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41.
42.
T. Tvrdik Suzanne Marcus Sai-Mei Hou Susann Fält Peri Noori Natalia Podlutskaja Folker Hanefeld Petter Strømme Bo Lambert 《Human genetics》1998,103(3):311-318
Mutations identified in the hypoxanthine phosphoribosyltransferase (HPRT) gene of patients with Lesch-Nyhan (LN) syndrome
are dominated by simple base substitutions. Few hotspot positions have been identified, and only three large genomic rearrangements
have been characterized at the molecular level. We have identified one novel mutation, two tentative hot spot mutations, and
two deletions by direct sequencing of HPRT cDNA or genomic DNA from fibroblasts or T-lymphocytes from LN patients in five
unrelated families. One is a missense mutation caused by a 610C→T transition of the first base of HPRT exon 9. This mutation
has not been described previously in an LN patient. A nonsense mutation caused by a 508C→T transition at a CpG site in HPRT
exon 7 in the second patient and his younger brother is the fifth mutation of this kind among LN patients. Another tentative
hotspot mutation in the third patient, a frame shift caused by a G nucleotide insertion in a monotonous repeat of six Gs in
HPRT exon 3, has been reported previously in three other LN patients. The fourth patient had a tandem deletion: a 57-bp deletion
in an internally repeated Alu-sequence of intron 1 was separated by 14 bp from a 627-bp deletion that included HPRT exon 2 and was flanked by a 4-bp repeat.
This complex mutation is probably caused by a combination of homologous recombination and replication slippage. Another large
genomic deletion of 2969 bp in the fifth patient extended from one Alu-sequence in the promoter region to another Alu-sequence of intron 1, deleting the whole of HPRT exon 1. The breakpoints were located within two 39-bp homologous sequences,
one of which overlapped with a well-conserved 26-bp Alu-core sequence previously suggested as promoting recombination. These results contribute to the establishment of a molecular
spectrum of LN mutations, support previous data indicating possible mutational hotspots, and provide evidence for the involvement
of Alu-mediated recombination in HPRT deletion mutagenesis.
Received: 21 April 1998 / Accepted: 16 July 1998 相似文献
43.
Ovsiannikova Natalia L. Lavrushkina Svetlana V. Ivanova Anastasia V. Mazina Ludmila M. Zhironkina Oxana A. Kireev Igor I. 《Biochemistry. Biokhimii?a》2021,86(10):1288-1300
Biochemistry (Moscow) - One of the main factors associated with worse prognosis in oncology is metastasis, which is based on the ability of tumor cells to migrate from the primary source and to... 相似文献
44.
Natalia A. Kolganova Vadim A. Vasiliskov Viktoriya E. Kuznetsova Valeriy E. Shershov Sergey A. Lapa Timur O. Guseinov Maksim A. Spitsyn Edward N. Timofeev Alexander V. Chudinov 《Molecular biotechnology》2018,60(12):879-886
The transferase activity of non-proofreading DNA polymerases is a well-known phenomenon that has been utilized in cloning and sequencing applications. The non-templated addition of modified nucleotides at DNA blunt ends is a potentially useful feature of DNA polymerases that can be used for selective transformation of DNA 3′ ends. In this paper, we characterized the tailing reaction at perfectly matched and mismatched duplex ends with Cy3- and Cy5-modified pyrimidine nucleotides. It was shown that the best DNA tailing substrate does not have a perfect Watson–Crick base pair at the end. Mismatched duplexes with a 3′ dC were the most efficient in the Taq DNA polymerase-catalysed tailing reaction with a Cy5-modified dUTP. We further demonstrated that the arrangement of the dye residue relative to the nucleobase notably affects the outcome of the tailing reaction. A comparative study of labelled deoxycytidine and deoxyuridine nucleotides showed higher efficiency for dUTP derivatives. The non-templated addition of modified nucleotides by Taq polymerase at a duplex blunt end was generally complicated by the pyrophosphorolysis and 5′ exonuclease activity of the enzyme. 相似文献
45.
Ivana A. Cavello Roque A. Hours Natalia L. Rojas Sebastián F. Cavalitto 《Process Biochemistry》2013,48(5-6):972-978
A keratinolytic serine protease secreted by Purpureocillium lilacinum (formerly Paecilomyces lilacinus) upon culture in a basal medium containing 1% (w/v) hair waste as carbon and nitrogen source was purified and characterized. After purification the keratinase was resolved by SDS-PAGE as a homogeneus protein band of molecular mass 37.0 kDa. The extracellular keratinase of P. lilacinum was characterized by its appreciable stability over a broad pH range (from 4.0 to 9.0), and up to 65 °C, along with its strong inhibition by phenylmethylsulphonyl fluoride among the protease inhibitors tested (98.2% of inhibition), thus suggesting its nature as a serine protease. The enzyme was active and stable in the presence of organic solvents such as dimethylsulfoxide, methanol, and isopropanol; certain surfactants such as Triton X-100, sodium dodecylsulfate, and Tween 85; and bleaching agents such as hydrogen peroxide. These biochemical characteristics suggest the potential use of this enzyme in numerous industrial applications. 相似文献
46.
Karen Valverde-Méndez Eduardo J. Hernández Dennis Matamoros Natalia Barboza 《The Annals of applied biology》2023,183(3):231-243
Begomoviruses (Geminiviridae family) are characterized by their high recombination rate and a wide range of hosts, making their control difficult. In Costa Rica, various species of bipartite begomoviruses have been reported, which are Pepper golden mosaic virus (PepGMV), Tomato yellow mottle virus (ToYMoV), Tomato leaf curl Sinaloa virus (ToLCSiV) and the monopartite begomovirus Tomato yellow leaf curl virus (TYLCV). Since the TYLCV first report in Costa Rica, neither additional knowledge has been produced on how this begomovirus has spread in the country's territory nor on the distribution of the other bipartite species. A total of 429 tomato samples collected during the years 2015–2016 were used to study these aspects. Each sample was georeferenced and analysed with various techniques such as nucleic acid hybridization, polymerase chain reaction (PCR) and sequencing for the begomoviruses previously reported in Costa Rica. It was found that the presence/absence of the different species can vary, depending on the province. TYLCV is present in the six provinces analysed in this work, with a proportion from 3.7 to 86.6 per cent. Alajuela, Cartago, and Heredia are the provinces most affected by tomato-infecting begomoviruses. Fourteen different haplotypes of TYLCV were detected, but all were identified as TYLCV-IL. The distribution of TYLCV was related to the presence of the whitefly Bemisia tabaci MED, especially in the country's main tomato production areas. This information allows the phytosanitary surveillance services to develop strategies for the integrated management of the disease and to contribute data to the genetic improvement programmes of the crop. 相似文献
47.
Hudson T. Pinheiro Bruno C. L. Macena Ronaldo B. Francini-Filho Carlos E. L. Ferreira Fernanda V. Albuquerque Natalia P. A. Bezerra Alfredo Carvalho-Filho Romulo C. P. Ferreira Osmar J. Luiz Thayna J. Mello Sibele A. Mendonça Diogo M. Nunes Caio R. Pimentel Alessandra M. A. Pires Abilio Soares-Gomes Danielle L. Viana Fabio H. V. Hazin Luiz A. Rocha 《Journal of fish biology》2020,97(4):1143-1153
Saint Peter and Saint Paul's Archipelago (SPSPA), one of the smallest and most isolated island groups in the world, is situated on the Mid-Atlantic Ridge, between Brazil and the African continent. SPSPA has low species richness and high endemism; nonetheless, the diversity of fishes from deep habitats (>30 m depth) had not been previously studied in detail. Several expeditions conducted between 2009 and 2018 explored the shallow and deep reefs of SPSPA using scuba, closed-circuit rebreathers, manned submersibles, baited remote underwater stereo-videos (stereo-BRUV) and fishing between 0 and 1050 m depth. These expeditions yielded 41 new records of fishes for SPSPA: 9 in open waters, 9 in shallow waters (0–30 m), 8 in mesophotic ecosystems (30–150 m) and 15 in deeper reefs (>150 m). Combined with literature records of adult pelagic, shallow and deep-reef species, as well as larvae, the database of the fish biodiversity for SPSPA currently comprises 225 species (169 recorded as adult fishes and 79 as larvae, with 23 species found in both stages). Most of them (112) are pelagic, 86 are reef-associated species and 27 are deep-water specialists. Species accumulation curves show that the number of fish species has not yet reached an asymptote. Whereas the number of species recorded in SPSPA is similar to that in other oceanic islands in the Atlantic Ocean, the proportion of shorefishes is relatively lower, and the endemism level is the third highest in the Atlantic. Twenty-nine species are listed as threatened with extinction. Observations confirm the paucity of top predators on shallow rocky reefs of the island, despite the presence of several pelagic shark species around SPSPA. Because all of the endemic species are reef associated, it is argued that the new marine-protected areas created by the Brazilian government do not ensure the protection and recovery of SPSPA's biodiversity because they allow exploitation of the most vulnerable species around the archipelago itself. This study suggests a ban on reef fish exploitation inside an area delimited by the 1000 m isobath around the islands (where all known endemics are concentrated) as the main conservation strategy to be included in the SPSPA management plan being prepared by the Brazilian government. 相似文献
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49.