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   2535篇
  免费   209篇
  国内免费   15篇
耳鼻咽喉   28篇
儿科学   68篇
妇产科学   76篇
基础医学   338篇
口腔科学   50篇
临床医学   395篇
内科学   485篇
皮肤病学   82篇
神经病学   193篇
特种医学   199篇
外科学   244篇
综合类   58篇
一般理论   2篇
预防医学   307篇
眼科学   18篇
药学   104篇
中国医学   1篇
肿瘤学   111篇
  2021年   21篇
  2019年   26篇
  2018年   31篇
  2017年   34篇
  2016年   39篇
  2015年   43篇
  2014年   54篇
  2013年   93篇
  2012年   115篇
  2011年   139篇
  2010年   85篇
  2009年   76篇
  2008年   87篇
  2007年   125篇
  2006年   98篇
  2005年   96篇
  2004年   80篇
  2003年   91篇
  2002年   53篇
  2001年   79篇
  2000年   53篇
  1999年   61篇
  1998年   40篇
  1997年   35篇
  1996年   49篇
  1995年   37篇
  1994年   37篇
  1993年   26篇
  1992年   42篇
  1991年   39篇
  1990年   40篇
  1989年   69篇
  1988年   51篇
  1987年   48篇
  1986年   72篇
  1985年   59篇
  1984年   46篇
  1983年   48篇
  1982年   24篇
  1981年   20篇
  1980年   26篇
  1979年   24篇
  1978年   23篇
  1977年   19篇
  1976年   21篇
  1975年   19篇
  1974年   30篇
  1972年   18篇
  1969年   19篇
  1968年   20篇
排序方式: 共有2759条查询结果,搜索用时 15 毫秒
1.
Bonfanti  R; Furie  BC; Furie  B; Wagner  DD 《Blood》1989,73(5):1109-1112
PADGEM protein (PADGEM), also known as GMP140, is a platelet alpha- granule membrane protein that is translocated to the external membrane after platelet activation. Although the biosynthesis of this protein was originally thought to be confined to megakaryocytes, the synthesis of PADGEM in endothelial cells was recently demonstrated (McEver et al: Blood 70:1974a, 1987). We now describe the subcellular localization of this protein in endothelial cells. Immunofluorescence staining of permeabilized human umbilical vein endothelial cells with KC4, a well characterized monoclonal antibody to PADGEM, showed positively stained elongated structures similar in distribution and shape to Weibel-Palade bodies. Their identity as Weibel-Palade bodies was confirmed by double label immunofluorescence using KC4 and a polyclonal antiserum to von Willebrand factor (vWf), a protein known to be specifically stored in these organelles. All Weibel-Palade bodies were found to contain PADGEM. In contrast to strong perinuclear staining produced with anti- vWf antibodies, no significant perinuclear staining was obtained with KC4, indicating that relatively little PADGEM is present in the endoplasmic reticulum and in the Golgi apparatus. In endothelial cells treated with secretagogues that stimulate vWf release the elongated structures positive for PADGEM disappeared, further identifying these structures as Weibel-Palade bodies. This observation extends the parallels between Weibel-Palade bodies and alpha-granules and suggests a possible functional association between vWf and PADGEM.  相似文献   
2.
Hydroxyethyl methacrylate (HEMA) has been advocated as a polymerizing solution with which to prevent deflation of detachable balloons in interventional neuroradiology. It is pertinent to know if unpolymerized HEMA would have untoward effects if accidentally released into the carotid artery by balloon rupture or deflation. Seven mongrel dogs underwent transfemoral catheterization of the common carotid artery and subsequent injection of HEMA solution in volumes of 1 cc in five dogs, 2 cc in one, and 4 cc in one. Angiography performed at the time of injection revealed evidence of intravascular thrombosis as well as possible spasm. Three surviving animals were sacrificed at 48 hours; the brains were fixed and examined histopathologically. One brain was normal and one was autolyzed and could not be examined. Five of the seven animals had histopathologically documented cerebral infarctions of varying size. No foreign substance was seen within the blood vessels to suggest intravascular polymerization. The animals injected with 2 or 4 cc HEMA solution did not survive 48 hours. Literature review reveals little documentation of the toxicology of intravascular HEMA. With its increasing popularity as a compound for polymerization in detachable balloons introduced into the brain, further investigations are warranted to understand the physical properties of the compound and potential risks of its use.  相似文献   
3.
While two prophylactic HPV vaccines have been proven notably efficacious in clinical trials, the effectiveness of these vaccines at the population level remains to be evaluated. To lay the foundation for understanding the strengths and limitations of different endpoints for future effectiveness research, we present a comprehensive review of HPV-related clinical outcomes, including: (i) HPV type-specific positivity and persistence, (ii) Pap diagnoses (ASC-US, LSIL, and HSIL), (iii) histologic cervical cancer precursor lesions (i.e., CIN1, CIN2, and CIN3), (iv) invasive cervical cancer (ICC), (v) anogenital warts, (vi) recurrent respiratory papillomatosis (RRP), and (vii) other HPV-associated cancers (vulvar, vaginal, anal, penile, and oropharyngeal). While research on the vaccines’ effects on these HPV clinical outcomes in the general population is presently limited, numerous large trials will soon be completed, making a priori discussion of these potential outcomes especially urgent. Furthermore, population level systems to track HPV-associated clinical outcomes may need to be developed for HPV vaccine effectiveness evaluation.  相似文献   
4.
5.
Segel  MC; Paulus  DD; Hortobagyi  GN 《Radiology》1988,169(1):49-54
The response to induction chemotherapy is an important prognostic factor in patients with nonmetastatic, locally advanced breast carcinomas. Assessment at mammography of the response of 60 breast cancers in 59 women was performed between 1974 and 1986. Responses were excellent in 13 tumors, moderate in 34, and poor in 13 (excellent moderate = 78%). Assessment of response of discrete masses in a fatty breast was easiest; assessment of response of tumor areas that were poorly defined-such as a focal area of architectural distortion or mass in dense breast parenchyma-was more difficult. Of 17 patients with excellent pathologic responses-that is, minimal or no residual tumor-15 (88%) had complete responses (no residual tumor) as determined with mammography, physical examination, or both. Mammography provides information complementary to physical examination and is essential in the accurate assessment of the response to chemotherapy of locally advanced breast cancer.  相似文献   
6.
We report five patients with normal diuretic renograms who underwent Whitaker pressure perfusion testing. They were found to have normal pressure at low flow rates (2-4 ml/min) and an abnormally elevated pressure at high flow rates (8-10 ml/min). Because of persistent symptoms, two patients underwent surgery, while the other three have been followed up. Our findings indicate that a negative diuretic renogram in a well hydrated patient with good renal function may not rule out low grade obstruction. Renal pelvic perfusion at low flow rates as well as high flow rates is recommended to determine better the function of the pelviureteric junction.  相似文献   
7.
Abstract. Medical and social problems related to alcohol use are frequently seen in the ED. Often, the tempo of emergency medicine practice seems to preclude assessment beyond that required by the acute complaint. However, detection of ED patients with alcohol problems can occur using brief screening tools. This article was developed by members of the SAEM Substance Abuse Task Force, and describes screening tools that have been used successfully to identify atrisk and dependent drinkers. Their brevity, reproducibility, and accuracy vary somewhat, but screening can be realistically performed in the busy ED setting. The early detection of patients with alcohol problems would provide the opportunity for early intervention, and may reduce subsequent morbidity and mortality in this patient population.  相似文献   
8.
9.
PURPOSE: The purpose of our study was to obtain a clear understanding of the various diagnoses within the closed neural tube defect (NTD) groups included in the large database of clients in our Spina Bifida Clinic and a clear picture of the outcomes for the various NTD groups. METHODS: One hundred and four clients with closed NTD were categorized using a classification system devised by Tortori-Donati et al. Various clinical markers were investigated, including ambulation and the need for orthoses and wheelchairs. RESULTS: Most clients are ambulatory, requiring an orthoses, but not a wheelchair, despite the high incidence of ankle/foot abnormalities. CONCLUSIONS: This classification system has enhanced our knowledge of this group of clients, provided a greater understanding of the varied outcomes of these children and clinical management required.  相似文献   
10.
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