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   20732篇
  免费   1063篇
  国内免费   152篇
耳鼻咽喉   220篇
儿科学   445篇
妇产科学   194篇
基础医学   2307篇
口腔科学   367篇
临床医学   1448篇
内科学   5831篇
皮肤病学   434篇
神经病学   1595篇
特种医学   781篇
外科学   3867篇
综合类   51篇
预防医学   491篇
眼科学   394篇
药学   1101篇
中国医学   49篇
肿瘤学   2372篇
  2024年   31篇
  2023年   194篇
  2022年   389篇
  2021年   683篇
  2020年   371篇
  2019年   460篇
  2018年   620篇
  2017年   411篇
  2016年   575篇
  2015年   540篇
  2014年   760篇
  2013年   874篇
  2012年   1389篇
  2011年   1614篇
  2010年   894篇
  2009年   800篇
  2008年   1313篇
  2007年   1358篇
  2006年   1319篇
  2005年   1378篇
  2004年   1415篇
  2003年   1273篇
  2002年   1170篇
  2001年   182篇
  2000年   164篇
  1999年   194篇
  1998年   239篇
  1997年   228篇
  1996年   160篇
  1995年   136篇
  1994年   144篇
  1993年   109篇
  1992年   93篇
  1991年   74篇
  1990年   54篇
  1989年   40篇
  1988年   36篇
  1987年   39篇
  1986年   28篇
  1985年   18篇
  1984年   30篇
  1983年   17篇
  1982年   22篇
  1981年   17篇
  1980年   16篇
  1979年   10篇
  1978年   10篇
  1977年   7篇
  1976年   9篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
We report a case of primary diffuse leptomeningeal gliomatosis (PDLG) followed up with serial magnetic resonance images (MRI). A 45‐year‐old man manifested with bilateral abducens nerve palsy and meningisms. Repeated MRI revealed diffuse leptomeningeal enhancement throughout the central nervous system without intra‐axial mass accompanied with the dilatation of ventricles and focally enlarged cerebral sulci. Brain biopsies showed a leptomeningeal gliomatosis. The MRI findings described here would contribute to the diagnosis of PDLG among other common diseases diffusely spreading along the leptomeningeal structures.  相似文献   
42.
A 57-year-old man with a history of renal cell carcinoma presented with presyncope. He underwent nephrectomy years earlier followed by HLA-matched allogeneic peripheral-blood stem-cell transplantation. Echocardiographic investigation revealed a solitary right ventricle mass without contiguous vena caval or right atrial involvement. The mass was pathologically confirmed to be metastatic carcinoma in the right ventricular cavity. This case highlights the need to consider an underlying neoplastic syndrome in patients presenting isolated right ventricle mass by echocardiography.  相似文献   
43.
We aimed to examine the effects of KTO-7924 (beta3-adrenoceptor agonist) on lipid metabolism and mRNA expressions in retroperitoneal white adipose tissue (RP WAT) in obese (fa/fa) Zucker rats using DNA microarray. Oral KTO-7924 for 28 days significantly decreased RP WAT weight, plasma triglyceride, free fatty acid, and insulin, and improved insulin resistance in oral glucose tolerance tests. In RP WAT of KTO-7924-treated rats, DNA microarray analysis revealed specifically enhanced mRNA expressions of uncoupling protein 1 (UCP1) and cytochrome c oxidase subunit VIII-H (COX8H), which are reportedly highly expressed in brown adipose tissue (BAT). Since these mRNA expression levels in RP WAT were significantly lower in obese (fa/fa) Zucker rats than in lean Zucker rats, these genes may be important in lipid metabolism. Our results imply that in obese (fa/fa) Zucker rats, continuous stimulation of beta3-adrenoceptors by KTO-7924 causes BAT-like adipocytes to appear in RP WAT, and improves lipid metabolism.  相似文献   
44.
PURPOSE: We assessed the feasibility of utilizing three-dimensional (3D) phase sensitive inversion recovery (IR) images for preoperatively determining deep brain stimulator position. METHODS: We measured geometric distortion with a grid phantom and evaluated images of 3 volunteers to determine optimum imaging parameters for 3D phase sensitive IR. RESULTS: Geometric distortion measured less than 1.0%. Respective inversion and recovery times, which provided high T(1) contrast between the subthalamic nucleus and adjacent tissue, were 200 and 4000 ms. In studies of 3 volunteers and 2 patients, the subthalamic nucleus was clearly depicted in 3D phase sensitive IR images. The measured coordinates of the subthalamic nucleus agreed well with those calculated by conventional estimation from midpoint of the anterior and posterior commissure. CONCLUSION: Three-dimensional phase sensitive inversion recovery was useful in visualizing the subthalamic nucleus for effective deep brain stimulation.  相似文献   
45.
We present here a rare case of left-side catamenial pneumothorax, in which endometrial tissue pleura was found on the visceral pleura histologically. A chest roentogenogram confirmed the left pneumothorax, but did not reveal bullae or any associated anomalies, in a 41-year-old woman with three documented episodes of left-side pneumothorax occurring every menstruation. Video-assisted thoracoscopic surgery revealed not only tiny holes in the diaphragm, but also a scattered small brown spots on the visceral pleura. Histological examination of the lung sections revealed the existence of endometrial tissue on the visceral pleura with disrupted pleural elastic fibers. Our case suggests that cyclic erosion of the visceral pleura by the implanted endometrial tissue caused air leakage from the lung, in addition to the most accepted concept that air is aspirated into the thoracic cavity via the abdomen through the acquired fenestration of the diaphragm.  相似文献   
46.
We report a rare case of constrictive pericarditis that stimulated a large mediastinal tumor obstructing the right ventricular inflow tract. A 58-year-old woman was referred to our hospital because of a recent increase of dyspnea and facial edema. Computed tomography revealed severely thickened calcification, including a low-density area, presenting as a mediastinal tumor, compressing the right ventricular inflow tract. A complete resection was performed, and her symptoms dramatically improved. Idiopathic constrictive pericarditis was diagnosed pathologically.  相似文献   
47.
A CASE OF METASTATIC YOLK SAC TUMOR OF TESTIS IN A CHILD   总被引:1,自引:0,他引:1  
We report a case of testicular yolk sac tumor in a child aged 3 years and 6 months with multiple bulky metastases to lung and retroperitoneum (stage 11182). After three courses of chemotherapy with a PV 8 regimen (cisplatin, vinblastine and bleomycin). complete and partial responses were obtained for lung and retroperitoneal lymph node metastases, respectively. The patient was followed-up closely. However, on the basis of a re-elevated alpha-letoprotein (AFP) after 4 months' follow-up, he was treated with three courses of salvage chemotherapy with a modified VAB-6 regimen (cyclophosphamide. etoposide. actinomycin D, bleomycin and cisplatin), lollowed by retroperitoneal lymph node dissection. Histologically, only necrotic tissue was found. There is no evidence of recurrence 24 months after lymphadenectomy. There is very little information in the literature on the appropriate management of postchemotherapy residual mass in pediatric testicular tumors.  相似文献   
48.
Airborne pollens collected in a pollen collector (Virtual Impactor) was treated with a fluorescein isothiocyanate-labeled monoclonal antibody (KW-S10) which was strictly specific to Japanese cedar pollen antigen (Cry j I). Flow cytometric analysis revealed that the intensity of fluorescence of the pollen samples treated with the antibody was greater than that of non-treated reference pollen or the antibody treated Hinoki-cypress pollen. By use of this method, it may be possible to display the airborne pollen concentration within 20 min after sampling.  相似文献   
49.
50.
Abstract: To be able to salvage heart failure patients, the need for an economical permanent ventricular assist device is increasing. To meet this increasing demand, a miniaturized centrifugal blood pump has been developed as a permanently implantable device. The Gyro permanently implantable model (PI-601) incorporates a sealless design with a blood stagnation free structure. The pump impeller is magnetically coupled to the driver magnet in a sealless manner. This pump is atraumatic and antithrombogenic and incorporates a double pivot bearing system. A miniaturized actuator was utilized in this system in collaboration with the University of Vienna. The priming volume of this pump is 20 ml. The overall size of the pump actuator package is 53 mm in height and 65 mm in diameter, 145 ml of displacement volume, and 305 g in weight. Testing to date has included in vitro hydraulic performance and hemolysis. This pump can provide 5 L/min against a 110 mm Hg total pressure head at 2,000 rpm and 8 Limin against 150 mm Hg at 2,500 rpm. The normalized index of hemo-lysis (NIH) value of this pump was 0.0028 g/100 L at 5 Limin against 100 mm Hg. A preliminary anatomical study revealed the possibility of the implantability of 2 such systems in biventricular bypass at a preperitoneal location. This system is feasible for use as a permanently implantable biventricular assist device.  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