全文获取类型
收费全文 | 353篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
387篇 |
出版年
2023年 | 2篇 |
2021年 | 4篇 |
2020年 | 17篇 |
2019年 | 40篇 |
2018年 | 29篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 7篇 |
2013年 | 22篇 |
2012年 | 5篇 |
2010年 | 10篇 |
2009年 | 5篇 |
2008年 | 12篇 |
2007年 | 15篇 |
2006年 | 17篇 |
2005年 | 10篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 9篇 |
2001年 | 15篇 |
2000年 | 5篇 |
1999年 | 11篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 4篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 12篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有387条查询结果,搜索用时 0 毫秒
51.
Gokalp O Uz E Cicek E Yilmaz HR Ozer MK Altunbas A Ozcelik N 《Molecular and cellular biochemistry》2006,290(1-2):55-59
Isoniazid (INH) still remains a first-line drug both for treatment and prophylaxis of tuberculosis, but various organs toxicity
frequently develops in patients receiving this drug. We aimed to investigate possible toxic effects of INH on rat red blood
cells (RBCs), and to elucidate whether Caffeic acid phenethyl ester (CAPE) prevents a possible toxic effect of INH. Experimental
groups were designed as follows: control group, INH group, INH + CAPE group. Compared with the control, the INH caused a significant
increase in superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels, and a decrease in glutathione peroxidase
(GSH-Px) and catalase (CAT), which are recently used to monitor the development and extent of damage due to oxidative stresses.
CAPE administration to INH group ameliorated above changes due to INH. 相似文献
52.
Cigremis Y Parlakpinar H Polat A Colak C Ozturk F Sahna E Ermis N Acet A 《Molecular and cellular biochemistry》2006,285(1-2):149-154
Doxorubicin (DOX) is a broad-spectrum anthracycline antibiotic that has cardiotoxicity as a major side effect. One mechanism of this toxicity is believed to involve the reactive oxygen radical species (ROS); these agents likely account for the pathophysiology of DOX-induced cardiomyopathy. Aminoguanidine (AG) is an effective antioxidant and free radical scavenger which has long been known to protect against ROS formation. We investigated the effects of AG on DOX-induced changes in thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) content. The rats were divided into four groups:1) Control; 2) DOX group; injected intraperitoneally (i.p.) with DOX 20 mg/kg in a single dose 3) AG-treated group; injected i.p. in single dose of 20 mg/kg DOX plus 100 mg/kg AG 1 h before the DOX for 3 days, 4) AG group; injected i.p. with AG 100 mg/kg for 3 days. DOX administration to control rats increased TBARS and decreased GSH levels. AG administration before DOX injection caused significant decrease in TBARS and increase in GSH levels in the heart tissue when compared with DOX only. Morphological changes, including severe myocardial fibrosis and inflammatory cell infiltration were clearly observed in the DOX-treated heart. AG reversed the DOX-induced heart damage. Therefore AG could protect the heart tissue against free radical injury. The application of AG during cancer chemotherapy may attenuate tissue damage and improve the therapeutic index of DOX. 相似文献
53.
54.
Bekele Afessa MD 《BMC pulmonary medicine》2001,1(1):1-7
Background
A prospective observational study was done to describe nonbacterial pulmonary complications in hospitalized patients with human immunodeficiency virus (HIV) infection. 相似文献55.
Ru Ping Lee David Wang Nien Tsung Lin Prof. Hsing I. Chen MD PhD 《Journal of biomedical science》2002,9(6):613-621
Endotoxin shock is a major cause of death in patients with septicemia. Endotoxin induces nitric oxide (NO) production and causes tissue damage. In addition, the release of oxygen free radicals has also been observed in endotoxin shock and was found to be responsible for the occurrence of multiple organ failure. The purpose of the present study was to evaluate suitable indicators for early and late stages of endotoxin shock. The experiments were designed to induce endotoxin shock in conscious rats by means of anEscherichia coli lipopolysaccharide (LPS) injection. Arterial pressure (AP) and heart rate (HR) were continuously monitored for 72 h after LPS administration. The maximal decrease in AP and increase in HR and nitrate/nitrite level occurred at 9–12 h following LPS administration. The white blood cell (WBC) count had decreased at 3 h. Hydroxyl radical (methyl guanidine, MG) decreased rapidly after LPS administration. Plasma levels of blood urea nitrogen (BUN), creatinine (Cr), lactic dehydrogenase (LDH), creatine phosphokinase (CPK), and glutamic oxaloacetic transaminase increased before the rise of amylase. Our results suggest that changes in AP, HR, WBC, free radicals, and chemical substances (BUN, Cr) can possibly serve as approximate indicators for the early stage of endotoxin shock. Severe multiple organ damage may be caused by amylase release in the late stage of endotoxin shock. 相似文献
56.
57.
Over the last decade, the genetic basis for CBAVD has been identified by its association with CFTR gene mutations, and CBAVD is now generally considered to be a mild or incomplete form of CF. In this review, the author summarizes the main results of compilation of CFTR gene analysis conducted in French laboratories for 3,923 patients with CF and 800 males with CABVD. The degree of clinical expression can be affected by several variables, including the molecular mechanisms by which the various CFTR mutations impair or disrupt the function of the CFTR chloride channel. Phenotypic expression of CFTR mutational genotypes varies from severe, progressive pulmonary disease with pancreatic insufficiency (CF-PI), to mild pulmonary disease with pancreatic sufficiency (PS) or singleorgan forms of “CFTR-opathies”. In CF, a total of 310 different CFTR mutations accounting for 94% of 7,846 CF alleles have generated almost 500 different genotypes, comprising 2 severe mutations in 88% of cases (CF-PI), one severe mutation in trans to a mild mutation in 11% (CF-PS), and 2 mild mutations in 1% of identified genotypes. In CBAVD, 137 mutations scattered over the whole gene were identified in 60% of 1,600 CBAVD alleles during the study. Among the 150 characterized mutational CFTR genotypes, compound heterozygosity was the rule, and the most frequent CBAVD combinations were ΔF508/5T (35%), ΔF508/other mutation (30%, including ΔF508/R117H-7T: 5,6%), and 5T/other mutation (17%). No combination of two severe mutations was found in CBAVD (0%); by contrast with the CF population, 88% of genotypes identified in CBAVD comprised a severe mutation in trans to a mild mutation, and 12% consisted of 2 mild mutations. A total of 22 genotypes were shared by both CF and CBAVD. The role of the 5T allele as a splicing variant with variable, incomplete disease penetrance in CBAVD is reviewed. Other haplotype backgrounds, such as the TG12 sequence and the M470V polymorphism, may influence CFTR splicing and/or function. This study confirms the high molecular heterogeneity of CFTR mutations in CBAVD and emphasizes the importance of extensive CFTR analysis in these patients. Longterm follow-up studies of CBAVD patients are necessary in order to predict the phenotypic consequences of numerous CFTR mutational genotypes. 相似文献
58.
A cancer microenvironment generates strong hydrogen bond network system by the positive feedback loops supporting cancer complexity and robustness. Such network functions through the AKT locus generating high entropic energy supporting cancer metastatic robustness. Charged lepton particle muon follows the rule of Bragg effect during a collision with hydrogen network in cancer cells. Muon beam dismantles hydrogen bond network in cancer by the muon-catalyzed fusion, leading to apoptosis of cancer cells. Muon induces cumulative energy appearance on the hydrogen bond network in a cancer cell with its fast decay to an electron and two neutrinos. Thus, muon beam, muonic atom, muon neutrino shower, and electrons simultaneously cause fast neutralization of the AKT hydrogen bond network by the conversion of hydrogen into deuterium or helium, inactivating the hydrogen bond networks and inducing failure of cancer complexity and robustness with the disappearance of a malignant phenotype. 相似文献
59.
Cheng Qian MD Danqi Chang MD Hang Li MD Yanggan Wang 《Journal of cellular biochemistry》2019,120(5):7771-7777
Heart failure (HF) remains a common complication after acute ST-segment elevation myocardial infarction (STEMI). Here, we aim to identify critical genes related to the developed HF in patients with STEMI using bioinformatics analysis. The microarray data of GSE59867, including peripheral blood samples from nine patients with post-infarct HF and eight patients without post-infarct HF, were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) between HF and non-HF groups were screened by LIMMA package. Functional enrichment analyses of DEGs were conducted, followed by construction of a protein-protein interaction (PPI) network. The dynamic messenger RNA (mRNA) level of the hub genes during the follow-up was analyzed to further elucidate their role in HF development. A total of 58 upregulated and 75 downregulated DEGs were screen out. They were mainly enriched in biological processes about inflammatory response, extracellular matrix organization, response to cAMP, immune response, and positive regulation of cytosolic calcium ion concentration. Pathway analysis revealed that the DEGs were also involved in hematopoietic cell lineage, pathways in cancer, and extracellular matrix-receptor interaction. In the PPI network consisting of 58 nodes and 72 interactions, CXCL8 (degree = 15), THBS1 (degree = 8), FOS (degree = 7), and ITGA2B (degree = 6) were identified as the hub genes. In the comparison of patients with and without post-infarct HF, the mRNA level of these hub genes were all higher within 30 days but reached similar at 6 months after STEMI. In conclusion, CXCL8, THBS1, FOS, and ITGA2B may play important roles in the development of HF after acute STEMI. 相似文献
60.
A journey through time: exploring temporal patterns amongst digitized plant specimens from Australia
MD. Mohasinul Haque David A. Nipperess John B. Baumgartner Linda J. Beaumont 《分类学与生物多样性》2018,16(6):604-613
Online access to species occurrence records has opened new windows into investigating biodiversity patterns across multiple scales. The value of these records for research depends on their spatial, temporal, and taxonomic quality. We assessed temporal patterns in records from the Australasian Virtual Herbarium, asking: (1) How temporally consistent has collecting been across Australia? (2) Which areas of Australia have the most reliable records, in terms of temporal consistency and inventory completeness? (3) Are there temporal trends in the completeness of attribute information associated with records? We undertook a multi-step filtering procedure, then estimated temporal consistency and inventory completeness for sampling units (SUs) of 50?km ×?50?km. We found temporal bias in collecting, with 80% of records collected over the period 1970–1999. South-eastern Australia, the Wet Tropics in north-east Queensland, and parts of Western Australia have received the most consistent sampling effort over time, whereas much of central Australia has had low temporal consistency. Of the SUs, 18% have relatively complete inventories with high temporal consistency in sampling. We also determined that 25% of digitized records had missing attribute information. By identifying areas with low reliability, we can limit erroneous inferences about distribution patterns and identify priority areas for future sampling. 相似文献