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   37553篇
  免费   2154篇
  国内免费   197篇
耳鼻咽喉   430篇
儿科学   1157篇
妇产科学   997篇
基础医学   3712篇
口腔科学   1221篇
临床医学   3410篇
内科学   8082篇
皮肤病学   677篇
神经病学   2251篇
特种医学   1319篇
外国民族医学   4篇
外科学   6790篇
综合类   860篇
现状与发展   3篇
一般理论   27篇
预防医学   2550篇
眼科学   1360篇
药学   2864篇
  10篇
中国医学   273篇
肿瘤学   1907篇
  2024年   209篇
  2023年   472篇
  2022年   1069篇
  2021年   1721篇
  2020年   1046篇
  2019年   1262篇
  2018年   1570篇
  2017年   1139篇
  2016年   1235篇
  2015年   1332篇
  2014年   1688篇
  2013年   2062篇
  2012年   3103篇
  2011年   2998篇
  2010年   1693篇
  2009年   1467篇
  2008年   2224篇
  2007年   2293篇
  2006年   2022篇
  2005年   1789篇
  2004年   1630篇
  2003年   1357篇
  2002年   1180篇
  2001年   363篇
  2000年   306篇
  1999年   281篇
  1998年   197篇
  1997年   134篇
  1996年   141篇
  1995年   108篇
  1994年   96篇
  1993年   77篇
  1992年   147篇
  1991年   161篇
  1990年   128篇
  1989年   123篇
  1988年   104篇
  1987年   97篇
  1986年   88篇
  1985年   116篇
  1984年   77篇
  1983年   52篇
  1982年   53篇
  1981年   55篇
  1980年   41篇
  1979年   50篇
  1978年   40篇
  1975年   35篇
  1974年   36篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The case of sarcoidosis of the lungs is described in a 50 years old female who presented with symptoms similar to pulmonary tuberculosis. As she showed no improvement on anti-tubercular therapy, sarcoidosis was suspected and confirmed by endobronchial biopsy and she responded well to treatment.  相似文献   
992.
993.
994.
We aimed to determine if there are mechanoreceptors in the hip joint capsule and ligamentum capitis femoris (LCF) of patients with developmental dysplasia of the hip (DDH). We took capsule and LCF biopsies from 20 hips of 20 patients who were operated on because of DDH. The mean age was 10.2 months (range 6-20 months) at the time of surgery. There were 12 girls and eight boys. Teratologic and secondary hip dislocations were not included in this study. Full thickness, 0.5 x 0.5 cm anterior capsule and LCF portions were taken for biopsy specimen. Specimens were stained with hemotoxylin eosin and examined immunohistochemically using monoclonal antibody against S-100 protein. In both analyses no mechanoreceptor was found in any samples of capsule or LCF. In this preliminary study we could not find mechanoreceptors in the local anterior joint capsule and LCF of the hip in children with DDH. We think that additional studies are necessary in order to understand the mechanoreceptor characteristics of the hip joint in children not only with DDH but also in children with healthy hips.  相似文献   
995.
A seven month old male baby presented to emergency room in shock. Patient had 3 hours history of massive fresh bleeding per rectum. Emergency laparotomy revealed Meckel's diverticulum (MD) with large vitello-intestinal artery responsible for massive bleeding. Diverticulectomy was performed.  相似文献   
996.
997.
The emergence of lamivudine-resistant hepatitis B mutations is a major complication during pretransplantation treatment. The proper time to begin Lamivudine before transplantation is not yet known. Twenty-six patients received preoperative lamivudine treatment followed by combined lamivudine and hepatitis B immunoglobulin after transplantation up to December 2002. The length of preoperative lamivudine treatment ranged from 13 to 200 days (mean, 52 +/- 37 days). Hepatitis B virus-DNA was positive in 22 of 26 (84.6%) patients before preoperative lamivudine prophylaxis and persistently positive among only 4 of 22 patients (18%) who at transplantation did not show a viral mutation. In all patients, hepatitis B virus-DNA became negative immediately after transplantation. At a median follow-up of 34 months, neither a hepatitis B recurrence nor a mutation had occurred in any patient. The ability to schedule the proper time for preoperative lamivudine prophylaxis is an advantage of living donor liver transplantation.  相似文献   
998.
Parenteral iron therapy exacerbates experimental sepsis   总被引:3,自引:0,他引:3  
BACKGROUND: Catalytic iron can potentiate systemic inflammation via its pro-oxidant effects. This raises the possibility that parenteral iron administration might exacerbate a concomitant septic state. This study sought to experimentally test this hypothesis. METHODS: Male CD-1 mice were subjected to experimental sepsis via intraperitoneal injection of heat-killed Escherichia coli +/- concomitant intravenous iron sucrose (Venofer; 2 mg). Nonseptic mice +/- iron therapy served as controls. Plasma tumor necrosis factor-alpha (TNF-alpha) levels were assessed 2 hours postinjections (serving as an inflammatory marker). Oxidative stress was gauged in heart or kidney tissue (at either 4 or 24 hours) by heme oxygenase-1 (HO-1) mRNA or protein levels. Overall sepsis severity was assessed by morbidity/mortality rates (at 24 hours). RESULTS: Iron alone or sepsis alone each induced oxidant stress in heart and kidney (HO-1 mRNA/protein increases). When iron and E. coli were coadministered, additive or synergistic HO-1 mRNA/protein increments resulted. Iron injection alone only slightly raised TNF-alpha levels (from 0 to 2.3 pg/mL; P= 0.01). However, iron approximately doubled the TNF-alpha increments which arose from the septic state (1400 --> 2600 pg/mL). Neither sepsis alone, nor iron alone, induced any mortality and no mice became moribund (0/24 mice). However, when iron + sepsis were combined, approximately 60% of mice either died (5/12) or developed a moribund (2/12) state (P= 0.005). CONCLUSION: Parenteral iron administration can induce systemic oxidative stress and modest TNF-alpha release. However, when iron is given during experimental sepsis, profound increases in both processes, and approximately 60% mortality, result. Given that renal failure patients have decreased antioxidant defenses and intermittently develop bacteremia, the potential for parenteral iron therapy to exacerbate clinical sepsis needs to be addressed.  相似文献   
999.
BACKGROUND: Patients with end-stage renal disease (ESRD) are at increased risk of cardiovascular mortality and morbidity. Many complications arise in ESRD patients as a result of the twin arterial pathologies of atherosclerosis and arteriosclerosis. Part of this latter process is calcification of the arterial media, which is thought significantly to increase vascular stiffness. The aim of our study was to explore the relationship between measures of arterial stiffness-pulse wave velocity (PWV)-and the extent of calcification in the coronary arteries (CAC). METHODS: Over a period of 2 years 82 patients from our renal unit were invited to participate in our study. Sixty-two patients agreed to undergo electron beam computerized tomography (EBCT), and in 55 (38 males and 17 females), PWV measurements were made. EBCT and PWV measurements were done according to previously described protocols. RESULTS: The mean age of the 55 patients was 56.4 years. The mean duration of dialysis was 65.4 months, and the mean CAC score was 2551. The mean PWV was 9.13 m/s. PWV strongly correlated with total CAC even after correction for age, dialysis duration, and time averaged C-reactive protein (CRP) (P= 0.0001). CAC scores were significantly different when compared according to PWV tertiles (P= 0.0001). CONCLUSION: We have demonstrated that PWV is strongly related to the degree of EBCT-derived coronary artery calcium score in chronic kidney disease patients.  相似文献   
1000.
BACKGROUND: We present a patient with a heterogeneously enhancing lesion within the body of the sacrum and the sacral canal. Sacral tuberculosis (TB) was suspected because of a history of familial exposure. Few cases isolated to the sacrum have been reported in the literature. The characteristic histopathologic and magnetic resonance imaging (MRI) findings are also presented. CASE DESCRIPTION: A 31-year-old African-American male presented with an 8-month history of lower back pain radiating into his legs as well as numbness and weakness of the right foot. His history revealed PPD conversion following an exposure to active pulmonary TB 3 years prior for which he received 6 months of isoniazid prophylaxis. An MRI scan revealed a large heterogeneously enhancing lesion involving the sacrum with extension into the sacral canal. The patient underwent computed tomography (CT)- guided needle biopsy of the sacral lesion. Cytopathologic examination revealed caseating granulomas. Acid-fast bacilli cultures were positive for Mycobacterium tuberculosis. He was placed on a 6-month course of isoniazid, rifampin, pyrazinamide, and ethambutol. At 3-month follow-up, his examination and symptoms had improved. CONCLUSIONS: Sacral TB is an extremely rare cause of lower back pain with radiation into the lower extremities. TB should always be considered in the differential diagnosis of isolated sacral masses, especially in light of today's increasing multidrug resistance and immunosuppressed population.  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