全文获取类型
收费全文 | 2468篇 |
免费 | 76篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 13篇 |
综合类 | 8篇 |
化学工业 | 610篇 |
金属工艺 | 73篇 |
机械仪表 | 46篇 |
建筑科学 | 100篇 |
矿业工程 | 7篇 |
能源动力 | 66篇 |
轻工业 | 305篇 |
水利工程 | 21篇 |
无线电 | 142篇 |
一般工业技术 | 382篇 |
冶金工业 | 450篇 |
原子能技术 | 28篇 |
自动化技术 | 299篇 |
出版年
2023年 | 14篇 |
2022年 | 17篇 |
2021年 | 38篇 |
2020年 | 21篇 |
2019年 | 26篇 |
2018年 | 31篇 |
2017年 | 35篇 |
2016年 | 49篇 |
2015年 | 45篇 |
2014年 | 59篇 |
2013年 | 77篇 |
2012年 | 111篇 |
2011年 | 136篇 |
2010年 | 96篇 |
2009年 | 100篇 |
2008年 | 126篇 |
2007年 | 108篇 |
2006年 | 92篇 |
2005年 | 78篇 |
2004年 | 60篇 |
2003年 | 55篇 |
2002年 | 53篇 |
2001年 | 41篇 |
2000年 | 47篇 |
1999年 | 49篇 |
1998年 | 126篇 |
1997年 | 89篇 |
1996年 | 54篇 |
1995年 | 49篇 |
1994年 | 44篇 |
1993年 | 37篇 |
1992年 | 30篇 |
1991年 | 32篇 |
1990年 | 38篇 |
1989年 | 37篇 |
1988年 | 36篇 |
1987年 | 32篇 |
1986年 | 30篇 |
1985年 | 38篇 |
1984年 | 32篇 |
1983年 | 29篇 |
1982年 | 16篇 |
1981年 | 22篇 |
1980年 | 30篇 |
1979年 | 18篇 |
1978年 | 23篇 |
1977年 | 20篇 |
1976年 | 26篇 |
1973年 | 16篇 |
1968年 | 11篇 |
排序方式: 共有2550条查询结果,搜索用时 484 毫秒
981.
982.
Nassim Jafarian Kamran Kazemi Hamid Abrishami Moghaddam Reinhard Grebe Marc Fournier Mohamad Sadegh Helfroush Catherine Gondry-Jouet Fabrice Wallois 《Signal, Image and Video Processing》2014,8(2):377-387
The newborn’s cranium is composed of flat cranial bone and fontanels forming together the envelope of the cerebral cavity. The fontanels are relatively flexible since they consist of fibrous membrane that ossifies during maturation becoming flat cranial bone as well. Fontanels give less contrast in computerized tomography (CT) images; they can be identified as gaps between the cranial bones. In this paper, we propose an automatic model-based method using variational level set to segment the skull and fontanels from CT images. In this approach, firstly a skull model consisting of cranial bones and fontanels is created and then used as constraint for level set evolution. Then, by removing the cranial bones from the segmented skulls, the fontanels are obtained. To verify the validity of the achieved results, automatically segmented skull and fontanels have been compared with the ones manually segmented by an expert using Dice similarity and Hausdorff dissimilarity measures, which show the good agreement between them. Furthermore, the surface areas of cranium and fontanel have been determined for these segmentations. The results for both, manual and automatic segmentation, are in good agreement. 相似文献
983.
Andréa Cristiane Krause Bierhalz Selma Aparecida Lopes Ana Luiza Resende Pires 《国际聚合物材料杂志》2017,66(4):193-202
Chitosan-alginate (CA) and chitosan-xanthan (CX) membranes containing aloin were developed for use as wound dressings. The effects of aloin-to-biopolymer ratio on membranes morphology, aspect, liquid uptake, mass loss, mechanical properties, thermal behavior, aloin incorporation efficiency, and release kinetics were analyzed. CA membranes showed higher stability in liquid media and greater elongation at break. CX membranes had more homogeneous microstructure and slightly higher tensile strength. The opacity and color intensity of both formulations increased with aloin incorporation. Maximum aloin incorporation efficiencies were 56.0% and 79.5% in CA and CX membranes, respectively, and slower aloin release was observed for CA membranes. 相似文献
984.
985.
The 2 primary goals of the current study were: (1) to generate data on gender and race differences on subjective well-being (life satisfaction, adjustment, and problems) and (2) to develop an improved measure of subjective outcomes after spinal cord injury. Ss were 125 Caucasian females, 109 Caucasian males, 96 minority males, and 30 minority females who completed the multidimensional adjustment profile (MAP). Mean age of Ss was 38.8 yrs. 10 subjective scales were developed from the MAP, 9 of which were based on factor analysis of sets of 20 life satisfaction items and 31 problem items. Compared with minority Ss, Caucasian Ss reported higher levels of career satisfaction and fewer problems with skills deficit and financial limitations. Interactions between gender and race were observed for 3 scales (emotional distress, physical discomfort, and adjustment), with more positive scores reported by minority males and Caucasian females. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
986.
Immunofluorescence staining techniques at present, when applied to follow the expression of HIV-1-specific antigens on infected cells, only give the information that the antigens detected are localized in the outer region of the membrane of the infected cell. We therefore set up a procedure using magnetic polystyrol particles coated with antibodies specific for the HIV-1 antigens under study, in combination with scanning electron microscopy. We were able to demonstrate that p24 and p18 structural antigens are clearly expressed on the surface of HIV-1-infected H9 lymphocytes. This means that there was no steric hindrance for structures of cell-like size specific for HIV-1 antigens to interact with their target antigens. Other antigens may be hidden in membrane structures and are therefore inaccessible, for example, to the beads used here, which were of a similar size to antigen-specific cells in vivo. The results of this model system must be seen with respect to the interaction of antigen-specific cell-mediated immunity with full antibody-dependent cellular cytotoxicity, or without cytotoxic T lymphocytes, the mediator function of antibodies. 相似文献
987.
Peter Schreiber Reinhard Siegmund-Schultze Wolfgang R. Dick Wolfgang Schreier Gerhard Rammer Reinhard Mocek Erhard Scholz Paul Ridder Renate Strohmeier 《NTM》2000,8(1):123-127
Ohne Zusammenfassung 相似文献
988.
989.
A Schneider M Possover S Kamprath U Endisch N Krause H N?schel 《Canadian Metallurgical Quarterly》1996,88(6):1057-1060
In laparoscopy-assisted radical vaginal hysterectomy, laparoscopy is used to develop the paravesical and pararectal spaces. The cardinal ligament is isolated and cut after bipolar coagulation to the level of the deep uterine vein. By the vaginal approach, the ureters are identified before their entry into the bladder pillar. The uterine vessels are pulled down until their laparoscopically coagulated ends become visible. After incision of the vesicocervical reflection, the uterine fundus is grasped and developed (D?derlein maneuver). The lower cardinal and uterosacral ligaments are exposed by pulling the cervix and fundus uteri to the contralateral side. The cardinal and uterosacral ligaments are dissected and ligated, and the specimen is removed. We combined laparoscopic lymphadenectomy with radical vaginal hysterectomy in 33 women with cervical cancer. The mean operating time was 80 minutes for the vaginal phase and 215 minutes for the laparoscopic phase, including paraaortic and pelvic lymphadenectomy and preparation of the cardinal ligaments. Blood transfusions were necessary in four women. Three patients sustained injury to the bladder, one patient to the left ureter, and another patient to the left internal iliac vein. Repair was achieved at primary surgery for all intraoperative complications. No fistula was observed. The patients had fully recuperated after a mean of 28 days. The laparoscopy-assisted Schauta-Stoeckel approach may prove to be a safe alternative to conventional radical abdominal hysterectomy. 相似文献
990.
Laessle Reinhold G.; Tuschl Reinhard J.; Waadt Sabine; Pirke Karl M. 《Canadian Metallurgical Quarterly》1989,57(6):772
The hypothesis that patients with bulimia nervosa and restrained eaters exist on a simple continuum of psychopathology was tested in 60 Ss (20 bulimics, 20 restrained eaters, 20 unrestrained eaters). Regarding measures related to dieting behavior and physical appearance, the restrained eaters differed significantly from unrestrained eaters and were similar to bulimic patients except for level of psychopathology. The restrained eaters could not be distinguished from the unrestrained eaters with regard to measures representing interoceptive perception, self-esteem, and fears about interpersonal relationships. On these traits, bulimic patients could be clearly distinguished from the normal Ss. The results support a 2-component model of the psychopathology of bulimia nervosa. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献