全文获取类型
收费全文 | 1176篇 |
免费 | 1篇 |
专业分类
电工技术 | 14篇 |
综合类 | 2篇 |
化学工业 | 142篇 |
金属工艺 | 66篇 |
机械仪表 | 37篇 |
建筑科学 | 10篇 |
矿业工程 | 6篇 |
能源动力 | 2篇 |
轻工业 | 5篇 |
水利工程 | 14篇 |
石油天然气 | 23篇 |
无线电 | 27篇 |
一般工业技术 | 166篇 |
冶金工业 | 553篇 |
原子能技术 | 90篇 |
自动化技术 | 20篇 |
出版年
2022年 | 14篇 |
2021年 | 22篇 |
2020年 | 11篇 |
2019年 | 10篇 |
2018年 | 17篇 |
2017年 | 18篇 |
2016年 | 17篇 |
2015年 | 8篇 |
2014年 | 20篇 |
2013年 | 16篇 |
2012年 | 25篇 |
2011年 | 23篇 |
2010年 | 15篇 |
2009年 | 18篇 |
2008年 | 20篇 |
2007年 | 25篇 |
2006年 | 21篇 |
2005年 | 17篇 |
2004年 | 17篇 |
2003年 | 10篇 |
2002年 | 15篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 24篇 |
1998年 | 149篇 |
1997年 | 84篇 |
1996年 | 81篇 |
1995年 | 42篇 |
1994年 | 42篇 |
1993年 | 30篇 |
1992年 | 16篇 |
1991年 | 19篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 23篇 |
1987年 | 17篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 17篇 |
1980年 | 16篇 |
1978年 | 11篇 |
1977年 | 25篇 |
1976年 | 53篇 |
1975年 | 14篇 |
1974年 | 16篇 |
1973年 | 9篇 |
1972年 | 10篇 |
1965年 | 4篇 |
排序方式: 共有1177条查询结果,搜索用时 15 毫秒
1.
2.
FL Kiselev 《Canadian Metallurgical Quarterly》1997,42(6):248-251
The migration of substances from rubber packaging materials into drug products can be significant with certain packaging materials in contact with organic solvent systems. Recommendations for testing drug products for leachables are continually evolving to address new developments. Testing packaging materials using simulated solvents is not always an acceptable protocol for the pharmaceutical industry. We describe a rational strategy for evaluation of the drug product for packaging extractables. A profile of the extractables from rubber packaging materials was made with a range of organic solvents and stress conditions to provide information on substances to target in the drug product. The drug product was evaluated to determine if the matrix would cause interferences that might inhibit detection of the found extractables. Analytical methods were selected based on these findings. The procedures were validated according to FDA guidelines. A stability program using time and storage conditions as variables provided information for acceptance criteria. This same strategy can be used on other types of pharmaceuticals and packaging materials. 相似文献
3.
Hepatitis B virus (HBV) infection is a major health problem in the United States; in 1995, approximately 128,000 cases occurred. Transmission of HBV occurs primarily by blood exchange (eg, by shared needles during injection drug use) and by sexual contact. Persons infected early in life are much more likely to become chronically infected than those infected during adulthood: as many as 90% of infants infected perinatally develop chronic infection and up to 25% will die of HBV-related chronic liver disease as adults. Clinical signs of acute hepatitis occur in about 50% of infected adults but in only 5% of infected preschool-aged children. In the United States, hepatitis B vaccine is currently made by recombinant DNA technology using baker's yeast. Preexposure vaccination results in protective antibody levels in almost all infants and children (> 95%) and healthy adults younger than 40 years of age (> 90%). The most common adverse event following administration of hepatitis B vaccine is pain at the injection site, which occurs in 13% to 29% of adult and 3% to 9% of children. A comprehensive hepatitis B vaccination policy is now recommended that includes (1) routine infant vaccination; (2) catch-up vaccination of 11- to 12-year-olds who were not previously vaccinated; (3) catch-up vaccination of young children at high risk for infection; (4) vaccination of adolescents and adults based on lifestyle or environmental, medical, and occupational situations that place them at risk; and (5) prevention of perinatal HBV infection. 相似文献
4.
5.
6.
Retroviral display of antibody fragments; interdomain spacing strongly influences vector infectivity 总被引:1,自引:0,他引:1
S Ager BH Nilson FJ Morling KW Peng FL Cosset SJ Russell 《Canadian Metallurgical Quarterly》1996,7(17):2157-2164
Five different single-chain antibody fragments (scFv) against human cell-surface antigens were displayed on murine ecotropic retroviral vectors by fusing them to the Moloney SU envelope glycoprotein. The spacing between the scFv and the SU glycoprotein was varied by fusing the scFv to residue +7 or to residue +1 of Moloney SU and by inserting linker sequences of different lengths between the domains. All of the chimeric envelopes were efficiently incorporated into vector particles and could bind to human cells through their displayed antibody fragments, but did not infect them. The spacing between the scFvs and the SU glycoproteins had no significant effect on the efficiency of envelope expression or viral incorporation and did not affect the binding properties of the chimeric envelopes, nor did it influence the efficiency of targeted gene delivery to human cells by scFv-displaying vectors. However, on murine fibroblasts the infectivity of vectors incorporating the chimeric envelopes was strongly influenced by the length of the interdomain spacer. The titers were very low when the single-chain antibodies were fused through a tripeptide linker to SU residue +7 and were greatly enhanced (up to 10(5)-fold) when they were fused to SU residue +1 through a heptapeptide linker. These results point to the importance of steric interactions between the domains of chimeric envelope glycoproteins and may have implications for retroviral vector design for human gene therapy. 相似文献
7.
岩心PI值试验研究及应用 总被引:5,自引:0,他引:5
主要论述了在多功能采油化学用剂评价仪上进行的岩心PI值试验的步骤,现象及结论。重点考察了岩心PI值与渗透率、流量及注入截面面积的关系;平行管岩心复合PI值和其中单管岩心PI值的关系。 相似文献
8.
The present study was undertaken to evaluate the postoperative relapse from the period of unwiring to 1 year postoperatively and its correlation to the amount of mandibular setback and change in vertical dimension after mandibular bilateral sagittal split osteotomy. Twenty-seven patients were evaluated cephalometrically by the time preoperatively, 6 weeks, 6 months and 1 year postoperatively. It was found that 1) the average amount of mandibular setback at pogonion point, 6 weeks postoperatively, is 7.6mm backward and 1.9mm downward, 2) the average amount of horizontal relapse at pogonion point, 6 months and 1 year postoperatively, are 1.9mm and 2.3mm respectively. 86% of the horizontal relapse, 1 year postoperatively, occurs in the first 6 months after removal of intermaxillary fixation, 3) the average amount of vertical relapse at pogonion point, 6 months and 1 year postoperatively, are 0.9mm and 1.1mm upward. 82% of the vertical relapse, 1 year postoperatively, occurs in the first 6 months after removal of intermaxillary fixation, 4) the amount of 1 year postoperatively horizontal relapse is significantly correlated both with the amount of horizontal mandibular set back and vertical downward change (r = 0.58, 0.67, p < 0.001), whereas the amount of vertical relapse is with the vertical downward change only, but horizontal setback isn't. 相似文献
9.
10.
Stekloplastik—Sertifikat Corporation Moscow. Translated from Khimicheskie Volokna, No. 2, pp. 58–59, March–April, 1994. 相似文献