全文获取类型
收费全文 | 1315篇 |
免费 | 1篇 |
专业分类
化学工业 | 14篇 |
金属工艺 | 2篇 |
机械仪表 | 6篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
轻工业 | 3篇 |
无线电 | 1篇 |
一般工业技术 | 14篇 |
冶金工业 | 1262篇 |
原子能技术 | 1篇 |
自动化技术 | 7篇 |
出版年
2024年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2013年 | 7篇 |
2012年 | 2篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 5篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 38篇 |
1998年 | 326篇 |
1997年 | 199篇 |
1996年 | 153篇 |
1995年 | 96篇 |
1994年 | 67篇 |
1993年 | 75篇 |
1992年 | 12篇 |
1991年 | 26篇 |
1990年 | 27篇 |
1989年 | 26篇 |
1988年 | 25篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 11篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1978年 | 8篇 |
1977年 | 42篇 |
1976年 | 80篇 |
1975年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有1316条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
105.
The effects of age and gender on the single dose pharmacokinetics of avitriptan and its three metabolites were assessed in 15 young men, 15 young women, 15 elderly men and 15 elderly women. Avitriptan was administered as a 150-mg capsule after a 10-hour fast and serial plasma and urine samples were collected up to 36 hours after the dose. Plasma samples were analyzed for avitriptan and its metabolites, N-desmethyl avitriptan (ND048), O-desmethyl avitriptan (OD048), and methoxypyrimidinyl piperazine (MPP). Urine samples were analyzed for only avitriptan and MPP. Avitriptan was well tolerated in all four groups. The drug was rapidly absorbed with a median time to maximum plasma concentration (tmax) between 0.5 and 1.5 hours. No significant gender-related differences were found in the maximum plasma concentration (Cmax) and area under the concentration-time curve extrapolated to infinity (AUC0-infinity) of avitriptan. Renal clearance of avitriptan was significantly smaller in young women compared with young men, but this is clinically not relevant because only 2% to 3% of the total dose is excreted unchanged. Compared with the young volunteers, mean Cmax was approximately 50% higher in the elderly but there was no difference in the AUC0-infinity between the 2 age groups. Plasma concentrations of ND048, OD048, and MPP were each 50 to 100 fold lower than those of avitriptan. Hence some age- and gender-related differences found in the pharmacokinetics of avitriptan metabolites are probably not relevant in the assessment of overall safety and efficacy of avitriptan. Based on the pharmacokinetics and tolerability, no age or gender-related dose adjustment is necessary for avitriptan. 相似文献
106.
107.
The role of apitherapy in the combined treatment of patients with chronic nonspecific lung diseases]
The authors suggest that apitherapy should be used in the treatment of patients with chronic non-specific pulmonary diseases (ChNPD) in order that it might be more effective. Apitherapeutic complex (bee venom and bee keeping apiculture produce) has been applied to the treatment of 104 ChNPD patients. High effectiveness of apitherapy in a combined treatment of ChNPD patients was demonstrated as was their stimulating and normalizing influence on the function of the adrenals. 相似文献
108.
Perfluorochemical or perfluorocarbon liquids have an enormous gas-carrying capacity. During tidal liquid ventilation the respiratory medium of both functional residual capacity and tidal volume is replaced by neat perfluorocarbon liquid. Tidal liquid ventilation is characterized by convective and diffusive limitations, but offers the advantage of preserved functional residual capacity, high compliance and improved ventilation-perfusion matching. During partial liquid ventilation only the functional residual capacity is replaced by perfluorocarbon liquid. Both tidal and partial liquid ventilation improve gas exchange and lung mechanics in hyaline membrane disease, adult respiratory distress models and meconium aspiration. Compared to gas ventilation, there is less histologic evidence of barotrauma after liquid ventilation. Cardio-pulmonary interaction, inherent to the high density of liquid, and long term safety need further study. However, extrapolating from animal data, and taking into account promising human pilot studies, liquid ventilation has the desired properties to occupy an important place in the therapy of restrictive lung disease in man. 相似文献
109.
Y Wu MJ Nadler LA Brennan GD Gish JF Timms N Fusaki J Jongstra-Bilen N Tada T Pawson J Wither BG Neel N Hozumi 《Canadian Metallurgical Quarterly》1998,8(18):1009-1017
BACKGROUND: Signals from the B-cell antigen receptor (BCR) help to determine B-cell fate, directing either proliferation, differentiation, or growth arrest/apoptosis. The protein tyrosine phosphatase SHP-1 is known to regulate the strength of BCR signaling. Although the B-cell co-receptor CD22 binds SHP-1, B cells in CD22-deficient mice are much less severely affected than those in SHP-1-deficient mice, suggesting that SHP-1 may also regulate B-cell signaling by affecting other signaling molecules. Moreover, direct substrates of SHP-1 have not been identified in any B-cell signaling pathway. RESULTS: We identified the B-cell transmembrane protein CD72 as a new SHP-1 binding protein and as an in vivo substrate of SHP-1 in B cells. We also defined the binding sites for SHP-1 and the adaptor protein Grb2 on CD72. Tyrosine phosphorylation of CD72 correlated strongly with BCR-induced growth arrest/apoptosis in B-cell lines and in primary B cells. Preligation of CD72 attenuated BCR-induced growth arrest/death signals in immature and mature B cells or B-cell lines, whereas preligation of CD22 enhanced BCR-induced growth arrest/apoptosis. CONCLUSIONS: We have identified CD72 as the first clear in vivo substrate of SHP-1 in B cells. Our results suggest that tyrosine-phosphorylated CD72 may transmit signals for BCR-induced apoptosis. By dephosphorylation CD72. SHP-1 may have a positive role in B-cell signaling. These results have potentially important implications for the involvement of CD72 and SHP-1 in B-cell development and autoimmunity. 相似文献
110.