首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   434篇
  免费   4篇
化学工业   26篇
金属工艺   31篇
机械仪表   26篇
建筑科学   1篇
矿业工程   3篇
轻工业   4篇
石油天然气   8篇
无线电   2篇
一般工业技术   25篇
冶金工业   296篇
原子能技术   13篇
自动化技术   3篇
  2022年   2篇
  2020年   3篇
  2019年   2篇
  2017年   4篇
  2014年   4篇
  2012年   5篇
  2011年   7篇
  2010年   7篇
  2009年   8篇
  2008年   5篇
  2007年   6篇
  2006年   1篇
  2005年   2篇
  2004年   2篇
  2003年   4篇
  2002年   4篇
  2000年   3篇
  1999年   2篇
  1998年   74篇
  1997年   52篇
  1996年   34篇
  1995年   19篇
  1994年   21篇
  1993年   10篇
  1992年   4篇
  1991年   2篇
  1989年   4篇
  1988年   7篇
  1987年   1篇
  1986年   2篇
  1985年   3篇
  1983年   3篇
  1982年   4篇
  1981年   5篇
  1980年   6篇
  1979年   2篇
  1978年   8篇
  1977年   28篇
  1976年   47篇
  1975年   3篇
  1974年   2篇
  1973年   6篇
  1972年   2篇
  1970年   3篇
  1969年   4篇
  1967年   1篇
  1966年   2篇
  1965年   2篇
  1962年   2篇
  1960年   1篇
排序方式: 共有438条查询结果,搜索用时 187 毫秒
301.
The wear resistance of fuel assemblies in the VVER-440 water-moderated reactor is investigated, with small fuel-rod diameter. The experimental apparatus, the model of the fuel rods, and the similarity conditions are described; the possibility of applying the experimental results to regular fuel rods is noted.  相似文献   
302.
303.
By means of a special technique, mobilising of a subject's selective attention upon the dynamics of the subjective sphere states, was reached. An involved biofeedback was positively reinforced by avoidance of an expected electric stimulus. The subjects revealed occurrence of an adaptive correction of their general behaviour. The EEG computer analysis manifested a specifics of structural-functional maintenance of different states evoked in the training process.  相似文献   
304.
305.
Renal lithium transport was studied at different hydration levels in five species of anuran amphibians (Bufo bufo, B. danatensis, B. viridis, Rana ridibunda, and R. temporaria), two species of urodeles (Triturus vulgaris and T. cristatus) and four species of reptiles (lizards Eremias multiocellata, Lacerta vivipara, Trapelus sanguinolentus, and Teratoscincus scincus). Under dehydration conditions, Li+ was reabsorbed in the kidneys of amphibians ans reptiles, but to a lesser degree than in mammalian kidneys: the ratio of lithium clearance (CLi) to glomerular filtration rate (GFR)--fractional lithium excretion--in dehydrated animals was in the range 0.5-0.8. The transition to the hydrated state resulted in a cessation of net renal lithium reabsorption. Under condition of high hydration, all the animals studied, except for urodeles, showed net renal secretion of Li+, i.e., CLi exceeded GFR. The ratio CLi/GFR was 1.2-1.3 in hydrated anurans and 1.7-2.3 in hydrated lizards. In urodeles, this ratio was approximately unity. It is suggested that renal lithium secretion in hydrated amphibians and reptiles reflects fluid secretion in the proximal tubule, which is additional to the glomerular filtration mechanism of fluid delivery to nephron under water loading.  相似文献   
306.
Extragonadal germ-cell tumors (EGCT) are uncommon and biologically distinct from their gonadal counterparts. Thirty-seven patients who had EGCT were treated over a ten-year period at the Regional Cancer Centre, Trivandrum, India. There were 26 men and boys and 11 women and girls. The sites of primary tumor were mediastinum (n=18), central nervous system (n=5), sacrococcygeal region (n=4), retroperitoneum (n=2), and other sites (n=8). After combined modality therapy, 13 of 18 patients who had mediastinal EGCT--1 of 2 with retroperitoneal, 1 of 4 with sacrococcygeal, 0 of 5 with central nervous system, and 2 of 8 patients with tumor in other sites-were alive with no evidence of disease at a median follow-up of 16 months. The overall 5-year survival rate was 40%. Histologic subtype and elevated marker levels were the significant prognostic factors on univariate analysis.  相似文献   
307.
BACKGROUND: In the setting of grossly resected stage IIIA (N2 involvement) non-small cell lung carcinoma, the role of adjuvant postoperative thoracic radiation therapy (TRT) remains controversial. This study was initiated to subcategorize these patients into high-, intermediate-, and low-risk groups with respect to local recurrence and survival rates, and to determine whether there were certain subgroups of patients who were particularly likely or unlikely to benefit from postoperative TRT. METHODS: Two hundred twenty-four patients were studied. A regression tree analysis was used to separate patients who had undergone operation alone into groups that had a high, intermediate, or low risk of local recurrence and death. The effect of adjuvant postoperative TRT then was examined in each of these groups. RESULTS: The use of adjuvant postoperative TRT (compared with operation alone) was associated with an improvement in freedom from local recurrence and survival for patients who had an intermediate or high risk of local recurrence and death. However, the greatest level of improvement in freedom from local recurrence (p < 0.0001) and survival (p = 0.0002) associated with the use of adjuvant postoperative TRT was in the high-risk group. Similarly, but of lesser magnitude, the intermediate-risk group had improved freedom from local recurrence and survival rates with the use of adjuvant post-operative TRT (p = 0.002 and p = 0.01, respectively). For the low-risk group, the freedom from local recurrence and survival rates were not statistically different between the patients who received adjuvant postoperative TRT and those who underwent observation. CONCLUSIONS: Patients with non-small cell lung carcinoma involving ipsilateral mediastinal lymph nodes (stage IIIA) who undergo gross resection and who are at either high or intermediate risk for local recurrence and death are likely to benefit from adjuvant postoperative irradiation. The role of radiation therapy in low-risk patients is unclear. Prospective confirmation of these observations is warranted.  相似文献   
308.
Marked antiulcerative properties of a Populus tremula bark extract were demonstrated in experiments on mice and rats with stress-, reserpine-induced, and acetylsalicylic ulcers. The gastroprotective activity of the extract was expressed in decrease in the number of animals with mucosal ulcers and in marked decrease in the number of ulcers. It exceeded similar parameters of alanton, plantaglucide, and Hippopheae oil.  相似文献   
309.
We report a case of a 1.5 cm cystine staghorn calculus of the right lower pole in a 32 year female known cystinuric patient. With a 200 microns Holmium laser probe through a 9,5 F flexible ureteroscope the calculus was fragmented in small particles. An internal ureteral stent was inserted at the end of the procedure. All but one small residual fragments were evacuated spontaneously after removal of the stent. This case shows that flexible ureteroscopy combined with the Holmium laser is a safe and efficient procedure to treat medium size renal cystine calculi. It can be repeated in case of recurrence with minimal trauma to the urologic tract.  相似文献   
310.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号