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   500篇
  免费   0篇
  国内免费   1篇
化学工业   4篇
建筑科学   12篇
轻工业   8篇
石油天然气   1篇
无线电   1篇
一般工业技术   1篇
冶金工业   471篇
原子能技术   1篇
自动化技术   2篇
  2013年   1篇
  2012年   2篇
  2011年   4篇
  2010年   2篇
  2009年   2篇
  2008年   4篇
  2007年   2篇
  2006年   1篇
  2005年   5篇
  2004年   2篇
  2003年   4篇
  2001年   1篇
  2000年   3篇
  1999年   15篇
  1998年   124篇
  1997年   75篇
  1996年   40篇
  1995年   27篇
  1994年   23篇
  1993年   33篇
  1992年   4篇
  1991年   11篇
  1990年   12篇
  1989年   9篇
  1988年   7篇
  1987年   6篇
  1986年   13篇
  1985年   8篇
  1983年   2篇
  1982年   2篇
  1981年   3篇
  1980年   3篇
  1979年   2篇
  1978年   1篇
  1977年   15篇
  1976年   30篇
  1975年   2篇
  1974年   1篇
排序方式: 共有501条查询结果,搜索用时 93 毫秒
81.
The authors show that intensification of peloid therapy, i.e. more frequent procedures, in patients with pulmonary diseases imposes additional load on the regulatory systems: vegetative, cardiovascular, immune. Moderate balneological reactions become more frequent, therapeutic results worsen. How to correct the above negative effects is proposed.  相似文献   
82.
The effect of leaf decoctions of three plants of the Pyrolaceae family, namely, umbrella wintergreen, one-side ortilia, and round-leaf Pyrola was studied in rat experiments. All plants under study were found to contain approximately equal amounts of tannins and arbutin glycoside. Their concentration was comparable though rather lower than in common bearberry, a well-known plant with diuretic and antiseptic activity. When given for a long time, all Pyrolaceae increased urination and sodium excretion. Besides, their decoctions caused an antimicrobial effect. Only round-leaf Pyrola weakened the development of experimental inflammation. Its anti-inflammatory effect was probably due the presence of flavonoids the content of which in Pyrola was maximum.  相似文献   
83.
The precentral P22/N30 cortical component of the median nerve somatosensory evoked potentials (SEPs) was recorded in 16 patients (11 women and five men) suffering from cervical dystonia before and after botulinum toxin therapy. Cervical dystonia was diagnosed as idiopathic in all patients: 13 patients suffered from right-sided torticollis, and three suffered from left-sided torticollis. The amplitude of the P22/N30 component and the side-to-side ratio of amplitude values were measured. Normal values were obtained by acquiring measurements in two groups of healthy volunteers (n1 = 20 and n2 = 20). The recordings in the first control group were done with the patient's head in a normal position, whereas, in the second control group, the patient kept the head intentionally rotated 60 degrees to the right. Patients were treated with local injections of botulinum toxin A (BTX-A). The mean duration of treatment was 8.3 months, and the mean total amount of BTX injected was 295 U. The P22/N30 precentral component was repeatedly recorded in patients after head posture had been corrected to the normal plane by BTX-A treatment. The recordings showed that the amplitude of the P22/N30 precentral component recorded contralaterally to the direction of head deviation was significantly higher in patients before treatment than after treatment. Contralateral pretreatment amplitudes were also significantly higher (p < 0.01 and p < 0.05, respectively) than amplitudes in both groups of healthy volunteers. The mean side-to-side ratio of precentral P22/N30 component amplitudes was significantly higher in patients before treatment compared with after treatment and also compared with both control groups. These changes in dystonic patients probably reflect the direction of head rotation, the muscle pattern of torticollis, and the change in force of dystonic contraction after the treatment. The changes presumably could be the result of higher excitability of the precentral cortex contralateral to head rotation in patients with cervical dystonia and its change after successful BTX-A treatment.  相似文献   
84.
OBJECTIVES: The objective was to compare hemoglobin A1C (HbA1C) results obtained by two methods based on different analytical principles for individuals with a structural hemoglobin variant. DESIGN AND METHODS: Hemoglobin A1C results were obtained using the Bio-Rad Variant (based on cation exchange chromatography) and the Bayer DCA 2000 (based on an immunological reaction) on individuals with a structural hemoglobin variant. The identity of the hemoglobin variant was confirmed by high pressure liquid chromatography (HPLC) and electrophoresis. RESULTS: Hemoglobin A1C results obtained by the two methods on individuals with S, C, D, and E trait were in close agreement. CONCLUSION: The Bio-Rad Variant and Bayer DCA 2000 produce equivalent hemoglobin A1C results on patients with S, C, and E trait. With appropriate correction, correlation of hemoglobin A1C results from the Bio-Rad Variant for individuals with D trait was good (r = 0.927). Glycohemoglobin results obtained by the two methods for some unusual structural hemoglobin variants were in close agreement.  相似文献   
85.
AIM: The expression of CD95(Fas/APO-1) antigen was studied on bone marrow cells of 19 MDS patients, peripheral blood blast cells of 15 acute myeloid leukemia (AML) patients, blast cells and granulocytes of 68 patients with chronic myeloid leukemia (CML)--24 in chronic, 9 in accelerated phase and 35 in blastic crisis (BC)--by indirect surface immunofluorescence assay using flow cytometry (FACScan, Becton Dickinson, USA). RESULTS: CD95(Fas/APO-1) antigen was revealed on bone marrow cells of 8 out of 19 (36.8%) MDS patients; the percentage of antigen-positive cells was 38.1 +/- 19.2%; on 45.5 +/- 22.8% of cells in 6(45%) of 15 AML patients. Fas/APO-1 antigen was totally absent in CML chronic stage; its expression was found in 34% (12 of 35) of our patients with CML BC on peripheral blood blasts and in 56% (5 of 9) on peripheral blast cells of CML patients in acceleration phase. CONCLUSION: The data on overall survival of CD95-positive MDS patients suggest that the presence of Fas antigen is a favorable prognostic sign for patients with MDS. The patients from CD95-negative group represent a risk group both for survival and AML transformation. In CML BC group the survival does not depend upon Fas-antigen expression.  相似文献   
86.
This prospective study was conducted over a period of 18 months (February 1989 to July 1990) in the State of Kuwait. It covered a population of 1,024,211 and eight multidisciplinary hospitals with an in-patient admission of 118,079 per year. Two hundred and twenty-six adult patients with acute renal failure (ARF) were seen and followed up by nephrologists. This made the calculated annual incidence of ARF 14.7 per 100,000 population, nearly five times that reported by the EDTA registry (Biesenbach et al. 1991). Drugs, sepsis and volume depletion were the most frequent causes, with sepsis resulting in 36% cause specific mortality compared to zero mortality with the other two. The overall mortality rate was only 14% which clearly indicated a markedly improved prognosis in cases of ARF. The prognosis in ARF depended on two major factors, viz. the type of aetiological insult and the presence of predisposing associated medical illnesses. Multiple insults, though common, do not affect the mortality rate. Secondary sepsis or gastrointestinal bleeding as a cause of death in ARF was rarely seen in our study. Those who required dialytic support for renal failure had a 45% patient mortality rate in general. Over 40% of our patients were 60 years or older compared with only 3.5% in the local population. This indicated old age as a major risk factor in the development of ARF. The overall mortality in the elderly did not differ from that in the young, but sepsis in the elderly carried a mortality rate of 60% compared to only 14.8% in the younger age group.  相似文献   
87.
Data on separation of purified galactose-specific lectin as well as its two polypeptide chains from inflorescences of European elder Sambucus nigra are represented. Their molecule quaternary structure after the pattern a2 b2 is suggested. It was shown that purified protein in concentration 2.0 mg/ml had mutagenic activity and might enhance mutagenic effect of alkylating substance MNNG. Thus, preparations of lectin from inflorescences of European elder influenced on spontaneous and induced by the alkylating agent mutagenicity in mammalian somatic cells in vitro.  相似文献   
88.
89.
90.
OBJECTIVE: To examine the current status of interactive health communication (IHC) and propose evidence-based approaches to improve the quality of such applications. PARTICIPANTS: The Science Panel on Interactive Communication and Health, a 14-member, nonfederal panel with expertise in clinical medicine and nursing, public health, media and instructional design, health systems engineering, decision sciences, computer and communication technologies, and health communication, convened by the Office of Disease Prevention and Health Promotion, US Department of Health and Human Services. EVIDENCE: Published studies, online resources, expert panel opinions, and opinions from outside experts in fields related to IHC. CONSENSUS PROCESS: The panel met 9 times during more than 2 years. Government agencies and private-sector experts provided review and feedback on the panel's work. CONCLUSIONS: Interactive health communication applications have great potential to improve health, but they may also cause harm. To date, few applications have been adequately evaluated. Physicians and other health professionals should promote and participate in an evidence-based approach to the development and diffusion of IHC applications and endorse efforts to rigorously evaluate the safety, quality, and utility of these resources. A standardized reporting template is proposed to help developers and evaluators of IHC applications conduct evaluations and disclose their results and to help clinicians, purchasers, and consumers judge the quality of IHC applications.  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