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991.
A proposed architecture for the central domain of the bacterial enhancer-binding proteins based on secondary structure prediction and fold recognition 下载免费PDF全文
Joel Osuna Xavier Soberon Enrique Morett 《Protein science : a publication of the Protein Society》1997,6(3):543-555
The expression of genes transcribed by the RNA polymerase with the alternative sigma factor <r54 (Ecr54) is absolutely dependent on activator proteins that bind to enhancer-like sites, located far upstream from the promoter. These unique prokaryotic proteins, known as enhancer-binding proteins (EBP), mediate open promoter complex formation in a reaction dependent on NTP hydrolysis. The best characterized proteins of this family of regulators are NtrC and Nif A, which activate genes required for ammonia assimilation and nitrogen fixation, respectively. In a recent IRBM course (“Frontiers of protein structure prediction,” IRBM, Pomezia, Italy, 1995; see web site http://www.mrc-cpe.cam.uk/ irbm-course95/), one of us (J.O.) participated in the elaboration of the proposal that the Central domain of the EBPs might adopt the classical mononucleotide-binding fold. This suggestion was based on the results of a new protein fold recognition algorithm (Map) and in the mapping of correlated mutations calculated for the sequence family on the same mononucleotide-binding fold topology. In this work, we present new data that support the previous conclusion. The results from a number of different secondary structure prediction programs suggest that the Central domain could adopt an alfi topology. The fold recognition programs ProFIT 0.9, 3D PROFILE combined with secondary structure prediction, and 123D suggest a mononucleotide-binding fold topology for the Central domain amino acid sequence. Finally, and most importantly, three of five reported residue alterations that impair the Central domain ATPase activity of the Eo-54 activators are mapped to polypeptide regions that might be playing equivalent roles as those involved in nucleotide-binding in the mononucleotide-binding proteins. Furthermore, the known residue substitutions that alter the function of the Ecr54 activators, leaving intact the Central domain ATPase activity, are mapped on a region proposed to play an equivalent role as the effector region of the GTPase superfamily. 相似文献
992.
993.
Sochung Chung Mi-Yeon Song Hyun-Dae Shin Deog-Yoon Kim Qing He Stan Heshka Jack Wang John Thornton Blandine Laferrère F Xavier Pi-Sunyer Dympna Gallagher 《Journal of applied physiology》2005,99(1):103-107
The aim of the study was to investigate in premenopausal women whether the relationship between percentage body fat (PBF) and body mass index (BMI; in kg/m2) differs between Korean Asians (Ko-As) living in Seoul, South Korea, and Caucasians (Ca) living in New York City. Healthy premenopausal women (50 Ko-As; 38 Ca), ages 22-50 yr, were studied. Weight, height, and PBF by dual-energy X-ray absorptiometry were measured. Total body dual-energy X-ray absorptiometry data were collected using GE-Lunar systems (Prodigy-Korea and DPXL-New York), and all scan analyses were performed by one technician in New York. Similar soft tissue phantoms were used for daily instrument calibrations at both sites. The relationship between PBF and BMI was assessed by multiple regression analysis with race, age, reciprocal of BMI (1/BMI), and a race-by-age interaction as the final independent variables. Race (P = 0.003) and 1/BMI (P < 0.001) were significantly related to PBF in this model. A significant race-by-age interaction (P = 0.039) indicated that the slope of the lines for PBF vs. age differed between Ko-As and Ca. This study demonstrates in a Ko-As sample that the BMI-fat relationship differs significantly from that in a comparable group of Caucasian women. Investigators who use BMI as an index of fatness should be aware of the well documented differences in the relationship of BMI and fatness across race/ethnic groups. 相似文献
994.
Therapeutic Approaches in Mitochondrial Dysfunction,Proteolysis, and Structural Alterations of Diaphragm and Gastrocnemius in Rats With Chronic Heart Failure 下载免费PDF全文
995.
Genetic markers validate using the natural phenotypic characteristics of shed feathers to identify individual northern goshawks Accipiter gentilis 下载免费PDF全文
Sarah R. Hoy Rachel E. Ball Xavier Lambin D. Philip Whitfield Michael Marquiss 《Journal of avian biology》2016,47(3):443-447
The recognition of individual animals is essential for many types of ecological research, as it enables estimates of demographic parameters such as population size, survival and reproductive rates. A popular method of visually identifying individuals uses natural variations in spot, stripe or scar markings. Although several studies have assessed the accuracy of these methods in mammals, crustaceans and fish, there have been few attempts to determine whether phenotypic characteristics are accurate when used for birds. Furthermore, even less is known about whether shed or moulted body parts can be reliably used to visually identify individuals. Here we assessed the accuracy of using phenotypic characteristics to identify avian individuals using a double‐marking experiment, whereby nine microsatellite genetic markers and natural markings on shed feathers were used to independently identify northern goshawks Accipiter gentilis. Phenotypic and genetic identification of individuals was consistent in 94.4% (51/54) comparisons. Our results suggest that the phenotypic characteristics of shed feathers can be reliably used as a non‐invasive and relatively inexpensive technique to monitor populations of an elusive species, the northern goshawk, without having to physically re‐capture or re‐sight individuals. We posit that using natural markings on shed feathers will also be a reliable method of identifying individuals in avian species with similar phenotypic characteristics, such as other Accipiter species. 相似文献
996.
The sliding clamp proliferating cell nuclear antigen (PCNA) plays a vital role in a number of DNA repair pathways in eukaryotes and archaea by acting as a stable platform onto which other essential protein factors assemble. Many of these proteins interact with PCNA via a short peptide sequence known as a PIP (PCNA interacting protein) motif. Here we describe the identification and functional analysis of a novel PCNA interacting protein NreA that is conserved in the archaea and that has a PIP motif at its C‐terminus. Using the genetically tractable euryarchaeon Haloferax volcanii as a model system, we show that the NreA protein is not required for cell viability but that loss of NreA (or replacement of the wild‐type protein with a truncated version lacking the C‐terminal PIP motif) results in an increased sensitivity to the DNA damaging agent mitomycin C (MMC) that correlates with delayed repair of MMC‐induced chromosomal DNA damage monitored by pulsed‐field gel electrophoresis. Genetic epistasis analysis in Hfx. volcanii suggests that NreA works together with the UvrABC proteins in repairing DNA damage resulting from exposure to MMC. The wide distribution of NreA family members implies an important role for the protein in DNA damage repair in all archaeal lineages. 相似文献
997.
Jonathan Maelfait Kenny Roose Lars Vereecke Conor Mc Guire Mozes Sze Martijn J. Schuijs Monique Willart Lorena Itati Iba?ez Hamida Hammad Bart N. Lambrecht Rudi Beyaert Xavier Saelens Geert van Loo 《PLoS pathogens》2016,12(1)
A20 negatively regulates multiple inflammatory signalling pathways. We here addressed the role of A20 in club cells (also known as Clara cells) of the bronchial epithelium in their response to influenza A virus infection. Club cells provide a niche for influenza virus replication, but little is known about the functions of these cells in antiviral immunity. Using airway epithelial cell-specific A20 knockout (A20AEC-KO) mice, we show that A20 in club cells critically controls innate immune responses upon TNF or double stranded RNA stimulation. Surprisingly, A20AEC-KO mice are better protected against influenza A virus challenge than their wild type littermates. This phenotype is not due to decreased viral replication. Instead host innate and adaptive immune responses and lung damage are reduced in A20AEC-KO mice. These attenuated responses correlate with a dampened cytotoxic T cell (CTL) response at later stages during infection, indicating that A20AEC-KO mice are better equipped to tolerate Influenza A virus infection. Expression of the chemokine CCL2 (also named MCP-1) is particularly suppressed in the lungs of A20AEC-KO mice during later stages of infection. When A20AEC-KO mice were treated with recombinant CCL2 the protective effect was abrogated demonstrating the crucial contribution of this chemokine to the protection of A20AEC-KO mice to Influenza A virus infection. Taken together, we propose a mechanism of action by which A20 expression in club cells controls inflammation and antiviral CTL responses in response to influenza virus infection. 相似文献
998.
Environmental and genetic interactions reveal FLOWERING LOCUS C as a modulator of the natural variation for the plasticity of flowering in Arabidopsis 下载免费PDF全文
Belén Méndez‐Vigo Marija Savic Mercedes Ramiro Beatriz Martín F. Xavier Picó Carlos Alonso‐Blanco 《Plant, cell & environment》2016,39(2):282-294
The timing of flowering initiation depends strongly on the environment, a property termed as the plasticity of flowering. Such plasticity determines the adaptive potential of plants because it provides phenotypic buffer against environmental changes, and its natural variation contributes to evolutionary adaptation. We addressed the genetic mechanisms of the natural variation for this plasticity in Arabidopsis thaliana by analysing a population of recombinant inbred lines derived from Don‐0 and Ler accessions collected from distinct climates. Quantitative trait locus (QTL) mapping in four environmental conditions differing in photoperiod, vernalization treatment and ambient temperature detected the folllowing: (i) FLOWERING LOCUS C (FLC) as a large effect QTL affecting flowering time differentially in all environments; (ii) numerous QTL displaying smaller effects specifically in some conditions; and (iii) significant genetic interactions between FLC and other loci. Hence, the variation for the plasticity of flowering is determined by a combination of environmentally sensitive and specific QTL, and epistasis. Analysis of FLC from Don identified a new and more active allele likely caused by a cis‐regulatory deletion covering the non‐coding RNA COLDAIR. Further characterization of four FLC natural alleles showed different environmental and genetic interactions. Thus, FLC appears as a major modulator of the natural variation for the plasticity of flowering to multiple environmental factors. 相似文献
999.
Evolutionarily distant pathogens require the Arabidopsis phytosulfokine signalling pathway to establish disease 下载免费PDF全文
1000.
Véronique Morel Dominique Joly Christine Villatte Claude Dubray Xavier Durando Laurence Daulhac Catherine Coudert Delphine Roux Bruno Pereira Gisèle Pickering 《PloS one》2016,11(4)
BackgroundNeuropathic pain following surgical treatment for breast cancer with or without chemotherapy is a clinical burden and patients frequently report cognitive, emotional and quality of life impairment. A preclinical study recently showed that memantine administered before surgery may prevent neuropathic pain development and cognitive dysfunction. With a translational approach, a clinical trial has been carried out to evaluate whether memantine administered before and after mastectomy could prevent the development of neuropathic pain, the impairment of cognition and quality of life.MethodA randomized, pilot clinical trial included 40 women undergoing mastectomy in the Oncology Department, University Hospital, Clermont-Ferrand, France. Memantine (5 to 20 mg/day; n = 20) or placebo (n = 20) was administered for four weeks starting two weeks before surgery. The primary endpoint was pain intensity measured on a (0–10) numerical rating scale at three months post-mastectomy.ResultsData analyses were performed using mixed models and the tests were two-sided, with a type I error set at α = 0.05. Compared with placebo, patients receiving memantine showed at three months a significant difference in post-mastectomy pain intensity, less rescue analgesia and a better emotional state. An improvement of pain symptoms induced by cancer chemotherapy was also reported.ConclusionsThis study shows for the first time the beneficial effect of memantine to prevent post-mastectomy pain development and to diminish chemotherapy-induced pain symptoms. The lesser analgesic consumption and better well-being of patients for at least six months after treatment suggests that memantine could be an interesting therapeutic option to diminish the burden of breast cancer therapy.