全文获取类型
收费全文 | 2657篇 |
免费 | 14篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 43篇 |
化学工业 | 198篇 |
金属工艺 | 29篇 |
机械仪表 | 26篇 |
建筑科学 | 44篇 |
矿业工程 | 23篇 |
能源动力 | 32篇 |
轻工业 | 99篇 |
水利工程 | 12篇 |
石油天然气 | 7篇 |
无线电 | 134篇 |
一般工业技术 | 193篇 |
冶金工业 | 1711篇 |
原子能技术 | 9篇 |
自动化技术 | 112篇 |
出版年
2022年 | 12篇 |
2018年 | 8篇 |
2017年 | 15篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 53篇 |
2012年 | 33篇 |
2011年 | 43篇 |
2010年 | 21篇 |
2009年 | 31篇 |
2008年 | 39篇 |
2007年 | 37篇 |
2006年 | 39篇 |
2005年 | 39篇 |
2004年 | 41篇 |
2003年 | 34篇 |
2002年 | 19篇 |
2001年 | 16篇 |
2000年 | 30篇 |
1999年 | 69篇 |
1998年 | 493篇 |
1997年 | 299篇 |
1996年 | 228篇 |
1995年 | 115篇 |
1994年 | 98篇 |
1993年 | 113篇 |
1992年 | 31篇 |
1991年 | 30篇 |
1990年 | 39篇 |
1989年 | 48篇 |
1988年 | 48篇 |
1987年 | 42篇 |
1986年 | 28篇 |
1985年 | 38篇 |
1984年 | 27篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 29篇 |
1980年 | 18篇 |
1979年 | 14篇 |
1978年 | 26篇 |
1977年 | 37篇 |
1976年 | 90篇 |
1975年 | 12篇 |
1974年 | 14篇 |
1973年 | 16篇 |
1972年 | 10篇 |
1971年 | 10篇 |
1967年 | 8篇 |
排序方式: 共有2672条查询结果,搜索用时 15 毫秒
41.
42.
Predictive modelling of the 3-D structure of interleukin-13 总被引:1,自引:0,他引:1
Bamborough Paul; Duncan David; Richards W.Graham 《Protein engineering, design & selection : PEDS》1994,7(9):1077-1082
Several atomic structures are now available for the family ofhelical cytokines, which includes growth hormone as well asmany of the interleukins. Using structural information fromfive members of this family, two alternative models of interleukin(IL)-13 are proposed. IL-13 has biological properties similarto those of IL-4 and, like the other interleukins, is a potentiallyimportant pharmaceutical target. The model of IL-13 is discussedand compared with the known interleukin structures. 相似文献
43.
Two cases of adverse reactions to intravesical treatment with bacillus Calmette-Guérin are reported. The first patient presented with a severe suppurating epididymo-orchitis three months after his last treatment. The second patient developed Reiter's disease with arthritis of one knee and conjunctivitis 1 week after the fourth instillation. 相似文献
44.
The postoperative radiographs of 35 patients who underwent impaction allografting of the proximal femur were reviewed. Of Gruen zones that could be clearly visualized, 39.9% contained areas where cement was absent. Even when an adequate mantle was present, cement voids were commonly seen. These cement mantle deficiencies were confirmed in a series of cadaveric impaction allografting procedures. They appear to be a consequence, at least in part, of an inadequate differential between trial and actual component sizes. Additionally, 4 patients were identified with significant component migration secondary to radiographically visible cement mantle fractures within the first 6 months of surgery. It is concluded that the surgical technique requires modification to ensure a more consistent cement mantle and clinical result. 相似文献
45.
H Moffet CL Richards F Malouin G Bravo G Paradis 《Canadian Metallurgical Quarterly》1994,75(4):415-426
The efficacy of an early, intensive, supervised rehabilitation program to accelerate knee strength recovery in the first 3 weeks postmeniscectomy by arthroscopy was evaluated using a randomized controlled trial design. The maximal voluntary isokinetic strength of 31 men, randomly allocated to either a treatment (EXP) or a control (CTL) group, was measured twice by a blind rater: preoperatively (pretest) and 3 weeks postsurgery (posttest), using a computer-controlled Kin-Com dynamometer (Chattecx Corporation, Chattanooga, TN). Strength deficits of the operated leg at the pretest and posttest were established in percent of the values obtained for the sound leg at the pretest. In the interval between the surgery and the posttest, the patients of the EXP group (n = 15) received nine supervised treatments combined to home exercises whereas patients of the control group (n = 16) had no specific physiotherapy treatment but were given instructions in postsurgical management and prescribed exercises by the orthopedic surgeons. Patients of the EXP group had better knee extensor strength recovery than patients of the CTL group (ANCOVA, p < 0.001). The size of the strength difference (3 weeks postsurgery) between EXP and CTL subgroups (n = 8) matched according to preoperative deficits was as large as 26% and the residual deficits of the untreated patients were two to three times larger than those of the treated patients. The results of this study highlight the importance of instituting an early intensive and supervised rehabilitation program, especially for workers returning to a strenuous job requiring good knee extensor muscle function. 相似文献
46.
HM Chaung CH Hong CP Chiang SK Lin YS Kuo WH Lan CC Hsieh 《Canadian Metallurgical Quarterly》1996,95(7):545-550
This review reports the different genetic factors that have been identified either as risk factor for Alzheimer's disease (AD) or directly causing the disease. First are reviewed epidemiological data and biological mechanisms about the apoplipoprotein E gene allele epsilon 4 that is a major risk factor for Alzheimer's disease. The second part describes the mutations responsible for early-onset autosomal dominant AD found in three different genes. The gene located on chromosome 21 encodes the amyloid precusor protein (APP). The presenilin 1 and presenilin 2 genes, located on chromosome 14 and 1 respectively, encode not yet known membrane proteins. 相似文献
47.
48.
49.
T De Brito CR Carneiro MC Nakhle DM Lima CP Abrantes-Lemos M Sandoval AM Silva 《Canadian Metallurgical Quarterly》1998,6(4):368-376
Gene therapy has the potential to provide cancer treatments based on novel mechanisms of action with potentially low toxicities. This therapy may provide more effective control of loco-regional recurrence in diseases such as non-small cell lung cancer (NSCLC), as well as systemic control of micrometastases. Despite current limitations, retroviral and adenoviral vectors can in certain circumstances provide an effective means of delivering therapeutic genes to tumour cells. Although multiple genes are involved in the process of carcinogenesis, mutations of the p53 gene are the most frequent abnormality identified in human tumours. Pre-clinical studies both in vitro and in vivo have shown that restoration of p53 function can induce apoptosis in cancer cells. Phase I clinical trials now show that p53 gene replacement therapy is feasible and safe using both retroviral and adenoviral vectors, and that it induces tumour regression in patients with advanced NSCLC and recurrent head and neck cancer. Other pre-clinical studies indicate that gene therapy may have useful synergy with cytotoxic and radiation therapy. This paper describes the different gene therapy strategies under investigation and the pre-clinical data that provides a rationale for the gene replacement approach, reviews clinical trial data and presents novel ideas for improving current vectors and gene delivery to tumours. 相似文献
50.
The aims of this study were to establish a working rabbit heart model of regional myocardial ischaemia in which electrophysiologic parameters and arrhythmogenesis could be correlated and to explore the mechanisms underlying the antiarrhythmic activity of lignocaine. Monophasic action-potential duration (MAPD90), effective refractory period (ERP), and conduction delay were measured at three ventricular sites in isolated hearts paced at 3.3 Hz. The hearts were treated before and throughout 30 min of ischaemia and 15 min of reperfusion with a vehicle or 20 microM lignocaine. In both groups, ischaemia produced a similar shortening in MAPD90. Lignocaine decreased ERP shortening during ischaemia from -56+/-4 to -32+/-6 ms. An ischaemia-induced increase in conduction delay was greater in the lignocaine than the control group (49+/-7 vs. 11+/-2 ms). Ischaemia-induced dispersion of repolarisation was reduced by lignocaine from 66+/-4 to 32+/-7 ms, and dispersion of refractoriness was decreased from 57+/-6 to 16+/-3 ms. Lignocaine decreased inducibility of ventricular fibrillation (VF) during ischaemia from 86 to 25%. We conclude that, in this model, the antiarrhythmic activity of lignocaine during regional ischaemia is associated with an increase in ischaemia-induced conduction delay and reduced dispersion of repolarisation and refractoriness. 相似文献