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991.
Methodology for assessing respiration and cellular incorporation of radiolabeled substrates by soil microbial communities 总被引:1,自引:0,他引:1
A method is described for determining biodegradation kinetics of both naturally occurring and xenobiotic compounds in surface and sub-surface soil samples. The method measures both respiration and uptake into cellular biomass of14C-labeled substrates. The estimation of biomass incorporation entailed removal of cells from soil particles by washing the soil with a polyvinyl-pyrrolidone/pyrophosphate solution and H2O2. After separation of the cells and the soil particles by centrifugation, the cells were trapped on membrane filters for liquid scintillation counting. Mass balances were easily obtained. The technique was used to measure metabolic activity in soil profiles, including unsaturated and saturated zones. First order rate constants (K1) were in the range of 10–3–10–2 hour–1 for amino acid metabolism and 10–5–10–4 hour–1 for m-cresol metabolism. Saturation kinetics were observed for amino acids and m-cresol. m-Cresol K1 values for uptake often exceeded those for respiration by greater than a factor of ten. Vmax values were low (amino acids, 101–102 ng g–1 hour–1; m-cresol, 10–1 ng g–1 hour–1), whereas Km values were quite high (amino acids, 103–104 ng g–1; m-cresol 103–105 ng g–1). Saturation was not observed in many horizons even at 105 ng g–1 dry soil. Frequently, respiration obeyed saturation kinetics whereas uptake was first order. It is concluded that measuring only kinetics of respiration may lead to severe underestimations of biodegradation rates. 相似文献
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993.
Improving cold storage and processing traits in potato through targeted gene knockout 总被引:3,自引:0,他引:3 下载免费PDF全文
Benjamin M. Clasen Thomas J. Stoddard Song Luo Zachary L. Demorest Jin Li Frederic Cedrone Redeat Tibebu Shawn Davison Erin E. Ray Aurelie Daulhac Andrew Coffman Ann Yabandith Adam Retterath William Haun Nicholas J. Baltes Luc Mathis Daniel F. Voytas Feng Zhang 《Plant biotechnology journal》2016,14(1):169-176
994.
Jean-Philippe Bertocchio Coralie Barbe Sylvie Lavaud Olivier Toupance Pierre Nazeyrollas Frederic Jaisser Philippe Rieu 《PloS one》2016,11(4)
BackgroundAnimal studies have highlighted the role of vascular mineralocorticoid receptor during Cyclosporine A-induced nephrotoxicity. Mineralocorticoid receptor antagonists could improve kidney survival but are not commonly used during renal impairment and in association with several immunosuppressive drugs due to a supposed higher risk of adverse events. We tested the tolerance of eplerenone according to its expected adverse events: hyperkalemia, metabolic acidosis, hypotension, acute kidney failure, or any other adverse event.MethodsWe conducted a single-center, prospective, open-label study in 31 kidney-transplant recipients with impaired renal function (30 and 50 mL/min/1.73m2) and receiving cyclosporine A. All patients received eplerenone 25 mg/d for 8 weeks. Serum potassium, renal function and expected adverse events were closely monitored.ResultsEight patients experienced mild hyperkalemia (>5 mmol/L), one moderate hyperkalemia (>5.5 mmol/L) and had to receive potassium-exchange resin. No severe hyperkalemia (>6 mmol/L) occurred. One acute kidney failure was observed, secondary to diarrhea. Basal serum potassium and bicarbonate were independently associated with a higher risk of developing mild hyperkalemia (>5 mmol/L) under treatment (OR 6.5, p = 0.003 and 0.7, p = 0.007, respectively). A cut-off value of 4.35 mmol/L for basal serum potassium was the best factor to predict the risk of developing mild hyperkalemia (>5 mmol/L).ConclusionsUntil eGFR falls to 30 mL/min/1.73m2, eplerenone could be safely given to kidney-transplant recipients receiving cyclosporine A, if kalemia is closely monitored. When renal function is impaired and if basal kalemia is >4.35 mmol/L, then clinicians should properly balance risk and benefit of eplerenone use and offer dietary advice. An adequately powered prospective randomized study is now needed to test its efficiency (and safety) in this population.
Trial Registration
ClinicalTrials.gov NCT01834768相似文献995.
Anita Pras Bert Houben Francesco A Aprile Rene Seinstra Rodrigo Gallardo Leen Janssen Wytse Hogewerf Christian Gallrein Matthias De Vleeschouwer Alejandro MataCabana Mandy Koopman Esther Stroo Minke de Vries Samantha Louise Edwards Janine Kirstein Michele Vendruscolo Salvatore Fabio Falsone Frederic Rousseau Joost Schymkowitz Ellen A A Nollen 《The EMBO journal》2021,40(21)
While aggregation‐prone proteins are known to accelerate aging and cause age‐related diseases, the cellular mechanisms that drive their cytotoxicity remain unresolved. The orthologous proteins MOAG‐4, SERF1A, and SERF2 have recently been identified as cellular modifiers of such proteotoxicity. Using a peptide array screening approach on human amyloidogenic proteins, we found that SERF2 interacted with protein segments enriched in negatively charged and hydrophobic, aromatic amino acids. The absence of such segments, or the neutralization of the positive charge in SERF2, prevented these interactions and abolished the amyloid‐promoting activity of SERF2. In protein aggregation models in the nematode worm Caenorhabditis elegans, protein aggregation and toxicity were suppressed by mutating the endogenous locus of MOAG‐4 to neutralize charge. Our data indicate that MOAG‐4 and SERF2 drive protein aggregation and toxicity by interactions with negatively charged segments in aggregation‐prone proteins. Such charge interactions might accelerate primary nucleation of amyloid by initiating structural changes and by decreasing colloidal stability. Our study points at charge interactions between cellular modifiers and amyloidogenic proteins as potential targets for interventions to reduce age‐related protein toxicity. 相似文献
996.
997.
998.
The growing capacity to process and store animal tracks has spurred the development of new methods to segment animal trajectories into elementary units of movement. Key challenges for movement trajectory segmentation are to (i) minimize the need of supervision, (ii) reduce computational costs, (iii) minimize the need of prior assumptions (e.g. simple parametrizations), and (iv) capture biologically meaningful semantics, useful across a broad range of species. We introduce the Expectation-Maximization binary Clustering (EMbC), a general purpose, unsupervised approach to multivariate data clustering. The EMbC is a variant of the Expectation-Maximization Clustering (EMC), a clustering algorithm based on the maximum likelihood estimation of a Gaussian mixture model. This is an iterative algorithm with a closed form step solution and hence a reasonable computational cost. The method looks for a good compromise between statistical soundness and ease and generality of use (by minimizing prior assumptions and favouring the semantic interpretation of the final clustering). Here we focus on the suitability of the EMbC algorithm for behavioural annotation of movement data. We show and discuss the EMbC outputs in both simulated trajectories and empirical movement trajectories including different species and different tracking methodologies. We use synthetic trajectories to assess the performance of EMbC compared to classic EMC and Hidden Markov Models. Empirical trajectories allow us to explore the robustness of the EMbC to data loss and data inaccuracies, and assess the relationship between EMbC output and expert label assignments. Additionally, we suggest a smoothing procedure to account for temporal correlations among labels, and a proper visualization of the output for movement trajectories. Our algorithm is available as an R-package with a set of complementary functions to ease the analysis. 相似文献
999.
Aude Pflieger Pierre Waffo Teguo Yorgos Papastamoulis Stéphane Chaignepain Frederic Subra Soundasse Munir Olivier Delelis Paul Lesbats Christina Calmels Marie-Line Andreola Jean-Michel Merillon Corinne Auge-Gouillou Vincent Parissi 《PloS one》2013,8(11)
Polynucleotidyl transferases are enzymes involved in several DNA mobility mechanisms in prokaryotes and eukaryotes. Some of them such as retroviral integrases are crucial for pathogenous processes and are therefore good candidates for therapeutic approaches. To identify new therapeutic compounds and new tools for investigating the common functional features of these proteins, we addressed the inhibition properties of natural stilbenoids deriving from resveratrol on two models: the HIV-1 integrase and the eukaryote MOS-1 transposase. Two resveratrol dimers, leachianol F and G, were isolated for the first time in Vitis along with fourteen known stilbenoids: E-resveratrol, E-piceid, E-pterostilbene, E-piceatannol, (+)-E-ε-viniferin, E-ε-viniferinglucoside, E-scirpusin A, quadragularin A, ampelopsin A, pallidol, E-miyabenol C, E-vitisin B, hopeaphenol, and isohopeaphenol and were purified from stalks of Vitis vinifera (Vitaceae), and moracin M from stem bark of Milliciaexelsa (Moraceae). These compounds were tested in in vitro and in vivo assays reproducing the activity of both enzymes. Several molecules presented significant inhibition on both systems. Some of the molecules were found to be active against both proteins while others were specific for one of the two models. Comparison of the differential effects of the molecules suggested that the compounds could target specific intermediate nucleocomplexes of the reactions. Additionally E-pterostilbene was found active on the early lentiviral replication steps in lentiviruses transduced cells. Consequently, in addition to representing new original lead compounds for further modelling of new active agents against HIV-1 integrase, these molecules could be good tools for identifying such reaction intermediates in DNA mobility processes. 相似文献
1000.
Paulo Pereira David Buzek J?rg Franke Wolfgang Senker Arkadiusz Kosmala Ulrich Hubbe Neil Manson Wout Rosenberg Roberto Assietti Frederic Martens Giovanni Barbanti Brodano Kai-Michael Scheufler 《PloS one》2015,10(3)
Minimally invasive lumbar interbody fusion (MILIF) offers potential for reduced operative morbidity and earlier recovery compared with open procedures for patients with degenerative lumbar disorders (DLD). Firm conclusions about advantages of MILIF over open procedures cannot be made because of limited number of large studies of MILIF in a real-world setting. Clinical effectiveness of MILIF in a large, unselected real-world patient population was assessed in this Prospective, monitored, international, multicenter, observational study. Objective: To observe and document short-term recovery after minimally invasive interbody fusion for DLD. Materials and Methods: In a predefined 4-week analysis from this study, experienced surgeons (≥30 MILIF surgeries pre-study) treated patients with DLD by one- or two-level MILIF. The primary study objective was to document patients’ short-term post-interventional recovery (primary objective) including back/leg pain (visual analog scale [VAS]), disability (Oswestry Disability Index [ODI]), health status (EQ-5D) and Patient satisfaction. Results: At 4 weeks, 249 of 252 patients were remaining in the study; the majority received one-level MILIF (83%) and TLIF was the preferred approach (94.8%). For one-level (and two-level) procedures, surgery duration was 128 (182) min, fluoroscopy time 115 (154) sec, and blood-loss 164 (233) mL. Time to first ambulation was 1.3 days and time to study-defined surgery recovery was 3.2 days. Patients reported significantly (P < 0.0001) reduced back pain (VAS: 2.9 vs 6.2), leg pain (VAS: 2.5 vs 5.9), and disability (ODI: 34.5% vs 45.5%), and a significantly (P < 0.0001) improved health status (EQ-5D index: 0.61 vs 0.34; EQ VAS: 65.4 vs 52.9) 4 weeks postoperatively. One adverse event was classified as related to the minimally invasive surgical approach. No deep site infections or deaths were reported. Conclusions: For experienced surgeons, MILIF for DLD demonstrated early benefits (short time to first ambulation, early recovery, high patient satisfaction and improved patient-reported outcomes) and low major perioperative morbidity at 4 weeks postoperatively. 相似文献