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   21100篇
  免费   1148篇
  国内免费   165篇
耳鼻咽喉   154篇
儿科学   415篇
妇产科学   617篇
基础医学   2394篇
口腔科学   584篇
临床医学   1686篇
内科学   5596篇
皮肤病学   357篇
神经病学   2113篇
特种医学   884篇
外科学   3118篇
综合类   70篇
一般理论   1篇
预防医学   769篇
眼科学   329篇
药学   1348篇
中国医学   31篇
肿瘤学   1947篇
  2024年   23篇
  2023年   200篇
  2022年   383篇
  2021年   680篇
  2020年   433篇
  2019年   538篇
  2018年   675篇
  2017年   468篇
  2016年   546篇
  2015年   609篇
  2014年   837篇
  2013年   998篇
  2012年   1563篇
  2011年   1570篇
  2010年   888篇
  2009年   807篇
  2008年   1285篇
  2007年   1281篇
  2006年   1224篇
  2005年   1136篇
  2004年   1106篇
  2003年   973篇
  2002年   838篇
  2001年   292篇
  2000年   288篇
  1999年   302篇
  1998年   217篇
  1997年   161篇
  1996年   165篇
  1995年   148篇
  1994年   108篇
  1993年   97篇
  1992年   185篇
  1991年   171篇
  1990年   133篇
  1989年   131篇
  1988年   105篇
  1987年   90篇
  1986年   118篇
  1985年   85篇
  1984年   79篇
  1983年   71篇
  1982年   52篇
  1981年   37篇
  1980年   28篇
  1979年   49篇
  1978年   42篇
  1976年   19篇
  1974年   20篇
  1973年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
With easy chemical synthesis from its precursor, methamphetamine (MA) is now widespread in many countries. The abuse of methamphetamine is associated with several negative effects on health, because MA is a neurotoxin and a dangerous central nervous system stimulant. It changes levels of neurotransmitters in the brain, releasing dopamine and inhibiting nor epinephrine uptake which increases sympathetic nervous system activity and can lead to cardiac arrhythmia, hypertension and tachypnea. The consequences of MA abuse are clearly manifested in oral diseases (like “meth mouth”) which is characterised by extensive caries, teeth grinding with ensuing dental wear and trismus. The present review was designed to fill the gap in knowledge about methamphetamine abuse in the European Union (EU) and to illustrate the main clinical effects of prolonged use. After describing the pharmacology and systemic effects of methamphetamine and concentrating on its effects on the mouth, the present review compares the epidemiology and incidence of abuse in the world, particularly the USA and the EU. Key words:Methamphetamine, “Meth mouth”, drug abuse, oral health.  相似文献   
2.
3.
4.
5.
6.
7.
Although the rate of patients reporting satisfaction is generally high after joint replacement surgery, up to 23% after total hip replacement and 34% after total knee arthroplasty of treated subjects report discomfort or pain 1 year after surgery. Moreover, chronic or subacute inflammation is reported in some cases even a long time after surgery. Another open and debated issue in prosthetic surgery is implant survivorship, especially when related to good prosthesis bone ingrowth. Pulsed Electro Magnetic Fields(PEMFs) treatment, although initially recommended after total joint replacement to promote bone ingrowth and to reduce inflammation and pain, is not currently part of usual clinical practice. The purpose of this review was to analyze existing literature on PEMFs effects in joint replacement surgery and to report results of clinical studies and current indications. We selected all currently available prospective studies or RCT on the use of PEMFs in total joint replacement with the purpose of investigating effects of PEMFs on recovery, pain relief and patients' satisfaction following hip, knee or shoulder arthroplasty. All the studies analyzed reported no adverse effects, and good patient compliance to the treatment. The available literature shows that early control of joint inflammation process in the first days after surgery through the use of PEMFs should be considered an effective completion of the surgical procedure to improve the patient's functional recovery.  相似文献   
8.
9.
Objective: To investigate on the feasibility, safety, and effectiveness of a new bioabsorbable material for lung staple-line reinforcement. Methods: This prospective open trial included 66 patients (mean age of 56 ± 17 years) who underwent various types of lung resection using staplers with knitted calcium alginate sleeves for buttressing (FOREseal™, Laboratoires Brothier, Nanterre, France) at three academic centers: 29 lobectomies, 22 emphysema surgeries, 15 wedge resections or lung biopsies. Intraoperative air leakage was assessed at a mean respiratory peak pressure of 30 cmH2O, and rated as grade 1, 2, or 3. Persistent air leakage in the postoperative course, as well as any relevant event, was assessed daily. The follow-up period was of 6 months. Results: No technical problem linked to the device occurred. Hemostasis of the cutting edges was completed in all patients. Fifty-six percent of the patients had no intraoperative air leak and 27.3% had grade 1 leaks. Mean postoperative air leaks and thoracic drainage times were 1.9 ± 2.3 days and 6 ± 5.3 days, respectively. In-hospital mortality was nil. There was no empyema. Mean hospital stay was 9.1 ± 6.6 days. At follow-up, one patient underwent lung transplantation, and pathology of the explanted specimen showed the absence of device-related foreign-body inflammation. One patient complained from metalloptysis, and another one, with a metastatic invasive aspergillosis, developed an infectious recurrence that required reoperation. Conclusions: FOREseal is an ergonomic, safe, and promising new material instead of nonabsorbable materials and xenomaterials for staple-line reinforcement. A randomized comparative study is now in progress.  相似文献   
10.
As a consequence of the time-varying magnetic field induced by eddy currents, frequency drifting occurs when the sampling window of localized spectroscopy continuously shifts. The frequency drifting and the concomitant phase variations can severely affect spectroscopy results when data are acquired with multiple echo times (TEs), such as in the measurement of glutamate (Glu) concentration using the TE-averaged method. Specifically, the averaged spectra are further broadened and distorted in the presence of residual eddy currents, and editing of the coupled spins of Glu C4 protons is affected, resulting in errors in the measured relative intensity ratio. Postacquisition correction using unsuppressed water as reference can effectively minimize this detrimental effect, as manifested by the significantly enhanced signal intensity. Also, it is demonstrated that the methyl signals of creatine (Cr) at 3.0 ppm and choline (Cho) at 3.2 ppm can be used as internal references in finding frequency and phase disparities between different TEs.  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