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   3530429篇
  免费   295158篇
  国内免费   14171篇
耳鼻咽喉   47900篇
儿科学   112575篇
妇产科学   92338篇
基础医学   561132篇
口腔科学   93796篇
临床医学   317244篇
内科学   629419篇
皮肤病学   93289篇
神经病学   303811篇
特种医学   137854篇
外国民族医学   490篇
外科学   541119篇
综合类   107624篇
现状与发展   24篇
一般理论   2337篇
预防医学   297067篇
眼科学   80596篇
药学   241597篇
  22篇
中国医学   10472篇
肿瘤学   169052篇
  2021年   55163篇
  2020年   35129篇
  2019年   58152篇
  2018年   71605篇
  2017年   54710篇
  2016年   60482篇
  2015年   74343篇
  2014年   108570篇
  2013年   173661篇
  2012年   98886篇
  2011年   99373篇
  2010年   117841篇
  2009年   122231篇
  2008年   86185篇
  2007年   89802篇
  2006年   100268篇
  2005年   95550篇
  2004年   96981篇
  2003年   87423篇
  2002年   76886篇
  2001年   118110篇
  2000年   111567篇
  1999年   107512篇
  1998年   66639篇
  1997年   64233篇
  1996年   62074篇
  1995年   57522篇
  1994年   51464篇
  1993年   48034篇
  1992年   74191篇
  1991年   69865篇
  1990年   65607篇
  1989年   64402篇
  1988年   59365篇
  1987年   58076篇
  1986年   54614篇
  1985年   54411篇
  1984年   49485篇
  1983年   45057篇
  1982年   42165篇
  1981年   39542篇
  1980年   37232篇
  1979年   40221篇
  1978年   35565篇
  1977年   32274篇
  1976年   29611篇
  1975年   27937篇
  1974年   29005篇
  1973年   28026篇
  1972年   26228篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
142.
143.
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   
144.
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   
145.
146.
We study the image formation of vibro-acoustography systems based on a concave sector array transducer taking into account depth-of-field effects. The system point-spread function (PSF) is defined in terms of the acoustic emission of a point-target in response to the dynamic radiation stress of ultrasound. The PSF on the focal plane and the axis of the transducer are presented. To extend the obtained PSF to the 3D-space, we assume it is a separable function in the axial direction and the focal plane of the transducer. In this model, an image is formed through the 3D convolution of the PSF with an object function. Experimental vibro-acoustography images of a breast phantom with lesion-like inclusions were compared with simulated images. Results show that the experimental images are in good agreement with the proposed model.  相似文献   
147.
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   
148.
149.
150.
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