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   7151篇
  免费   24篇
  国内免费   2篇
电工技术   5篇
综合类   1篇
化学工业   90篇
金属工艺   10篇
机械仪表   11篇
建筑科学   3篇
能源动力   11篇
轻工业   42篇
水利工程   5篇
石油天然气   4篇
无线电   78篇
一般工业技术   110篇
冶金工业   6735篇
原子能技术   3篇
自动化技术   69篇
  2023年   8篇
  2022年   23篇
  2021年   33篇
  2020年   15篇
  2019年   25篇
  2018年   21篇
  2017年   23篇
  2016年   19篇
  2015年   13篇
  2014年   21篇
  2013年   30篇
  2012年   17篇
  2011年   31篇
  2010年   21篇
  2009年   10篇
  2008年   7篇
  2007年   14篇
  2006年   9篇
  2005年   5篇
  2004年   10篇
  2003年   18篇
  2002年   5篇
  2001年   2篇
  2000年   7篇
  1999年   216篇
  1998年   2309篇
  1997年   1285篇
  1996年   818篇
  1995年   426篇
  1994年   341篇
  1993年   423篇
  1992年   40篇
  1991年   47篇
  1990年   53篇
  1989年   47篇
  1988年   54篇
  1987年   56篇
  1986年   55篇
  1985年   38篇
  1984年   2篇
  1983年   18篇
  1982年   24篇
  1981年   30篇
  1980年   61篇
  1979年   4篇
  1978年   13篇
  1977年   138篇
  1976年   277篇
  1975年   11篇
  1955年   3篇
排序方式: 共有7177条查询结果,搜索用时 31 毫秒
91.
92.
In April 1991, 91 hospitalized patients in Cairo were reported to the Egyptian Ministry of Health with botulism intoxication. To define the spectrum of illness and identify a food vehicle, 45 patients were interviewed and a case-control investigation was conducted among families of 5 hospitalized patients. Clinical specimens and specimens of implicated food were tested for toxin and cultured for Clostridium botulinum. Hospitalized patients had symptoms consistent with botulism; 18 (20%) of 91 reported patients died. Illness was associated with eating faseikh (uneviscerated, salted mullet fish; lower 95% confidence limit of odds ratio = 6.6, P < .001). All 5 case-families purchased faseikh from one shop. Very high levels of type E botulinal toxin were detected in faseikh reported to be purchased from the implicated shop; C. botulinum type E was isolated from cultures of clinical specimens and from the faseikh. This is the first documented outbreak of botulism in Egypt and the largest type E outbreak ever reported.  相似文献   
93.
94.
95.
96.
OBJECTIVES: Antral gastritis is frequent in alcoholics. The role of H. pylori in the pathogenesis of gastritis in these patients is not well known. The aim of our study was to study the role of H. pylori and cirrhosis in the pathogenesis of antral gastritis in alcoholic patients. METHODS: Seventy-nine patients were included in the study. All underwent upper gastrointestinal tract endoscopy with antral biopsies, independently of the presence of abdominal pain, and had serological examination for H. pylori antibodies. RESULTS: Cirrhosis and gastritis were present in 50 and 40 patients respectively, H. pylori serological assay and histological identification of the bacterium were positive in 35 (44%) and 19 (24%) patients respectively. Discrepancy between the 2 tests were observed more frequently in cirrhotic patients. A positive serology with a negative histologic examination for H. pylori was present for 18 cirrhotic and 4 noncirrhotic patients (p < 0.05). A gastritis without evidence of H. pylori was more frequent in cirrhotic than in noncirrhotic patients. H. pylori was histologically present in 11 of 29 cirrhotic patients and in 8 of the 11 noncirrhotic patients with a gastritis (p < 0.05). CONCLUSIONS: Discrepancies between histological examination and H. pylori serology in patients with cirrhosis might be due to the inhospitable environment for H. pylori in case of portal hypertension; the positive serology could be in relation with a past infection.  相似文献   
97.
PURPOSE: To demonstrate a superselective intraarterial chemotherapy as a therapeutic alternative in the treatment of previously treated recurrent lymph node metastases in breast cancer. METHODS: 14 patients with recurrent lymph node metastases in cases of breast cancer were presented to be treated by intraarterial chemotherapy of 25 mg mitoxantrone/m2 over a period of 24 hours. In two patients with superclavicular lymph node involvement an intraarterial therapy could not be carried out because of a vascular connection to the anterior spinal artery. Involved lymph stations could be reached in superselective technique by side branches of the subclavian artery. Heparin coverage was given intravenously. Every patient had had surgery, radiation, systemic chemo- and hormonal therapy before and was now graded as inoperable. Therapy indication was given by local tumour-induced symptoms. RESULTS: In the 12 treated cases complete remission was seen in three, partial remission in 4, a steady state in two and a progressive disease in three. There were no complications or severe side effects. CONCLUSION: Intraarterial chemotherapy is an effective and well tolerated treatment in recurrent lymph node metastases in cases of breast cancer even if conventional therapies can no longer be used.  相似文献   
98.
99.
We have identified 79 mutations in BRCA1 in a set of 643 Dutch and 23 Belgian hereditary breast and ovarian cancer families collected either for research or for clinical diagnostic purposes. Twenty-eight distinct mutations have been observed, 18 of them not previously reported and 12 of them occurring more than once. Most conspicuously, a 2804delAA mutation has been found 19 times and has never been reported outside the Netherlands. A common haplotype spanning > or = 375 kb could be identified for each of the nine examined recurrent mutations, indicating the presence of multiple BRCA1 founder mutations in the Dutch population. The 2804delAA mutation has been estimated to have originated approximately 32 generations ago. No specific breast or ovarian cancer phenotype could be assigned to any of the common mutations, and the ovarian cancer incidence among 18 families with the 2804delAA mutation was heterogeneous.  相似文献   
100.
The author describes a patient who has a successful coronary artery bypass. Six weeks later, after a physical examination of the chest, she had unbearable sharp, stabbing pain around the incision which was not responding to nerve blocks, analgesics, nonsteroidal anti inflammatory agents, and epidural blocks. The pain was responsive to mexilitine and disappeared after three weeks of treatment.  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