全文获取类型
收费全文 | 1073篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 1篇 |
化学工业 | 13篇 |
金属工艺 | 3篇 |
建筑科学 | 5篇 |
轻工业 | 18篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 11篇 |
一般工业技术 | 91篇 |
冶金工业 | 910篇 |
原子能技术 | 4篇 |
自动化技术 | 13篇 |
出版年
2022年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2013年 | 7篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 6篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 17篇 |
2000年 | 4篇 |
1999年 | 29篇 |
1998年 | 306篇 |
1997年 | 166篇 |
1996年 | 106篇 |
1995年 | 47篇 |
1994年 | 46篇 |
1993年 | 49篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1978年 | 1篇 |
1977年 | 25篇 |
1976年 | 62篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1968年 | 1篇 |
1966年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有1075条查询结果,搜索用时 12 毫秒
31.
G- and C-banded karyotypes of Damaliscus hunteri, D. lunatus and D. pygargus were compared using the standard karyotype of Bos taurus. Chromosomal complements were 2n = 36 in D. lunatus jimela, 2n = 38 in D. pygargus phillipsi and D. p. pygargus, and 2n = 44 in D. hunteri. The fundamental number in all karyotypes was 60. Among the three species of Damaliscus, seven autosomal pairs and the X chromosomes were conserved. Y-chromosome differences were attributed to heterochromatic additions or deletions. Banded karyotypes of the two subspecies of D. pygargus exhibited complete homology. Chromosomal complements of D. pygargus and D. lunatus differed by a simple centric fusion. However, karyotypes of D. pygargus and D. lunatus differed from D. hunteri by numerous centric fusions, several of which were related by monobrachial chain complexes. Between the karyotypes of D. hunteri and D. pygargus or D. lunatus, there were two chain complexes, one involving five chromosomes (chain V) and the other involving 12 in pygargus (chain XII) or 13 in lunatus (chain XIII). There were also two simple centric fusions between D. hunteri and D. lunatus/D. pygargus; acrocentric chromosomes 13, 15, 20 and 22 in D hunteri were fused as 13;15 and 20;22 in D. lunatus and D. pygargus. 相似文献
32.
R. Bruce Godfrey J. F. Scott H. Brett Meadows Manooch Golabi C. Araujo L. McMillan 《Ferroelectrics Letters Section》1986,5(6):167-172
The coercive field of KNO3 films 75 to 400nm thick is found to satisfy the empirical relation EC ∼d -1.3, where d is the thickness, in agreement with earlier work on BaTiO3 by Stadler and on TGS by Hadni et al. The switching times for large area devices (20Ox200μm) vary as E-1.5 in agreement with early work on BaTiO3 by Stadler and Zachmanidis, and indicate that the limiting parameter is the velocity of domain growth perpendicular t o the applied field. 相似文献
33.
We present the characteristic features of 14 children with the recessive form of Robinow syndrome and the growth hormone (GH) response to provocation with clonidine and the serum insulin-like growth factor-I (IGF-I) concentration in 12 of these children. The gonadotropin (luteinizing hormone [LH] and follicle-stimulating hormone [FSH]) response to gonadotropin-releasing hormone (GnRH) was evaluated in early pubertal and pubertal patients, and the testosterone response to human chorionic gonadotropin (HCG) was evaluated in males. Children with Robinow syndrome, born at full-term, were short at birth (length, 41.4+/-2.1 cm) and had markedly slow growth velocity (GV) during the first year (13.1+/-2.1 cm/yr); consequently, they were significantly short at the end of the first year of life (length, 54.4+/-2.9 cm). This intrauterine and early extrauterine growth delay reflected low growth potential. During childhood, the GV standard deviation score (GVSDS) remained low (-2.17+/-0.83). Despite the presence of empty sella in all of the patients, they had an adequate GH response to clonidine provocation (peak, 19.3+/-5.8 microg/L) and a normal serum IGF-I concentration (309+/-142 ng/mL) for their age. During childhood and early adolescence, boys with Robinow syndrome had low basal testosterone and a low testosterone response to HCG stimulation (3,000 IU/m2/d intramuscularly [IM] for 3 days). However, their basal and GnRH-stimulated FSH concentrations were normal. Two girls (Tanner II breast development) had a normal serum estradiol (E2) concentration but high LH and FSH responses to GnRH stimulation. This suggested either defective feedback of E2 on the hypothalamic-pituitary axis or hyporesponsiveness of the ovaries to gonadotropin. Four weeks of HCG therapy (2,500 IU/m2 IM twice weekly) in three boys with Robinow syndrome increased the penile length and testicular volume, denoting a significant Leydig cell response to prolonged HCG stimulation and the presence of functioning androgen receptors. It is suggested that HCG and/or testosterone therapy during infancy may improve the severe micropenis in these patients. 相似文献
34.
35.
Animal transgenesis has proven to be useful for physiological as well as physiopathological studies. Besides the classical approach based on the random integration of a DNA construct in the mouse genome, gene targeting can be achieved using totipotent embryonic stem (ES) cells for targeted transgenesis. Transgenic mice are then derived from the transgenic ES cells. This allows the introduction of null mutations in the genome (so-called knock-out) or the control of the transgene expression by the endogenous regulatory sequences of the gene of interest (so-called knock-in). Development of these transgenic animals leads to a better understanding of the cellular function of many genes or to the generation of animal models for human diseases. The purpose of this short review is to describe animal models in renal tubular physiopathology. Recent progresses will allow the generation of animal models with conditional expression of the transgene of interest or with a conditional gene mutation. This permits spatial and temporal control of the expression of the transgene or of the mutation. This should allow the generation of models suitable for physiological analysis or closer to disease state. 相似文献
36.
Demethylation of the progesterone receptor CpG island is not required for progesterone receptor gene expression 总被引:1,自引:0,他引:1
In a previous study we have shown that an intravenous infusion of pramlintide (an analogue of human amylin) delayed gastric emptying, but the dose of pramlintide was supraphysiological in relation to the amylin response to food in non-diabetic subjects. The purpose of this study was to examine the dose response relationship of subcutaneous injections of pramlintide on gastric emptying and to determine whether administration of the drug before one meal has an impact on the subsequent meal. Eleven men with insulin-dependent diabetes mellitus were studied in a double-blind, randomised, four-way crossover design. None had autonomic neuropathy. Euglycaemia was maintained overnight before the study day. At -30 min the patients self-injected their usual morning insulin and at -15 min they injected the study drug (either placebo or 30, 60 or 90 microg pramlintide) subcutaneously. At 0 min they ate a standard meal consisting of a pancake, labelled with 99mTc, and a milkshake containing 3-ortho-methylglucose (3-OMG). Gastric emptying images were obtained for the next 8 h. At 240 min the subjects ate a similar meal, but on this occasion the pancake was labelled with (111)In. All three doses of pramlintide delayed emptying of the solid component of the first meal (p < 0.004) with no significant difference between the drug doses. There were no differences between placebo and pramlintide after the second meal. All three doses of pramlintide resulted in a prolongation in the time to peak plasma 3-OMG level (p < 0.0001) after the first meal but there was no difference after the second meal. 相似文献
37.
NI Strelkova AT Gavrilkov NF Diuzhilova EN Strel'tsova 《Canadian Metallurgical Quarterly》1981,81(8):1162-1166
Results of treating 181 patients for hemiparesis after a cerebral stroke or a craniocerebral injury by local exposure of the pathological focus to decimeter electromagnetic waves (DW) and alternating magnetic field (AMF) are presented. It is shown that these treatment methods improve the cerebral circulation and contribute to earlier restoration of the motor functions, especially, if used in combination with sulfide baths, therapeutic physical exercises and massage. The therapeutic effectiveness of the DW- and AMF-therapy is confirmed objectively by so informative examination methods, as rheoencephalography, ultrasonic dopplerography, and thermography. 相似文献
38.
39.
Systemic lupus erythematosus with a protein-losing enteropathy 总被引:2,自引:0,他引:2
Anasarca with pronounced hypoalbuminemia developed in a young woman 15 months after the onset of a mild, arthralgic type of systemic lupus erythematosus (SLE) without evidence of active nephritis. Investigation indicated a gastrointestinal rather than a renal site for protein loss. A full clinical remission was achieved with low-dose corticosteroid therapy. 相似文献
40.