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   5553篇
  免费   3篇
  国内免费   1篇
电工技术   2篇
综合类   2篇
化学工业   29篇
建筑科学   5篇
轻工业   7篇
水利工程   1篇
无线电   9篇
一般工业技术   59篇
冶金工业   5419篇
原子能技术   3篇
自动化技术   21篇
  2013年   3篇
  2012年   3篇
  2011年   13篇
  2010年   2篇
  2009年   3篇
  2008年   6篇
  2007年   5篇
  2006年   14篇
  2005年   11篇
  2004年   10篇
  2003年   8篇
  2002年   12篇
  2001年   2篇
  2000年   5篇
  1999年   165篇
  1998年   1671篇
  1997年   921篇
  1996年   585篇
  1995年   334篇
  1994年   294篇
  1993年   311篇
  1992年   41篇
  1991年   61篇
  1990年   70篇
  1989年   61篇
  1988年   69篇
  1987年   69篇
  1986年   56篇
  1985年   65篇
  1984年   3篇
  1983年   13篇
  1982年   28篇
  1981年   31篇
  1980年   54篇
  1979年   6篇
  1978年   16篇
  1977年   158篇
  1976年   343篇
  1975年   7篇
  1973年   4篇
  1972年   3篇
  1963年   2篇
  1960年   1篇
  1959年   1篇
  1955年   5篇
  1947年   1篇
  1946年   1篇
  1941年   1篇
  1934年   1篇
  1933年   2篇
排序方式: 共有5557条查询结果,搜索用时 15 毫秒
1.
2.
When radiation is used to treat nervous system cancer, exposure of adjacent normal nervous system tissue is unavoidable, and radiation-induced injury may occur. Acute injury is usually mild and transient, but late forms of radiation-induced nervous system injury are usually progressive and debilitating. Treatment with corticosteroids, surgery, and antioxidants is often ineffective. We treated 11 patients with late radiation-induced nervous system injuries (eight with cerebral radionecrosis, one with a myelopathy, and two with plexopathies, all unresponsive to dexamethasone and prednisone) with full anticoagulation. Some recovery of function occurred in five of the eight patients with cerebral radionecrosis, and all the patients with myelopathy or plexopathy. Anticoagulation was continued for 3 to 6 months. In one patient with cerebral radionecrosis, symptoms recurred after discontinuation of anticoagulation and disappeared again after reinstitution of treatment. We hypothesize that anticoagulation may arrest and reverse small-vessel endothelial injury--the fundamental lesion of radiation necrosis--and produce clinical improvement in some patients.  相似文献   
3.
PURPOSE: We describe a new method of using a Foley catheter to assist vesicourethral anastomosis during radical retropubic prostatectomy. MATERIALS AND METHODS: A total of 81 patients underwent radical retropubic prostatectomy with this technique. Followup ranged from 4 to 48 months. Peri-catheter urethrograms were performed at 3 weeks. Patients were evaluated specifically for bladder neck contracture, urinary continence and prolonged catheterization. RESULTS: Bladder neck contracture, occurred in 4.9% of the patients and 87.6% were completely continent of urine. Only 1 patient required extended postoperative catheterization. CONCLUSIONS: Use of a Foley catheter for vesicourethral anastomosis is consistent and simple, and provided good surgical results in our experience.  相似文献   
4.
5.
Although jejunal atresia occasionally may occur with a familial pattern, an association with renal disease has not been described. The authors report on three family members treated over two generations, all of whom had both proximal jejunal atresia and renal dysplasia. This association was most likely inherited as an autosomal dominant trait.  相似文献   
6.
7.
The objective of this study was to determine whether differential labeling of 13C occurs in pigs fed diets with different 13C abundances and, if so, to use 13C as a label to determine true amino acid digestibility. Forty-eight pigs averaging 10.5 kg BW were fed dietary treatments consisting of a corn-corn gluten meal-crystalline amino acid diet (C-CGM) and a wheat-soybean meal diet (W-SBM). The 13C abundance of the amino acid fraction (AAF) of the C-CGM and W-SBM diets averaged delta 13C -14.19 and -26.36/1000, respectively. Three pigs/treatment group were killed when groups averaged 10.5 (initial), 22.9, and 46.6 kg BW, and AAF of organs were analyzed for 13C abundance. Carbon 13 in empty body AAF increased (-18.14, -13.98, and -12.66/1000) with increasing body weight in pigs fed the C-CGM diet and decreased (-18.06, -22.78, and -24.76/1000) in pigs fed the W-SBM diet. Liver, small intestine, and longissimus muscle tissues showed similar trends. Each tissue had dietary treatment effects (P < .001) and dietary treatment x weight group (P < .001) interactions. Ten pigs averaging 55.0 kg BW from each treatment group were assigned to metabolism cages and fed at 0700 and 1900. Six of these pigs from each treatment group were implanted with T-cannulas in the ileum and given a 17-d recovery period. At 1900 on d 0 of the collection phase, pigs were switched to the opposite diet that contained chromic oxide.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
8.
A case of Macrozamia riedlei seed poisoning is described in a young Dachshund. Vomiting and depression commenced within 6 h of ingestion; other signs that developed included severe hepatopathy, jaundice, abdominal pain that was unresponsive to analgesics, severe gastro-intestinal haemorrhage and thrombocytopenia as well as crystalluria and marrow dyserythropoiesis. The dog was euthanased 6 days after ingestion of the seeds.  相似文献   
9.
A role for endogenous histamine and its H3 receptor subtype for mediating drinking elicited by eating was examined in adult male Sprague-Dawley rats. The i.p. injection of the H3 agonist R-alpha-methylhistamine (Ramh, 2.5 mg/kg) shortened the latency to initiate drinking and increased 1-h water intake in nondeprived rats freely eating pellets and drinking water. The ICV injection (through a surgically implanted chronic cannula) of 10 micrograms Ramh increased water intake; this Ramh-induced drinking was abolished by previous ICV injection of the H3 antagonist thioperamide (Th, 60 micrograms). For rats drinking and eating after 24-h food deprivation, s.c. Th inhibited drinking behavior: for example, 10 mg/kg Th s.c. delayed the latency to initiate drinking and inhibited 1-h water intake without inhibition of food intake. In contrast, 60 micrograms Th ICV failed to inhibit food-related drinking in rats eating after food deprivation. For nondeprived rats eating a small cracker, 10 mg/kg Th s.c. delayed the latency to initiate drinking and abolished water intake without effect of eating, and 60 micrograms Th ICV had similar effects upon drinking elicited by ingestion of cracker. The IG infusion (through a surgically implanted gastric catheter) of 2 ml 600 or 900 mOsm/kg NaCl, a treatment that is subthreshold for increase in systemic plasma osmolality at the initiation of drinking, elicited drinking that was abolished by 10 mg/kg Th s.c. and attenuated by 60 micrograms Th ICV. The IG infusion of 2 ml 1800 mOsm/kg NaCl, a treatment that is above threshold for increase in systemic plasma osmolality, elicited drinking that was attenuated by 10 mg/kg s.c. or 60 micrograms Th ICV. These results demonstrate that peripheral and central H3 receptors for histamine have a role in drinking elicited by eating and the postprandial gastrointestinal osmotic consequences of eating. These findings extend the evidence demonstrating a histaminergic contribution to food-related drinking in rats.  相似文献   
10.
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