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   2487篇
  免费   237篇
  国内免费   9篇
耳鼻咽喉   7篇
儿科学   99篇
妇产科学   63篇
基础医学   302篇
口腔科学   76篇
临床医学   333篇
内科学   491篇
皮肤病学   22篇
神经病学   125篇
特种医学   201篇
外科学   301篇
综合类   97篇
一般理论   2篇
预防医学   272篇
眼科学   52篇
药学   162篇
中国医学   1篇
肿瘤学   127篇
  2022年   13篇
  2021年   30篇
  2020年   25篇
  2019年   37篇
  2018年   66篇
  2017年   36篇
  2016年   49篇
  2015年   61篇
  2014年   67篇
  2013年   102篇
  2012年   88篇
  2011年   99篇
  2010年   87篇
  2009年   80篇
  2008年   93篇
  2007年   87篇
  2006年   84篇
  2005年   78篇
  2004年   62篇
  2003年   59篇
  2002年   58篇
  2001年   59篇
  2000年   59篇
  1999年   47篇
  1998年   58篇
  1997年   52篇
  1996年   67篇
  1995年   45篇
  1994年   35篇
  1993年   43篇
  1992年   48篇
  1991年   54篇
  1990年   67篇
  1989年   66篇
  1988年   56篇
  1987年   40篇
  1986年   50篇
  1985年   55篇
  1984年   41篇
  1983年   40篇
  1982年   27篇
  1981年   27篇
  1980年   19篇
  1979年   37篇
  1978年   25篇
  1977年   17篇
  1976年   33篇
  1975年   16篇
  1970年   14篇
  1969年   17篇
排序方式: 共有2733条查询结果,搜索用时 62 毫秒
1.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
2.
3.
4.
5.
While the family's primacy in the patient's adaptation to chronic illness increasingly is being recognized by health professionals and social scientists, the reverse side of the coin, that is, the impact of chronicity on the family, has received little attention. A life-span development perspective is used to enrich the more traditional frameworks employed to study family development and also as a unifying framework from which to view the impact of illness on individual family members and the family as a unit. A review of selected literature reveals a profile of families most at risk for serious disruption in situations involving chronic illness. Propositions suggesting interventions directed at patients and families experiencing chronicity are derived.  相似文献   
6.
7.

Background  

Glioblastoma multiforme is the most malignant form of brain tumor. Despite treatment including surgical resection, adjuvant chemotherapy, and radiation, these tumors typically recur. The recurrent tumor is often resistant to further therapy with the same agent, suggesting that the surviving cells that repopulate the tumor mass have an intrinsic genetic advantage. We previously demonstrated that cells selected for resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) are near-diploid, with over-representation of part or all of chromosomes 7 and 22. While cells from untreated gliomas often have over-representation of chromosome 7, chromosome 22 is typically under-represented.  相似文献   
8.
9.
Esmolol, administered as a bolus followed by continuous infusion, was used to treat the occurrence of transient tachycardia and hypertension or tachycardia alone before cardiopulmonary bypass in 45 patients. The study was conducted in two phases. Phase I (15 patients) was a dose-finding study and phase II (30 patients) was a randomized, double-blind, placebo-controlled efficacy study. All patients received the last dose of their usual beta-adrenergic blocker the night before the operation and were anesthetized with midazolam, vecuronium, and enflurane in oxygen. Treatment criteria were either a systolic blood pressure greater than 140 mm Hg and a heart rate greater than 70 or a heart rate greater than 80 beats/min. In phase I, graduated doses of esmolol were given to successive patients. A dose of 80 mg followed by a 12 mg/min infusion was declared effective. Phase II patients were randomized to receive esmolol (n = 16) or placebo (n = 14). Hemodynamic data were collected at baseline and 1, 3, 5, and 10 minutes after the administration of esmolol. Plasma norepinephrine was measured at baseline, 1, and 10 minutes. Esmolol significantly (p less than 0.05) reduced heart rate at 1, 3, 5, and 10 minutes but did not change blood pressure, pulmonary artery diastolic pressure, right atrial pressure, cardiac output, or systemic vascular resistance. Our results show that a bolus loading dose of esmolol is safe and effective in the treatment of tachycardia in patients with ischemic heart disease and that esmolol rapidly blocks the beta-adrenergic effects of norepinephrine associated with surgical stress.  相似文献   
10.
Aniline and its halogenated derivatives are widely used as chemical intermediates. The purpose of this study was to determine the hepatotoxic and nephrotoxic potential of the 2-haloanilines. Male Fischer 344 rats (n > or = 4) were injected (i.p.) with 1.0 or 1.25 mmol/kg of: aniline (A), 2-fluoroaniline (2-FA), 2-chloroaniline (2-ClA), 2-bromoaniline (2-BrA), 2-iodoaniline (2-IA) or vehicle (0.9% saline, 2.5 ml/kg). All compounds were injected as hydrochloride salts. Renal and hepatic function was monitored 24 h after treatment. All of the 2-haloanilines induced oliguria, diminished kidney weight, tubular casts and decreased renal cortical slice accumulation of organic anions. Blood urea nitrogen (BUN) levels were increased (P < 0.05) by treatment with 1.0 or 1.25 mmol/kg of 2-FA, 2-ClA or 2-BrA. Hepatic alterations were also observed and characterized by elevated plasma ALT/GPT activity and altered morphology in the centrilobular region. The nephrotoxic and hepatotoxic potentials were similar among the 2-haloanilines but aniline was less toxic than its 2-halo derivatives. These results demonstrated that halogen substitution at the 2-position of aniline increased hepatic and renal toxicity. However, the severity of toxicity was not influenced by the nature of the halogen substituent.  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