全文获取类型
收费全文 | 1487篇 |
免费 | 5篇 |
专业分类
化学工业 | 12篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 12篇 |
轻工业 | 5篇 |
无线电 | 5篇 |
一般工业技术 | 19篇 |
冶金工业 | 1432篇 |
自动化技术 | 3篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 12篇 |
2010年 | 4篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1999年 | 32篇 |
1998年 | 377篇 |
1997年 | 249篇 |
1996年 | 155篇 |
1995年 | 87篇 |
1994年 | 81篇 |
1993年 | 75篇 |
1992年 | 11篇 |
1991年 | 34篇 |
1990年 | 28篇 |
1989年 | 30篇 |
1988年 | 35篇 |
1987年 | 34篇 |
1986年 | 18篇 |
1985年 | 17篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 15篇 |
1978年 | 4篇 |
1977年 | 41篇 |
1976年 | 90篇 |
1975年 | 4篇 |
1955年 | 1篇 |
排序方式: 共有1492条查询结果,搜索用时 15 毫秒
991.
A 34-year-old man came to this Emergency Room because of fever, swelling and pain in the right thigh. Tetralogy of Fallot with bicuspid pulmonary valve was diagnosed after serial examination, and computed tomography of the right thigh revealed pyogenic myositis. Surgical drainage of the right thigh abscess and a further pus culture yielded viridans streptococci. There has been no record in the medical literature of a pyogenic myositis caused by viridans streptococci in an adult tetralogy of Fallot. This is thus the first case reported. 相似文献
992.
CW Trotter 《Canadian Metallurgical Quarterly》1997,11(1):52-64
Management of ductal carcinoma in situ has become one of the most controversial topics in breast disease. While mastectomy has been the traditional treatment, many now feel it is excessive in most cases. As a result, a great effort has been made to identify pathobiological characteristics of DCIS that can be used to stratify appropriate treatment decisions. This article reviews efforts to relate pathobiological characteristics to disease management and provides treatment recommendations based on the latest evidence. 相似文献
993.
OBJECTIVE: To compare fragment reconstruction and bone plate fixation versus bridging plate fixation for treating highly comminuted (> 4 fragments) femoral fractures in dogs. DESIGN: Retrospective study. ANIMALS: 35 dogs with highly comminuted fractures of the femur. PROCEDURE: Medical records of all dogs included in this study were reviewed. Dogs had been treated with fragment reconstruction and bone plate application (n = 20) or major fragment alignment and bridging plate fixation (15). Postoperative and follow-up radiographs were evaluated. Operating and hospitalization times, bone alignment, bone healing, and complications were considered. RESULTS: There were no differences in hospitalization times, limb alignment, and complications between dogs with fractures treated with fragment reconstruction and dogs with fractures treated with bridging plate fixation. Dogs with fractures treated with bridging plate fixation had shorter operative times and faster times to radiographic evidence of bone healing. CLINICAL IMPLICATIONS: Bridging plate fixation is quicker to perform and results in faster healing than fragment reconstruction and bone plate fixation when used to treat comminuted femoral fractures. 相似文献
994.
A 68 year-old woman underwent replacement of the descending thoracic aorta with a cryopreserved aortic homograft for the treatment of a Stanford B dissecting aneurysm. After surgery, the patient made an uneventful recovery without recurrent infection. In such cases, the use of aortic homografts to replace aortic segments is a promising and effective therapeutic option. 相似文献
995.
996.
997.
ME Grigg CW McMahon S Morkowski AY Rudensky AM Pullen 《Canadian Metallurgical Quarterly》1998,72(4):2577-2588
Presentation of the Mtv-1 superantigen (vSag1) to specific Vbeta-bearing T cells requires association with major histocompatibility complex class II molecules. The intracellular route by which vSag1 trafficks to the cell surface and the site of vSag1-class II complex assembly in antigen-presenting B lymphocytes have not been determined. Here, we show that vSag1 trafficks independently of class II to the plasma membrane by the exocytic secretory pathway. At the surface of B cells, vSag1 associates primarily with mature peptide-bound class II alphabeta dimers, which are stable in sodium dodecyl sulfate. vSag1 is unstable on the cell surface in the absence of class II, and reagents that alter the surface expression of vSag1 and the conformation of class II molecules affect vSag1 stimulation of superantigen reactive T cells. 相似文献
998.
OBJECTIVES: This study identified behavioral and psychosocial/interpersonal factors in young adolescence that are associated with handgun carrying in later adolescence. METHODS: A sample of 2200 high school students was surveyed at 9th grade and again at 12th grade. RESULTS: Multivariate logistic regression analyses indicated that measures of risk-taking preference, depression, stress, temper, and drug use assessed while the students were in 9th grade were predictive of handgun carrying in 12th grade for both male and female students. CONCLUSIONS: These findings suggest the need for a comprehensive approach to prevention that focuses on both individual and interpersonal factors associated with adolescents' decision to carry a handgun. 相似文献
999.
Localized in vivo 1H nuclear MR spectroscopy for evaluation of human uterine cervical carcinoma 总被引:1,自引:0,他引:1
JH Lee KS Cho YM Kim ST Kim CW Mun JH Na JE Mok TH Lim 《Canadian Metallurgical Quarterly》1998,170(5):1279-1282
Spontaneous abortion occurs in 15% to 20% of all human pregnancies. Since the late 1800s, the management of incomplete spontaneous abortion has focused on using curettage to empty the uterus as quickly as possible. This practice began to reduce blood loss and infection and has been unquestioned for 4 decades. In today's medical climate, few spontaneous abortions are the resuslt of illegal manipulation, given the availability of legal pregnancy termination. Antibiotics and transfusions are available, should complications arise in conservatively managed cases. Two prospective randomized trials suggest that conservative management may be advantageous for women who have stable vital signs without evidence of infection. They will have fewer perforations and, possibly, fewer infections and uterine synechiae with expectant or medical management. Larger trials should be undertaken to critically assess surgical evacuation compared to medical management, factoring in the psychologic impact of treatment. We believe that medical management will prove to be the most appropriate treatment for uncomplicated spontaneous incomplete abortion in the 21st century. 相似文献
1000.