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   304篇
  免费   27篇
耳鼻咽喉   2篇
儿科学   6篇
妇产科学   6篇
基础医学   78篇
口腔科学   5篇
临床医学   38篇
内科学   65篇
皮肤病学   12篇
神经病学   13篇
特种医学   30篇
外科学   28篇
综合类   9篇
预防医学   20篇
眼科学   4篇
药学   9篇
中国医学   1篇
肿瘤学   5篇
  2021年   5篇
  2020年   4篇
  2018年   4篇
  2017年   5篇
  2016年   9篇
  2015年   5篇
  2014年   4篇
  2013年   9篇
  2012年   6篇
  2011年   8篇
  2010年   16篇
  2009年   12篇
  2008年   8篇
  2007年   15篇
  2006年   12篇
  2005年   7篇
  2004年   23篇
  2003年   8篇
  2002年   5篇
  2001年   4篇
  1998年   6篇
  1997年   5篇
  1996年   7篇
  1994年   4篇
  1993年   4篇
  1992年   3篇
  1989年   4篇
  1988年   5篇
  1987年   5篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1983年   7篇
  1982年   6篇
  1981年   4篇
  1980年   3篇
  1979年   7篇
  1978年   10篇
  1977年   2篇
  1976年   12篇
  1975年   8篇
  1973年   5篇
  1971年   6篇
  1970年   5篇
  1969年   5篇
  1968年   4篇
  1967年   5篇
  1966年   6篇
  1965年   2篇
  1959年   2篇
排序方式: 共有331条查询结果,搜索用时 15 毫秒
91.
92.
Recent proliferation of low-cost DNA sequencing techniques will soon lead to an explosive growth in the number of sequenced genomes and will turn manual annotations into a luxury. Mass spectrometry recently emerged as a valuable technique for proteogenomic annotations that improves on the state-of-the-art in predicting genes and other features. However, previous proteogenomic approaches were limited to a single genome and did not take advantage of analyzing mass spectrometry data from multiple genomes at once. We show that such a comparative proteogenomics approach (like comparative genomics) allows one to address the problems that remained beyond the reach of the traditional "single proteome" approach in mass spectrometry. In particular, we show how comparative proteogenomics addresses the notoriously difficult problem of "one-hit-wonders" in proteomics, improves on the existing gene prediction tools in genomics, and allows identification of rare post-translational modifications. We therefore argue that complementing DNA sequencing projects by comparative proteogenomics projects can be a viable approach to improve both genomic and proteomic annotations.  相似文献   
93.
94.
Previous studies showed differences in in vitro heterophil function between parental (A > B) broilers and F1 reciprocal crosses (D > C). Our objectives were to (1) determine if in vitro variations translate to differences in resistance to Salmonella enteritidis (SE) and (2) quantitate cytokine mRNA in heterophils from SE-infected chicks. One-day-old chicks were challenged and organs were cultured for SE. Chicks with efficient heterophils (A and D) were less susceptible to SE compared to chicks with inefficient heterophils (B and C). Heterophils were isolated from SE-infected chicks and cytokine mRNA expression was evaluated using quantitative real-time RT-PCR. Pro-inflammatory cytokine mRNA was up-regulated in heterophils from SE-resistant chicks compared to susceptible chicks. This is the first report to quantitate cytokine mRNA in heterophils from SE-infected chicks. These data show a relationship between in vitro heterophil function, increased pro-inflammatory cytokine mRNA expression, and increased resistance to SE in 1-day-old chicks.  相似文献   
95.
BACKGROUND: There is a paucity of research on bidi use in the US and the few studies conducted have focused solely on adolescents. This article describes patterns and explores factors associated with bidi use among young adults, aged 18-24. METHODS: Data from 63,728 adults, including 5,324 young adults, aged 18-24, were derived from an optional tobacco module on the 2001 Behavioral Risk Factor Surveillance System, administered by 15 states. Logistic regression was utilized to examine factors associated with ever and current bidi use among young adults. RESULTS: Nearly two thirds of adults who reported current bidi use were under the age of 25; 16.5% of young adults reported ever use and 1.4% reported current bidi use. Among young adults, higher rates of ever and current bidi use were noted for males, blacks, and current cigarette smokers. CONCLUSIONS: The rates of ever bidi use among young adults may reflect experimentation with bidis during adolescence and raises questions about whether bidis may act as a gateway product to regular cigarette use. The disparities among certain subgroups are noteworthy and deserve further exploration. Tobacco prevention and control programs should address all forms of tobacco use and be cognizant of emerging products.  相似文献   
96.
The content of acid proteins in nuclei of neurons and glial satellite cells in the medial preoptic region and supraoptic nucleus of the rat hypothalamus was studied by two-wave cytospectrophotometry on the 1st, 3rd, 7th, and 15th days of adaptation of the animal to cold (temperature 2–4°C). Cooling led to an initial decrease in the content of nuclear proteins in the whole neuronal-neuroglial system of the medial preoptic region, followed by gradual restoration to normal by the 15th day of cooling. In the glial cells of this region, before the return to normal there was a temporary increase in the content of acid proteins above the control level. In the neuronal-neuroglial system of the supraoptic nucleus a gradual accumulation of acid proteins was followed by a return to the control level. By the 15th day of the rats' stay in the cold, the content of neuronal and glial acid proteins of this nucleus fell somewhat below the control level.Department of Biochemistry, Rostov-on-Don University. Laboratory of Functional Neurochemistry, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 8, pp. 187–190, August, 1978.  相似文献   
97.
Hemoglobin M equon beta 41 (C7) phenylalanine leads to tyrosine   总被引:1,自引:0,他引:1  
A severe hemolytic crisis was observed in a 34-yr-old female of English- Irish extraction following a viral illness treated with acetaminophen. Heinz bodies and heat instability were present only during a transient hemolytic event. A challenge dose of acetaminophen caused no detectable hematologic abnormality. Structural studies of the hemoglobin during hemolysis and again after complete recovery localized the abnormality to tryptic peptide beta Tp-5, and automated sequencing of I 125-labeled beta chains indicated a replacement of phenylalanine (C7) beta 41 by tyrosine. Substitution of the next residue, phenylalanine (CD1) beta 42 by serine (Hb Hammersmith), has resulted in chronic severe Heinz body hemolytic anemia. The lack of chronic anemia in the present disorder may reflect the different relationships of beta41 and beta 42 and/or the similarities in volume and hydrophobicity of tyrosine and phenylalanine. It is suggested that substitution of tyrosine for phenylalanine in Hb Mequon may disturb the critical environment around the heme group and render it susceptible to oxidative denaturation in the presence of infections and/or drugs.  相似文献   
98.

INTRODUCTION

This is a 7-year retrospective review summarising the North of England Bone and Soft Tissue Tumour Service''s experience of managing 13 cases of groin sarcoma requiring soft tissue flap reconstruction. This study was performed to try to identify where national referral guidelines in sarcoma management had been followed and reasons for any delays. The study also includes outcome data relating to these patients.

PATIENTS AND METHODS

A retrospective, case-note review was undertaken using the local sarcoma database to identify approriate patients.

RESULTS

In nine patients, national referral guidelines were not followed. This resulted in a mean delay of presentation to the multidisciplinary team of 4.4 months. Ten patients had unplanned excision or exploration of tumours before referral. There were no lower limb amputations. All patients with narrow margins or high grade tumours were referred for radiotherapy. Four patients died; three as a result of distant metastases and one as a result of local recurrence.

CONCLUSIONS

Despite delays in referral, treatment by wide excision and plastic surgical reconstruction allowed for local control of these tumours with functional limb salvage. Implementation of National Institute for Health and Clinical Excellence (NICE) guidelines and local strategies could improve the expedient management of these patients.  相似文献   
99.
The purpose of our prospective study is to evaluate the surgical outcome among patients aged 80 years and above, who underwent surgery for lumbar spinal stenosis. We assessed patients’ clinical and demographic data, procedures, perioperative complications, preoperative and postoperative pain intensity, basic activities of daily living (BADL), patients’ satisfaction, the need for repeated surgery, and overall mortality. Thirty-nine patients more than 80 years of age were operated in our institution in the last decade. Twenty-five of them were followed-up with a mean 36.8 months after the operation. The Barthel index was used to evaluate pre and postsurgery ADL, and the visual analogue scale (VAS) was used to evaluate pain. The satisfaction rate of the patients before and after the operation and the complication rate were also evaluated. A significant reduction in VAS (P < 0.001) and a significant increase in the Barthel index (P < 0.001) were recorded. Seventy-six percent of the patients were very satisfied or somewhat satisfied with the operative results. Fifty-two percent of the patients had complications (0.9 complications per patients), however, about half of them were minor. No operative or perioperative mortality was noticed and the overall hospital stay for these elderly patients was 3.6 days on average. Surgery in very old elderly patients is safe and effective in the treatment of spinal stenosis, who did not respond well to the conservative treatment. The surgery did not increase the associated morbidity and mortality and most of the patients benefited from the surgery in terms of reduction in pain, increase in ADL and walking ability and overall increase in the satisfaction rate. An erratum to this article can be found at  相似文献   
100.
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