全文获取类型
收费全文 | 2889篇 |
免费 | 186篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 14篇 |
综合类 | 2篇 |
化学工业 | 780篇 |
金属工艺 | 14篇 |
机械仪表 | 22篇 |
建筑科学 | 205篇 |
矿业工程 | 8篇 |
能源动力 | 51篇 |
轻工业 | 381篇 |
水利工程 | 43篇 |
石油天然气 | 4篇 |
无线电 | 171篇 |
一般工业技术 | 440篇 |
冶金工业 | 573篇 |
原子能技术 | 6篇 |
自动化技术 | 363篇 |
出版年
2024年 | 7篇 |
2023年 | 55篇 |
2022年 | 111篇 |
2021年 | 179篇 |
2020年 | 91篇 |
2019年 | 111篇 |
2018年 | 127篇 |
2017年 | 96篇 |
2016年 | 113篇 |
2015年 | 68篇 |
2014年 | 103篇 |
2013年 | 183篇 |
2012年 | 157篇 |
2011年 | 244篇 |
2010年 | 165篇 |
2009年 | 183篇 |
2008年 | 159篇 |
2007年 | 153篇 |
2006年 | 122篇 |
2005年 | 77篇 |
2004年 | 89篇 |
2003年 | 76篇 |
2002年 | 47篇 |
2001年 | 40篇 |
2000年 | 37篇 |
1999年 | 25篇 |
1998年 | 20篇 |
1997年 | 19篇 |
1996年 | 21篇 |
1995年 | 22篇 |
1994年 | 16篇 |
1993年 | 12篇 |
1992年 | 9篇 |
1991年 | 6篇 |
1990年 | 14篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 5篇 |
1982年 | 4篇 |
1979年 | 4篇 |
1976年 | 4篇 |
1974年 | 4篇 |
1947年 | 8篇 |
1946年 | 5篇 |
1945年 | 6篇 |
1944年 | 11篇 |
1943年 | 7篇 |
1942年 | 10篇 |
排序方式: 共有3077条查询结果,搜索用时 15 毫秒
31.
Heil Sarah H.; Sigmon Stacey C.; Mongeon Joan A.; Higgins Stephen T. 《Canadian Metallurgical Quarterly》2005,13(3):238
The present study was an experimental test of efficacy of a brief education intervention for increasing HIV/AIDS knowledge among cocaine-dependent outpatients. Participants were randomly assigned to an HIV/AIDS education intervention (experimental condition) or a sham intervention (control condition). Control participants were subsequently crossed over to the HIV/AIDS education intervention. Experimental participants had higher scores on tests of HIV/AIDS knowledge after receiving the education intervention than did control participants. Further supporting the intervention's efficacy, control participant scores also increased once participants were crossed over and received the education intervention. Scores at follow-up were lower than at postintervention but remained higher than baseline scores. Results support the intervention's efficacy for increasing HIV/AIDS knowledge among cocaine-dependent outpatients. This intervention is brief, inexpensive, and easily implemented. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
A dynamic feedback controller design method is proposed for multiple input systems. The method uses a novel choice of sliding surface to effect asymptotic linearisation of nonlinear differential input output systems and a class of state space systems. The stability of the overall system, that is a canonical state space form with a dynamic feedback, is analysed with a generalised Lyapunov approach plus an asymptotic analysis in a neighbourhood of the origin. The nonlinear system does not have to be expressed in regular form as is the case in many other sliding mode control approaches. A type of zero dynamics, which are the dynamics of the control, are involved. The resulting dynamic feedback is shown to provide chatter free control if the system is minimum phase with respect to the zero dynamics. The theoretical results are applied to Gas Jet systems with two controls. 相似文献
33.
Miller Joshua D.; Reynolds Sarah K.; Pilkonis Paul A. 《Canadian Metallurgical Quarterly》2004,16(3):310
The authors examined the validity of D. R. Lynam and T. A. Widiger's (2001) prototypes for personality disorders (PDs) derived from the facets of the 5-factor model (FFM) of personality in 2 clinical samples. In the 1st sample (N = 94), there was good agreement between the prototypes generated by experts and the profiles reported by patients. These FFM PD similarity scores also demonstrated good convergent and discriminant validity with results from a semistructured interview and a self-report measure of Axis II pathology. In the 2nd sample (N = 132), the FFM PD similarity scores demonstrated excellent longitudinal stability and good predictive validity with regard to consensus ratings of PD features. The implications of these findings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
34.
Sarah Gordon 《Network Security》2004,2004(6):17-18
Antivirus software tests are important when selecting antivirus software. However, there are many different tests, and interpreting the results can be challenging. Additionally, the needs of the corporate customer and home user differ, and it is important to understand these differences in order to evaluate antivirus software tests critically. 相似文献
35.
Mariana P. Pinho Guilherme A. Lepski Roberta Rehder Nadia E. Chauca-Torres Gabriela C. M. Evangelista Sarah F. Teixeira Elizabeth A. Flatow Jaqueline V. de Oliveira Carla S. Fogolin Nataly Peres Analía Arvalo Venncio Alves Jos A. M. Barbuto Patricia C. Bergami-Santos 《International journal of molecular sciences》2022,23(10)
Immunotherapy has brought hope to the fight against glioblastoma, but its efficacy remains unclear. We present the case of CST, a 25-year-old female patient with a large right-hemisphere glioblastoma treated with a dendritic–tumor cell fusion vaccine. CST showed a near-complete tumor response, with a marked improvement in her functional status and simultaneous increases in tumor-specific CD8+ and CD4+ T cells. Two months before recurrence, the frequency of tumor-specific T cells decreased, while that of IL-17 and CD4+ T cells increased. CST passed away 15 months after enrollment. In this illustrative case, the tumor-specific CD4+ T-cell numbers and phenotype behaved as treatment efficacy biomarkers, highlighting the key role of the latter in glioblastoma immunotherapy. 相似文献
36.
Songyu Dong Weili Zheng Nicholas Pinkerton Jacob Hansen Svetlana B. Tikunova Jonathan P. Davis Sarah M. Heissler Elena Kudryashova Edward H. Egelman Dmitri S. Kudryashov 《International journal of molecular sciences》2022,23(13)
Due to its essential role in cellular processes, actin is a common target for bacterial toxins. One such toxin, TccC3, is an effector domain of the ABC-toxin produced by entomopathogenic bacteria of Photorhabdus spp. Unlike other actin-targeting toxins, TccC3 uniquely ADP-ribosylates actin at Thr-148, resulting in the formation of actin aggregates and inhibition of phagocytosis. It has been shown that the fully modified F-actin is resistant to depolymerization by cofilin and gelsolin, but their effects on partially modified actin were not explored. We found that only F-actin unprotected by tropomyosin is the physiological TccC3 substrate. Yet, ADP-ribosylated G-actin can be produced upon cofilin-accelerated F-actin depolymerization, which was only mildly inhibited in partially modified actin. The affinity of TccC3-ADP-ribosylated G-actin for profilin and thymosin-β4 was weakened moderately but sufficiently to potentiate spontaneous polymerization in their presence. Interestingly, the Arp2/3-mediated nucleation was also potentiated by T148-ADP-ribosylation. Notably, even partially modified actin showed reduced bundling by plastins and α-actinin. In agreement with the role of these and other tandem calponin-homology domain actin organizers in the assembly of the cortical actin network, TccC3 induced intense membrane blebbing in cultured cells. Overall, our data suggest that TccC3 imposes a complex action on the cytoskeleton by affecting F-actin nucleation, recycling, and interaction with actin-binding proteins involved in the integration of actin filaments with each other and cellular elements. 相似文献
37.
38.
Manuel Lasch Kritika Sudan Corinna Paul Christian Schulz Thomas Kolben Julia van Dorp Sibel Eren Susanne Beyer Lorenzo Siniscalchi Sven Mahner Udo Jeschke Sarah Meister 《International journal of molecular sciences》2022,23(11)
(1) Background: Placental immune cells are playing a very important role in a successful placentation and the prevention of pregnancy complications. Macrophages dominate in number and relevance in the maternal and the fetal part of the placenta. The evidence on the polarization state of fetal and maternal macrophages involved in both, healthy and pregnancy-associated diseases, is limited. There is no representative isolation method for the direct comparison of maternal and fetal macrophages so far. (2) Material and Methods: For the isolation of decidual macrophages and Hofbauer cells from term placenta, fresh tissue was mechanically dissected and digested with trypsin and collagenase A. Afterwards cell enrichment was increased by a Percoll gradient. CD68 is represented as pan-macrophage marker, the surface markers CD80 and CD163 were further investigated. (3) Results: The established method revealed a high cell yield and purity of the isolated macrophages and enabled the comparison between decidual macrophages and Hofbauer cells. No significant difference was observed in the percentage of single CD163+ cells in the distinct macrophage populations, by using FACS and immunofluorescence staining. A slight increase of CD80+ cells could be found in the decidual macrophages. Considering the percentage of CD80+CD163− and CD80−CD163+ cells we could not find differences. Interestingly we found an increased number of double positive cells (CD80+CD163+) in the decidual macrophage population in comparison to Hofbauer cells. (4) Conclusion: In this study we demonstrate that our established isolation method enables the investigation of decidual macrophages and Hofbauer cells in the placenta. It represents a promising method for direct cell comparison, enzyme independently, and unaffected by magnetic beads, to understand the functional subsets of placental macrophages and to identify therapeutic targets of pregnancy associated diseases. 相似文献
39.
Marleen Julia Meyer Simon Falk Sarah Rmer Clarissa Prinzinger Sabine Tacke Joachim Geyer Stefan Simm Mladen Vassilev Tzvetkov 《International journal of molecular sciences》2022,23(9)
OCT1 and OCT2 are polyspecific membrane transporters that are involved in hepatic and renal drug clearance in humans and mice. In this study, we cloned dog OCT1 and OCT2 and compared their function to the human and mouse orthologs. We used liver and kidney RNA to clone dog OCT1 and OCT2. The cloned and the publicly available RNA-Seq sequences differed from the annotated exon-intron structure of OCT1 in the dog genome CanFam3.1. An additional exon between exons 2 and 3 was identified and confirmed by sequencing in six additional dog breeds. Next, dog OCT1 and OCT2 were stably overexpressed in HEK293 cells and the transport kinetics of five drugs were analyzed. We observed strong differences in the transport kinetics between dog and human orthologs. Dog OCT1 transported fenoterol with 12.9-fold higher capacity but 14.3-fold lower affinity (higher KM) than human OCT1. Human OCT1 transported ipratropium with 5.2-fold higher capacity but 8.4-fold lower affinity than dog OCT1. Compared to human OCT2, dog OCT2 showed 10-fold lower transport of fenoterol and butylscopolamine. In conclusion, the functional characterization of dog OCT1 and OCT2 reported here may have implications when using dogs as pre-clinical models as well as for drug therapy in dogs. 相似文献
40.