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   959267篇
  免费   69063篇
  国内免费   1517篇
耳鼻咽喉   13174篇
儿科学   24958篇
妇产科学   23609篇
基础医学   136660篇
口腔科学   28924篇
临床医学   82504篇
内科学   190654篇
皮肤病学   19667篇
神经病学   74251篇
特种医学   37743篇
外国民族医学   79篇
外科学   157262篇
综合类   18163篇
现状与发展   1篇
一般理论   234篇
预防医学   62671篇
眼科学   21663篇
药学   74505篇
  3篇
中国医学   2265篇
肿瘤学   60857篇
  2018年   9581篇
  2017年   7526篇
  2016年   8331篇
  2015年   9497篇
  2014年   12800篇
  2013年   18451篇
  2012年   25609篇
  2011年   26673篇
  2010年   15720篇
  2009年   14990篇
  2008年   26005篇
  2007年   27212篇
  2006年   27979篇
  2005年   26944篇
  2004年   26104篇
  2003年   25063篇
  2002年   24644篇
  2001年   55471篇
  2000年   57217篇
  1999年   47651篇
  1998年   11161篇
  1997年   9808篇
  1996年   9896篇
  1995年   9200篇
  1994年   8526篇
  1993年   7830篇
  1992年   35947篇
  1991年   34312篇
  1990年   33054篇
  1989年   32261篇
  1988年   29293篇
  1987年   28564篇
  1986年   26619篇
  1985年   25444篇
  1984年   18030篇
  1983年   15314篇
  1982年   7905篇
  1981年   6886篇
  1979年   15940篇
  1978年   10727篇
  1977年   9159篇
  1976年   7969篇
  1975年   8739篇
  1974年   10577篇
  1973年   9954篇
  1972年   9438篇
  1971年   8957篇
  1970年   8503篇
  1969年   8016篇
  1968年   7288篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Purpose: Small pulmonary lesions that include ground-glass attenuation have been increasingly discovered because of progressive imaging diagnostic technologies. Despite the detection of such small lesions, sometimes it is quite difficult to localize them because of their size or considerable depth from the visceral pleura. In the present study, we examined the usefulness of computed tomography-guided lipiodol marking for thoracoscopic resection of impalpable pulmonary nodules.Methods: Fifty-six patients with an undiagnosed peripheral lesion(s) of the lung who had undergone preoperative computed tomography-guided lipiodol marking followed by video-assisted thoracoscopic surgery were studied.Results: All of the nodules were successfully marked by computed tomography-guided lipiodol marking, and all except for one case were localized by means of intraoperative fluoroscopy as clear spots. With regard to complications, pneumothorax occurred in 21 patients (37.5%), and only one patient required transient drainage. Although hemorrhaging in the lung parenchyma and hemosputum occurred in nine patients (16.1%) and one patient (1.8%), respectively, no patients were in serious condition. No intra- or postoperative mortality or morbidity was observed.Conclusion: Preoperative computed tomography-guided lipiodol marking of small or impalpable pulmonary nodules is a safe and useful procedure for thoracoscopic resection of the lung.  相似文献   
53.
Journal of Thrombosis and Thrombolysis - Amniotic fluid embolism (AFE) is a catastrophic condition in the peripartum period and still remains as a leading cause of maternal death. Although over 80%...  相似文献   
54.
PurposeOur purpose was to determine the effect of chemoradiotherapy (CRT) on patient-reported quality of life (QOL) for patients with intact pancreas cancer.Methods and MaterialsWe reviewed a prospective QOL registry for patients with intact, clinically localized pancreatic ductal adenocarcinoma treated with CRT between June 2015 and November 2018. QOL was assessed pre-CRT (immediately before CRT, after neoadjuvant chemotherapy) and at the completion of CRT with the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) and its component parts: FACT-General (FACT-G) and hepatobiliary cancer subscore (HCS). A minimally important difference from pre-CRT was defined as ≥ 6, 5, and 8 points for FACT-G, HCS, and FACT-Hep, respectively.ResultsOf 157 patients who underwent CRT, 100 completed both pre- and post-CRT surveys and were included in the primary analysis. Median age at diagnosis was 65 years (range, 23-90). National Comprehensive Cancer Network resectability status was resectable (3%), borderline resectable (40%), or locally advanced (57%). Folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) (75%) or gemcitabine and nab-paclitaxel (42%) were given for a median of 6 cycles (range, 0-42) before CRT. Radiation therapy techniques included 3-dimensional conformal (22%), intensity modulated photon (55%), and intensity modulated proton (23%) radiation therapy to a median dose of 50 Gy (range, 36-62.5). Concurrent chemotherapy was most commonly capecitabine (82%). Sixty-three patients (63%) had surgery after CRT. The mean decline in FACT-G, HCS subscale, and FACT-Hep from pre- to post-CRT was 3.5 (standard deviation [SD], 13.7), 1.7 (SD 7.8), and 5.2 (SD 19.4), respectively. Each of these changes were statistically significant, but did not meet the minimally important difference threshold. Pancreatic head tumor location was associated with decline in FACT-Hep. Nausea was the toxicity with the greatest increase from pre- to post-CRT by both physician-assessment and patient-reported QOL.ConclusionsFor patients with intact pancreatic adenocarcinoma, modern CRT is well tolerated with minimal decline in QOL during treatment.  相似文献   
55.
The retroviral protease of human immunodeficiency virus (HIV) is an excellent target for antiviral inhibitors for treating HIV/AIDS. Despite the efficacy of therapy, current efforts to control the disease are undermined by the growing threat posed by drug resistance. This review covers the historical background of studies on the structure and function of HIV protease, the subsequent development of antiviral inhibitors, and recent studies on drug-resistant protease variants. We highlight the important contributions of Dr. Stephen Oroszlan to fundamental knowledge about the function of the HIV protease and other retroviral proteases. These studies, along with those of his colleagues, laid the foundations for the design of clinical inhibitors of HIV protease. The drug-resistant protease variants also provide an excellent model for investigating the molecular mechanisms and evolution of resistance.  相似文献   
56.
57.
58.
59.
We report a case of intestinal obstruction in a 73-year-old woman caused by ileocolic intussusception. The underlying cause was a giant submucosal ulcerating lipoma (6?×?3.3?×?3.8 cm) extending from the superior mucosal lip of Bauhin’s valve. Abdominal ultrasonography showed a pathognomonic target-like mass appearing as multiple concentric rings. CT scan confirmed the diagnosis. Because of apparent obstruction, a laparotomy with right hemicolectomy and ileocolic anastomosis was performed. Lipomas most frequently occur in the cecum and ascending colon where they represent the most common submucosal mesenchymal tumor. They typically occur in elderly women with an incidence that varies from 0.15 to 0.56 %. Pain, rectal bleeding, and obstruction are typical symptoms. When faced with an intussusception in children, reduction with air per rectum can be performed. In adults, however, malignant cell spreading and seeding is of big concern. Since approximately 20–50 % of all underlying causes are malignant, explorative surgery is favored in adults.  相似文献   
60.
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