首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2176篇
  免费   0篇
  国内免费   1篇
电工技术   4篇
化学工业   8篇
机械仪表   2篇
建筑科学   6篇
能源动力   4篇
轻工业   15篇
水利工程   1篇
无线电   6篇
一般工业技术   18篇
冶金工业   2096篇
原子能技术   1篇
自动化技术   16篇
  2022年   1篇
  2021年   2篇
  2020年   1篇
  2019年   4篇
  2015年   1篇
  2014年   2篇
  2013年   8篇
  2012年   2篇
  2011年   6篇
  2010年   5篇
  2009年   2篇
  2008年   5篇
  2007年   5篇
  2006年   5篇
  2005年   1篇
  2004年   2篇
  2003年   5篇
  2002年   5篇
  2001年   2篇
  2000年   1篇
  1999年   76篇
  1998年   694篇
  1997年   398篇
  1996年   246篇
  1995年   139篇
  1994年   112篇
  1993年   127篇
  1992年   17篇
  1991年   21篇
  1990年   15篇
  1989年   23篇
  1988年   24篇
  1987年   19篇
  1986年   11篇
  1985年   13篇
  1983年   3篇
  1982年   12篇
  1981年   8篇
  1980年   13篇
  1978年   4篇
  1977年   41篇
  1976年   91篇
  1975年   2篇
  1973年   1篇
  1971年   1篇
  1955年   1篇
排序方式: 共有2177条查询结果,搜索用时 203 毫秒
961.
The purpose of this longitudinal investigation was to study changes in the dental arches and dentition that occur in midadulthood in an untreated, normal sample. The subjects had Class I molar and canine relationships with less than 4.0 mm of overjet and less than 50% overbite. None had undergone previous orthodontic treatment. Evaluations and measurements were made from dental casts and periapical radiographic surveys of 15 females and 15 males from approximately 25 years to 46 years. The findings indicate that over the span of the study, significant changes occur in the maxillary and mandibular dental arches and dentition in both males and females, including a clinically significant increase in tooth size-arch length (circumference) discrepancy. These changes should be considered part of the normal maturational process and should be taken into consideration when planning treatment and retention options for adolescent and adult patients.  相似文献   
962.
963.
OBJECTIVE: To determine the effects of regular exercise on women receiving danazol for the treatment of endometriosis. METHODS: Thirty-nine patients were randomized to a danazol-only or a danazol/exercise regimen in a prospective clinical trial carried out at tertiary care institutions. Patients in the danazol/exercise group were instructed to exercise four times per week, for 40 min per session, at an intensity of 20 metabolic units. Side effect profiles, pelvic symptoms, aerobic fitness, strength and hormone levels were compared for all subjects. The number of side effects of danazol was analyzed by the method of generalized estimating equations. RESULTS: The number of side effects reported during a 4-week period was 1.09-2.17 times greater for the danazol-only than for the danazol/exercise group. All patients had improvement of symptoms during treatment. The danazol/exercise group had significantly lower testosterone levels during treatment. The time to recurrence of endometriosis was not different between groups. CONCLUSIONS: Exercise during danazol therapy reduces the number of androgenic side effects. Relief of pain and time to recurrence are unaffected.  相似文献   
964.
965.
966.
967.
968.
The study aim was to investigate the role of the parasympathetic nervous system in the control of glucose tolerance in man. Glucose kinetics were determined during an oral glucose tolerance test (OGTT) in six subjects with truncal vagotomies and six control subjects. Basal plasma glucose levels in the two groups were equal; however, 20 to 40 minutes after the OGTT, glucose was higher in vagotomized compared with control subjects (P < .02). There were no differences in insulin levels between the subjects. Glucagon decreased after the OGTT in the controls, whereas in the vagotomized subjects it increased transiently and did not decrease beyond basal levels. There was no difference in basal hepatic glucose production, but suppression was greater in controls in the first 10 minutes (P < .01). Gut-derived glucose appearance increased faster and to a higher level (56.0 +/- 8 v 29.7 +/- 2.9 mumol/kg/min, P < .02) in vagotomized subjects. There were no differences in the metabolic clearance rate of glucose between the two groups. It is concluded that parasympathetic innervation of the pancreas is essential for suppression of glucagon secretion during hyperglycemia. However, abnormal glucose tolerance in vagotomized subjects is primarily due to rapid gut glucose absorption, with the denervated parasympathetic system playing only a minor role.  相似文献   
969.
PURPOSE: Paclitaxel is a highly active single agent in the treatment of breast cancer. However, its optimal incorporation into combination regimens awaits definition. In this phase II study, we added paclitaxel, administered by 1-hour infusion, to a previously described combination regimen that included mitoxantrone, fluorouracil (5-FU), and high-dose leucovorin (NFL). PATIENTS AND METHODS: Forty-six patients with metastatic breast cancer received the following regimen as first- or second-line treatment: paclitaxel 135 mg/m2 by 1-hour intravenous (i.v.) infusion on day 1, mitoxantrone 10 mg/m2 by i.v. bolus on day 1, 5-FU 350 mg2/m by i.v. bolus on days 1, 2, and 3, and leucovorin 300 mg i.v. over 30 to 60 minutes immediately preceding 5-FU on days 1, 2, and 3. Courses were administered at 3-week intervals for a total of eight courses in responding patients. RESULTS: Twenty-three of 45 assessable patients (51%) had major responses. Previous chemotherapy, and in particular previous treatment with doxorubicin, did not affect response rate. The median response duration was 7.5 months. Myelosuppression was moderately severe, with 76% of courses resulting in grade 3 or 4 leukopenia. Hospitalization for treatment of fever during neutropenia was required in 13% of courses, and two patients died as a result of sepsis. Two patients developed severe congestive heart failure after a large cumulative anthracycline dose. CONCLUSION: This combination regimen was active as first- or second-line therapy for metastatic breast cancer, although its activity compared with other combination regimens or with paclitaxel alone is unclear. Myelosuppression was more severe than anticipated based on previous results with the NFL regimen or with paclitaxel administered at this dose and schedule as a single agent. The infrequent development of cardiotoxicity in these patients suggests that the paclitaxel/mitoxantrone combination may not share the problems previously reported with the paclitaxel/doxorubicin combination.  相似文献   
970.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号