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   1582篇
  免费   1篇
电工技术   6篇
化学工业   5篇
金属工艺   5篇
机械仪表   1篇
矿业工程   1篇
轻工业   5篇
水利工程   2篇
石油天然气   9篇
一般工业技术   17篇
冶金工业   1525篇
原子能技术   6篇
自动化技术   1篇
  2018年   1篇
  2016年   3篇
  2015年   2篇
  2013年   4篇
  2012年   4篇
  2011年   1篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   5篇
  2003年   2篇
  2002年   2篇
  2000年   1篇
  1999年   27篇
  1998年   405篇
  1997年   252篇
  1996年   166篇
  1995年   94篇
  1994年   74篇
  1993年   101篇
  1992年   10篇
  1991年   13篇
  1990年   7篇
  1989年   8篇
  1988年   8篇
  1987年   9篇
  1986年   7篇
  1985年   7篇
  1983年   4篇
  1982年   14篇
  1981年   22篇
  1980年   28篇
  1979年   3篇
  1978年   4篇
  1977年   93篇
  1976年   183篇
  1975年   8篇
  1973年   3篇
  1972年   1篇
  1955年   1篇
排序方式: 共有1583条查询结果,搜索用时 0 毫秒
91.
Endoscopic treatment of chronic pancreatitis has drawn benefits from endoscopic procedures previously described for the main bile duct. Endotherapy is developing throughout the world. Cyst drainage procedures certainly represent the largest step forward in that non-surgical approach, whatever it is either direct (through the stomach or the duodenum) or indirect through the papilla in the duodenum. This procedure gives similar results to surgery with a lower morbidity. Pancreatic duct drainage associated with stone clearance is feasible and provides good results which have not yet been compared with those obtained thanks to surgery. Nonetheless, when the duct is not widely dilated it has been proven to be a satisfactory alternative to surgery. By contrast, chronic cholestasis does not appear to be a good indication of endotherapy.  相似文献   
92.
We have studied the polarized resolved photoluminescence of n-type GaAs/AlAs/GaAlAs resonant tunneling diodes under magnetic field parallel to the tunnel current. Under resonant tunneling conditions, we have observed two emission lines attributed to neutral (X) and negatively charged excitons (X). We have observed a voltage-controlled circular polarization degree from the quantum well emission for both lines, with values up to −88% at 15 T at low voltages which are ascribed to an efficient spin injection from the 2D gases formed at the accumulation layers.  相似文献   
93.
The efficacy of treatment with cambendazole was tested in 1-year-old horses on a farm in Dubrovka, Ukraine. Thirty-five horses were treated. Their egg output was compared on the day of treatment and 14 days later with that of 33 untreated horses. Before treatment the mean number of eggs g-1 faeces was 614 in the controls and 766 in horses that had been treated. After 14 days the mean egg output in the controls was 580 and in the treated horses 369. This means a reduction of 54.5%. Only cyathostome larvae could be cultured from faeces collected after treatment. It can be concluded that benzimidazole resistance in cyathostomes is present in the Ukraine.  相似文献   
94.
OBJECTIVE: The authors examined the efficacy of intramuscular flunitrazepam compared with intramuscular haloperidol for the immediate control of agitated or aggressive behavior in acutely psychotic patients. METHOD: Twenty-eight actively psychotic inpatients, aged 20-60 years, who were under treatment with neuroleptic agents were selected for the study. Each was randomly assigned on a double-blind basis to receive either 5 mg i.m. of haloperidol (N=13) or 1 mg i.m. of flunitrazepam (N=15) during an aggressive event. Verbal and physical aggression was measured over time with the Overt Aggression Scale. Patients were also rated with the Brief Psychiatric Rating Scale and the Clinical Global Impression scale. RESULTS: Both flunitrazepam and haloperidol exhibited acute antiaggressive activity. This beneficial effect, as assessed by the Overt Aggression Scale, was obtained within 30 minutes. CONCLUSIONS: Intramuscular flunitrazepam may serve as a convenient, rapid, safe, and effective adjunct to neuroleptics in reducing aggressive behavior in emergency psychiatric settings.  相似文献   
95.
Atypical cell surface lipoprotein-binding proteins of 105 kDa and 130 kDa are present in membranes of vascular smooth muscle cells. We recently identified the 105 kDa protein from human aortic media as T-cadherin, an unusual glycosylphosphatidylinositol (GPI)-anchored member of the cadherin family of cell adhesion proteins. The goal of the present study was to determine the identity of 130 kDa lipoprotein-binding protein of smooth muscle cells. We applied different approaches that included protein sequencing of purified protein from human aortic media, the use of human T-cadherin peptide-specific antisera, and enzymatic treatment of cultured cells with trypsin and GPI-specific phospholipase C. Our results indicate that the 130 kDa protein is a partially processed form of T-cadherin which is attached to the membrane surface of smooth muscle cells via a GPI anchor and contains uncleaved N-terminal propeptide sequence. Our data disclose that, in contrast to classical cadherins, T-cadherin is expressed on the cell surface in both its precursor (130 kDa) and mature (105 kDa) forms.  相似文献   
96.
Erythropoesis activation, realizing by microenvironmental cells, was noted in hepar of the tailless amphibians R. Lessonae and R. Ridibunda, living in the Chernobyl AES alienation zone. Destructive changes, and the ribosome-protein complexes, fibrillar structures synthesis intensification was revealed in hepatocytes. Ribosome-protein complexes and fibrillar-granular material of hepatocytes enter the blood stream, where they incorporate into the erythroblasts cytoplasm. Focal hyperplasia and macrophages hypertrophy were revealed. Macrophages, transporting the hepatocytes cytoplasm components into erythroblasts and supplementing them with their cytoplasm synthesis products, take an active part in supply of differentiating red blood cells with different materials.  相似文献   
97.
Incubation of mixed human saliva with arginine, ornithine, and proline for 30 min to 2 h at 40 degrees C leads to an appreciable consumption of the above amino acids. The rate of utilization is 0.2 to 0.5 ncat/ml of saliva. The rate of urea loss is higher by an order of magnitude: up to 11 ncat/ml. Putrescin, urea (after incubation with arginine), and ammonium are identified as the products of these reactions. The biological significance of such reactions is believed to consist in neutralization of carbohydrate fermentation products. The detected consumption of amino acids and urea indicates that mixed human saliva contains urease, arginase, ornithine decarboxylase, and, probably, proline reductase. Since the origin of these enzymes is probably bacterial, changes in their activity in the saliva can be regarded as an indicator of dysbacteriosis and a diagnostically important parameter.  相似文献   
98.
The Bladder Neck Support Prosthesis (BNSP) was used in 21 women with combined genuine stress incontinence (GSI) and detrusor instability (DI). Outcomes included frequency volume charts, pad tests, voiding cystometry and quality of life scores, up to the sixth month. Of the 21 recruits, 5 never wore the BNSP home, leaving 16 participants. A further 2 did not reach week 4 because of poor efficacy or inability to fit the device. In the 14 who reached week 4, the median number of leaks/day declined from 4.3 to 1.0 (p = 0.002). Median pad test loss fell from 53 to 7 mL (p = 0.012). Cystometry showed an increase in maximum bladder capacity (p < 0.05) and a modest reduction in severity of detrusor instability, with no evidence of outflow obstruction. Three further women discontinued because of poor efficacy (2) or a poorly fitting device (1), leaving 11 of 16 participants (69%) at week 8, when median pad test loss fell to 2 mL. The BNSP is a useful option in patients with the unfortunate combination of an unstable bladder and an incompetent urethra, but requires careful fitting and attention to detail.  相似文献   
99.
100.
The kinetics of A1H3 decomposition were studied as a function of temperature and hydrogen pressure. Analysis of the experimental data in the formal heterogeneous kinetic approach suggests that the rate of the process is limited by the breaking of Al-H bonds.  相似文献   
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