全文获取类型
收费全文 | 2502篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 22篇 |
金属工艺 | 2篇 |
机械仪表 | 8篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 2篇 |
轻工业 | 26篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 8篇 |
一般工业技术 | 12篇 |
冶金工业 | 2404篇 |
原子能技术 | 2篇 |
自动化技术 | 11篇 |
出版年
2023年 | 1篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 18篇 |
2012年 | 6篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 9篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 61篇 |
1998年 | 801篇 |
1997年 | 425篇 |
1996年 | 285篇 |
1995年 | 158篇 |
1994年 | 111篇 |
1993年 | 149篇 |
1992年 | 14篇 |
1991年 | 20篇 |
1990年 | 21篇 |
1989年 | 22篇 |
1988年 | 19篇 |
1987年 | 26篇 |
1986年 | 23篇 |
1985年 | 16篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 20篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 52篇 |
1976年 | 153篇 |
1975年 | 3篇 |
1971年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2512条查询结果,搜索用时 15 毫秒
991.
992.
S Francione C Munari D Hoffmann G Lo Russo JF Le Bas B Pasquier AL Benabid 《Canadian Metallurgical Quarterly》1996,48(6):39-48
A structural lesion of the brain is a frequent finding in intractable partial epileptic patients. We analyse anatomo-electro-clinical characteristics of 58 patients in which MR showed a lesion inside the temporal lobe. They are 29 males and 29 females with a mean age at surgery of 23.5 +/- 10.7 years (2.6-45.9). The mean epilepsy duration is of 13.4 +/- 8 years (1.3-35.5), with a mean seizure frequency of 28.7 +/- 43.6 per month, with a great inter-individual variability (from 3 per month to 15 a day). The minimum follow-up is 3.5 years. A video-EEG monitoring was performed in 21 cases, while a stereo-EEG investigation was judged mandatory in 26. On the basis of anatomo-electro-clinical correlations and of the results of presurgical investigations, the epileptogenic area was proved to be temporal in 49 cases, temporal but controlateral to the lesion in 1, and at least bilobar in 8 patients. 相似文献
993.
994.
AL Farone CW Frevert MB Farone MJ Morin BN Fields JD Paulauskis L Kobzik 《Canadian Metallurgical Quarterly》1996,70(10):7079-7084
Reovirus type 3 Dearing (T3D) causes a prominent neutrophil influx, substantially greater than seen with reovirus type 1 Lang (T1L) in a rat model of viral pneumonia. We sought to measure reovirus-mediated increases in chemokine mRNA expression in pulmonary cells. We found that the neutrophilia induced by T1L and T3D infection in vivo correlated directly with increased levels of chemokine mRNA expression in T3D-infected compared with those of T1IL-infected lungs. In vitro, reovirus-infected normal alveolar macrophages (AMs) and the rat AM cell line NR8383 expressed greater levels of macrophage inflammatory protein 2, KC, and tumor necrosis factor alpha mRNA. A synergism between reovirus and lipopolysaccharide was also detected for macrophage inflammatory protein 2 and KC mRNA expression. Tumor necrosis factor protein secretion was also increased to a greater extent by T3D than by T1L in primary rat AMs and the NR8383 cells. We conclude that the virus-mediated inflammatory cytokine induction suggests a role for these cytokines in the neutrophil influx observed in the rat reovirus pneumonia model. 相似文献
995.
BS Carson SP Javedan JM Freeman EP Vining AL Zuckerberg JA Lauer M Guarnieri 《Canadian Metallurgical Quarterly》1996,84(6):903-911
Between 1975 and 1994, 52 hemispherectomies, of which two were anatomical and 50 hemidecortications, were performed at Johns Hopkins Medical Institutions. Eighteen patients were 2 years old or less. There were three perioperative mortalities and one patient died 9 months later from causes not related to surgery. One patient developed hydrocephalus 6 years postsurgery and has been treated effectively. Seizure control and the functional status of each patient were measured as outcome variables. Forty-six (96%) of the surviving patients were seizure free or had reduced seizures as of their last follow-up examination. Twenty-one individuals (44%) were participating in age-appropriate classes or working independently, 18 were classified as semiindependent, and nine children will likely depend on a lifetime of assisted living. The relationships between the outcome variables and the patient's age at surgery, the interval to surgery, and the etiology of the disease were compared. The authors' clinical experiences strongly suggest the importance of a multidisciplinary approach to patient selection and follow-up care. Moreover, anesthetic management of infant surgery is a major component of success. 相似文献
996.
HC Schwartz KC King AL Schwartz D Edmunds R Schwartz 《Canadian Metallurgical Quarterly》1976,25(12):1118-1122
Hemoglobin AIc, a normal minor hemoglobin, has glucose linked by a Schiff base to the N-terminal end of the beta chain. The glucose interferes with the binding of 2,3 diphosphoglycerate, probably resulting in an increased affinity of that hemoglobin for oxygen. Hb AIc is increased to twice normal levels in juvenile-onset (insulin-dependent) diabetes. In the present studies, the Hb AIc, when expressed as per cent of total hemoglobin, was found to be elevated slightly in pregnany normal (m = 6.97 per cent), pregnant nondiabetic obese (m = 6.89 per cent), and gestationally diabetic subjects (m = 8.77 per cent) above that of normal females (m = 5.68 per cent). A remarkable difference was observed between the nonpregnant diabetics (m = 12.77 per cent) and the pregnant diabetics (m = 8.46 per cent). This decrease in the level of Hb AIc in diabetics who are pregnant more than 30 weeks may reflect either a better state of diabetic control and/or a compensatory mechanism to protect the fetus by facilitating oxygen exchange from mother to fetus. 相似文献
997.
AP Kappeler PW Siegrist P Peter HR Koelz GJ Krejs AL Blum 《Canadian Metallurgical Quarterly》1976,101(31):1145-1148
Oesophageal functions were measured in 18 patients with angina, 13 healthy volunteers and 29 age-matched patients with reflux disease. Acid clearance was as abnormal in angina patients (88 +/- 46 swallows) as in those with reflux disease (97 +/- 45). The pressure in the lower oesophageal sphincter was low in patients with angina (13 +/- 8 mm Hg). The incidence of hiatal hernia, subjective symptoms during acidification of the oesophagus and results of the reflux provocation test were similar in patients with angina pectoris and healthy controls. 相似文献
998.
MR Goldberg BM Chapnick PD Joiner AL Hyman PJ Kadowitz 《Canadian Metallurgical Quarterly》1976,198(2):357-365
The interrelationship between prostaglandins (PGs) and bradykinin (BK) was studied in isolated canine saphenous veins. The hypothesis that PGs mediate the venoconstrictor effect of bradykinin was evaluated by determining the influence of low concentrations of indomethacin (Indo) (1 muM) or eicosa-5,8,11,14-tetraynoic acid (ETA) (3 muM), two inhibitors of PG synthesis, on cumulative concentration-response curves for BK or norepinephrine (NE). In the tissue bath, responses to BK improved with time while responses to NE did not vary. When strips were least responsive to BK, Indo and ETA enhanced these responses. When strips were most responsive to BK, neither inhibitor enhanced the responses. Neither Indo nor ETA altered responses to NE. Phentolamine (10(-8) M) did not alter responses to BK. These data suggest that endogenous PGs act to attenuate, rather than mediate, the venoconstrictor response to BK. Progressive enhancement of responses to BK of untreated saphenous vein strips is associated with a decreased ability of inhibitors of PG synthesis to enhance those responses also. Thus, there may be a time-related decrease in the ability of this preparation to synthesize PGs. From the present results, it cannot be determined whether saphenous veins in vivo are highly responsive or relatively unresponsive to the peptide. However, these data do suggest that PGs are a determinant of venous responsiveness to BK. 相似文献
999.
A resuscitation equipment board for mounting in delivery rooms and nurseries facilitates orderly and effective resuscitation of asphyxiated neonates. 相似文献
1000.
RL McGowan TG Welch BL Zaret AL Bryson ND Martin MD Flamm 《Canadian Metallurgical Quarterly》1976,38(4):422-428
Noninvasive myocardial imaging with potassium-43 and rubidium-81 has been used successfully to identify areas of infarction and exercise-induced ischemia as regions of decreased radioactivity. The image defects observed are believed to be due to a decreased radionuclide uptake in regions of myocardial scar or to heterogeneous myocardial accumulation of tracer as a result of regional ischemia. Of 27 patients with left bundle branch block studied with noninvasive imaging at rest and during exercise, 25 manifested at rest reduced radioactivity in the region of the interventricular septum. This pattern is similar to that seen in patients with anteroseptal myocardial infarction. Sixteen of the 27 patients underwent diagnostic coronary arteriography and left ventriculography. Only five of these patients had evidence of either previous infarction or significant obstructive coronary artery disease as assessed with clinical or angiographic criteria, or both. Although the image defect was routinely demonstrated at rest in patients with left bundle branch block, this defect was generally normalized or less distinct with exercise in patients with no anatomic heart disease. In contrast, a larger, more distinct or new image defect with exercise correctly identified the presence of significant obstructive coronary artery disease in patients with left bundle branch block. In the clinical application of noninvasive myocardial imaging, these image defects observed at rest can lead to the false pasitive radionuclide interpretation of anteroseptal myocardial infarction. 相似文献