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   2562篇
  免费   14篇
电工技术   8篇
化学工业   48篇
机械仪表   5篇
建筑科学   10篇
矿业工程   1篇
能源动力   17篇
轻工业   52篇
石油天然气   1篇
无线电   53篇
一般工业技术   53篇
冶金工业   2246篇
自动化技术   82篇
  2021年   3篇
  2020年   7篇
  2019年   3篇
  2018年   6篇
  2017年   8篇
  2016年   7篇
  2015年   4篇
  2014年   6篇
  2013年   15篇
  2012年   12篇
  2011年   13篇
  2010年   15篇
  2009年   13篇
  2008年   19篇
  2007年   14篇
  2006年   22篇
  2005年   18篇
  2004年   11篇
  2003年   12篇
  2002年   18篇
  2001年   9篇
  2000年   15篇
  1999年   106篇
  1998年   701篇
  1997年   380篇
  1996年   247篇
  1995年   160篇
  1994年   132篇
  1993年   125篇
  1992年   24篇
  1991年   24篇
  1990年   20篇
  1989年   32篇
  1988年   35篇
  1987年   32篇
  1986年   31篇
  1985年   26篇
  1984年   7篇
  1983年   5篇
  1982年   10篇
  1981年   16篇
  1980年   17篇
  1979年   2篇
  1978年   5篇
  1977年   66篇
  1976年   97篇
  1975年   8篇
  1972年   2篇
  1939年   2篇
  1938年   2篇
排序方式: 共有2576条查询结果,搜索用时 31 毫秒
101.
102.
103.
This case of ectopic pancreas found in the pre-pyloric channel of a 2-day-old infant is unique. A review of the literature reveals no other cases of symptomatic ectopic pancreas in an infant of this age. In this patient, signs and symptoms were consistent with pyloric stenosis. Upper gastrointestinal study and esophagogastroduodenoscopy (EGD) revealed the diagnosis. This case is examined and the literature is reviewed.  相似文献   
104.
Conditions affecting either or both extremities offer unique opportunities and challenges for investigators and clinicians. When the condition is purely unilateral, observations on the unaffected extremity may be used as a within-patient control, and thereby strengthen the ability to identify changes in the affected limb. However, such use presumes that the condition will not subsequently develop in the unaffected extremity. Bilateral presentations or subsequent development of disease in the unaffected extremity is common in conditions such as the carpal tunnel syndrome (CTS). Treatment of one extremity may lead to development or aggravation of CTS in the other extremity. Since both extremities may be necessary to perform certain activities, it can be difficult to clearly identify treatment effects when looking at functional outcomes. In an effort to avoid these complexities, investigators have used one of two approaches in studying CTS: either selecting only those patients with unilateral disease, or analyzing results by extremity, often avoiding any outcome measures that might depend upon both extremities (such as driving). We illustrate some of the shortcomings of this approach, such as loss of patients and data, with preliminary information from our ongoing prospective study of carpal tunnel surgery outcomes. We develop a dynamic model that incorporates etiologic factors and treatment effects to describe changes in CTS over time. This model accounts for extremity-specific and systemic factors, as well as possible interaction of the disease process in both hands. The advantages of this model include a more rational approach to research and care of extremity disorders, and research strategies which address a wider scope of patients and outcomes; however, its application is limited by the need for more extensive data collection.  相似文献   
105.
PURPOSE: To evaluate the feasibility of high-dose chemotherapy (HDC) with autologous hematopoietic progenitor-cell support (AHPCS) as part of combined modality therapy (CMT) in patients with inflammatory breast cancer (IBC). PATIENTS AND METHODS: From April 1993 to March 1997, 30 patients with IBC were treated at our program. Twenty-three patients received neoadjuvant chemotherapy (NAC) before HDC; 18 patients also received adjuvant chemotherapy following surgery, but before HDC. All patients received HDC with high-dose cyclophosphamide, cisplatin, and carmustine (BCNU) with AHPCS. Every patient underwent surgery either before (27 patients) or after (three patients) HDC. Patients received radiotherapy after HDC in addition to tamoxifen if their tumors were estrogen receptor-positive. RESULTS: Thirteen patients experienced grade 3 or 4 nonhematologic noninfectious toxicities. In 12 patients (40%), this represented drug-induced lung injury, which in all cases responded to a 10-week course of corticosteroids. The only treatment-related death was secondary to hemolytic-uremic syndrome (HUS). Another patient suffered grade 4 CNS toxicity, which was completely reversible. All patients engrafted promptly. Eight patients relapsed, five of whom had a poor pathologic response to NAC. Relapses were local (five patients), local plus systemic (one), or systemic only (two). Median follow-up time from diagnosis and HDC is 23.5 (range, 7 to 49) and 19 (range, 4 to 44) months, respectively. Twenty-one patients (70%; 95% confidence interval [CI], 51% to 86%) remain alive and free of disease 4 to 44 months after HDC. Median disease-free survival (DFS) and overall survival have not yet been reached. CONCLUSION: HDC as part of CMT is feasible in patients with IBC. The toxicity of this treatment program is significant, but tolerable. Despite the short follow-up duration, the promising DFS observed in this group of patients warrants randomized studies that include a HDC-containing arm in patients with IBC.  相似文献   
106.
107.
An actin-depolymerizing marine natural product, mycalolide B, and a related compound, kabiramide D, were labeled with biocytin, a biotin derivative, and used to specify target molecules in cultured rat 3Y1 fibroblasts. Mycalolide B exhibited the ability to bind to various intracellular proteins, probably through the Michael addition of a sulfhydryl group to C5 of mycalolide B. However, no intracellular proteins other than actin apparently reacted with biocytinylated kabiramide D, demonstrating that the binding of kabiramide D to actin was highly specific. Cells treated with biocytinylated kabiramide D followed by staining with fluorescein isothiocyanate-conjugated avidin showed that biocytinylated kabiramide D bound to stress fibers composed of F-actin, although the staining intensity was weaker than the fluorescent phalloidin staining. The assay for the binding of kabiramide D to actin, which had previously been treated with other actin-depolymerizing agents, showed that the actin-binding site for kabiramide D was the same as that for bistheonellide A, but not those for latrunculin A and cytochalasin D.  相似文献   
108.
The causes of 59 postneonatal deaths of very low birthweight infants were determined. Bronchopulmonary dysplasia (BPD) was the cause of 19 deaths. It also coexisted in 12/20 deaths from infection and 9/20 deaths from other causes. Improvement will be best achieved by advances in the prevention and treatment of BPD.  相似文献   
109.
110.
The present research examines episodes of favor exchange among peer employees. We posit that favor receivers' and favor givers' commitment to their exchange relationships with one another will be accounted for by different factors. As predicted, in 2 different organizational contexts, receivers' commitment to their relationships with givers was found to be more related to their judgments of the givers' interactional justice when performing the favor, whereas givers' commitment to their relationships with receivers was shown to be more associated with their judgments of the favorability of the outcomes associated with the favor that they performed. The implications of these findings for how givers and receivers can better manage favor exchange, and hence their relationships with each other, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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