全文获取类型
收费全文 | 1878篇 |
免费 | 3篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 23篇 |
金属工艺 | 2篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
能源动力 | 2篇 |
轻工业 | 5篇 |
水利工程 | 1篇 |
无线电 | 19篇 |
一般工业技术 | 13篇 |
冶金工业 | 1801篇 |
原子能技术 | 2篇 |
自动化技术 | 7篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 1篇 |
2011年 | 4篇 |
2010年 | 1篇 |
2007年 | 10篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 7篇 |
1999年 | 57篇 |
1998年 | 601篇 |
1997年 | 301篇 |
1996年 | 205篇 |
1995年 | 86篇 |
1994年 | 84篇 |
1993年 | 105篇 |
1992年 | 12篇 |
1991年 | 30篇 |
1990年 | 24篇 |
1989年 | 26篇 |
1988年 | 21篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 27篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 9篇 |
1980年 | 18篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 41篇 |
1976年 | 91篇 |
1975年 | 5篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1962年 | 1篇 |
1955年 | 1篇 |
1928年 | 2篇 |
排序方式: 共有1881条查询结果,搜索用时 15 毫秒
91.
EL Lee MJ Robinson ML Thong SD Puthucheary TH Ong KK Ng 《Canadian Metallurgical Quarterly》1977,91(6):991-995
All of 16 infants with neonatal meningitis treated during a 30-month period were found to have accompanying ventriculitis at the time of the initial ventricular puncture. Fifteen of these infants were caused by gramm-negative organisms. All infants received antibiotics systemically and intraventricularly via an implanted ventriculostomy reservoir or by direct ventricular injection. Antibiotic concentrations within the ventricular fluid were monitored during chemotherapy; the complications encountered during treatment are discussed. Fifteen infants survived the infection; of these, seven infants were normal at follow-up examinations. In our experience intraventricular chemotherapy as an adjunct to systemic administration of antibiotics has greatly reduced the mortality rate in neonatal meningitis. 相似文献
92.
A reduction of red cell SA in patients following acute myocardial infarction is reported and the effects of SA-depleted red cells on cardiac index and alveolar capillary blood flow in the dog are described. The mean red cell SA in 26 patients following acute myocardial infarction was 0.021 +/- 0.001 compared with a mean of 0.031 +/- 0.002 mumol./0.1 ml RBC in 12 normal subjects (p less than 0.01). In five dogs injected with neuraminidase, an enzyme which removes SA from the red cell membrane, a 43% decrease in mean cardiac index from 2.3 +/- 0.22 to 1.3 +/- 0.16 (p less than 0.01) occurred. In films of the pulmonary microcircuation the mean widths of typical alveolar capillary beds decreased 42.6% +/- 5% (p less than 0.01). In three other dogs, autotransfusion with SA-depleted stored blood resulted in a 25% decrease in mean cardiac index from 2.0 +/- 0.21 to 1.5 +/- 0.21 (p less than 0.2), and a 21.7% +/- 0.9% (p less than 0.01) decrease in mean widths of typical alveolar capillary beds. We conclude that a reduction of red cell SA follows acute myocardial infarction and that SA-depleted red cells decrease cardiac index and alveolar capillary blood flow in the dogs. 相似文献
93.
The effects of feeding diest containing either cholesterol (0.24% w/w) or cholestyramine (2.5% w/w) and of fasting on sterol synthesis in the liver, ileum, and lung of both male and female guinea pigs have been studied by measuring the incorporation by tissue slices of 14C-labeled acetate into total digitoninpredipitable sterols. Cholesterol feeding significantly decreased (P less than 0.05) sterol synthesis in the liver, ileum, and lung of the males and in the ileum of females. Cholestyramine feeding stimulated the rate of hepatic sterol synthesis 13-fold but did not significantly affect sterologenesis in the ileum. Sterol synthesis in the lung was significantly increased (P less than 0.05) but to a much lesser extent than in the liver. Fatty acid synthesis in the liver, ileum, and lung was not significantly affected by either cholesterol or cholestyramine feeding. In guinea pigs fasted for 24 hr, sterol synthesis was inhibited in all three tissues, the most pronounced effect occurring in the liver. Only in the lung was fatty acid synthesis significantly decreased (P less than 0.001) by fasting. Cholesterol feeding resulted in increased concentrations of cholesterol in the plasma and liver. Cholestyramine feeding reduced plasma cholesterol concentration by 81% in females and by 64% in males. However, it did not significantly change the tissue cholesterol concentrations. Fasting resulted in a significant increase (P less than 0.05) in plasma cholesterol concentration but did not effect the concentration of cholesterol in the tissues. It was concluded that in the normal guinea pig, the feedback inhibition produced by both cholesterol and also possibly by bile acids suppresses sterol synthesis in the liver to very low rates compared to those in the small intestine, where sterologenesis is not only less sensitive to the cholesterol negative feedback system than that in the liver, but also is not subject to regulation by the bile acid negative feedback system. 相似文献
94.
Two cases of perforated diverticula of the terminal ileum are presented with a discussion of the literature. Primary resection is the treatment of choice. Asymptomatic diverticula discovered on routine contrast studies should not be managed surgically. 相似文献
95.
Jejunal villous changes associated with farmer's lung 总被引:1,自引:0,他引:1
TJ Robinson SD Nelson M Haire D Middleton SA McMillan JP Evans 《Canadian Metallurgical Quarterly》1981,57(673):697-701
96.
97.
98.
99.
In the present research, consisting of 2 correlational studies (N = 616) including a representative U.S. sample and 2 experiments (N = 350), the authors investigated how stereotypes and emotions shape behavioral tendencies toward groups, offering convergent support for the behaviors from intergroup affect and stereotypes (BIAS) map framework. Warmth stereotypes determine active behavioral tendencies, attenuating active harm (harassing) and eliciting active facilitation (helping). Competence stereotypes determine passive behavioral tendencies, attenuating passive harm (neglecting) and eliciting passive facilitation (associating). Admired groups (warm, competent) elicit both facilitation tendencies; hated groups (cold, incompetent) elicit both harm tendencies. Envied groups (competent, cold) elicit passive facilitation but active harm; pitied groups (warm, incompetent) elicit active facilitation but passive harm. Emotions predict behavioral tendencies more strongly than stereotypes do and usually mediate stereotype-to-behavioral-tendency links. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
100.
The accuracy of absolute quantitation within thick, mineralized tissue specimens is influenced by count rate variations of characteristic X-rays during electron microprobe analysis. The variations occur for electron doses approximately greater than 10(-10) C/micrometer2 and are primarily dependent upon the light element fraction within the irradiated volume. Specimen preparation procedures affect both count rate dynamics and interpretatin of microanalytical results. X-ray intensity data acquird at initial electron exposure and utilized in standard matrix correction schemes will project valid elemental concentrations for known calcium compounds over wide ranges of specimen density. Measurement error could approach +/- 2-3% for the major elemental constituents in mineralized tissues, but only with appropriate control or interpretation of electron irradiation phenomena. 相似文献