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   2477篇
  免费   8篇
电工技术   3篇
化学工业   48篇
金属工艺   2篇
机械仪表   12篇
建筑科学   17篇
能源动力   4篇
轻工业   30篇
水利工程   6篇
石油天然气   1篇
无线电   65篇
一般工业技术   67篇
冶金工业   2158篇
原子能技术   15篇
自动化技术   57篇
  2022年   3篇
  2021年   4篇
  2020年   2篇
  2018年   5篇
  2017年   2篇
  2016年   2篇
  2014年   7篇
  2013年   20篇
  2012年   7篇
  2011年   10篇
  2010年   7篇
  2009年   15篇
  2008年   18篇
  2007年   19篇
  2006年   21篇
  2005年   18篇
  2004年   15篇
  2003年   13篇
  2002年   15篇
  2001年   12篇
  2000年   13篇
  1999年   84篇
  1998年   643篇
  1997年   374篇
  1996年   221篇
  1995年   123篇
  1994年   114篇
  1993年   149篇
  1992年   26篇
  1991年   38篇
  1990年   34篇
  1989年   50篇
  1988年   40篇
  1987年   44篇
  1986年   42篇
  1985年   22篇
  1984年   6篇
  1983年   10篇
  1982年   7篇
  1981年   11篇
  1980年   11篇
  1979年   3篇
  1978年   6篇
  1977年   54篇
  1976年   116篇
  1975年   7篇
  1974年   5篇
  1973年   3篇
  1970年   2篇
  1955年   3篇
排序方式: 共有2485条查询结果,搜索用时 15 毫秒
71.
As patients with HIV/AIDS are living longer with the illness, pain and symptom management are increasingly important health issues. This article will discuss the assessment and management of such common problems as pain, fatigue and weakness, dyspnea and cough, anorexia and weight-loss, nausea and vomiting, sleep disorders, dry mouth, diarrhea, itching, and fever and night sweats.  相似文献   
72.
73.
74.
Eosinophilic myocarditis followed by fibrosis of the cardiac muscle was observed in addition to peripheral blood eosinophilia in CBA/J mice infected with Toxocara canis. The infected mice were used as an experimental model of eosinophilic endomyocarditis associated with hypereosinophilic syndrome. Effects of in vivo treatment with MoAbs to adhesion molecules on eosinophilic myocarditis were examined using this experimental model. Expressions of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on endothelial cells of capillaries in myocardium were increased 1 and 2 weeks after infection. Infiltration of very late antigen (VLA)-4+ and/or CD11a+ cells into the cardiac muscles was also observed 1 and 2 weeks after infection. Infiltration of eosinophils into the heart was significantly suppressed by anti-CD18 MoAb and anti-VLA-4 MoAb, and focal fibrosis of the cardiac muscle was also significantly suppressed by combined administration of anti-CD18 and anti-ICAM-1 MoAbs. These results indicate that adhesion molecules may play important roles in eosinophilic myocarditis, and that blockade of interaction between adhesion molecules and their ligands may help to control it.  相似文献   
75.
76.
A prospective study was performed to establish criteria for the microbiological diagnosis of prosthetic joint infection at elective revision arthroplasty. Patients were treated in a multidisciplinary unit dedicated to the management and study of musculoskeletal infection. Standard multiple samples of periprosthetic tissue were obtained at surgery, Gram stained, and cultured by direct and enrichment methods. With reference to histology as the criterion standard, sensitivities, specificities, and likelihood ratios (LRs) were calculated by using different cutoffs for the diagnosis of infection. We performed revisions on 334 patients over a 17-month period, of whom 297 were evaluable. The remaining 37 were excluded because histology results were unavailable or could not be interpreted due to underlying inflammatory joint disease. There were 41 infections, with only 65% of all samples sent from infected patients being culture positive, suggesting low numbers of bacteria in the samples taken. The isolation of an indistinguishable microorganism from three or more independent specimens was highly predictive of infection (sensitivity, 65%; specificity, 99.6%; LR, 168.6), while Gram staining was less useful (sensitivity, 12%; specificity, 98%; LR, 10). A simple mathematical model was developed to predict the performance of the diagnostic test. We recommend that five or six specimens be sent, that the cutoff for a definite diagnosis of infection be three or more operative specimens that yield an indistinguishable organism, and that because of its low level of sensitivity, Gram staining should be abandoned as a diagnostic tool at elective revision arthroplasty.  相似文献   
77.
78.
The computations performed within cortex are likely to be determined by its internal dynamics in addition to its pattern of afferent input. As a step toward characterizing these dynamics, we have imaged electrical activity in slices from rat primary visual cortex stained with the voltage-sensitive dye di-4-ANEPPS. In response to electrical stimulation two fluorescence signals of similar maximum amplitude are elicited, (i) A fast signal that peaks in a few milliseconds, is dependent on membrane voltage, and has a significant presynaptic component. This signal can be used to image electrical activity ratiometrically. (ii) A slow signal that peaks a few seconds after stimulation, does not reflect voltage changes, and may originate from changes in scattering properties of the slice and from interactions of the dye with the cells. The spatial pattern of fast signals obtained in response to focal stimulation of coronal slices is consistent with known interlaminar projection patterns. In tangential slices, imaging of fast signals reveals clustered horizontal responses. Finally, imaging of fast signals during epileptiform activation of the disinhibited circuit reveals propagating responses, without evidence for modular activation.  相似文献   
79.
80.
Laparoscopically assisted vaginal hysterectomy   总被引:1,自引:0,他引:1  
OBJECTIVE: To report our experience with laparoscopically assisted vaginal hysterectomy (LAVH) and evaluate the advantages of LAVH. STUDY DESIGN: From January 1991 to August 1992, 176 LAVHs were performed at the Department of Obstetrics and Gynecology, College of Medicine, Chung-Ang University, Seoul, Korea. The indications for LAVH, based on the preoperative diagnosis, were uterine myomas, dysmenorrhea, chronic pelvic inflammatory disease or pelvic pain, dysfunctional uterine bleeding and cervical intraepithelial neoplasia (in order of frequency). RESULTS: Patients had concomitant procedures, including incidental appendectomy, posterior wall repair, pelvic adhesiolysis and salpingo-oophorectomy. Bipolar forceps were used to compress and desiccate vessels. The Nd-YAG laser, scissors and/or unipolar electrode were used for tissue division, excision of adhesions and cutting. The intraoperative complications were bladder perforation, massive hemorrhage and inferior epigastric vessel injury (one case each). The postoperative complications were infection, voiding difficulty, febrile morbidity, pelvic abscess, incisional hernia, vaginal vault bleeding and peroneal nerve palsy (one case each). CONCLUSION: Hysterectomy can be safely performed vaginally assisted by operative laparoscopy by well-trained laparoscopists, resulting in reduced surgical morbidity, blood loss, postoperative discomfort, recovery time and hospitalization.  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