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   4297113篇
  免费   350737篇
  国内免费   15305篇
耳鼻咽喉   61081篇
儿科学   133586篇
妇产科学   112254篇
基础医学   656878篇
口腔科学   118986篇
临床医学   390201篇
内科学   778142篇
皮肤病学   103397篇
神经病学   367908篇
特种医学   171041篇
外国民族医学   913篇
外科学   653544篇
综合类   126621篇
现状与发展   23篇
一般理论   2649篇
预防医学   364742篇
眼科学   100956篇
药学   302840篇
  24篇
中国医学   11376篇
肿瘤学   205993篇
  2021年   55897篇
  2020年   35650篇
  2019年   58842篇
  2018年   73519篇
  2017年   56172篇
  2016年   62484篇
  2015年   75699篇
  2014年   110493篇
  2013年   175960篇
  2012年   119083篇
  2011年   122206篇
  2010年   123349篇
  2009年   126361篇
  2008年   109119篇
  2007年   115561篇
  2006年   125083篇
  2005年   120074篇
  2004年   120913篇
  2003年   111563篇
  2002年   102092篇
  2001年   154501篇
  2000年   150688篇
  1999年   139772篇
  1998年   71380篇
  1997年   67805篇
  1996年   65682篇
  1995年   61534篇
  1994年   55603篇
  1993年   51632篇
  1992年   103686篇
  1991年   99089篇
  1990年   94189篇
  1989年   91818篇
  1988年   85423篇
  1987年   83890篇
  1986年   79583篇
  1985年   78017篇
  1984年   66011篇
  1983年   58909篇
  1982年   48185篇
  1981年   44913篇
  1980年   42197篇
  1979年   57896篇
  1978年   47071篇
  1977年   41633篇
  1976年   38702篇
  1975年   37890篇
  1974年   42481篇
  1973年   40599篇
  1972年   38068篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Allergoid immunotherapy is a new form of allergen immunotherapy allowing safe administration of high allergen doses. There is limited information on the effects of allergoid immunotherapy in children with allergic rhinitis. To investigate the immunological and clinical effects of allergoid immunotherapy in children with allergic rhinitis due to grass pollen allergy. Children with allergic rhinitis were assigned to allergoid immunotherapy (n = 27) or control (n = 26, no immunotherapy) groups. Children in the immunotherapy group received seven injections of grass pollen allergoid immunotherapy before grass pollen season and continued to receive maintenance immunotherapy for 27 months. All patients were offered a pharmacotherapy regimen to be used on demand during the pollen seasons. Clinical and laboratory parameters were compared between the immunotherapy and control groups. The rhinoconjunctivitis symptom-medication score and asthma symptom score were lower in the immunotherapy group after 1 yr of maintenance immunotherapy (p < 0.01 for both). Skin test reactivity and nasal reactivity as determined by nasal provocation testing for grass pollen were significantly decreased after 1 yr of immunotherapy (p < 0.001 for both). The seasonal increase in bronchial reactivity and nasal lavage eosinophil cationic protein levels were prevented after the first year of immunotherapy (p < 0.05 for both). The seasonal increase in immunoglobulin (Ig)E decreased (p < 0.05) and grass-specific IgG, IgG(1) and IgG(4) increased significantly already at the end of the seven-injection build-up therapy (p < 0.001, for all). Interleukin (IL)-4 levels in the culture supernatants showed a steady decline from baseline at first and second year of immunotherapy (p < 0.001) but remained unchanged in the control group. Allergoid immunotherapy is an effective method in the treatment of grass pollen-induced allergic rhinitis in children and prevents the seasonal increase in bronchial hyper-reactivity. Changes in specific IgE and IgG levels and decreased IL-4 production in peripheral blood mononuclear cell culture supernatants may account for the observed clinical effects.  相似文献   
992.
993.

Background  

The Association of Surgeons of Great Britain and Ireland (ASGBI) devised the electronic surgical logbook (version 2.4) for higher trainees in General Surgery enabling trainees to compile a uniform data set of their operative and training experience. This is in use by higher surgical trainees (HST) in the United Kingdom. This logbook permits trainees to submit data centrally into a Regional Analysis Database (RAD). With the implementation of the European Working Time Directive (EWTD) there is need for reliable data to assess the effects of the directive on training. In order to draw meaningful conclusions from the database the quality of data needs to be validated. We critically analysed the RAD in the Yorkshire region for a one-year period.  相似文献   
994.
On September 11, 2001 two hijacked airplanes struck the Twin Towers at the World Trade Center in New York City. All of the remains (19,915) were examined by the Office of Chief Medical Examiner (OCME) of New York City. The major goals of the OCME were to accurately identify the decedents and to promptly issue death certificates. As of September 2005, there were 1594 identifications of a total of 2749 people reported missing. Of these, 976 were identified by a single means, which included DNA analysis in 852 of the victims. Use of legal statues can assist in the timely issuance of death certificates in mass fatalities, which benefit surviving family members. DNA analysis markedly improves the ability to identify remains and has become the standard method for identification in these types of disasters. Certain postmortem tissue samples are better suited for DNA analysis and yield better results than others.  相似文献   
995.
996.
997.
We have carried out a prospective randomised, single blind clinical trial to investigate the effect of continuous passive motion on range of knee flexion, lack of extension, pain levels and analgesic use after total knee replacement surgery. 85 subjects were randomly allocated to control or study group. All subjects followed the existing rehabilitation protocol, which permits immediate active range of motion exercises and mobilisation with the study group using continuous passive motion for 1 h, twice a day. Outcome measures employed were range of motion, pain assessed on a visual analogue scale and analgesic use according to the WHO ladder. Blinded evaluation was carried out preoperatively, at time of discharge from hospital, 6 weeks, 6 and 12 months postoperation. No significant difference was observed between groups at all time intervals for each outcome variable using Wilcoxon Rank sum tests. The results substantiate previous findings that short duration continuous passive motion following total knee arthroplasty does not influence outcome of range of motion or reported pain.  相似文献   
998.
999.
目的 研究模拟舰船两种剂量水平磁场复合噪声、高温对机体联合作用的特点。方法 采用有交互作用的三因素二水平的正交试验设计方法及方差分析法,按正交表L8(2^7)的要求安排8种复合暴露剂量组合,分别将兔和大鼠分为8个复合暴露组和8个对照组。结果 兔球结膜毛细血管管径、大鼠肝和脾脏HSP70的分析结果显示出磁场是对其影响的主因素(均为P〈0.01),其次是高温(均为P〈0.05),大鼠下丘脑AVP和大鼠脑组织HSP70的分析结果显示出磁场是对其影响的主因素(均为P〈0.05)。兔血浆内皮素的分析结果显示出磁场与噪声交互作用所对应的F值有非常显著性意义(P〈0.01),磁场与噪声、高温三者之间交互作用所对应的F值也有显著性意义(P〈0.05)。结论 磁场是对上述指标影响的主因素,而高温也是重要因素;磁场与噪声有交互作用,磁场与噪声、高温三者之间也有交互作用;应该重视舰船环境因素对舰船人员的复合作用。  相似文献   
1000.
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