全文获取类型
收费全文 | 3947篇 |
免费 | 15篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 43篇 |
化学工业 | 194篇 |
金属工艺 | 30篇 |
机械仪表 | 26篇 |
建筑科学 | 43篇 |
矿业工程 | 23篇 |
能源动力 | 32篇 |
轻工业 | 102篇 |
水利工程 | 12篇 |
石油天然气 | 8篇 |
无线电 | 134篇 |
一般工业技术 | 194篇 |
冶金工业 | 2996篇 |
原子能技术 | 9篇 |
自动化技术 | 117篇 |
出版年
2022年 | 12篇 |
2018年 | 8篇 |
2017年 | 15篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 18篇 |
2013年 | 54篇 |
2012年 | 33篇 |
2011年 | 42篇 |
2010年 | 21篇 |
2009年 | 30篇 |
2008年 | 39篇 |
2007年 | 37篇 |
2006年 | 39篇 |
2005年 | 37篇 |
2004年 | 42篇 |
2003年 | 38篇 |
2002年 | 19篇 |
2001年 | 15篇 |
2000年 | 30篇 |
1999年 | 106篇 |
1998年 | 932篇 |
1997年 | 499篇 |
1996年 | 369篇 |
1995年 | 208篇 |
1994年 | 158篇 |
1993年 | 220篇 |
1992年 | 50篇 |
1991年 | 42篇 |
1990年 | 54篇 |
1989年 | 52篇 |
1988年 | 54篇 |
1987年 | 55篇 |
1986年 | 41篇 |
1985年 | 47篇 |
1984年 | 26篇 |
1983年 | 17篇 |
1982年 | 27篇 |
1981年 | 33篇 |
1980年 | 37篇 |
1979年 | 14篇 |
1978年 | 28篇 |
1977年 | 73篇 |
1976年 | 140篇 |
1975年 | 11篇 |
1974年 | 15篇 |
1973年 | 16篇 |
1972年 | 10篇 |
1971年 | 10篇 |
1967年 | 8篇 |
排序方式: 共有3963条查询结果,搜索用时 21 毫秒
31.
HY Yune EC Klatte CE Grim MH Weinberger JP Donohue MN Yum HN Wellman 《Canadian Metallurgical Quarterly》1976,127(5):761-767
Autonomous hypersecretion of aldosterone (primary hyperaldosteronism) is caused by either hyperplasia (usually bilateral) or an adenoma (frequently unilateral) of the adrenal cortex. Systemic hypertension due to an aldosteronoma is a potentially curable condition through surgical extirpation of the offending organ. In our experience with 37 patients clinically suspected to have primary hyperaldosteronism, radiological methods contributed significantly in preoperative diagnosis. These included (1) selective bilateral adrenal vein catheterization and blood sample collection, (2) adrenal venography, and (3) radioisotope adrenal scan. Unilateral hyperfunction could be accurately detected by the aldosterone assays from the collected samples. When adrenal venography was technically satisfactory, a nodule or aggregate of nodules measuring at least 7 mm and located on the margin of the gland or 1.5 cm or more in diameter when located in the center of the gland were readily identified. Enlarged adrenal gland on venography, in itself, was not a dependable index of a hyperfunctioning gland. Presence of a higher uptake on one side on the radioisotope adrenal scan did not always indicate the hyperfunctioning gland, but lack of lateralization of adrenal hyperfunction was more accurately predicted on the radioisotope scan than by venography. Four histopathological patterns were recognized in the surgically removed adrenal glands, but no correlation between these patterns and clinical behavior or postoperative course was found. 相似文献
32.
Acute, exsanguinating hemorrhagic cystitis secondary to cyclophosphamide therapy, radiation therapy, or an infiltrating bladder tumor may be managed successfully with intravesical Formalin therapy. The indications for its use, the technique, success rates, and complications are discussed. This treatment was effective in 14 of 16 patients in the present series and 79 of 90 cases reported in the literature. Dilutions of 4% or less were as effective as a 10% dilution and were associated with far fewer complications. The early use of Formalin in the treatment of intractable hemorrhagic cystitis is recommended. 相似文献
33.
The authors present clinical and case material on two male triplets with aberrant gender identity. Their findings coincide with those of the few family studies reported in which there were two or more transsexual members; they also reveal patterns generally in keeping with the psychological determinants of transsexualism suggested by Stoller. 相似文献
34.
CL Witte TW Ovitt DB Van Wyck MH Witte RE O'Mara JM Woolfenden 《Canadian Metallurgical Quarterly》1976,111(10):1115-1121
Percutaneous transfemoral arterial balloon occlusion or gelatin sponge embolization of the splenic artery or both were carried out in three high-risk patients with hepatic cirrhosis to reduce splenic hyperfunction and improve severe thrombocytopenia. Although this maneuver raised peripheral platelet counts in each patient, in one patient left upper quadrant pain with splinting of the lower chest cage led to hypostatic lower lobe pneumonia, while in another septic splentitis with gas-forming organisms necessitated splecectomy. Transfemoral occlusion of the splenic artery, although an effective, noninvasive approach to control splenic hyperfunction, has at the same time potential dangers that should be viewed with extreme caution in therapeutic application. 相似文献
35.
Beclomethasone dipropionate aerosol at a dose of 100 mug four times a day was administered to 32 patients suffering from chronic perennial asthma. Twenty-three of these patients had previously received prolonged treatment with corticosteroids, causing various degrees of adrenal suppression in some patients. Almost complete recovery of adrenal function was observed within a period of six months in most patients. Treatment with beclomethasone dipropionate did not affect the hypothalamic-pituitary-adrenal axis in the other nine asthmatic patients who had not received prolonged corticosteroid therapy previously and who served as a control group. 相似文献
36.
Metallothionein (MTN), a low molecular weight cytoplasmic metalloprotein has previously been implicated in the metabolism of Zn. Experiments were conducted with rats to determine the effect of feeding varying levels of dietary Zn for short periods on the increase or decrease in MTN-bound Zn. The results indicated that MTN-Zn in both liver and intestinal mucosal cytosol responded rapidly to an altered dietary Zn level and that serum Zn was directly related to the appearance of MTN. 65Zn absorption also responded rapidly to a change in dietary Zn and was inversely correlated with intestinal mucosal MTN-Zn. Hepatic 65Zn uptake appeared to be directly correlated with liver MTN-Zn. A 24 hour fast increased MTN-Zn in rats fed two different levels of Zn except in those rats that were previously treated with actinomycin D. The antibiotic, which blocks DNA-dependent RNA synthesis, appeared to block Zn uptake from blood to the liver. These findings offer support for the involvement of MTN in zinc metabolism. 相似文献
37.
38.
Acute choroidal ischemia as a complication of photocoagulation 总被引:2,自引:0,他引:2
MH Goldbaum SO Galinos D Apple GK Asdourian K Nagpal L Jampol MB Woolf B Busse 《Canadian Metallurgical Quarterly》1976,94(6):1025-1035
Acute choroidal vascular insufficiency as a complication of photocoagulation has been little noticed. In 17 eyes of 16 patients photocoagulated with either xenon or argon sources for proliferative sickle cell retinopathy, gray lesions of the fundus developed peripheral to the photocoagulation sites. Histologic examination of similar gray lesions produced in monkeys showed necrosis and atrophy of the outer half of the retina. Intense photocoagulation of the human fundus, even with smaller spot sizes, may occlude a choroidal artery, producing separate gray lesions of distinctive shape. The lesions in both the patients and the monkeys progressed to granular hyperpigmentation by two to three weeks after photocoagulation. 相似文献
39.
ME Raichle RL Grubb MH Gado JO Eichling MM Ter-Pogossian 《Canadian Metallurgical Quarterly》1976,33(8):523-526
To test the hypothesis that regional cerebral blood flow (rCBF) is normally regulated by regional metabolic activity, rCBF and the regional cerebral metabolic rate for oxygen (rCMRO2) were compared in selected human subjects. In normal subjects and patients with chronic, stable diseases of brain, rCBF correlated well with rCMRO2. In one individual with mild dementia, rCBF and rCMRO2 were measured before and during exercise of the hand and forearm contralateral to the hemisphere studied. Appropriate parallel changes occurred in both rCBF and rCMRO2 during hand exercise. In patients with acute diseases affecting the hemisphere studied, however, the correlation between rCBF and rCMRO2 was unpredictable. 相似文献
40.
Study of the rat embryo surface under the scanning electron microscope shows the superficial structure of the pellucid membrane as a perforated network cover which does not change throughout the preimplantation period (1 to 41/2 days). Dissolution of the pellucid membrane by brief ATP treatment reveals a zygotic surface which changes from day to day. The number and length of microvilli increase with development. At the early blastula stage there is a great heterogeneity of microvilli of different size and shape as well as large membranous ruffles mainly located at one pole of the embryo. The significance of these structures may relate to the changing metabolic requirements of the developing embryo and to the invasive properties of the trophoblast. 相似文献