全文获取类型
收费全文 | 2755篇 |
免费 | 0篇 |
专业分类
化学工业 | 13篇 |
机械仪表 | 1篇 |
建筑科学 | 5篇 |
轻工业 | 26篇 |
石油天然气 | 2篇 |
无线电 | 3篇 |
一般工业技术 | 11篇 |
冶金工业 | 2689篇 |
自动化技术 | 5篇 |
出版年
2014年 | 1篇 |
2013年 | 15篇 |
2012年 | 2篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 80篇 |
1998年 | 819篇 |
1997年 | 473篇 |
1996年 | 305篇 |
1995年 | 169篇 |
1994年 | 135篇 |
1993年 | 174篇 |
1992年 | 33篇 |
1991年 | 39篇 |
1990年 | 27篇 |
1989年 | 34篇 |
1988年 | 49篇 |
1987年 | 34篇 |
1986年 | 30篇 |
1985年 | 27篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 13篇 |
1981年 | 18篇 |
1980年 | 23篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 50篇 |
1976年 | 155篇 |
1975年 | 10篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1958年 | 1篇 |
1957年 | 2篇 |
1955年 | 3篇 |
排序方式: 共有2755条查询结果,搜索用时 15 毫秒
31.
Cryosurgery of bronchopulmonary structures. An approach to lesions inaccessible to the rigid bronchoscope 总被引:1,自引:0,他引:1
Cryonecrosis of the upper lobe of the lung and bronchi was safely inudced in healthy dogs by application of the cryoprobe to serosal surfaces or, through a bronchotomy, to the mucosal surfaces under direct vision. Seven days after cryosurgery, hyperemia of the bronchus was seen. By 14 days the bronchus at the target site was covered with cuboidal epithelium. Reappearance of normal ciliated epithelium occurred by 180 days after cryosurgery. Cartilage remained intact, and there was no evidence of formation of a stricture or other gross alteration of bronchial architecture. In the lung there was coagulation necrosis; and by 14 days after cryosurgery, there was fibrosis in the target area. There were no complications of the pleural space. Cryosurgery of tissues at the margins of the bronchotomy does not impair healing. Cryosurgery may reduce the necessity for extensive surgery in selected patients with bronchopulmonary tumors, including those inaccessible to the rigid bronchoscope. Clinically, eight patients with recurrent bronchogenic tumors have received palliation by transbronchoscopic cryosurgery. 相似文献
32.
33.
34.
35.
36.
Binding of an arm repeat protein to the kinase domain of the S-locus receptor kinase 总被引:1,自引:0,他引:1
Screening of a yeast two-hybrid library for proteins that interact with the kinase domain of an S-locus receptor kinase (SRK) resulted in the isolation of a plant protein called ARC1 (Arm Repeat Containing). This interaction was mediated by the C-terminal region of ARC1 in which five arm repeat units were identified. Using the yeast two-hybrid system and in vitro binding assays, ARC1 was found to interact specifically with the kinase domains from SRK-910 and SRK-A14 but failed to interact with kinase domains from two different Arabidopsis receptor-like kinases. In addition, treatment with a protein phosphatase or the use of a kinase-inactive mutant reduced or abolished the binding of ARC1 to the SRK-910 kinase domain, indicating that the interaction was phosphorylation dependent. Lastly, RNA blot analysis revealed that the expression of ARC1 is restricted to the stigma, the site of the self-incompatibility response. 相似文献
37.
38.
A model system for cytochrome P-450 comprised of hemin, thiosalicylic acid, and solvent (acetone and water), oxidized cyclohemne and n-hexane at pH 2.7. Oxidation of cyclohexane yielded more cyclohexanol than cyclohexanone under mild reaction conditions, whereas the oxidation of n-hexane generated more 3- and 2-hexanones than 3- and 2-hemnols. Oxygen was a limiting factor in the reaction, and increased oxygen pressures increased the ratio of cyclohexanone to cyclohexanol formed. Lag time for product formation decreased in a linear fashion with an increase in temperature. In addition, cyclohexanone decreased relative to cyclohexanol as the temperature was increased. Antioxidants increased the lag time for product formation, but had little effect on the final quantity or ratios of the oxidative products generated. 1,3 Diphenylisobenzafiran had no effect on the lag time, whereas Tiron and catechol increased the lag time. In contrast to aliphatic thiols, aromatic thiols were capable of driving the oxidative reaction. The model hemin system was approximately 6% as active as natural cytochrome P-450. Hemin immobilized on glass beads effectively catalyzed the oxidation of cyclohexane. 相似文献
39.
The Federal German Water Law of 1976 postulated for the first time that a licence for the discharge of wastewater into public watercourses might only be granted when the wastewater, prior to discharge, is treated according to laid-down standards. In 1976 it was also decided that for the residual pollution load in sewage-treatment plant effluents a pollution fee has to be paid.
At present three pollution units have to be paid per capita and annually for untreated domestic wastewater. One pollution unit is assessed at 17/annum, but the price will be increased to 30/annum in future.
Since the pollution units encompass COD, nitrogen, phosphorus, heavy metals, and chlorinated hydrocarbon compounds, the pollution unit is a good tool to compare the effectiveness of treatment. For different drainage systems the residual pollution units (per litre and second) can also be calculated for low-flow conditions. 相似文献
At present three pollution units have to be paid per capita and annually for untreated domestic wastewater. One pollution unit is assessed at 17/annum, but the price will be increased to 30/annum in future.
Since the pollution units encompass COD, nitrogen, phosphorus, heavy metals, and chlorinated hydrocarbon compounds, the pollution unit is a good tool to compare the effectiveness of treatment. For different drainage systems the residual pollution units (per litre and second) can also be calculated for low-flow conditions. 相似文献
40.
BACKGROUND: Chylothorax is a rare primary or secondary condition the optimum management of which remains uncertain. METHODS: Twenty cases of chylothorax, including ten of primary chylothorax and ten secondary to either malignancy, subclavian vein thrombosis or lymphangioma treated between 1956 and 1986 have been reviewed. RESULTS: Open pleurectomy was the most successful treatment in preventing reaccumulation of the effusion. Three patients had thoracic duct-azygous vein anastomoses, but all anastomoses were probably occluded within a year of surgery. Three patients have been lost to follow-up and five died within 2 years of their treatment, but 12 patients were alive and free from an effusion 3-22 years after treatment. CONCLUSION: Patients with chylothorax should undergo lymphangiography to identify the cause and site of the lymphatic abnormality. Conservative treatment is successful in some patients but should be abandoned if the fluid loss exceeds 1.5 l/day for more than 5-7 days in an adult or more than 100 ml/day in a child. Parietal pleurectomy is the most successful treatment when no distinct chylous leak can be identified. Less commonly, an isolated chylous leak either in the chest or in the abdomen may be identified and this should be treated by direct ligation. 相似文献