全文获取类型
收费全文 | 7002篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
综合类 | 6篇 |
化学工业 | 105篇 |
金属工艺 | 4篇 |
机械仪表 | 8篇 |
建筑科学 | 36篇 |
矿业工程 | 3篇 |
能源动力 | 17篇 |
轻工业 | 56篇 |
水利工程 | 10篇 |
石油天然气 | 2篇 |
无线电 | 98篇 |
一般工业技术 | 121篇 |
冶金工业 | 6432篇 |
原子能技术 | 4篇 |
自动化技术 | 102篇 |
出版年
2021年 | 7篇 |
2019年 | 6篇 |
2017年 | 3篇 |
2016年 | 9篇 |
2015年 | 4篇 |
2013年 | 33篇 |
2012年 | 20篇 |
2011年 | 22篇 |
2010年 | 19篇 |
2009年 | 16篇 |
2008年 | 18篇 |
2007年 | 23篇 |
2006年 | 17篇 |
2005年 | 22篇 |
2004年 | 12篇 |
2003年 | 38篇 |
2002年 | 21篇 |
2001年 | 13篇 |
2000年 | 17篇 |
1999年 | 226篇 |
1998年 | 2059篇 |
1997年 | 1121篇 |
1996年 | 818篇 |
1995年 | 431篇 |
1994年 | 352篇 |
1993年 | 394篇 |
1992年 | 51篇 |
1991年 | 96篇 |
1990年 | 55篇 |
1989年 | 74篇 |
1988年 | 65篇 |
1987年 | 69篇 |
1986年 | 73篇 |
1985年 | 59篇 |
1984年 | 8篇 |
1983年 | 10篇 |
1982年 | 34篇 |
1981年 | 47篇 |
1980年 | 75篇 |
1979年 | 17篇 |
1978年 | 21篇 |
1977年 | 146篇 |
1976年 | 323篇 |
1975年 | 16篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1972年 | 7篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1955年 | 5篇 |
排序方式: 共有7011条查询结果,搜索用时 15 毫秒
1.
Electronic BITE is poor at identifying hardware failure and in present design approaches tends to create the reviled ‘unconfirmed failure’. A different approach to BITE and unconfirmed failure could improve both operational performance and the cost of maintenance. 相似文献
2.
As an alternative to surgical splenectomy, partial splenic embolization was performed in seven children for hypersplenism manifested by splenomegaly, thrombocytopenia, leukopenia, and erythrocyte hemolysis. Within a few days, platelet and leukocyte counts rose significantly in all patients and were maintained in six of seven patients during a follow-up period of 9 to 69 months. Spleen size and abdominal distention also decreased significantly in all children. There were no infectious complications. 相似文献
3.
4.
5.
6.
7.
8.
9.
We examined the ability of anti-human recombinant interleukin-2 (hu rIL-2) monoclonal antibody DMS-1.10 to increase serum half-life of hu rIL-2, and the effect of this complex on inhibition of tumor progression in a B16-F10 murine melanoma model. In C57B1/6 mice, intravenous (i.v.) injection of DMS-1.10 premixed with 1 x 10(4) units (U) of hu rIL-2 at a 1:1 molar ratio extended serum half-life greater than 10-fold (222 min) when compared to the same dose of hu rIL-2 alone (20 min). In a murine tumor model, multiple intraperitoneal (i.p.) injections of non-neutralizing DMS-1.10 premixed with hu rIL-2 at a 5:1 molar ratio reduced the growth rate of subcutaneous (s.c.) B16-F10 tumor in C57B1/6 mice by 64% when compared to PBS and irrelevant antibody treated controls. Although similar treatment with hu rIL-2 alone reduced tumor growth rate by 46%, it was significantly less effective than the premixed treatment. Results from a flow cytometry assay confirm B16-F10 does not have IL-2 receptors, precluding direct inhibition of tumor growth by hu rIL-2 treatments. We propose that therapeutic efficacy of hu rIL-2 is improved by prolonging the in vivo half-life with an anti-IL-2 antibody, thus augmenting hu rIL-2 bioactivity and enhancing the hosts immune response against tumor. 相似文献
10.
INTRODUCTION: The aim of the study was the evaluation of the usefulness of transesophageal atrial pacing in predicting chronic oral treatment efficacy of symptomatic reciprocating supraventricular tachycardia in infants and in avoiding the risk of very dangerous recurrences at home. METHODS: We studied 13 infants (11 males, 2 females, mean age 43 +/- 31 days) with symptomatic reciprocating supraventricular tachycardia and no structural heart disease. All patients had chronic oral therapy, using the drug effective in acute i.v. somministration. Each patient was discharged when supraventricular tachycardia was not inducible with transesophageal atrial pacing after 5 half-lives of the drug used in chronic oral treatment. All patients, every 6 months, were retested with transesophageal atrial pacing alternatively during chronic oral therapy and after complete wash out. Oral therapy was stopped in each patient when supraventricular tachycardia was not inducible after the wash out. RESULTS: The number of oral treatments tested for each patient were 2 +/- 1 (range 1-5). The number of transesophageal studies performed for each patient were 4 +/- 2 (range 3-7). No patient had symptomatic episodes of supraventricular tachycardia or needed to change therapy during the follow-up. The oral treatment was stopped after the twelfth month of life in 8 patients and after the twenty-fourth in 2 others without recurrences. CONCLUSION: Transesophageal atrial pacing seems to be useful in predicting accurately and rapidly the oral treatment efficacy of supraventricular tachycardia in infants. Our protocol seems to be effective to avoid dangerous recurrences of tachycardia and to decide when we can stop therapy without risk. 相似文献