全文获取类型
收费全文 | 4429篇 |
免费 | 203篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 56篇 |
化学工业 | 1325篇 |
金属工艺 | 139篇 |
机械仪表 | 72篇 |
建筑科学 | 93篇 |
矿业工程 | 12篇 |
能源动力 | 127篇 |
轻工业 | 565篇 |
水利工程 | 11篇 |
石油天然气 | 9篇 |
无线电 | 88篇 |
一般工业技术 | 668篇 |
冶金工业 | 1073篇 |
原子能技术 | 22篇 |
自动化技术 | 375篇 |
出版年
2023年 | 38篇 |
2022年 | 171篇 |
2021年 | 279篇 |
2020年 | 98篇 |
2019年 | 84篇 |
2018年 | 150篇 |
2017年 | 152篇 |
2016年 | 160篇 |
2015年 | 122篇 |
2014年 | 163篇 |
2013年 | 267篇 |
2012年 | 182篇 |
2011年 | 227篇 |
2010年 | 146篇 |
2009年 | 130篇 |
2008年 | 130篇 |
2007年 | 130篇 |
2006年 | 78篇 |
2005年 | 63篇 |
2004年 | 70篇 |
2003年 | 55篇 |
2002年 | 52篇 |
2001年 | 29篇 |
2000年 | 30篇 |
1999年 | 27篇 |
1998年 | 191篇 |
1997年 | 210篇 |
1996年 | 141篇 |
1995年 | 97篇 |
1994年 | 50篇 |
1993年 | 73篇 |
1992年 | 24篇 |
1991年 | 14篇 |
1990年 | 21篇 |
1989年 | 17篇 |
1988年 | 18篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 21篇 |
1984年 | 33篇 |
1983年 | 23篇 |
1982年 | 42篇 |
1981年 | 48篇 |
1980年 | 57篇 |
1979年 | 29篇 |
1978年 | 37篇 |
1977年 | 110篇 |
1976年 | 239篇 |
1975年 | 14篇 |
1973年 | 12篇 |
排序方式: 共有4635条查询结果,搜索用时 0 毫秒
51.
52.
53.
K Karczewska A Dyduch B Malinowska J Górnial J Kasner K Szumilas M Gizewski D Pawelke-Krombholz D Sońta-Jakimczyk A Wasowicz-Bober W Grzywna 《Canadian Metallurgical Quarterly》1976,51(8):957-964
The response of the rabbit utero-ovarian ligament to catecholamines has been studied in vitro, with contractile activity being recorded isometrically from whole rabbit ligaments obtained under various hormonal conditions. Both the catecholamines norepinephrine (NE) and epinephrine (EPI) produced dose-dependent (10(-2) mug/ml threshold; 10(2) mug/ml maximum) tetanic contractions of rabbit ligament. There was no difference (P less than 0.05) between estrous and ovulatory ligaments either in terms of the dose-response curves or maximal force of contraction. Both agonists were 100% antagonized by the alpha-blockers, phentolamine and phenoxybenzamine. The beta-agonist, isoproterenol, had little effect on ligament tonus but did inhibit spontaneous activity and attenuated the response to both NE and EPI. Propranolol, a beta-blocker, slightly (less than 10%) potentiated the stimulatory effects of NE and EPI. It is concluded that the utero-ovarian ligament of the rabbit contains predominately alpha-stimulatory and possibly weak beta-inhibitory receptors analogous to receptors in ovarian and oviductal smooth muscles. 相似文献
54.
M Bartkowska-Or?owska K Boduch-Cie?lińska A Dalkowska 《Canadian Metallurgical Quarterly》1976,46(11):1243-1248
One hundred sixteen patients underwent operation for renovascular hypertension from 1962 through 1975; 64% had aortorenal reconstruction and 36% had nephrectomy. Sixty-six percent were cured and 19% were improved. Rapid sequence intravenous pyelography, radioisotope renography, and renal arteriography were equal in ability to detect renovascular hypertension. Bilateral renal biopsy specimens had excellent prognostic value when performed in a graded semiquantitative manner. Plasma renin activity was the most consistently useful criterion for prediction of surgical cure if the following requirements were used: (1) elevated peripheral plasma renin activity, (2) elevated renin from the affected kidney, and (3) suppressed renin secretion from the contralateral kidney. An angiotensin II antagonist, saralasin acetate, used in six patients before operation in an attempt to identify those whose hypertension depended on angiotensin II activity, produced a depressor response correlating well with the surgical result. 相似文献
55.
56.
S Zarski W Leo H Pawlik-Dobrowolska T Styczyński H Garwolińska A Filipowicz-Sosnowska M Sadowska-Wroblewska 《Canadian Metallurgical Quarterly》1976,14(3):253-261
The effect of various heme compounds on growth and maturation of Hymenolepis microstoma in vitro has been determined. At 4 days p.i., worms were collected and cultured in vitro for 6 days in a medium containing various concentrations of haemoglobin, hemin, and bilirubin. Addition of haemoglobin to a medium resulted in significant increases in length, wet weight, number of immature and mature proglottids as compared to the control medium. Supplements of hemin did not seem to affect worm length; however, they caused a significant weight increase, and the numbers of immature and mature proglottids were also more than those in control medium. Bilirubin supplements failed to show any effect on growth and maturation of H. microstoma, and the experimental and control worms were found similar in all respects. In the light of the success with haemoglobin and hemin as growth promoting substances, the role of blood ingredients was also considered. For strobilization and maturation of H. microstoma in vitro, the presence of some kind of heme protein seems essential. 相似文献
57.
K Moszyński 《Canadian Metallurgical Quarterly》1976,34(1-4):295-296
The effects of hyperventilation, osmotic and diuretic agents (urea, frusemide), thiopentone and succinylcholine chloride on the intracranial pressure were studied in neurosurgical patients with brain tumours. We have shown that hyperventilation together with osmotic and diuretic agents is very useful for reducing increased intracranial pressure. 相似文献
58.
K Niedzielska-Zawadzka M Barańska-Gieruszczak W Kuran M Zaremba 《Canadian Metallurgical Quarterly》1976,10(4):507-512
A multistep immunocytochemical method utilizing horseradish peroxidase as an immunologically bound marker was used to detect and localize IgA deposits in skin of patients with dermatitis herpetiformis at the ultrastructural level. IgA was found in the upper papillary dermis forming irregular aggregates in seemingly haphazard distribution. These aggregates were associated with microfibrillar bundles and with the microfibrillar component of the elastic tissue. IgA was also detected on anchoring fibrils, but showed no topical relationship to the basal lamina which was always spared. This finding indicates that basal lamina components do not serve as target sites for the immunologic reaction occurring in dermatitis herpetiformis. The selective affinity of IgA deposits to microbfibrillar bundles may be relevant to the hypothesis that the skin pathology in dermatitis herpetiformis is caused by circulating gluten-antigluten complexes, trapped in the skin by reticulin-bound antireticulin antibodies which cross-react with gluten. 相似文献
59.
60.