全文获取类型
收费全文 | 3956篇 |
免费 | 5篇 |
专业分类
化学工业 | 40篇 |
金属工艺 | 1篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 1篇 |
轻工业 | 61篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 5篇 |
一般工业技术 | 8篇 |
冶金工业 | 3811篇 |
原子能技术 | 1篇 |
自动化技术 | 27篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 3篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 2篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 11篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 4篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 1篇 |
2000年 | 6篇 |
1999年 | 138篇 |
1998年 | 1261篇 |
1997年 | 782篇 |
1996年 | 478篇 |
1995年 | 233篇 |
1994年 | 216篇 |
1993年 | 220篇 |
1992年 | 19篇 |
1991年 | 31篇 |
1990年 | 36篇 |
1989年 | 46篇 |
1988年 | 31篇 |
1987年 | 26篇 |
1986年 | 22篇 |
1985年 | 24篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1982年 | 13篇 |
1981年 | 23篇 |
1980年 | 28篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 57篇 |
1976年 | 134篇 |
1975年 | 2篇 |
1970年 | 1篇 |
排序方式: 共有3961条查询结果,搜索用时 15 毫秒
101.
The coexistence of large granular lymphocytic leukemia (LGLL) and pure red cell aplasia (PRCA) has been previously described, but is rare in Western countries (7% in a recent series of LGLL cases). We present the clinical features, hematological parameters and immunophenotype of two patients with PRCA associated with CD3+ LGLL. 相似文献
102.
PH van der Meide MC de Labie SR Ruuls RJ Groenestein CA Botman T Olsson CD Dijkstra 《Canadian Metallurgical Quarterly》1998,84(1):14-23
BACKGROUND: It is important for HIV/AIDS control programmes to determine population knowledge on AIDS in order to develop appropriate Information, Education and Communication (IEC) messages. The objectives of our study were to determine the seroprevalence of HIV and syphilis among pregnant women, female prostitutes and long-distance truck drivers and to evaluate knowledge, attitudes, beliefs, and practice (KABP) with respect to the HIV/AIDS epidemic in these three groups in Burkina Faso. METHODS: We performed three cross-sectional serosurveys including face-to-face interviews on KABP between October 1994 and February 1995 in three population groups. RESULTS: Overall, 1,294 pregnant women, 236 long-distance truck drivers and 426 female prostitutes were recruited. HIV seroprevalence was 8% (95% Confidence Interval (CI): 6.6-9.6) among pregnant women, 18.6% (95% CI: 13.9-24.2) among long-distance truck drivers and 58.2% (95% CI: 53.4-62.9) in female prostitutes. The prevalence of syphilis was 2.5%, 9.3% and 15%, respectively. Most pregnant women (98%), long-distance truck drivers (96%) and female prostitutes (98%) had already heard of AIDS. However, the level of knowledge of HIV transmission routes, of risk factors for HIV transmission and of available preventive measures was very low. Consequently, 41% of pregnant women, 40% of long-distance truck drivers and an alarming 61% of female prostitutes reported that they did not feel themselves at risk for HIV. In each group, high levels of knowledge on AIDS were associated with increased awareness of AIDS risk and the adoption of preventive behaviours. Level of education was associated with knowledge of AIDS and condom use. However, in the 12 months preceding the surveys, condom use was very low among pregnant women (0.1%), long-distance truck drivers (18%) and among female prostitutes (42%). CONCLUSIONS: These results indicate that HIV is widespread in Burkina Faso and that there is an urgent need to develop and evaluate HIV prevention strategies in the general population and among core groups such as female prostitutes and long-distance truck drivers. Interventions must include information campaigns, condom promotion and distribution, and sexually transmitted diseases control. 相似文献
103.
104.
105.
106.
We herein report a simple method using intestinal clamps to prevent intraoperative contamination during an immediate mucocutaneous suture of the intestinal stoma. Using this technique, a protruded intestinal stoma can be constructed reliably without soiling. The technique can be used both for constructing an end as well as a loop intestinal stoma. 相似文献
107.
108.
Mutation in transcription factor POU4F3 associated with inherited progressive hearing loss in humans
109.
CG Salomon CL Kalbhen CM Dudiak MC Olson ME Flisak RC Flanigan 《Canadian Metallurgical Quarterly》1998,206(2):533-538
The effects of denervation of central noradrenergic system on the interpartner relationships of adult cats were examined in a predatory test in the competitive situation for paired animals. Direct administration of the noradrenaline neurotoxin, N-2-chloroethyl-N-ethyl-2-bromobenzylamine (DSP-4 12 microg) into the medial forebrain bundle (MFB) of submissive cats changed previously established dominant-submissive relationship. Biochemical analysis demonstrated a significant reduction of noradrenaline (NA) concentration in the hypothalamus (AH), amygdala (AM), hippocampus (HC), and frontal cortex (CTX), and elevation of NA content in the midbrain central gray matter (CG) in MFB-lesioned cats. Simultaneously, DSP-4-induced lesions exerted significant decrease of 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) content in AH, CG, HC and CTX, and increased GABA level in AH, CG, AM, and HC. These results suggest that a coincident decrease of NA metabolism and increase of GABA metabolism led to fear drive reduction. 相似文献
110.