首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   110篇
  免费   8篇
  2022年   1篇
  2020年   2篇
  2019年   1篇
  2018年   3篇
  2017年   2篇
  2016年   5篇
  2015年   6篇
  2014年   4篇
  2013年   7篇
  2012年   7篇
  2011年   9篇
  2010年   1篇
  2009年   4篇
  2008年   7篇
  2007年   3篇
  2006年   9篇
  2005年   2篇
  2004年   7篇
  2003年   7篇
  2002年   4篇
  2001年   6篇
  2000年   3篇
  1999年   1篇
  1997年   2篇
  1995年   1篇
  1991年   2篇
  1990年   1篇
  1989年   5篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1982年   1篇
  1971年   1篇
排序方式: 共有118条查询结果,搜索用时 109 毫秒
41.

Background

Projectile foreign bodies are known to cause chronic heavy metal toxicity due to the release of metal into the bloodstream. However, the local effect around the metallic object has not been investigated and the main goal of our study is to examine the influence of the object in close proximity of the object.

Case presentation

A 36-year-old Caucasian woman with one metallic pellet close to her sciatic nerve due to a previous shotgun injury at the gluteal area presented with a diagnosis of recurrent lumbar disk herniation at L4–5 level. A physical examination confirmed chronic neuropathy and she underwent a two-stage surgery. The surgery included removal of the foreign body, followed by discectomy and fusion at the involved level. During the removal of the metallic foreign body, a tissue sample around the pellet and another tissue sample from a remote area were obtained. The samples were analyzed by scanning acoustic microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Lead, chromium, copper, cadmium, iron, manganese, selenium, and zinc elements in tissue, blood, and serum specimens were detected by inductively coupled plasma optical emission spectroscopy.

Conclusions

An acoustic impedance map of the tissue closer to the metallic body showed higher values indicating further accumulation of elements. Energy-dispersive X-ray spectroscopy results confirmed scanning acoustic microscopy results by measuring a higher concentration of elements closer to the metallic body. Scanning electron microscopy images showed that original structure was not disturbed far away; however, deformation of the structure existed in the tissue closer to the foreign body. Element analysis showed that element levels within blood and serum were more or less within acceptable ranges; on the other hand, element levels within the tissues showed pronounced differences indicating primarily lead intoxication in the proximity of the metallic body. We can state that residues of metallic foreign bodies of gunshot injuries cause chronic metal infiltration to the surrounding tissue and induce significant damage to nearby neural elements; this is supported by the results of scanning acoustic microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma optical emission spectroscopy.
  相似文献   
42.
This study investigated the neuroprotection provided by cytidine 5'-diphosphocholine (citicoline) during interrupted and uninterrupted occlusion of the basilar artery after subarachnoid hemorrhage (SAH) in 121 hypotensive rats. Animals were anesthetized and the basilar artery was exposed through a transclival approach. Baseline local cerebral blood flow (LCBF) values were recorded, and then the basilar artery was punctured, causing SAH. Blood was drawn to induce hypotension [60-70 mmHg mean arterial blood pressure (MABP)]. Control rats received intraperitoneal (i.p.) injections of 0.5 ml saline immediately after SAH before hypotension induction and after 60 min of occlusion. Experimental rats received 400-mg/kg citicoline i.p. at the same time points. Control group I and treatment group III were subjected to 60 min of interrupted occlusion (5 min of reperfusion after each 10 min of occlusion). Control group II and treatment group IV were subjected to 60 min of uninterrupted occlusion. MABP and LCBF were recorded every 5 minutes. Brain edema was evaluated in seven rats from each group at 24 hours after ischemic injury. At 3 days after occlusion, another set of 28 rats was killed and coronal brain slices were stained to assess infarct volume. The groups' physiological and edema findings were similar. In all groups, LCBF fell immediately after SAH and remained below baseline throughout the experiment. In the citicoline-treated rats, arterial pressure increased significantly after 30-40 min of occlusion, and brain slices showed significantly smaller infarct volumes compared to control slices (p < 0.05). Mortality was significantly lower in the citicoline-treated animals (p < 0.001). The results suggest that citicoline provides significant neuroprotection during cerebral ischemia, and that it significantly reduces mortality. Part of the neuroprotective effect may be mediated by recovery of arterial pressure.  相似文献   
43.
Three Turkish isolates of the entomopathogenic nematodes Steinernema carpocapsae, Steinernema feltiae and Heterorhabditis bacteriophora were evaluated under laboratory conditions (in different temperatures and doses) for their biocontrol efficiency against last instar Leptinotarsa decemlineata. Herein, the effects of infective juveniles in aqueous suspension against L. decemlineata were evaluated. S. feltiae appeared to be the most pathogenic nematode among the tested species.  相似文献   
44.
45.
Arabidopsis thaliana CEL1 protein was detected in young expanding tissues. Immunostaining revealed that CEL1 accumulated mostly in xylem cells. The primary, as well as the secondary xylem showed considerable CEL1 staining. CEL1 was also observed in young epidermal cells, in which the thicker lateral and tangential walls stained more intensely than the inner walls. In newly formed cell walls, the lateral tangential walls were labeled more intensively than the inner walls. Cellulase activity was found to be significantly higher in growing tissue compared to mature parts of the plant. Cel1 expression concurrently with cellulase activity could be restored in detached matured leaves by sucrose treatment after 48 h in the culture medium.  相似文献   
46.
47.
48.
Limitations of next-generation genome sequence assembly   总被引:1,自引:0,他引:1  
High-throughput sequencing technologies promise to transform the fields of genetics and comparative biology by delivering tens of thousands of genomes in the near future. Although it is feasible to construct de novo genome assemblies in a few months, there has been relatively little attention to what is lost by sole application of short sequence reads. We compared the recent de novo assemblies using the short oligonucleotide analysis package (SOAP), generated from the genomes of a Han Chinese individual and a Yoruban individual, to experimentally validated genomic features. We found that de novo assemblies were 16.2% shorter than the reference genome and that 420.2 megabase pairs of common repeats and 99.1% of validated duplicated sequences were missing from the genome. Consequently, over 2,377 coding exons were completely missing. We conclude that high-quality sequencing approaches must be considered in conjunction with high-throughput sequencing for comparative genomics analyses and studies of genome evolution.  相似文献   
49.
50.
The aim of this study was to evaluate the effect of presynchronization with or without the detection of estrus on first service pregnancy per artificial insemination (P/AI) and on Ovsynch outcome in lactating dairy cows. A total of 511 cows were divided randomly but unevenly into 3 treatment groups at 44 to 50 days in milk (DIM). Ovsynch was started at the same time (69 to 75 DIM) in all three groups. Cows in the Ovsynch group (CON, N = 126) received no presynchronization before Ovsynch, and all cows were bred by timed AI (TAI). Cows in the presynchronization with estrus detection (PED) and the presynchronization with only TAI (PTAI) groups received two doses of prostaglandin F (PGF) 14 days apart, starting at 44 to 50 DIM. Ovsynch was initiated 11 days after the second PGF treatment. Cows in the PED group (N = 267) received AI if estrus was detected after either PGF injection. Cows that were not determined to be in estrus after PGF injection received Ovsynch and TAI. Cows in the PTAI group (N = 118) were not inseminated to estrus, with all cows receiving TAI after Ovsynch. The ovulatory response to the first GnRH injection administered as part of Ovsynch differed (P = 0.002) among treatment groups (83.1% in PTAI, 72.6% in PED, and 62.7% in CON). However, the ovulatory response to the second injection of GnRH during Ovsynch did not differ among treatment groups. Of the 267 PED cows, a total of 132 (49.4%) exhibited estrus and were inseminated. The P/AI at the 31-day pregnancy diagnosis was similar between the cows in the PED group with AI after estrus detection (37.9%; 50/132) and those bred with TAI (34.1%; 46/135). The P/AI in the CON group (46.8%; 59/126) was greater (P < 0.05) than that in the PED group (36.0%; 96/267). In addition, the P/AI in the CON group was greater (P = 0.04) than that in the PED cows receiving TAI (34.1%; 46/135) but less than that in the PED cows bred to estrus (37.9%; 50/132) (P = 0.16). At the 31-day pregnancy diagnosis, the cows in the PTAI group had greater P/AI (55.9%; 66/118) than both those in the PED group (P < 0.01; either estrus or TAI) and those in the CON group (P = 0.08). Thus, presynchronization with PGF (PTAI) increased the ovulatory response to Ovsynch and improved P/AI in dairy cows. Interestingly, the breeding of cows to estrus during presynchronization reduced fertility to the TAI and overall fertility, including cows bred to estrus and TAI. These results indicate that maximal fertility is obtained when all cows receive TAI after the presynchronization protocol.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号