全文获取类型
收费全文 | 2772篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 17篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 5篇 |
能源动力 | 5篇 |
轻工业 | 22篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 26篇 |
一般工业技术 | 24篇 |
冶金工业 | 2639篇 |
自动化技术 | 16篇 |
出版年
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2014年 | 1篇 |
2013年 | 8篇 |
2012年 | 2篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 11篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 79篇 |
1998年 | 806篇 |
1997年 | 470篇 |
1996年 | 295篇 |
1995年 | 152篇 |
1994年 | 145篇 |
1993年 | 155篇 |
1992年 | 28篇 |
1991年 | 35篇 |
1990年 | 34篇 |
1989年 | 44篇 |
1988年 | 38篇 |
1987年 | 33篇 |
1986年 | 28篇 |
1985年 | 30篇 |
1984年 | 2篇 |
1983年 | 9篇 |
1982年 | 17篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 4篇 |
1978年 | 11篇 |
1977年 | 59篇 |
1976年 | 180篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
1968年 | 1篇 |
1960年 | 1篇 |
1957年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有2775条查询结果,搜索用时 10 毫秒
111.
JR Blair-West DA Denton MI McBurnie RS Weisinger 《Canadian Metallurgical Quarterly》1996,60(2):481-487
The Banff classification of acute rejection is based on histologic grades and scores for borderline changes, glomerular, vascular, interstitial and tubular lesions. We reviewed 56 episodes of acute rejection occurring in 44 kidney allograft recipients (30 cadaveric and 14 living donor transplants), comparing Banff classification to degree of reversibility of rejection. Rejection reversal was defined as complete if serum creatinine returned < or = 25% of baseline, partial if creatinine was > 25% to < 75% of baseline, and irreversible if creatinine was > or = 75% of baseline or graft loss occurred. Eight biopsies were classified as borderline (SUM score 1.6 +/- 0.5), 14 grade I (SUM score 3.3 +/- 0.4), 19 grade II (SUM score 4.2 +/- 0.3), and 15 grade III (SUM score 8.5 +/- 0.4). SUM distinguished borderline and grade III rejections, but not grades I and II. Clinically, grade and SUM score correlated with rejection reversal. Complete reversal of rejection occurred in 93% of patients with grade I rejection, while 47% of patients with grade III had irreversible rejection. The mean SUM for complete reversal was 3.9 +/- 0.34 and was different from SUM of partial (6.0 +/- 0.86) and irreversible (8.5 +/- 0.93), P < 0.006. Meanwhile, vascular scores were similar for rejections with complete (0.9 +/- 0.2) or partial (1.0 +/- 0.4) reversal, but significantly higher in those with irreversible rejection (3.0 +/- 0.4, P < 0.000). Likewise, mean scores for tubulitis and interstitial inflammation were significantly higher for irreversible rejection. Resolution of rejection by steroids was correlated to low vascular score (steroid sensitive 0.65 +/- 0.25 vs. steroid resistant 1.42 +/- 0.18, P < 0.01), and low SUM score (steroid sensitive 3.7 +/- 0.5 vs. steroid resistant 5.22 +/- 0.43, P < 0.04). Neither scores for tubulitis nor interstitial cellular inflammation were predictive of steroid sensitivity. These data demonstrate that Banff scoring has clinical relevance in predicting rejection reversal and has implications to first-line therapy of rejection episodes. 相似文献
112.
RS Beaser 《Canadian Metallurgical Quarterly》1998,69(11):711-725
BACKGROUND: Diabetes is a significant cause for morbidity and mortality in developed countries. Current diabetes treatment goals involve more than normalizing glucose levels and preventing the acute effects of high or low glucose levels. RESULTS: People with diabetes are hospitalized 1.5 to 3 times more often than people who do not have diabetes, have 2 to 4 times greater risk of atherosclerotic disease, and have the highest incidence of adult blindness, chronic renal failure, and nontraumatic amputations. CONCLUSION: The challenge that faces clinicians who care for people with diabetes is to prevent--or at least attenuate--the effects of the chronic complications of this disease. 相似文献
113.
MD Rugg PC Fletcher CD Frith RS Frackowiak RJ Dolan 《Canadian Metallurgical Quarterly》1997,8(5):1283-1287
Regional brain activity associated with intentional and incidental memory retrieval was studied with PET. Previously studied and new words were presented in either an intentional or an incidental memory task. Type of task was crossed with an encoding manipulation ('deep' vs 'shallow') which varied the probability that studied items would be remembered. In both tasks, deeply encoded items were associated with greater activation in the left hippocampus than were items that had received shallow encoding, suggesting that the involvement of the hippocampus in memory retrieval is independent of whether remembering is intentional or incidental. Right prefrontal and bilateral parietal cortex were more activated during the international task than during the incidental task, irrespective of encoding condition. Thus, these regions play a more extensive role in memory retrieval when remembering is intentional. 相似文献
114.
115.
Tolcapone (Ro 40-7592) is a novel inhibitor of catechol-O-methyltransferase that is being developed for clinical use in the treatment of Parkinson's disease as add-on therapy to a combination of levodopa and a peripheral amino acid decarboxylase inhibitor (benserazide or carbidopa). The current single-blind, randomized study was designed to evaluate the effect of tolcapone compared with placebo on plasma levodopa concentrations in healthy volunteers concomitantly receiving 25 mg of carbidopa and 100 mg of levodopa (Sinemet 25-100) and to assess the tolerability and safety of this combination. Placebo or tolcapone at doses of 5, 10, 25, 50, 100, 200, 400, and 800 mg was coadministered orally with Sinemet 25-100. Each dose was tested in a crossover fashion in a new group of six participants who each received active drug on one occasion and placebo on the other. Tolcapone increased the area under the plasma concentration-time curve and half-life of levodopa approximately twofold, without appreciably increasing the peak concentration. The maximum effect on levodopa half-life was observed with the 200-mg dose. Adverse effects were minor at all doses. 相似文献
116.
Adult male rats of wistar strain were fed diets containing (w/w) 2% garlic (group II), 0.5% ginger (group III) and a combination of garlic plus ginger (group IV) for 4 weeks to study their effects on serum biochemical parameters. A significant increase in body weight was observed in all groups except that fed ginger (group III). A significant decrease in blood glucose, serum total cholesterol and serum alkaline phosphatase were found in all groups, whereas serum triglycerides were decreased significantly only in group IV. Serum HDL-cholesterol was significantly increased only in groups III and IV. However, HDL-cholesterol, VLDL-cholesterol and atherogenic index were significantly decreased in animals fed with combination of the two, compared to garlic/ginger alone. Hence, a combination of garlic and ginger is much more effective in reducing blood glucose and serum lipids. 相似文献
117.
118.
OBJECTIVE: To determine, among dogs with urolithiasis, whether dogs that had hyperadrenocorticism would be more likely to have calcium-containing uroliths than would dogs that did not have clinical evidence of hyperadrenocorticism. DESIGN: Retrospective case-control study. ANIMALS: 20 dogs that had urolithiasis and hyperadrenocorticism and 42 breed-matched dogs that had urolithiasis but did not have clinical evidence of hyper-adrenocorticism. PROCEDURE: Signalment, urolith composition, results of bacterial culture of urine, and results of adrenal axis tests were recorded. A multivariate logistic regression model was created, including terms for age, sex, and hyperadrenocorticism. The outcome variable was presence or absence of calcium-containing uroliths. RESULTS: Among dogs with urolithiasis, those that had hyperadrenocorticism were 10 times as likely to have calcium-containing uroliths as were dogs that did not have clinical evidence of hyperadrenocorticism (odds ratio, 10.5; 95% confidence interval, 1.5 to 23.4). Neutered and sexually intact females were less likely to have calcium-containing uroliths than were neutered males (odds ratios, 0.041 [95% confidence interval, 0.0057 to 0.29] and 0.024 [95% confidence interval, 0.0012 to 0.51, respectively). CLINICAL IMPLICATIONS: Prompt diagnosis and treatment of hyperadrenocorticism may decrease prevalence of calcium-containing uroliths in dogs. 相似文献
119.
120.