全文获取类型
收费全文 | 1077篇 |
免费 | 0篇 |
专业分类
化学工业 | 6篇 |
建筑科学 | 1篇 |
轻工业 | 3篇 |
无线电 | 1篇 |
一般工业技术 | 9篇 |
冶金工业 | 1052篇 |
自动化技术 | 5篇 |
出版年
2013年 | 3篇 |
2012年 | 1篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 5篇 |
2006年 | 1篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 1篇 |
1999年 | 28篇 |
1998年 | 339篇 |
1997年 | 170篇 |
1996年 | 139篇 |
1995年 | 72篇 |
1994年 | 55篇 |
1993年 | 65篇 |
1992年 | 5篇 |
1991年 | 15篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 37篇 |
1976年 | 54篇 |
1975年 | 1篇 |
排序方式: 共有1077条查询结果,搜索用时 15 毫秒
921.
922.
NK Alkjaersig AP Fletcher ML Lewis BR Cole JR Ingelfinger AM Robson 《Canadian Metallurgical Quarterly》1976,10(4):319-328
1. The effects of clonidine on blood pressure, cerebral norepinephrine content and vascular structures of the kidneys were investigated in 21 SHR. Although the body weight was not affected by long term clonidine treatment up to 36 weeks, the syatolic blood pressure was significantly reduced. The reduction of the blood pressure was already obvious after 1 week administration of clonidine but the effect was more prominent after long term treatment of 30 weeks or longer. 2. The cerebral norepinephrine content was significantly lower in SHR, regardless of with or without clonidine treatment, than in the control Wistar rats. Although the cerebral norepinephrine content was slightly increased following clonidine treatment SHR, the increase was not statistically significant. 3. Angiographic study of the kidneys revealed a poor opacification of the blood vessels and glomeruli in SHR compared with the control Wistar rats. There was no difference in the sizes of the arcuate and interlobular arteries in SHR and the control Wistar rats, although the medial muscular hypertrophy of the arteries was slightly more prominent in the SHR histologically. The more prominent in the SHR histologically. The angiographic and histologic findings of the renal arteries were not altered following long term clonidine treatment. A possibility was considered that the renal arterioles are mainly functionally affected in SHR. 相似文献
923.
Effects of a Haemophilus gallinarum bacterin and its components were studied in young broiler chickens. When the bacterin was administered subcutaneously in the dorsal neck region at 2 weeks of age, no significant differences in weight gains of vaccinated and control birds were detected at eight weeks of age. In four groups vaccinated at 1, 2, 3, or 4 weeks of age and challenged with virulent haemophilus organisms 3 weeks later, the incidence of clinical signs was 30% in the vaccinates and 60% in controls. The bacterin was equally protective at the four ages of administration. Caseous plugs were found at the vaccination sites in all birds which had received adjuvant either alone or in the complete bacterin. Signs of depression lasting about 24 hours were observed in the youngest birds injected with the bacterin, but overall weight gains were normal. 相似文献
924.
Three experiments were designed to investigate some effects of low-level stimulation of the amygdaloid complex (AMYG) and the mesencephalic reticular formation (MRF). Experiment 1 used a tilt box to test for motivational and/or reinforcement effects and failed to demonstrate these effects with stimulation of either structure. Experiment 2 used a one-trial fear-conditioning task and revealed that stimulation of the AMYG disrupted retention when given immediately after training or, under some conditions, 4 days after training. In the same task, Experiment 3 showed that stimulation of the MRF enhanced retention when given immediately after training or, under some conditions, 4 days after training. These data indicate that under these conditions, modification of retention by low-level stimulation of specific brain structures is independent of the age of the memory. Some implications of this result are discussed. 相似文献
925.
KE Landys GE Berg JS Torgerson HA Klingenstierna BS Ridell BR Johansson 《Canadian Metallurgical Quarterly》1995,76(7):1261-1267
BACKGROUND: Patients with central nervous system (CNS) involvement by high grade non-Hodgkin's lymphoma (NHL) have a poor prognosis. The roles of computed tomography, radiotherapy, and intrathecal and systemic chemotherapy still need to be defined. METHODS: A patient with bulky cranial lymphoma mimicking brain involvement is reported. A 62-year-old man was admitted with a huge scalp lump, headache, fatigue, and focal and generalized neurologic symptoms. Computed tomography showed an abnormal mass in the frontoparietal region involving the subcutaneous scalp, osteolytic destruction of the cranial vault, and a bulky mass that was interpreted to be intracranial. A systemic survey also revealed bulky retroperitoneal involvement and focal involvement of the spleen. Biopsy revealed a B-cell NHL of centroblastic type according to the Kiel classification. RESULTS: The patient was treated with a modified combination of cyclophosphamide plus mitoxantrone plus vincristine plus prednisone (CNOP) and intrathecal methotrexate. The patient responded with complete remission, including partial bone restoration of the cranium. At the time of this writing, his relapse free survival lasted 5 years. CONCLUSIONS: The initial interpretation of this case indicated that systemic chemotherapy with modified CNOP plus intrathecal methotrexate would be useful in the management of NHL with CNS involvement. The clinical outcome with rapid neurologic repair and also bone restoration of the cranial vault within 5 years suggests that the lymphoma probably never penetrated the dura and a successful treatment was achieved with combination chemotherapy only. 相似文献
926.
PM Stewart BR Walker G Holder D O'Halloran CH Shackleton 《Canadian Metallurgical Quarterly》1995,80(12):3617-3620
A characteristic feature of the ectopic ACTH syndrome is a state of mineralocorticoid excess, although the etiology remains obscure. Some forms of endocrine hypertension, such as licorice ingestion, have been explained by cortisol acting as a mineralocorticoid in the setting of inhibition or deficiency of 11 beta-hydroxysteroid dehydrogenase (11 beta HSD). This enzyme is responsible for the conversion of cortisol (F) to hormonally inactive cortisone, and its activity in vivo can be inferred from the ratio of the urinary excretion of tetrahydrocortisol (THF) and its isomer (5 alpha THF) to tetrahydrocortisone. Twenty-two patients with Cushing's syndrome (11 pituitary dependent, 9 ectopic, and 2 adrenal adenomas) and 13 controls were studied. Compared to controls. Cushing's patients had a significant increase (P < 0.001) in the excretion of all principal metabolites of F, secondary to a 5- to 6-fold increase in the cortisol secretion rate [median, 34.0 (range, 13.3-327) mg/day in Cushing's vs. 6.1 (range, 2.5-10.3) mg/day in controls]. The THF plus 5 alpha THF/tetrahydrocortisone ratio was significantly increased in Cushing's syndrome regardless of etiology [mean, 1.81 (range, 1.09-9.99) in Cushing's vs. 0.81 (range, 0.51-1.47) in controls; P < 0.001), indicative of defective 11 beta HSD activity. Furthermore, compared to patients with pituitary-dependent Cushing's, this ratio was significantly higher in patients with the ectopic ACTH syndrome (4.12 vs. 1.49; P < 0.01) and was inversely correlated with serum potassium levels (r = -0.57; P = 0.01; n = 22). One explanation for the mineralocorticoid excess state of the ectopic ACTH syndrome appears to be that cortisol gains inappropriate access to the mineralocorticoid receptor through failure of its normal metabolism by 11 beta HSD. The reason for the defective 11 beta HSD activity is unclear, but it may be secondary to substrate saturation, inhibition by other adrenal steroids, or product inhibition. 相似文献
927.
928.
929.
930.