全文获取类型
收费全文 | 555篇 |
免费 | 0篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 16篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
轻工业 | 5篇 |
无线电 | 7篇 |
一般工业技术 | 4篇 |
冶金工业 | 516篇 |
原子能技术 | 2篇 |
自动化技术 | 2篇 |
出版年
2021年 | 1篇 |
2020年 | 1篇 |
2016年 | 1篇 |
2014年 | 5篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2003年 | 1篇 |
2002年 | 2篇 |
1999年 | 17篇 |
1998年 | 150篇 |
1997年 | 87篇 |
1996年 | 57篇 |
1995年 | 28篇 |
1994年 | 22篇 |
1993年 | 32篇 |
1992年 | 5篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 14篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1977年 | 14篇 |
1976年 | 40篇 |
1975年 | 2篇 |
排序方式: 共有557条查询结果,搜索用时 15 毫秒
91.
JR Green JA Gibson GD Kerr ET Swarbrick AJ Lobo CD Holdsworth JP Crowe KJ Schofield MD Taylor 《Canadian Metallurgical Quarterly》1998,12(12):1207-1216
BACKGROUND: Despite widespread use of aminosalicylates as maintenance treatment for ulcerative colitis (UC), patients still report troublesome symptoms, often nocturnally. AIM: To compare the efficacy and safety of balsalazide (Colazide) with mesalazine (Asacol) in maintaining UC remission. METHODS: A randomized, double-blind comparison of balsalazide 3 g daily (1.04 g 5-ASA) and mesalazine 1.2 g daily for 12 months, in 99 (95 evaluable) patients in UC remission. RESULTS: Balsalazide patients experienced more asymptomatic nights (90% vs. 77%, P=0.0011) and days (58% vs. 50%, N.S.) during the first 3 months. Balsalazide patients experienced more symptom-free nights per week (6.4+/-1.7 vs. 4.7+/-2.8; P=0.0006) and fewer nights per week with blood on their stools or on the toilet paper, mucus with their stools or with sleep disturbance resulting from symptoms or lavatory visits (each P < 0.05). Fewer balsalazide patients relapsed within 3 months (10% vs. 28%; P=0.0354). Remission at 12 months was 58%, in both groups. Similar proportions of patients reported adverse events (61% balsalazide vs. 65% mesalazine). There were five serious adverse events (two balsalazide, three mesalazine) and four withdrawals due to unacceptable adverse events (three balsalazide, one mesalazine), of which one in each group was also a serious adverse event. CONCLUSIONS: Balsalazide 3 g/day and mesalazine 1.2 g/ day effectively maintain UC remission and are equally well tolerated over 12 months. At this dose balsalazide prevents more relapses during the first 3 months of treatment and controls nocturnal symptoms more effectively. 相似文献
92.
A Fagot-Campagna RG Nelson WC Knowler DJ Pettitt DC Robbins O Go TK Welty ET Lee BV Howard 《Canadian Metallurgical Quarterly》1998,41(9):1002-1009
Animal studies suggest that lipids are risk factors for kidney diseases. Some prospective studies and clinical trials have reported predictive effects of lipoproteins on different stages of diabetic nephropathy in humans. We examined lipoprotein abnormalities to determine if they predict abnormal urinary excretion of albumin (> or = 30 mg albumin/g creatinine), using logistic regression. We followed 671 American Indians (211 men, 460 women) with Type II diabetes for a mean of 3.9 years (range 1.7-6.2). Participants were aged 45-74 years. They had normal excretion of albumin and normal serum creatinine at baseline. 67 men and 144 women developed abnormal excretion of albumin. In models controlled for age, treatment with oral hypoglycaemic agents or insulin, HbA1c, study site, degree of Indian heritage, mean arterial blood pressure, albumin excretion at baseline and duration of diabetes, a high HDL cholesterol was a protector for abnormal excretion of albumin in women [odds ratio (OR) comparing the 90th with the 10th percentile = 0.56, 95% confidence interval (CI) = 0.32-0.98], but not in men (OR = 1.5, 95% CI = 0.66-3.4). Further adjustment for obesity, insulin concentration, alcohol consumption or physical activity did not change the results. There was a tendency for high values of VLDL and total triglyceride and small LDL size to predict abnormal excretion of albumin in women only. We conclude that low HDL cholesterol was a risk factor for abnormal excretion of albumin in women, but not in men. Sex hormones may be responsible for sex differences in the association between HDL cholesterol and abnormal excretion of albumin. 相似文献
93.
94.
ET Janson M Stridsberg A Gobl JE Westlin K Oberg 《Canadian Metallurgical Quarterly》1998,58(11):2375-2378
We have shown previously that expression of mRNA for somatostatin receptor subtype 2 (sst2) detected by in situ hybridization correlates to therapeutic outcome in patients with carcinoid tumors treated with somatostatin analogues. However, in situ hybridization is laborious and not practical in clinical routine work. We have, therefore, developed polyclonal antibodies directed against sst2 that may be used for immunohistochemistry on tissue specimens. The staining is specific and is highly correlated to expression of mRNA for sst2 (P < 0.01) as well as to tracer uptake at somatostatin receptor scintigraphy (P < 0.01). There is also a good correlation to the therapeutic response in carcinoid patients treated with somatostatin analogues (P < 0.05). Of 35 patients with carcinoid tumors included in this investigation, 25 stained positive with the antibodies. Twenty-two of these were investigated by somatostatin receptor scintigraphy and showed tracer uptake in metastases. An additional two patients that did not stain with the antibodies showed pathological uptake of the tracer in metastases, which might indicate binding to somatostatin receptor subtype 5. None of the 10 patients without positive immunostaining responded to somatostatin analogue treatment, whereas patients with a positive stain had a biochemical response or remained stable during treatment. Thus, these antibodies may be used to determine the presence of sst2 in carcinoid tumors and to select patients suitable for somatostatin analogue treatment. The method is easily applicable in clinical practice. 相似文献
95.
96.
HE Greenberg MJ England ET Hellriegel TD Bjornsson 《Canadian Metallurgical Quarterly》1997,37(6):480-485
The time of peak concentration after administration of oral drug is an often quoted and used pharmacokinetic parameter. It is not well appreciated, however, that the peak times after a single dose and a dose at steady state during a multiple administration regimen can differ significantly. This article derives the mathematical relationships that determine how a peak time at steady state differs from that after a single or first dose. These relationships are then evaluated using three different approaches: 1) graphic simulations of time courses of drug concentration for three hypothetical drugs; 2) comparisons of predicted and observed peak times using examples from the literature; and 3) comparisons of predicted and simulated peak times based on different sampling schedules for three hypothetical drugs. The key finding is that peak times after a dose at steady state can occur considerably earlier after administration than after a single dose. However, the manner by which peak times are usually determined, that is, the sampling time corresponding to the highest measured drug concentration, imposes significant limitations on the usefulness of this parameter. 相似文献
97.
98.
Viruses that establish persistent infections in their host, such as herpesviruses, adenoviruses or HIV, express proteins designed to pre-empt or evade recognition and elimination by MHC class I restricted CD8+ T lymphocytes. Notable discoveries during the annual period of review have demonstrated that, in principle, each single step within the MHC class I pathway of antigen processing and presentation is fair game for manipulation by viral functions. The viral factors that are natural inhibitors of this pathway have been instrumental for the elucidation of the distinct molecular mechanisms that are exploited by viruses. The viral stealth strategies that downregulate MHC class I protein surface expression may lead, however, to a higher susceptibility of virus-infected cells to natural killer cell activity. Strikingly, there is evidence that some viruses counteract increased natural killer cell recognition by expressing viral MHC class I homologues that function as surrogate inhibitors of natural killer cell activity. 相似文献
99.
100.
Efficacy of praziquantel (0.25 mg kg(-1)) on the cecal tapeworm (Anoplocephala perfoliata) in horses
Aspiration of inflorescence or grass heads (seed head of grasses) often presents with atypical signs and symptoms because grass heads have a tendency to rapidly migrate to the periphery of the lung. If this is not recognized, it can lead to delay in diagnosis and serious complications. Removal with rigid bronchoscopy maybe difficult, and surgery is often needed. We report a case of a seven-month-old child who had a delayed diagnosis of grass head aspiration and subsequently presented with a life threatening tension pneumothorax. This case highlights the importance of obtaining a detailed history in cases of foreign body aspiration and the need to include it in the differential diagnosis of unexplained respiratory symptoms, especially those of sudden onset in children. 相似文献