全文获取类型
收费全文 | 23493篇 |
免费 | 792篇 |
国内免费 | 48篇 |
专业分类
电工技术 | 282篇 |
综合类 | 27篇 |
化学工业 | 4411篇 |
金属工艺 | 517篇 |
机械仪表 | 457篇 |
建筑科学 | 1056篇 |
矿业工程 | 121篇 |
能源动力 | 670篇 |
轻工业 | 1962篇 |
水利工程 | 194篇 |
石油天然气 | 89篇 |
无线电 | 1931篇 |
一般工业技术 | 3962篇 |
冶金工业 | 5040篇 |
原子能技术 | 167篇 |
自动化技术 | 3447篇 |
出版年
2023年 | 133篇 |
2022年 | 238篇 |
2021年 | 362篇 |
2020年 | 264篇 |
2019年 | 293篇 |
2018年 | 406篇 |
2017年 | 411篇 |
2016年 | 446篇 |
2015年 | 369篇 |
2014年 | 587篇 |
2013年 | 1393篇 |
2012年 | 949篇 |
2011年 | 1281篇 |
2010年 | 900篇 |
2009年 | 936篇 |
2008年 | 1056篇 |
2007年 | 1013篇 |
2006年 | 868篇 |
2005年 | 863篇 |
2004年 | 700篇 |
2003年 | 650篇 |
2002年 | 624篇 |
2001年 | 421篇 |
2000年 | 394篇 |
1999年 | 444篇 |
1998年 | 810篇 |
1997年 | 553篇 |
1996年 | 532篇 |
1995年 | 444篇 |
1994年 | 424篇 |
1993年 | 401篇 |
1992年 | 341篇 |
1991年 | 217篇 |
1990年 | 297篇 |
1989年 | 258篇 |
1988年 | 222篇 |
1987年 | 218篇 |
1986年 | 209篇 |
1985年 | 256篇 |
1984年 | 255篇 |
1983年 | 230篇 |
1982年 | 224篇 |
1981年 | 215篇 |
1980年 | 195篇 |
1979年 | 212篇 |
1978年 | 166篇 |
1977年 | 183篇 |
1976年 | 246篇 |
1975年 | 163篇 |
1973年 | 139篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Development of a new scale to measure patient behavior in group psychotherapy, the Individual Group Member Interpersonal Process Scale (IGIPS), is described. This scale captures clinically important aspects of how patients act in group, including how they respond to the other group members. The IGIPS was applied to videotapes of the first four sessions of seven 15-session outpatient therapy groups (52 patients) in the Mental Health Department of a health maintenance organization. The scale was found to have five factors (Activity, Interpersonal Sensitivity, Comfort with Self, Self-Focus, and Psychological Mindedness). Patient behavior that was moderate on two IGIPS dimensions was connected with better outcome than was that of patients with more extreme behavior in either direction. 相似文献
62.
Ellen Y. Sun Kathleen B. Alexander Paul F. Becher Shyh-Lung Hwang 《Journal of the American Ceramic Society》1996,79(10):2626-2632
Interfacial microstructures in βP-Si3 N4 ( w )-Si-Al-Y-O-N-glass systems were investigated by systematically varying the nitrogen content and the Al:Y ratio of the glass matrix. High-resolution and analytical transmission electron microscopy (HREM and AEM) studies revealed that the interfacial microstructure is a function of the glass composition. No interfacial phases were formed in glasses with low Al:Y ratios and in glasses with high Al:Y ratios and low nitrogen content, whereas epitaxial growth of an interfacial layer (100–200 μm thick) on the βP-Si3 N4 ( w ) occurred in a glass matrix with high Al:Y ratio and high nitrogen content. The interfacial layer was identified to be a β'-SiAION phase. Interfaces containing the SiAION layer exhibited high debonding energy compared to Si3 N4 ( w )–glass interfaces. HREM studies indicated that the lattice-mismatch strain in the SiAION layer was relieved by dislocation formation at the SiAION–Si3 N4 ( w ) interface. The difference in interfacial debonding energy was, hence, attributed to the local atomic structure and bonding between the glass-β-Si3 N4 and the glass–β'-SiAION phases. This observation was clear evidence of the strong influence of glass chemistry on the interfacial debonding behavior by altering the interfacial microstructure. 相似文献
63.
In many firms' experience, reusing elements of proven systems designs and software is best done through a companywide program. Reuse means savings in design, testing, manufacturing and support. The author gives the basic information a company needs to get started. The author discusses the context for reuse, planning and strategy involved in a reuse program 相似文献
64.
65.
One hundred and twelve bilateral thyroidectomies for solitary thyroid nodules with suspected malignancy were performed. The incidence of malignancy in the 112 primary nodules was 42%. Twenty-nine of the 112 contralateral lobes (26%) contained malignancy, which was unsuspected in 80%. Of these 29, 20 were foci of papillary cancer < or = 5 mm and 9 were larger papillary tumors or follicular carcinoma. We analyzed these 112 patients to determine whether there was a simple method to identify those patients at risk for contralateral, unsuspected malignancy. With use of the AMES clinical staging retrospectively, 70 of the 112 patients were classified as having low-stage disease. Fifty percent (35) had cancers on the primary side and 27% (19) on the contralateral side. Of these 19 contralateral cancers, 14 were papillary cancers < or = 5 mm, 4 were papillary cancer > 5 mm and one was a 1.5 cm follicular carcinoma, a similar distribution as in the whole group of 112. When the AMES analysis then excluded those thought to be at risk for multicentricity or papillary carcinoma and examined female patients only with nonpapillary frozen sections, nonpapillary aspiration cytological results, and no history of radiation exposure, no further reduction in the proportion of contralateral cancers (7 of 26, 27%) was found. Fifty-five of the 112 patients underwent preoperative ultrasound scans. In those cases in whom the contralateral lobe had no intraoperative palpable or preoperative sonographic mass, 5 of 20 still had contralateral cancers, but all were papillary < or = 5 mm.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
66.
67.
68.
69.
Sven Beyer Christian Jacobi Daniel Kröning Dirk Leinenbach Wolfgang J. Paul 《International Journal on Software Tools for Technology Transfer (STTT)》2006,8(4-5):411-430
In the verified architecture microprocessor (VAMP) project we have designed, functionally verified, and synthesized a processor
with full DLX instruction set, delayed branch, Tomasulo scheduler, maskable nested precise interrupts, pipelined fully IEEE
compatible dual precision floating point unit with variable latency, and separate instruction and data caches. The verification
has been carried out in the theorem proving system PVS. The processor has been implemented on a Xilinx FPGA.
A shorter version of this article with the title “Instantiating uninterpreted functional units and memory system: functional
verification of the VAMP” appeared in [8]. The work reported here was done while all the authors were with Saarland University. 相似文献
70.
Examined the job performance of 420 credit managers (mean age at hiring 25 yrs) from a large finance company who either quit their job, were fired, or were promoted to a higher position in the company. Six biographical variables and 12 performance appraisal scores accumulated from data in employee files were used in a cross-validated multiple discriminant analysis to predict membership in the 3 classification groups. Results reveal a systematic relation between the performance appraisal variables and the classification groups: The performance of promoted Ss was significantly superior to that of Ss who quit, which in turn was significantly superior to the performance of the fired Ss. 18 discriminating variables accounted for a 46.7% hit rate in group membership. Findings are discussed in the context of research on performance antecedents of voluntary and involuntary turnover, as well as the feedback properties of performance appraisal information. It is suggested that no single performance–turnover relation exists. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献