全文获取类型
收费全文 | 736篇 |
免费 | 40篇 |
专业分类
电工技术 | 5篇 |
综合类 | 1篇 |
化学工业 | 155篇 |
金属工艺 | 6篇 |
机械仪表 | 7篇 |
建筑科学 | 25篇 |
能源动力 | 5篇 |
轻工业 | 76篇 |
水利工程 | 4篇 |
无线电 | 39篇 |
一般工业技术 | 83篇 |
冶金工业 | 254篇 |
原子能技术 | 5篇 |
自动化技术 | 111篇 |
出版年
2022年 | 27篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 16篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 17篇 |
2015年 | 17篇 |
2014年 | 27篇 |
2013年 | 19篇 |
2012年 | 32篇 |
2011年 | 32篇 |
2010年 | 41篇 |
2009年 | 28篇 |
2008年 | 34篇 |
2007年 | 29篇 |
2006年 | 29篇 |
2005年 | 23篇 |
2004年 | 19篇 |
2003年 | 21篇 |
2002年 | 19篇 |
2001年 | 15篇 |
2000年 | 8篇 |
1999年 | 8篇 |
1998年 | 52篇 |
1997年 | 24篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 16篇 |
1993年 | 18篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1972年 | 2篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有776条查询结果,搜索用时 15 毫秒
1.
2.
YL Liu SJ Riederer PJ Rossman RC Grimm JP Debbins RL Ehman 《Canadian Metallurgical Quarterly》1993,30(4):507-511
OBJECTIVE: To evaluate the diagnostic accuracy and clinical usefulness of high-resolution transvaginal duplex Doppler ultrasound in postpartum and post-abortion patients with excessive hemorrhage who are suspected of having residual trophoblast. METHODS: Forty-eight women with excessive hemorrhage referred for possible residual trophoblastic tissue were evaluated by transvaginal duplex Doppler ultrasonography. Based on two-dimensional imaging, the patients were divided prospectively into groups: women who had an empty uterus with a normal uterine cavity, those with a pure endometrial fluid collection and no echogenic foci, those who had a mixed endometrial fluid collection with foci of echogenicity, and those with intracavitary heterogeneous material with mixed echo patterns of fluid and solid components. In each group, Doppler studies were performed and the resistance index (RI) was calculated. The two-dimensional patterns and Doppler results were correlated with clinical and pathologic follow-up. RESULTS: Twenty-eight subjects had a normal uterine cavity and seven had a pure endometrial fluid collection; all were treated conservatively and none showed later clinical evidence of residual trophoblastic tissue. In 13 women, residual trophoblast was strongly suggested from the images of two-dimensional ultrasonography: Five showed an endometrial fluid collection with some echogenic foci, and eight exhibited intracavitary mixed echogenic material. All underwent curettage, and residual trophoblastic tissue was found in ten of the 13. The mean (+/- standard deviation) RI to flow in the myometrial arteries was 0.54 +/- 0.15 in women without residual trophoblast and 0.35 +/- 0.1 in those with residual trophoblastic tissue (P < .01). CONCLUSION: Our experience suggests that transvaginal duplex Doppler ultrasonography is an effective noninvasive method for evaluating patients with excessive postpartum and post-abortion hemorrhage who are suspected of having residual trophoblastic tissue. Its use enhances the positive preoperative diagnosis of residual trophoblastic tissue and may reduce unnecessary curettage procedures. 相似文献
3.
W. Grimm 《Drug development and industrial pharmacy》1996,22(9):851-871
The stability program for clinical samples as presented is based on the ICH Tripartite Guideline for Stability Testing of New Drug Substances and Products and the same principles that the program followed throughout the development of a drug product. But the Guideline and the basic principles were adapted to deal with the specific problems encountered with clinical samples. The expiration dates represent minimum shelf lives, storage conditions, and storage periods, and the minimum shelf lives correspond the duration of the clinical trials in phases I to III. Shelf lives are established on the basis of stress and accelerated tests to provide all batches with an open expiration date. They are supported and confirmed by long-term tests conducted under the storage conditions presenting climate zone II, 25°C/60% RH. The self lives determined apply to all the batches of the relevant development stage, although only the batches in the final phase of development originate from a validated manufacturing phase. For different dosages, dosage forms, and packaging materials, the number of batches and analysis is reduced by scientifically based rationalization measures such as bracketing and matrixing. The stability results obtained with clinical samples are a major factor for achieving a comprehensive assessment of the quality of a finished medicinal product. In this way it is possible to establish a link between the quality of clinical batches for phases I-III and the quality of the finished drug product. 相似文献
4.
Crocker Jennifer; Thompson Leigh L.; McGraw Kathleen M.; Ingerman Cindy 《Canadian Metallurgical Quarterly》1987,52(5):907
In two studies, we explored the effects of trait self-esteem and threats to the self-concept on evaluations of others. In Study 1, subjects high, moderate, and low in self-esteem received either success, failure, or no feedback on a test and later evaluated three pairs of targets: ingroups and outgroups based on a minimal intergroup manipulation, those who scored above average and those who scored below average on the test, and themselves and the average college student. Study 2 explored the effects of self-esteem and threat on ingroup favoritism in a real-world setting, campus sororities. Together, the results of these studies indicate that individuals high in self-esteem, but not those low in self-esteem, respond to threats to the self-concept by derogating outgroups relative to the ingroup when the group boundaries have evaluative implications. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Juntunen Cindy L.; Atkinson Donald R.; Reyes Carla; Gutierrez Maria 《Canadian Metallurgical Quarterly》1994,31(2):327
Investigated whether (1) feminist identity development for women therapists was related to their use of feminist therapy behaviors (FTBs) and (2) feminist identity development and use of FTBs for women therapists were related to self-identification as a feminist therapist. 153 women psychologists (aged 30–77 yrs) were administered a women's issues in therapy questionnaire, which included a short version of the Feminist Identity Scale (FIS; K. M. Rickard, 1989, 1990). Ss were categorized into stages of feminine identity development according to their scores on 4 subscales of the FIS: Passive-Acceptance (PA), Revelation (REV), Embeddedness (EMB), and Synthesis (SYN). Ss scoring high on SYN and REV, and low on PA, reported greater use of FTBs; scores on the EMB were not related to the use of FTBs. All 4 subscales were predictive of women therapists who self-identified as feminist therapists. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Kessler Ronald C.; Foster Cindy; Webster Pamela S.; House James S. 《Canadian Metallurgical Quarterly》1992,7(1):119
There is inconsistency in the literature on the relationship between age and depressive symptoms. Although a careful review shows that some of this inconsistency can be reconciled by recognizing the nonlinear relationship (J. P. Newmann, 1989), 2 additional issues remain unclear. One is that most previous studies used depression screening scales that contain somatic items that could introduce an age bias. The other is that most previous studies combined samples of men and women even though there is evidence that the sex difference in depressive symptoms varies with age. These 2 issues are addressed in this article, using analyzed data from 2 large national surveys. There is a consistent, but quite modest, nonlinear association between age, somatic, and nonsomatic depressive symptoms in both surveys. There is no significant sex difference in the age curves. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
We introduce a novel concept called perceptually meaningful image editing and present techniques for manipulating the apparent depth of objects and creating the illusion of motion in 2D images. Our techniques combine principles of human visual perception with approaches developed by traditional artists. For our depth manipulation technique, the user loads an image, selects an object and specifies whether the object should appear closer or further away. The system automatically determines luminance or color temperature target values for the object and/or background that achieve the desired depth change. Our approach for creating the illusion of motion exploits the differences between our peripheral vision and our foveal vision by introducing spatial imprecision to the image. 相似文献
8.
State psychological associations can respond to supply and demand problems for postdoctoral residencies and internships by creating statewide training programs. A state psychological association training model is presented. The Arizona Psychological Association (AzPA) created a nonprofit subsidiary corporation- the Arizona Psychology Training Consortium-to increase the number of high-quality training opportunities in Arizona. The structure and operation of the program are described. The training model emphasizes cultural diversity, psychotherapy, and independent practice. Members of the practice community in Arizona serve as supervisors, trainers, and mentors. From 2001 through 2006, 19 postdoctoral residents and 51 interns completed the program. AzPA has benefited from increased student involvement. Many residents and interns later became association members. Arizona can serve as a model for other states that wish to help their professionals in training. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
JC Meltzer V Sanders PC Grimm N Chiasson HJ Hoeltke KL Garrett AH Greenberg DM Nance 《Canadian Metallurgical Quarterly》1998,19(8-9):1351-1355
The application of nonradioactive RNA probes for Northern blotting offers the advantage of a rapid turn-around time for results without the loss of sensitivity for target mRNA detection. However, a problem that has impeded the widespread use of nonradioactive RNA probes for use in Northern blotting is the difficulty in stripping these probes from nylon membranes after hybridization. In this report we describe two protocols for stripping digoxigenin (Dig)-labeled RNA probes from nylon membranes. One protocol utilizes a phosphate-buffered formamide stripping solution to remove nonchemically modified (regular) RNA probes while the other method utilizes strippable probes that were produced with a chemically modified nucleotide (CTP) and removed by a specific stripping solution. This latter method was developed by Ambion Inc. and is called Strip-EZ. We also describe a protocol for the detection of two separate rat mRNAs using both biotin and digoxigenin-labeled RNA probes that does not require stripping the membrane after hybridization. Finally, we describe the use of another new labeling technology, called Chem-Link, that quickly and conveniently labels RNA for use in Northern blotting. 相似文献
10.
A robustness analysis and synthesis for incomplete nonlinear decoupling for a class of nonlinear systems is discussed. Rigid and elastic-joint robot models belong to this class. For the elastic case, a transformation facilitates the robustness analysis under a weak assumption. Charts with H
1- and H
- norms of closed-loop disturbance transfer functions of the nonlinear-decoupled system are presented for a robust pole assignment. 相似文献