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   4495篇
  免费   325篇
  国内免费   8篇
耳鼻咽喉   24篇
儿科学   206篇
妇产科学   144篇
基础医学   478篇
口腔科学   109篇
临床医学   404篇
内科学   1063篇
皮肤病学   49篇
神经病学   295篇
特种医学   479篇
外国民族医学   1篇
外科学   509篇
综合类   99篇
一般理论   1篇
预防医学   414篇
眼科学   15篇
药学   220篇
  1篇
中国医学   1篇
肿瘤学   316篇
  2021年   42篇
  2019年   48篇
  2018年   55篇
  2017年   45篇
  2016年   43篇
  2015年   40篇
  2014年   104篇
  2013年   132篇
  2012年   183篇
  2011年   180篇
  2010年   124篇
  2009年   126篇
  2008年   148篇
  2007年   211篇
  2006年   202篇
  2005年   185篇
  2004年   155篇
  2003年   152篇
  2002年   117篇
  2001年   114篇
  2000年   128篇
  1999年   114篇
  1998年   111篇
  1997年   105篇
  1996年   106篇
  1995年   88篇
  1994年   56篇
  1993年   70篇
  1992年   77篇
  1991年   81篇
  1990年   77篇
  1989年   99篇
  1988年   100篇
  1987年   87篇
  1986年   94篇
  1985年   98篇
  1984年   83篇
  1983年   55篇
  1982年   43篇
  1981年   53篇
  1980年   67篇
  1978年   56篇
  1977年   44篇
  1976年   37篇
  1975年   41篇
  1974年   44篇
  1970年   48篇
  1969年   33篇
  1968年   34篇
  1966年   34篇
排序方式: 共有4828条查询结果,搜索用时 31 毫秒
121.
Seventy-five patients with resistant acute leukemia or lymphoma received high-dose cyclophosphamide and etoposide to explore the activity of this combination in resistant hematologic malignancies, and to determine the maximum doses of these drugs that can be combined without bone marrow transplantation. Etoposide was administered over 29 to 69 hours by continuous infusion corresponding to total doses of 1.8 g/m2 to 4.8 g/m2. Cyclophosphamide, 50 mg/kg/d, was administered on 3 or 4 consecutive days total 150 to 200 mg/kg ideal body weight). At all dose levels myelosuppression was severe but reversible. Mucosal toxicity was dose-limiting with the maximum tolerated dose level combining etoposide 4.2 g/m2 with cyclophosphamide 200 mg/kg. Continuous etoposide infusion produced stable plasma levels that were lower than would be achieved after administration by short intravenous infusion, and this could explain our ability to escalate etoposide above the previously reported maximum tolerated dose. There were 28 complete (35%) and 12 partial (16%) responses. Median duration of complete response (CR) was 3.5 months (range 1.1 to 20+). Seventeen of 40 patients (42%) with acute myelogenous leukemia (AML) achieved CR, including 6 of 20 (30%) with high-dose cytosine arabinoside resistance. We conclude that bone marrow transplantation is not required after maximum tolerated doses of etoposide and cyclophosphamide. This regimen is active in resistant hematologic neoplasms, and the occurrence of CR in patients with high-dose cytosine arabinoside-resistant AML indicates a lack of complete cross-resistance between these regimens.  相似文献   
122.
Sixty-five multiply transfused patients with severe aplastic anemia were given cyclophosphamide followed by grafts anemia were given cyclophosphamide followed by grafts from HLA-identical siblings. The effect of the administration of viable donor buffy coat cells following the marrow inoculum was evaluated with regard to graft rejection and survival. Results in 43 patients so treated are presented along with those in 22 concurrent patients given marrow alone. Most patients given buffy coat had positive in vitro tests of sensitization indicating a high risk for graft rejection, while all but one of the patients given marrow alone had negative tests. Thirty of the 43 (70%) patients given marrow and buffy coat are alive between 10 and 61 mo (median 36) after grafting; 4 died after graft rejection and 6 with acute or chronic graft-versus-host disease (GVHD). Eleven of the 22 (50%) patients given marrow alone are alive between 29 and 65 mo (median 52); 7 died after graft rejection and 3 with GVHD. The addition of buffy coat cell infusions to the marrow inoculum reduced the risk of rejection and increased survival in the currently reported transfused patients when compared to patients grafted before 1976. However, there was an increased risk of chronic GVHD. Recipients of marrow from female donors survived slightly better (73%) than recipients of male marrow (58%).  相似文献   
123.

Background and purpose

Pneumonia is the most important respiratory problem in low‐to‐middle income countries. Airway clearance therapy continues to be used in children with pneumonia and secretion retention; however, there is lack of evidence to support or reject this treatment. This study aimed to investigate the feasibility of a randomized controlled trial (RCT) on the efficacy and safety of assisted autogenic drainage (AAD) compared to standard nursing care in children hospitalized with uncomplicated pneumonia.

Methods

A single‐blinded pilot RCT was conducted on 29 children (median age 3.5 months, IQR 1.5–9.4) hospitalized with uncomplicated pneumonia. The intervention group received standard nursing care with additional bi‐daily AAD, for 10 to 30 min. The control group only received standard nursing care, unless otherwise deemed necessary by the physician or physiotherapist. The primary outcome measure was duration of hospitalization. The secondary outcome measures included days of fever and supplemental oxygen support; respiratory rate (RR) and heart rate adjusted for age; RR and oxygen saturation pre‐, post‐, and 1‐hr post‐treatment; oxygen saturation; adverse events; and mortality.

Results

No difference was found for duration of hospitalization (median 7.5 and 7.0 days for the control and intervention groups, respectively); however, Kaplan–Meier analysis revealed a strong tendency towards a shorter time to discharge in the intervention group (p = .06). No significant differences were found for the other outcome measures at time of discharge. No adverse events were reported. Within the intervention group, a significant reduction in RR adjusted for age was found.

Discussion

As no adverse events were reported, and AAD did not prolong hospitalization; AAD might be considered as safe and effective in young children with uncomplicated pneumonia. However, a larger multicentred RCT is warranted to determine the efficacy of AAD compared to standard nursing care.  相似文献   
124.
125.
126.
127.
128.
129.
Since 1976, we have implanted bilateral phrenic nerve electrodes for diaphragm pacing in 33 infants and children. This population includes 23 patients with congenital central hypoventilation syndrome (CHS), two with late onset CHS and hypothalamic dysfunction, three with hypoventilation associated with Chiari II malformation and myelomeningocele, and five with quadriplegia. Our experience, totalling 192 system-years and 96 patient-years of pacing, has enabled us to document the nature and frequency of problems related to the implanted components of the Avery Laboratories (S-232-1) pacemaker system when used in a pediatric population. By life table analysis, the mean time to need for replacement of any implanted component was 56.3 months. A total of 26 failures requiring component replacement occurred and were classified into four types: (1) receiver failure (15 cases), (2) electrode wire or wire insulation breakage (six cases), (3) infection requiring diaphragm pacer system removal (three cases), and (4) mechanical nerve injury (two cases). We conclude that the present diaphragm pacing system is effective but not without risk of biomedical component failure. The present system might be substantially improved by (1) a modified receiver design with a hermetic seal to prevent fluid penetration, (2) stronger, better insulated electrode wires, and (3) modifications of surgical technique and electrode type to prevent phrenic nerve damage.  相似文献   
130.
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