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   1193篇
  免费   30篇
  国内免费   1篇
电工技术   17篇
综合类   1篇
化学工业   138篇
金属工艺   17篇
机械仪表   17篇
建筑科学   45篇
矿业工程   4篇
能源动力   26篇
轻工业   112篇
水利工程   4篇
石油天然气   1篇
无线电   88篇
一般工业技术   147篇
冶金工业   454篇
原子能技术   13篇
自动化技术   140篇
  2020年   8篇
  2019年   7篇
  2018年   11篇
  2017年   17篇
  2016年   15篇
  2015年   13篇
  2014年   17篇
  2013年   37篇
  2012年   27篇
  2011年   39篇
  2010年   17篇
  2009年   27篇
  2008年   50篇
  2007年   42篇
  2006年   32篇
  2005年   42篇
  2004年   34篇
  2003年   23篇
  2002年   30篇
  2001年   22篇
  2000年   25篇
  1999年   34篇
  1998年   105篇
  1997年   63篇
  1996年   46篇
  1995年   46篇
  1994年   33篇
  1993年   35篇
  1992年   13篇
  1991年   14篇
  1990年   20篇
  1989年   14篇
  1988年   22篇
  1987年   18篇
  1986年   23篇
  1985年   19篇
  1984年   24篇
  1983年   9篇
  1982年   15篇
  1981年   11篇
  1979年   11篇
  1978年   12篇
  1977年   11篇
  1976年   19篇
  1975年   5篇
  1973年   7篇
  1972年   10篇
  1970年   8篇
  1968年   4篇
  1967年   4篇
排序方式: 共有1224条查询结果,搜索用时 468 毫秒
1.
This study examined the relation between changes in clinical functioning and changes in verbal expression in 81 seriously disturbed and treatment-resistant young adults seen in a comprehensive, psychoanalytically oriented inpatient treatment. Clinical functioning was evaluated with a battery of clinical and social measures. Verbal representations were assessed using computer-assisted scoring of Thematic Apperception Test responses. Changes in the frequency of verbal content and style in the narratives of these patients covaried with changes in clinical functioning. Significantly different covariations of verbal and clinical change, particularly differences in covariates of referential activity, were found for patients with anaclitic versus introjective personality configurations. The implications of these findings for understanding and treating severe psychopathology are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
2.
Genetic and biochemical studies have provided convincing evidence that the 5' noncoding region (5' NCR) of hepatitis C virus (HCV) is highly conserved among viral isolates worldwide and that translation of HCV is directed by an internal ribosome entry site (IRES) located within the 5' NCR. We have investigated inhibition of HCV gene expression using antisense oligonucleotides complementary to the 5' NCR, translation initiation codon, and core protein coding sequences. Oligonucleotides were evaluated for activity after treatment of a human hepatocyte cell line expressing the HCV 5' NCR, core protein coding sequences, and the majority of the envelope gene (E1). More than 50 oligonucleotides were evaluated for inhibition of HCV RNA and protein expression. Two oligonucleotides, ISIS 6095, targeted to a stem-loop structure within the 5' NCR known to be important for IRES function, and ISIS 6547, targeted to sequences spanning the AUG used for initiation of HCV polyprotein translation, were found to be the most effective at inhibiting HCV gene expression. ISIS 6095 and 6547 caused concentration-dependent reductions in HCV RNA and protein levels, with 50% inhibitory concentrations of 0.1 to 0.2 microM. Reduction of RNA levels, and subsequently protein levels, by these phosphorothioate oligonucleotides was consistent with RNase H cleavage of RNA at the site of oligonucleotide hybridization. Chemically modified HCV antisense phosphodiester oligonucleotides were designed and evaluated for inhibition of core protein expression to identify oligonucleotides and HCV target sequences that do not require RNase H activity to inhibit expression. A uniformly modified 2'-methoxyethoxy phosphodiester antisense oligonucleotide complementary to the initiator AUG reduced HCV core protein levels as effectively as phosphorothioate oligonucleotide ISIS 6095 but without reducing HCV RNA levels. Results of our studies show that HCV gene expression is reduced by antisense oligonucleotides and demonstrate that it is feasible to design antisense oligonucleotide inhibitors of translation that do not require RNase H activation. The data demonstrate that chemically modified antisense oligonucleotides can be used as tools to identify important regulatory sequences and/or structures important for efficient translation of HCV.  相似文献   
3.
4.
Utilizing data from the Riggs-Yale Project, 45 male and 45 female 18-29-year-old treatment-resistant inpatients undergoing intensive psychoanalytically oriented treatment were studied. Twenty-seven mixed-type anaclitic-introjective inpatients were compared with 29 "pure" anaclitic and 34 "pure" introjective inpatients. At intake, mixed-type inpatients were more clinically impaired (i.e., were more symptomatic, cognitively impaired, and thought disordered) and more vulnerable (i.e., less accurate object representations and more frequently used maladaptive defense mechanisms) in comparison with clearly defined anaclitic and introjective patients. Mixed-type patients, however, improved significantly more in the course of psychoanalytically oriented treatment, in terms of clinical functioning (i.e., symptoms, cognitive functioning) and psychological vulnerability (i.e., utilization of more adaptive defense mechanisms). (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Multichannel security protocols transmit messages over multiple communication channels, taking into account each channel's security properties. Our first intentional use of these protocols goes back to a 1999 article that proposed physical contact for imprinting as opposed to the wireless channel used in subsequent operations. Only later did we understand three key points. First, explicit use of multiple channels in the same protocol can offer significant advantages for both security and usability. Second, explicitly stating the properties of the channel on which each protocol message is transmitted is useful for understanding one's own protocol in greater depth and therefore for addressing subtle vulnerabilities early on. Third, multichannel protocols existed long before we recognized them as such - think of the courier handcuffed to the briefcase carrying the code book that will later protect postal or telegraphic traffic. The paper presents a security protocol that exploit additional transmissions over lower-capacity channels, typically found in ubicomp environments, that offer a different combination of security properties.  相似文献   
6.
7.
8.
Intrathecal narcotics are a relatively recent addition to the list of analgesic options that are available for the management of labor pain. Pain during the first stage of labor is related to repetitive uterine contractions and resultant cervical dilatation, while pain during the second stage is due to stretching of the perineum. Traditionally, continuous epidural analgesia has been used as the reference standard for providing comfort during labor. Intrathecal narcotics represent a safe and effective alternative that provides significant, rapid relief of labor pain during the first stage of labor. The drugs most often used for intrathecal administration include sufentanil, fentanyl, meperidine and morphine. Use of intrathecal narcotics does not significantly affect the natural progression of labor, and no adverse fetal outcomes have been reported.  相似文献   
9.
Two forms of glutathione synthetase deficiency have been described. While one form is mild, causing hemolytic anemia, the other more severe form causes 5-oxo-prolinuria with secondary neurological involvement. Despite the existence of two deficiency phenotypes, Southern blots hybridized with a glutathione synthetase cDNA suggest that there is a single glutathione synthetase gene in the human genome. Analysis of somatic cell hybrids showed the human glutathione synthetase gene (GSS) to be located on chromosome 20, and this assignment has been refined to subband 20q11.2 using in situ hybridization.  相似文献   
10.
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