全文获取类型
收费全文 | 1504篇 |
免费 | 13篇 |
国内免费 | 2篇 |
学科分类
工业技术 | 1519篇 |
出版年
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 19篇 |
2017年 | 18篇 |
2016年 | 12篇 |
2015年 | 6篇 |
2014年 | 18篇 |
2013年 | 40篇 |
2012年 | 37篇 |
2011年 | 26篇 |
2010年 | 24篇 |
2009年 | 24篇 |
2008年 | 29篇 |
2007年 | 22篇 |
2006年 | 16篇 |
2005年 | 20篇 |
2004年 | 21篇 |
2003年 | 13篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 38篇 |
1998年 | 248篇 |
1997年 | 154篇 |
1996年 | 126篇 |
1995年 | 76篇 |
1994年 | 64篇 |
1993年 | 70篇 |
1992年 | 21篇 |
1991年 | 24篇 |
1990年 | 20篇 |
1989年 | 24篇 |
1988年 | 23篇 |
1987年 | 25篇 |
1986年 | 15篇 |
1985年 | 24篇 |
1984年 | 8篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 4篇 |
1978年 | 8篇 |
1977年 | 17篇 |
1976年 | 53篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1970年 | 2篇 |
排序方式: 共有1519条查询结果,搜索用时 0 毫秒
1.
Family nursing, always a component of nursing, has been recently receiving increased attention through publications, educational programs, clinical practice settings and family nursing research. Nurses are in the best position to assist families experiencing the illness of a loved one, but often lack the skills and confidence necessary to assist with the psychosocial needs. The purpose of this paper is to describe the development and implementation of a family nursing program within a large, tertiary care facility. The program's evaluation is ongoing but early outcomes indicate that day-to-day nursing practice has been positively influenced and improved job satisfaction may result. 相似文献
2.
3.
Sintering and grain growth of nano-crystalline undoped ZnO has been studied in detail over a wide range of temperature and holding time. Below 800 °C, sintering of over 70% theoretical density is not observed, irrespective of particle size. At 900 °C for 6 h, the nano-crystalline sample sinters to 99% of theoretical density whereas the density for as received sample is 93% of theoretical density. However, at 1300 °C or higher, the densification is found to be much faster and after a few hours becomes independent of holding time. Grain growth studies reveal a similar feature of attaining saturation over holding time. The average saturated grain size is found to be ∼1.5 and ∼2.2 μm at 800 and 900 °C, respectively, while at 1300 °C or higher, it is in between 12 and 13 μm. 相似文献
4.
EB Poluéktova NK Khitrov VI Andreev SG Pak BK Danilkin 《Canadian Metallurgical Quarterly》1997,69(11):14-16
Changes in the activity of acid phosphatase (AP) and its isoenzymes (tartrate-insensitive AP and formalin-insensitive AP) were investigated in patients with food poisoning in the course of the disease. The activity of AP and its isoenzymes in the serum started to grow in early convalescence and reached maximum in late convalescence. Total activity of AP in food toxic infections consists primarily of the activity of its platelet fraction. AP activity may serve as an additional criterion to predict vascular platelet involvement of hemostasis. 相似文献
5.
CV Fletcher BK Goodroad LM Cummins K Henry HH Balfour FS Rhame 《Canadian Metallurgical Quarterly》1997,41(7):1571-1574
Hyperimmune anti-human immunodeficiency virus immunoglobulin (HIVIG) is an intravenous immunoglobulin prepared from HIV-infected asymptomatic donors with a CD4 cell count greater than 400 cells/microl and a high titer of antibody to HIV-1 p24 protein. Twelve persons with AIDS received four doses of HMG (two at 50 mg/kg of body weight and then two at 200 mg/kg) every 28 days. Pharmacokinetics were evaluated by measurement of anti-p24 antibody. HIVIG was well tolerated, and all participants completed the study. Three subjects who were not receiving Pneumocystis carinii pneumonia (PCP) prophylaxis developed PCP. The mean value for HIVIG clearance was 3.02 ml/kg/day at 50 mg/kg and 3.65 ml/kg/day at 200 mg/kg (P = 0.027); the mean trough antibody titers (reciprocal units) were 1,442 and 4,428, respectively. This study indicates that high titers of anti-p24 antibody can be maintained with a monthly administration schedule of HIVIG and that short-term safety is acceptable. Comparisons to evaluate the therapeutic potential of HIVIG are justified. 相似文献
6.
Earlier studies have established that mutant strains of Azotobacter vinelandii that do not synthesize ferredoxin I (AvFdI) overexpress another protein designated Protein X (Morgan, T. V., Lundell, P. J., and Burgess, B. K. (1988) J. Biol. Chem. 263, 1370-1375). This protein has now been purified using two-dimensional gel electrophoresis as an assay. The purified protein is a monomer with M(r) approximately 29,000 which degrades slowly to a specific M(r) approximately 22,000 form when stored in solution. The native protein is bright yellow and contains noncovalently attached FAD that is reduced by either dithionite or NADPH without formation of a stable semiquinone. Titration with NADP+/NADPH gives an E0' value of approximately -327 mV versus SHE. Because this E0' is so close to that of the NADP+/NADPH couple it is not clear if Protein X is an NADPH oxidase or an NADP+ reductase in vivo. Comparison of the NH2-terminal sequence and other properties of Protein X with those of other proteins, suggests that it is likely to be related to the Escherichia coli ferredoxin NADP+ reductase (the fpr gene product), and affinity chromatography shows that Protein X binds specifically to AvFdI. 相似文献
7.
Animesh Chakrabarti Man Mohan Sharma 《Journal of the American Oil Chemists' Society》1992,69(12):1251-1253
Anhydrous esterification of myristic acid with propylene was carried out in the temperature range of 110–145°C and pressure
from 190–195 psig in the presence of Amberlyst-15 (cation exchange resin) and Filtrol-24 (acid-treated clay) as catalysts.
The product ester, isopropyl myristate finds use in cosmetic and topical medicinal preparations where good absorption through
the skin is desired. Filtrol-24 is the catalyst of choice, and the recommended operating temperature is 130°C with a pressure
of 190 psig. 相似文献
8.
9.
10.