全文获取类型
收费全文 | 406篇 |
免费 | 3篇 |
专业分类
综合类 | 2篇 |
化学工业 | 7篇 |
金属工艺 | 1篇 |
机械仪表 | 5篇 |
建筑科学 | 3篇 |
能源动力 | 2篇 |
轻工业 | 13篇 |
无线电 | 6篇 |
一般工业技术 | 30篇 |
冶金工业 | 336篇 |
自动化技术 | 4篇 |
出版年
2022年 | 1篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2009年 | 1篇 |
2008年 | 4篇 |
2007年 | 3篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 9篇 |
1998年 | 104篇 |
1997年 | 58篇 |
1996年 | 42篇 |
1995年 | 34篇 |
1994年 | 20篇 |
1993年 | 14篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 14篇 |
1976年 | 26篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有409条查询结果,搜索用时 15 毫秒
401.
Here we describe the localization of a potent vasodilator, calcitonin gene-related peptide (CGRP), in pelvic autonomic neurons containing four other inhibitory transmitters: vasoactive intestinal peptide (VIP), neuropeptide Y, nitric oxide and acetylcholine. These neurons mediate endothelium-independent vasodilation by releasing nitric oxide and one or more neuropeptides. Sixty percent of nerve cell bodies in guinea-pig paracervical ganglia with immunoreactivity (IR) for VIP, choline acetyltransferase (ChAT) and nitric oxide synthase (NOS), also contained IR for CGRP. Furthermore, many VIP-IR varicose nerve terminals at the adventitia-medial junction of the guinea-pig uterine artery contained IR for CGRP, ChAT and NOS. Both alpha-hCGRP and beta-hCGRP were potent dilators of the uterine artery (pD2 values 8.1, 8.3, respectively), but 1 microM hCGRP(8-37) did not antagonize dilations produced by either agonist. Dilations produced by alpha-hCGRP were unaffected by removal of the endothelium. Taken together with results of our previous studies, we propose that CGRP can contribute directly to autonomic vasodilation, possibly via CGRP2 receptors on smooth muscle cells, and that CGRP is the fifth inhibitory transmitter co-existing in pelvic vasodilator neurons. 相似文献
402.
The cause, prevention, and treatment of recurrent groin hernia 总被引:1,自引:0,他引:1
At present, groin hernia repair is associated with a 10% recurrence rate. Despite innumerable modifications of the Bassini technique, this depressing figure remains essentially unimproved. This article documents the two major reasons for failure and presents techniques that are simple, can be performed under local anesthesia in an outpatient setting, allow patients to return home within hours of their surgery, encourage rapid return to unrestricted activity, and are associated with a recurrence rate approaching 0%. 相似文献
403.
Three main classes of human serum lipoproteins (LP), very low density lipoproteins (VLDLP), low density lipoproteins (LDLP), and high density lipoproteins (HDLP) were selectively sedimented by heparin and dextran sulfate in the presence of metal ions. These data were used for the development of a method for preparation of fractions of human serum enriched with certain class of LP. Using isolated fractions serums with increased content of total cholesterol, cholesterol of HDLP and triglycerides were prepared. These fractions may be used as control samples for evaluation of corresponding parameters in native samples. 相似文献
404.
Problems concerned with the use of desk computers in the nuclear medicine are considered, viz. the structure of technical components in the radiodiagnostic systems and mathematical logistics, an analysis into comparative characteristics of some systems, as well as the experience gained by the authors in elaborating specialized mathematical logistics. This experience and a pertinent analysis prompted the authors to conclude that the use of a computer at each stage of a radioisotope investigation is a matter of necessity and of top importance, without, however, being of cardinal aid in establishing a diagnosis. An effective instrument that will be capable of rendering good service to medicine at the present level of its development should be complex diagnostic systems, whose creation will be the aim of further research work. 相似文献
405.
406.
Retroperitoneal and mediastinal emphysema as a complication of colonoscopy, though infrequent, may occur. It is important to realize that this can be a benign clinical condition that will resolve with conservative management. A case of retroperitoneal emphysema after routine colonoscopy is reported with a review of literature and a brief discussion. 相似文献
407.
408.
409.
P Bogner P Csutora IL Cameron DN Wheatley A Miseta 《Canadian Metallurgical Quarterly》1998,75(6):3085-3091
We investigated a link between hemoglobin primary structure, hemoglobin hydrophobicity-hydrophilicity, and erythrocyte water content in various mammalian species. Some hemoglobin molecules, particularly those of the camel and camelids, contain more charged amino acid residues and are more hydrophilic than the hemoglobins of human and a number of other mammalian species. To test the in vivo significance of these alterations of hemoglobin primary structure, we determined the osmotically unresponsive erythrocyte water fractions in mannit solutions of various osmolarities at 4 degreesC. Among the species investigated, the size of the osmotically unresponsive erythrocyte water fraction relates in a positive linear way to hemoglobin hydrophilicity. The extreme low total erythrocyte water content of camel erythrocytes (1.1-1.3 g water/g dry mass) may be explained by a comparatively high osmotically unresponsive erythrocyte water fraction. It is proposed that alterations of hemoglobin sequences of camel and camelids may be the part of a natural selection process aimed at protecting these animals against osmotic dehydration in arid environments. 相似文献