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排序方式: 共有278条查询结果,搜索用时 15 毫秒
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Suborganellar Localization and Molecular Characterization of Nonproteolytic Degraded Leukoplast Pyruvate Kinase from Developing Castor Oil Seeds 总被引:1,自引:1,他引:0 下载免费PDF全文
Several genes involved in the ability of Synechococcus sp. PCC 7942 to grow under different CO2 concentrations were mapped in the genomic region of rbcLS (the operon encoding the large and small subunits of ribulose-1,5-bisphosphate carboxylase/oxygenase). Insertion of a cartridge encoding kanamycin resistance within open reading frame (ORF) 78, designated ccmJ, located 7 kb upstream of rbcLS, resulted in a kanamycin-resistant, high-CO2-requiring mutant, M3, which does not contain normal carboxysomes. ccmJ shows significant homology to csoS1 encoding a carboxysomal shell polypeptide in Thiobacillus neopolitanus. Analysis of the polypeptide pattern of a carboxysome-enriched fraction indicated several differences between the wild type and the mutant. The amount of the ribulose-1,5-bisphosphate carboxylase/oxygenase subunits was considerably smaller in the carboxysomal fraction of the mutant when compared to the wild type. On the basis of the sequence analyses, ORF286 and ORF466, located downstream of ccmJ, were identified as chlL and chlN, respectively, which are involved in chlorophyll biosynthesis in the dark. 相似文献
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George C. Nadăş Marian A. Taulescu Lidia Ciobanu Nicodim I. Fiţ Chirilă Flore Sorin Răpuntean Cosmina M. Bouari Cornel Catoi 《Mycopathologia》2013,175(3-4):221-230
Recent studies suggest that Candida albicans colonization is associated with several gastrointestinal inflammatory disorders and is also responsible for the delay in ulcer healing. No data are reported about the effects of C. albicans on the nonsteroidal anti-inflammatory drugs (NSAIDs)-induced necroinflammatory lesions. On the other hand, beneficial effects of NSAIDs regarding the colonization potential with C. albicans have been reported. Our aim was to investigate whether the association between NSAIDs and C. albicans could potentially induce necroinflammatory lesions in the guinea pigs gastric and enteral mucosa. Three interventional groups of 11 guinea pigs each were investigated after 5 days of receiving indomethacin, C. albicans or the association of both. C. albicans and necroinflammatory lesions were graded based on histological examinations. Statistical analysis used Mann–Whitney nonparametric test. NSAIDs did not significantly decrease C. albicans colonization grades on gastrointestinal mucosa. Administration of indomethacin subsequent to C. albicans determined significantly more severe necroinflammatory lesions compared to group that only received C. albicans. The association of NSAIDs and C. albicans did not cause significantly more severe degenerative or inflammatory lesions compared to the administration of only NSAIDs in this experimental model. Associations between NSAIDs and C. albicans caused significantly more severe necroinflammatory injuries than the lesions produced by C. albicans, without enhancing the mucosal injury or inflammation caused by NSAIDs. 相似文献
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Mark AJ Roberts Elias August Abdullah Hamadeh Philip K Maini Patrick E McSharry Judith P Armitage Antonis Papachristodoulou 《BMC systems biology》2009,3(1):105-14
Background
Developing methods for understanding the connectivity of signalling pathways is a major challenge in biological research. For this purpose, mathematical models are routinely developed based on experimental observations, which also allow the prediction of the system behaviour under different experimental conditions. Often, however, the same experimental data can be represented by several competing network models. 相似文献6.
Direct sequencing of the mitochondrial displacement loop (D-loop) of shrews
(genus Sorex) for the region between the tRNA(Pro) and the conserved
sequence block-F revealed variable numbers of 79-bp tandem repeats. These
repeats were found in all 19 individuals sequenced, representing three
subspecies and one closely related species of the masked shrew group (Sorex
cinereus cinereus, S. c. miscix, S. c. acadicus, and S. haydeni) and an
outgroup, the pygmy shrew (S. hoyi). Each specimen also possessed an
adjacent 76-bp imperfect copy of the tandem repeats. One individual was
heteroplasmic for length variants consisting of five and seven copies of
the 79-bp tandem repeat. The sequence of the repeats is conducive to the
formation of secondary structure. A termination-associated sequence is
present in each of the repeats and in a unique sequence region 5' to the
tandem array as well. Mean genetic distance between the masked shrew taxa
and the pygmy shrew was calculated separately for the unique sequence
region, one of the tandem repeats, the imperfect repeat, and these three
regions combined. The unique sequence region evolved more rapidly than the
tandem repeats or the imperfect repeat. The small genetic distance between
pairs of tandem repeats within an individual is consistent with a model of
concerted evolution. Repeats are apparently duplicated and lost at a high
rate, which tends to homogenize the tandem array. The rate of D- loop
sequence divergence between the masked and pygmy shrews is estimated to be
15%-20%/Myr, the highest rate observed in D-loops of mammals. Rapid
sequence evolution in shrews may be due either to their high metabolic rate
and short generation time or to the presence of variable numbers of tandem
repeats.
相似文献
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Umans VA Cornel JH Velthoven SS Kloeg P Bartels P Bronzwaer J 《International journal of cardiovascular interventions》1999,2(4):223-230
BACKGROUND: Although balloon angioplasty has assumed an important role in the management of refractory unstable angina (UA), that is, UA that does not respond to conventional therapy, it is limited by complications related to thrombosis and acute coronary occlusion. The complication rate is higher in patients with UA than in those whose condition is stable. Preprocedural use of abciximab, a monoclonal platelet glycoprotein IIb/IIIa receptor blocker, has been used effectively in patients with UA, but its acceptance may be limited by safety concerns and economic constraints. The current trial investigated a protocol for abciximab pretreatment in patients with UA awaiting transfer from referring hospitals to a site of intervention (the 'drip and ship' protocol). AIMS: This observational study was conducted to evaluate whether a prophylactic, preprocedural regimen of abciximab can be safely and effectively administered to UA patients in referring hospitals while awaiting coronary angioplasty at the interventional clinic. METHODS: From April 1996 to December 1998, 168 consecutive patients with refractory UA (Braunwald class II or III) received abciximab prospectively at the referring clinic before undergoing PTCA or stent implantation at the interventional clinic. The following cost-conscious protocol was used: a 0.25 mg/kg bolus of abciximab followed by 10 micro g/min intravenously for 16 hours, in addition to intravenous nitrates, heparin and aspirin therapy. Patients were then transferred to a facility with PTCA capability via high-speed ambulance transport. No specific alterations of routine-transfer protocol were needed. Platelet aggregation studies were conducted during abciximab infusion. All interventions were performed while abciximab was given. Procedural and clinical success and long-term outcomes also were assessed. RESULTS: The primary angiographic success rate (patients with post-PTCA diameter stenosis < 50%) was 98%, and the in-hospital clinical success rate (angiographic success without major complications) was 98%. No major bleeding complications occurred during the abciximab pretreatment period. Platelet aggregation findings in the study patients showed a stable inhibition of >80% at the time of angioplasty. At 30-day follow-up, all patients were alive and 91% were free of major adverse events. Outcomes of balloon angioplasty and stenting were equally favorable, indicating no device-specific effect. Event-free survival at six months was 89% with a target vessel revascularization rate of 10%. CONCLUSION: Abciximab was administered safely and effectively to angioplasty patients with refractory UA awaiting transfer from a noninterventional setting to the site of angioplasty. These results extend the current knowledge base that has been established in randomized trials performed in interventional centers. The study protocol potentially could make abciximab therapy more feasible economically, and therefore more widely available to patients who are most likely to benefit from prophylactic administration. 相似文献
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The scientific community's reliance on active-controlled trials is steadily increasing, as widespread agreement emerges concerning the role of these trials as viable alternatives to placebo trials. These trials present substantial challenges with regard to design and interpretation as their complexity increases, and the potential need for larger sample sizes impacts the cost and time variables of the drug development process. The potential efficacy and safety benefits derived from these trials may never be demonstrated by other methods. Active-controlled trials can develop valuable data to inform both prescribers and patients about the dose- and time-dependent actions of any new drug and can contribute to the management and communication of risks associated with the relevant therapeutic products. 相似文献
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