全文获取类型
收费全文 | 7360篇 |
免费 | 706篇 |
国内免费 | 366篇 |
专业分类
电工技术 | 41篇 |
技术理论 | 1篇 |
综合类 | 156篇 |
化学工业 | 4002篇 |
金属工艺 | 238篇 |
机械仪表 | 223篇 |
建筑科学 | 173篇 |
矿业工程 | 33篇 |
能源动力 | 21篇 |
轻工业 | 694篇 |
水利工程 | 17篇 |
石油天然气 | 178篇 |
武器工业 | 1篇 |
无线电 | 508篇 |
一般工业技术 | 841篇 |
冶金工业 | 483篇 |
原子能技术 | 176篇 |
自动化技术 | 646篇 |
出版年
2024年 | 36篇 |
2023年 | 286篇 |
2022年 | 1419篇 |
2021年 | 1319篇 |
2020年 | 464篇 |
2019年 | 380篇 |
2018年 | 259篇 |
2017年 | 243篇 |
2016年 | 346篇 |
2015年 | 317篇 |
2014年 | 393篇 |
2013年 | 489篇 |
2012年 | 432篇 |
2011年 | 336篇 |
2010年 | 274篇 |
2009年 | 207篇 |
2008年 | 201篇 |
2007年 | 183篇 |
2006年 | 121篇 |
2005年 | 146篇 |
2004年 | 109篇 |
2003年 | 78篇 |
2002年 | 83篇 |
2001年 | 71篇 |
2000年 | 30篇 |
1999年 | 26篇 |
1998年 | 22篇 |
1997年 | 29篇 |
1996年 | 22篇 |
1995年 | 18篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 5篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1966年 | 1篇 |
1964年 | 2篇 |
1963年 | 1篇 |
1959年 | 1篇 |
1956年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有8432条查询结果,搜索用时 15 毫秒
71.
Zakowski Sandra G.; Ramati Alona; Morton Carla; Johnson Peter; Flanigan Robert 《Canadian Metallurgical Quarterly》2004,23(6):555
The aims of the present study were to examine whether written emotional disclosure would reduce distress among cancer patients and whether it would buffer the effects of high levels of social constraint (negative social responses to patients' expressions of emotion regarding their cancer) on distress. Cancer patients (N=104) were randomly assigned to write about their emotions regarding their cancer 20 min a day for 3 days or to write about a nonemotional topic. They completed questionnaires at baseline and 6 months postintervention. Results showed that written disclosure buffered the effects of social constraints on stress at the 6-month follow-up and that avoidance partly mediated these effects. The present data reinforce the notion that interventions should be tailored to patients' needs. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
72.
Andrykowski Michael A.; Boerner Laura M.; Salsman John M.; Pavlik Edward 《Canadian Metallurgical Quarterly》2004,23(6):622
To identify the psychological impact of receipt of an abnormal yet benign screening test result, the authors examined the response to a transvaginal ultrasound screening (TVS) test for ovarian cancer (OC) in asymptomatic women (N=540) undergoing an initial TVS screening test. Interviews were conducted prior to undergoing TVS screening and at 2 weeks and 4 months following this baseline. Women receiving an abnormal yet benign TVS test result (n=33) reported elevated OC-specific, but not general, distress at 2-week follow-up. Distress returned to baseline levels at 4-month follow-up. Consistent with the monitoring process and cognitive-social health information processing models, response to an abnormal TVS result was moderated by a monitoring coping style, low optimism, and a family history of OC. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
73.
The application of design-based stereological methods for estimating nuclear features quantitatively in invasive ductal breast cancer is described. Nuclear number, size and size variability are explored in relation to the tumour grade and patient prognosis. The study includes an examination of the efficiency in estimating different nuclear volumes, and two different estimators of the nuclear size variability are contrasted. Forty-two invasive ductal breast carcinomas diagnosed and graded by two pathologists were used. Both 5-μm and 25-μm-thick sections were obtained from paraffin blocks for stereological study. More undifferentiated tumours show significantly larger nuclei than low-grade tumours. The estimates based on the disector method demonstrate a decrease in the number of tumour cell nuclei per unit volume of tissue from grades 1 to 2 and especially from grades 2 to 3. The univariate survival analysis shows a high prognostic value of the nuclear volume estimates. The study shows that an efficient sampling procedure was performed, particularly when estimating volume-weighted mean nuclear volume using the point-sampled intercepts method. This method is more efficient than estimation of the number-weighted mean nuclear volume using the selector method; however, the latter provides paired estimates of volume- and number-weighted mean nuclear volume, as well as an estimate of the coefficient of variation of nuclear volume in the number distribution of the same cells. 相似文献
74.
Andrykowski Michael A.; Carpenter Janet S.; Studts Jamie L.; Cordova Matthew J.; Cunningham Lauren L. C.; Beacham Abbie; Sloan David; Kenady Daniel; McGrath Patrick 《Canadian Metallurgical Quarterly》2002,21(5):485
The impact of benign breast biopsy (BBB) on distress and perceptions of risk for breast cancer (BC) was examined. Interviews were conducted with 100 women shortly after notification of biopsy results and 4 and 8 months post-BBB. Compared with matched healthy comparison (HC) women without BBB, the BBB group evidenced greater BC-specific distress at baseline. BC-specific distress declined after BBB, remaining elevated relative to the HC group at the 8-month follow-up. Dispositional (optimism, informational coping style), demographic (education), clinical (family history of BC), and cognitive (BC risk perception) variables were associated with baseline levels of BC-specific distress or persistence of distress. Results support the monitoring process model (S. M. Miller, 1995) and the cognitive social health information processing model (S. M. Miller, Y. Shoda, & K. Hurley, 1996). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
75.
应用基因芯片技术初步筛选人大肠癌细胞辐射敏感相关基因.培养2种不同辐射敏感性的人大肠癌细胞LOVO和SW480,收集细胞至少达到107数量级,提取细胞总RNA,采用人全基因组表达谱芯片获得该两株细胞的基因表达谱,分析比较两者之间基因表达的差异.1、LOVO细胞组检出基因16882个,SW480细胞组检出基因17114个.2、在2倍以上差异表达基因中筛选出上调基因908个,下调基因1312个.上调基因中包括Fas基因、NFkB基因等,下调基因中包括Caspas6基因、RAD21基因等,已有研究证明与辐射敏感相关.3、LOVO细胞中高表达的基因主要有CEACAM5、THBS1、SERPINE2、ARL7、HPGD,提示与辐射敏感相关;SW480细胞中高表达的基因主要有SCD、NQ01、LYZ、KRT20、ATP1B1,提示与辐射抵抗有关.1、大肠癌辐射敏感性的预测可以从基因水平来体现.2、表达谱基因芯片技术能快速、灵敏地预测大肠癌辐射敏感性,筛选大肠癌辐射敏感性相关基因. 相似文献
76.
为研究聚对苯二甲酸乙二醇酯(PET)单面蚀刻的详细过程,利用自制蚀刻装置的电流信号对核孔膜单面蚀刻过程进行监测。对装置的本底电流进行研究分析,发现本底电流主要由装置中的电容控制,受膜厚影响,与温度无关。利用装置的电流信号对蚀刻过程进行了记录,根据电流信号的变化可将整个蚀刻过程分为3个阶段。综合研究了外加高频交流电场的有无及强度对蚀刻过程、通孔时间及核孔膜微孔孔形的影响。发现高频交流电场的存在使通孔时间缩短;在相同的蚀刻条件下,孔形更接近柱形,且这两种作用随着电场强度的增加而加强,并在10V/cm的电场强度附近时达到饱和。 相似文献
77.
78.
Rami T. ElAfandy Ayman F. AbuElela Pawan Mishra Bilal Janjua Hassan M. Oubei Ulrich Büttner Mohammed A. Majid Tien Khee Ng Jasmeen S. Merzaban Boon S. Ooi 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(7)
Knowledge of materials' thermal‐transport properties, conductivity and diffusivity, is crucial for several applications within areas of biology, material science and engineering. Specifically, a microsized, flexible, biologically integrated thermal transport sensor is beneficial to a plethora of applications, ranging across plants physiological ecology and thermal imaging and treatment of cancerous cells, to thermal dissipation in flexible semiconductors and thermoelectrics. Living cells pose extra challenges, due to their small volumes and irregular curvilinear shapes. Here a novel approach of simultaneously measuring thermal conductivity and diffusivity of different materials and its applicability to single cells is demonstrated. This technique is based on increasing phonon‐boundary‐scattering rate in nanomembranes, having extremely low flexural rigidities, to induce a considerable spectral dependence of the bandgap‐emission over excitation‐laser intensity. It is demonstrated that once in contact with organic or inorganic materials, the nanomembranes' emission spectrally shift based on the material's thermal diffusivity and conductivity. This NM‐based technique is further applied to differentiate between different types and subtypes of cancer cells, based on their thermal‐transport properties. It is anticipated that this novel technique to enable an efficient single‐cell thermal targeting, allow better modeling of cellular thermal distribution and enable novel diagnostic techniques based on variations of single‐cell thermal‐transport properties. 相似文献
79.
研究了NaCl-MnO2改性沸石填料柱对水中Zn2+的动态吸附性能。探讨了填料厚度、Zn2+的初始质量浓度和流速对穿透曲线的影响。结果表明,NaCl-MnO2改性沸石能有效去除水中的Zn2,填料层增厚,穿透曲线上的穿透点向右移动,穿透时间延长;而流速、Zn2+的初始浓度增大,穿透曲线上的穿透点向左移动,穿透时间缩短;用Thomas模型描述Zn2+初始质量浓度为50mg/L、滤速为4mL/min时改性沸石对Zn2+的吸附动力学,相关系数为0.9994,平衡吸附容量为12.04mg/g。 相似文献
80.
目的 2013年至今,艺术品交易APP的数量迅速增长,但整体发展极不平衡,5G技术的发展为用户体验的提升提供了良好的契机。厘清艺术品交易APP的用户痛点与用户需求,基于5G时代背景挖掘提升用户体验的机会点,对艺术品交易APP的良性发展有着重要的理论与现实意义。方法 综合运用文献研究法、网络调查法、深度访谈法,基于用户体验满意度调研与深度访谈的综合结果,归纳总结出提升艺术品交易APP用户体验的机会点、策略与方向。结论 艺术品交易APP用户在功能体验、环境体验与情感体验等方面都存在尚未满足的需求,设计者应秉承高效率、情感化、个性化的优化设计策略,为用户提供简单高效的功能操作、个性化的界面与服务、智能化的人机交互,并不断对艺术品交易APP进行优化设计,从而提升其用户体验。 相似文献