Mfd188 (D17S579) polymorphism at 5% recombination. The maximum lod score for DCC was 0.323 at 0.1% recombination. In this family our results are consistent with a predisposing gene for breast/ovarian cancer being located at chromosome 17q21. 相似文献
122.
Direct Cloning of Yeast Genes from an Ordered Set of Lambda Clones in Saccharomyces Cerevisiae by Recombination in Vivo 总被引:6,自引:1,他引:5 下载免费PDF全文
We describe a technique that facilitates the isolation of yeast genes that are difficult to clone. This technique utilizes a plasmid vector that rescues lambda clones as yeast centromere plasmids. The source of these lambda clones is a set of clones whose location in the yeast genome has been determined by L. Riles et al. in 1993. The Esherichia coli-yeast shuttle plasmid carries URA3, ARS4 and CEN6, and contains DNA fragments from the lambda vector that flank the cloned yeast insert. When yeast is cotransformed with linearized plasmid and lambda clone DNA, Ura(+) transformants are obtained by a recombination event between the lambda clone and the plasmid vector that generates an autonomously replicating plasmid containing the cloned yeast DNA sequences. Genes whose genetic map positions are known can easily be identified and recovered in this plasmid by testing only those lambda clones that map to the relevant region of the yeast genome for their ability to complement the mutant phenotype. This technique facilitates the isolation of yeast genes that resist cloning either because (1) they are underrepresented in yeast genomic libraries amplified in E. coli, (2) they provide phenotypes that are too marginal to allow selection of the gene by genetic complementation or (3) they provide phenotypes that are laborious to score. We demonstrate the utility of this technique by isolating three genes, GAL83, SSN2 and MAK7, each of which presents one of these problems for cloning. 相似文献
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124.
Logan J. Pallin Nick M. Kellar Debbie Steel Natalia Botero-Acosta C. Scott Baker Jack A. Conroy Daniel P. Costa Chris M. Johnson David W. Johnston Ross C. Nichols Doug P. Nowacek Andrew J. Read Oksana Savenko Oscar M. Schofield Sharon E. Stammerjohn Deborah K. Steinberg Ari S. Friedlaender 《Global Change Biology》2023,29(8):2108-2121
The krill surplus hypothesis of unlimited prey resources available for Antarctic predators due to commercial whaling in the 20th century has remained largely untested since the 1970s. Rapid warming of the Western Antarctic Peninsula (WAP) over the past 50 years has resulted in decreased seasonal ice cover and a reduction of krill. The latter is being exacerbated by a commercial krill fishery in the region. Despite this, humpback whale populations have increased but may be at a threshold for growth based on these human-induced changes. Understanding how climate-mediated variation in prey availability influences humpback whale population dynamics is critical for focused management and conservation actions. Using an 8-year dataset (2013–2020), we show that inter-annual humpback whale pregnancy rates, as determined from skin-blubber biopsy samples (n = 616), are positively correlated with krill availability and fluctuations in ice cover in the previous year. Pregnancy rates showed significant inter-annual variability, between 29% and 86%. Our results indicate that krill availability is in fact limiting and affecting reproductive rates, in contrast to the krill surplus hypothesis. This suggests that this population of humpback whales may be at a threshold for population growth due to prey limitations. As a result, continued warming and increased fishing along the WAP, which continue to reduce krill stocks, will likely impact this humpback whale population and other krill predators in the region. Humpback whales are sentinel species of ecosystem health, and changes in pregnancy rates can provide quantifiable signals of the impact of environmental change at the population level. Our findings must be considered paramount in developing new and more restrictive conservation and management plans for the Antarctic marine ecosystem and minimizing the negative impacts of human activities in the region. 相似文献
125.
Kayleigh M. Hansford Sara L. Gandy Emma L. Gillingham Liz McGinley Benjamin Cull Colin Johnston Matthew Catton Jolyon M. Medlock 《Medical and veterinary entomology》2023,37(1):152-163
Tick-borne disease risk is intrinsically linked to the distribution of tick vector species. To assess risk and anticipate disease emergence, an understanding of tick distribution, host associations, and seasonality is needed. This can be achieved, to some extent, using passive surveillance supported by engagement with the public, animal health, and public health experts. The Tick Surveillance Scheme (TSS) collects data and maps tick distribution across the United Kingdom (UK). Between 2017 and 2020, 3720 tick records were received and 39 tick species were detected. Most records were acquired in the UK, with a subset associated with recent overseas travel. The dominant UK acquired species was Ixodes ricinus (Ixodida: Ixodidae, Linnaeus), the main vector of Lyme borreliosis. Records peaked during May and June, highlighting a key risk period for tick bites. Other key UK species were detected, including Dermacentor reticulatus (Ixodida: Ixodidae, Fabricius) and Haemaphysalis punctata (Ixodida: Ixodidae, Canestrini & Fanzago) as well as several rarer species that may present novel tick-borne disease risk to humans and other animals. Updated tick distribution maps highlight areas in the UK where tick exposure has occurred. There is evidence of increasing human tick exposure over time, including during the COVID-19 pandemic, but seasonal patterns remain unchanged. 相似文献
126.
127.
Martin J. Michaelson H. James Price John R. Ellison J. Spencer Johnston 《American journal of botany》1991,78(2):183-188
An improved procedure is reported for determining DNA amounts of plant nuclei. Nuclei stained with propidium iodide, isolated from chopped plant leaves, were passed through an Ortho Cytofluorograph with a Lexel model 95 argon laser (514 nm) and the fluorescence measured, integrated, and recorded using an Ortho 2140 Data Acquisition computer. All nuclear samples were mixed with nuclei of Sultan barley (2C DNA content = 11.12 pg [picogram]) as an internal standard. DNA contents of ten plant species, ranging from 2C = 1.7 pg to 36.1 pg measured by flow cytometry, correlated strongly (r = 0.99, slope = + 1.00) with DNA contents determined from Feulgen-stained nuclei of the same species using microspectrophotometry. The flow cytometric procedures were sufficiently sensitive to detect differences in DNA content between inbred lines of corn and their F1 hybrids. Our results obtained with improved procedures, specifically using propidium iodide as a fluorochrome and plant nuclei instead of chicken erythrocytes as an internal standard, demonstrate that laser flow cytometry can be a precise, rapid, and reliable method for determining nuclear DNA content of plants. 相似文献
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129.
The use of bulk segregant analysis to identify a RAPD marker linked to leaf rust resistance in barley 总被引:4,自引:0,他引:4
D. M. E. Poulsen R. J. Henry R. P. Johnston J. A. G. Irwin R. G. Rees 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1995,91(2):270-273
An F2 population from a cross between barley accession Q21861 and the Australian barley variety Galleon was used to develop RAPD markers for resistance to barley leaf rust (Puccinia hordei). Resistant and susceptible DNA bulks were constructed following the classification of F2 plants by leaf rust infection type. Bulked segregant analysis was then used to identify a 2.7-kb marker, designated OU022700 and located approximately 12cM from RphQ, a leaf rust resistance gene in Q21861. The marker was generated by PCR with the oligonucleotide primer OPU-02 (Operon). Infection types of F3 progeny were used to confirm assignment of F2 genotypes. OU022700 was shown, retrospectively, to be useful in the identification of individual F2 plants that had been originally misclassified as having susceptible infection types. Both the RAPD marker and RphQ will be potentially useful in the development of new barley cultivars. 相似文献
130.
NMR solution structure of a dsRNA binding domain from Drosophila staufen protein reveals homology to the N-terminal domain of ribosomal protein S5. 总被引:7,自引:3,他引:4 下载免费PDF全文
The double-stranded RNA binding domain (dsRBD) is an approximately 65 amino acid motif that is found in a variety of proteins that interact with double-stranded (ds) RNA, such as Escherichia coli RNase III and the dsRNA-dependent kinase, PKR. Drosophila staufen protein contains five copies of this motif, and the third of these binds dsRNA in vitro. Using multinuclear/multidimensional NMR methods, we have determined that staufen dsRBD3 forms a compact protein domain with an alpha-beta-beta-beta-alpha structure in which the two alpha-helices lie on one face of a three-stranded anti-parallel beta-sheet. This structure is very similar to that of the N-terminal domain of a prokaryotic ribosomal protein S5. Furthermore, the consensus derived from all known S5p family sequences shares several conserved residues with the dsRBD consensus sequence, indicating that the two domains share a common evolutionary origin. Using in vitro mutagenesis, we have identified several surface residues which are important for the RNA binding of the dsRBD, and these all lie on the same side of the domain. Two residues that are essential for RNA binding, F32 and K50, are also conserved in the S5 protein family, suggesting that the two domains interact with RNA in a similar way. 相似文献