全文获取类型
收费全文 | 2587篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
综合类 | 4篇 |
化学工业 | 52篇 |
金属工艺 | 6篇 |
机械仪表 | 5篇 |
建筑科学 | 6篇 |
能源动力 | 6篇 |
轻工业 | 36篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 51篇 |
一般工业技术 | 48篇 |
冶金工业 | 2317篇 |
原子能技术 | 2篇 |
自动化技术 | 53篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2017年 | 1篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 13篇 |
2011年 | 14篇 |
2010年 | 4篇 |
2009年 | 14篇 |
2008年 | 4篇 |
2007年 | 12篇 |
2006年 | 11篇 |
2005年 | 13篇 |
2004年 | 13篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 81篇 |
1998年 | 772篇 |
1997年 | 442篇 |
1996年 | 253篇 |
1995年 | 151篇 |
1994年 | 126篇 |
1993年 | 150篇 |
1992年 | 26篇 |
1991年 | 25篇 |
1990年 | 29篇 |
1989年 | 28篇 |
1988年 | 38篇 |
1987年 | 37篇 |
1986年 | 20篇 |
1985年 | 25篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 11篇 |
1981年 | 8篇 |
1980年 | 18篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 45篇 |
1976年 | 97篇 |
1975年 | 3篇 |
1973年 | 3篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有2591条查询结果,搜索用时 15 毫秒
921.
922.
923.
IV Poddoubnyi AF Dronov OI Blinnikov AN Smirnov IA Darenkov KA Dedov 《Canadian Metallurgical Quarterly》1998,33(8):1194-1197
PURPOSE: The technique and outcome of minimally invasive laparoscopic treatment of various forms of intussusception in children after ineffective attempt at conservative treatment are described. METHODS: Ninety-eight patients from 2 months to 11 years of age were analyzed. RESULTS: Suggested scheme of surgical treatment using laparoscopic technique was successful in 64 patients (65.3%), and conversion to open procedure occurred in 34 (34.7%). There was no mortality or intraoperative complications in our series. CONCLUSION: Practically every form of intussusception without bowel necrosis, including the most complex forms, can be reduced now using modern videolaparoscopic equipment and atraumatic instruments. 相似文献
924.
We present a case of sudden death in a 24-year-old, healthy white female who was physically active and participated in sports, including soccer. Two weeks prior to her death, an insurance physical examination revealed an abnormal electrocardiogram which demonstrated flipped T waves in the anterior leads. There was no other remarkable medical history. At autopsy, only one coronary ostium was demonstrated and it originated from the right aortic sinus. Approximately 0.8 cm from this right coronary artery (RCA) ostium, a left coronary artery (LCA) branched off the RCA at a 90-degree angle. The LCA had luminal diameter of 0.4 m but the LCA had a luminal diameter of only 0.1 cm. The LCA coursed anterior to the base of the pulmonary artery and down the anterior ventricular septum reflecting the usual course of the left anterior descending (LAD) coronary artery. The LCA and RCA paths appeared to merge or terminate at the anterior left ventricular myocardium which was discolored gray, a process that involved the inner and middle thirds of the myocardium. Based on the autopsy findings, we certified the cause of death as a probable arrhythmia due to myocardial fibrosis and dystrophic calcification resulting from complications of an anomalous hypoplastic left coronary artery. Anomalies of coronary arteries have been classified and studied at autopsy and by clinical angiography. Coronary artery anomalies can be divided into minor and major forms with major anomalies often resulting in cardiac dysfunction that may cause failure and death. Minor anomalies, in general, have no pathophysiological significance and are compatible with life. Minor anomalies include variations in number and location of coronary ostia. A single coronary ostia is exceedingly rare in hearts with no other congenital malformations. The prognostic significance can be unpredictable. A single coronary artery has the potential to be dangerous if obstructed at its main stem, or if it branches at an acute angle. Additionally, hypoplasia of one or more coronary arteries has been found to be associated with sudden death. 相似文献
925.
926.
JE Schmitz MA Forman MA Lifton O Concepción KA Reimann CS Crumpacker JF Daley RS Gelman NL Letvin 《Canadian Metallurgical Quarterly》1998,92(1):198-206
CD8(+) T lymphocytes play a pivotal role in controlling human immunodeficiency virus (HIV)-1 replication in vivo. We have performed four-color flow cytometric analysis of CD8(+) peripheral blood lymphocytes (PBL) from 21 HIV-1 seronegative and 103 seropositive individuals to explore the phenotypic heterogeneity of CD8beta-chain expression on CD8(+) T lymphocytes and to clarify how its expression on CD8(+) T lymphocytes may relate to acquired immunodeficiency syndrome (AIDS) clinical progression. We showed that the single monoclonal antibody (MoAb) 2ST8-5H7, directed against the CD8alpha beta-heterodimer, identifies CD8(+) T lymphocytes as effectively as the conventional combination of anti-CD3 and anti-CD8alpha antibodies. However, we detected a significantly lower mean fluorescence (MF) of anti-CD8alpha beta staining on PBL from HIV-1 seropositive donors as compared with seronegative donors. In fact, CD8(+) T lymphocytes from HIV-1-infected individuals with the lowest CD4 counts showed the lowest levels of CD8alpha beta MF. To explore further this change in CD8alpha beta expression, we assessed the expression of 14 different cell surface molecules on CD8alpha beta+ T lymphocytes of PBL from 11 HIV-1 seronegative and 22 HIV-1 seropositive individuals. The MF of anti-CD8alpha beta staining was significantly reduced on CD8(+) T lymphocyte subsets that showed immunophenotypic evidence of activation. The subset of lymphocytes expressing low levels of CD8alpha beta expressed higher levels of activation, adhesion, and cytotoxic-associated molecules and was predominantly CD45RO+ and CD28(-). Finally, we monitored the expression of the CD8alpha beta-heterodimer on PBL of eight HIV-1-infected individuals over a 16-week period after the initiation of highly active antiretroviral therapy (HAART), including zidovudine (ZDV), lamivudine (3TC), and indinavir (IDV), and found a significant increase in the expression of the CD8alpha beta-heterodimer. These results suggest that antibodies recognizing the CD8alpha beta-heterodimer are useful tools to specifically identify CD8(+) T lymphocytes. Moreover, the quantitative monitoring of CD8alpha beta expression allows the detection of discrete CD8(+) T lymphocyte subsets and may be useful for assessing the immune status of individuals infected with HIV-1. 相似文献
927.
Electrical activity of the duodenum increased after the immobilisation or haemorrhage stress to a greater extent than the stomach and pylorus myoelectrical activity. Pentagastrin or serotonine increased the electrical activity of the duodenum and decreased the stomach and pylorus myoelectrical activity. Chronophysiological mechanism of the gastro-duodenal discoordination is analysed. 相似文献
928.
KA Bushe 《Canadian Metallurgical Quarterly》1998,92(8-9):564-567
With regard to the revision of the criminal code, the BJM has suggested two regulations concerning the lawsuit of medical malpractice. The text expounds the contence of section 229 E (wrongful treatment, personal injury) and section 230 E (unwillful negligence). It appears disturbing that constitutes for wrongful treatment in the context of assault upon the patient have been included in criminal law so the offence is now rated at the same level as (grievous) personal injury. The aim of the revision being further protection of personal rights and the right of self-determination. The proposed section 229 E and section 230 E are not able to guard the clinician against allegations of assault under criminal law prosecution. The code of civil law should suffice to balance most conditions of malpractice and assault upon the patient. Prosecution by criminal code should be held back for willful offences and wanton or reckless negligence. 相似文献
929.
In situ immunodetection of activated caspase-3 in apoptotic neurons in the developing nervous system
A Srinivasan KA Roth RO Sayers KS Shindler AM Wong LC Fritz KJ Tomaselli 《Canadian Metallurgical Quarterly》1998,5(12):1004-1016
Activation of caspase-3 requires proteolytic processing of the inactive zymogen into p18 and p12 subunits. We generated a rabbit polyclonal antiserum, CM1, which recognizes the p18 subunit of cleaved caspase-3 but not the zymogen. CM1 demonstrated an apparent specificity for activated caspase-3 by specifically immunolabelling only apoptotic but not necrotic cortical neurons in vitro. In the embryonic mouse nervous system, CM1 immunoreactivity was detected in neurons undergoing programmed cell death and was markedly increased in Bcl-xL-deficient embryos and decreased in Bax-deficient embryos. CM1 immunoreactivity was absent in the nervous system of caspase-3-deficient mouse embryos and in neurons cultured from caspase-3-deficient mice. Along with neuronal somata, extensive neuritic staining was seen in apoptotic neurons. These studies indicate that caspase-3 is activated during apoptosis in the developing nervous system in vivo and that CM1 is a useful reagent for its in situ detection. 相似文献
930.