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   34014篇
  免费   1644篇
  国内免费   136篇
耳鼻咽喉   295篇
儿科学   536篇
妇产科学   415篇
基础医学   4504篇
口腔科学   1008篇
临床医学   2338篇
内科学   8590篇
皮肤病学   754篇
神经病学   2419篇
特种医学   1278篇
外科学   5623篇
综合类   132篇
一般理论   1篇
预防医学   1177篇
眼科学   619篇
药学   2339篇
中国医学   67篇
肿瘤学   3699篇
  2022年   324篇
  2021年   600篇
  2020年   300篇
  2019年   411篇
  2018年   545篇
  2017年   448篇
  2016年   531篇
  2015年   539篇
  2014年   732篇
  2013年   886篇
  2012年   1405篇
  2011年   1618篇
  2010年   845篇
  2009年   817篇
  2008年   1425篇
  2007年   1520篇
  2006年   1566篇
  2005年   1538篇
  2004年   1415篇
  2003年   1525篇
  2002年   1578篇
  2001年   1446篇
  2000年   1448篇
  1999年   1250篇
  1998年   473篇
  1997年   340篇
  1996年   309篇
  1995年   270篇
  1994年   238篇
  1993年   229篇
  1992年   907篇
  1991年   806篇
  1990年   730篇
  1989年   740篇
  1988年   675篇
  1987年   689篇
  1986年   602篇
  1985年   571篇
  1984年   366篇
  1983年   308篇
  1982年   158篇
  1979年   244篇
  1978年   181篇
  1977年   152篇
  1975年   153篇
  1974年   155篇
  1973年   170篇
  1970年   151篇
  1969年   154篇
  1967年   155篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
71.
Magnetic resonance cholangiopancreatography (MRCP) was performed in 35 patients to evaluate the feasibility of its use as a postsurgical imaging technique after resection of the pancreas. The surgical procedures performed were: pancreatoduodenectomy in 22 patients, segmental pancreatectomy in 1, distal pancreatectomy in 7, and pyroluspreserving pancreatoduodenectomy in 5. The pancreatic duct was shown in its entirety in 24 of the 35 patients (68.6%) and was partially visualized in 8 patients (22.9%), but the intrahepatic and extrahepatic bile ducts were visualized completely in all patients. Furthermore, MRCP was able to demonstrate lesions in 3 of 6 patients who had shown clinical evidence of recurrence. The visualization of the pancreatic and bile duct system was satisfactory despite anatomical changes brought about by resection of the pancreas. Thus, we conclude that MRCP is an appropriate follow-up screening test for patients with suspected abnormalities of the biliary and pancreatic duct system.  相似文献   
72.
73.
We investigated the temporal and spatial expression of transforming growth factor-β in the healing patellar ligament of the rat by immunohistochemistry. The mid-portion of the medial half of the patellar ligament in 14-week-old male Wistar rats was cut transversely with a scalpel. On day 1 after ligament injury, diffuse staining for transforming growth factor-β was observed in the extracellular matrix filling the wound, and the staining in the adjacent ligament tissue was as weak as it was in the normal ligament. On day 3, the intensity of the diffuse extracellular staining decreased, and the staining was observed in correspondence with the cellular distribution in the wound site and in the adjacent uninjured ligament tissue. On day 7, the intense staining was widely distributed over the whole length of the ligament tissue. On day 28, the staining for transforming growth factor-β was still observed at the wound site and in the adjacent uninjured ligament tissue, where the staining was reduced in intensity but still stronger than it was in the normal ligament. On day 56, the expression of transforming growth factor-β was still detectable at the wound site: however, in the adjacent uninjured ligament tissue, it had almost subsided to the normal level. The results of the present study suggest that ligament healing may be accompanied by extensive changes in the expression of transforming growth factor-β over the whole length of ligament tissue.  相似文献   
74.
-Hydroperoxy diethyl peroxide, a novel compound found in the tunic of ascidians, has two peroxide moieties per molecule. Since ascidians are a widely served food item in Japan, human exposure to this compound potentially exists in the seafood preparation industries. No toxicological data have so far been published on this compound, and so we determined the intraperitoneal 6-day LD50 in mice and conducted histopathological examinations. The 6-day LD50, was found to be 199 mg/kg with 95% confidence limits of 126–314 mg/kg. Histopathological examination revealed necrosis induced in a variety of cells that had been directly exposed to the compound. These cells included hepatocytes, parenchymal pancreatic cells and fat cells. It is concluded that direct contact with this compound is likely to elicit cellular necrosis of various organs. The specific toxicological effects are probably dependent on the route of exposure.  相似文献   
75.
A 18-year-old boy was admitted to hospital in an unconsciousness state as a result of taking a large dose of several psychotropic drugs simultaneously in an attempt to commit suicide. Blood studies revealed hypoxia (55.7 mmHg) and hypercapnia (59.7 mmHg). Hypoxia (74.3 mmHg) and hypercapnia (46.7 mmHg) were still present on the fourth day after admission, and the patient was becoming lethargic. Reduced vascular markings in the right upper lung field on chest roentgenogram in spite of hypercapnia suggested that the persistent hypoxia was the result of a pulmonary embolism. This diagnosis was supported by a perfusion defect on 99mTc-MAA scintigram and arterial obstruction in right pulmonary angiogram. Hypercapnia is an unusual finding in pulmonary embolism, and in this case was considered due to depression of respiration by psychotropic drugs.  相似文献   
76.
We used a thin-sectioning technique for the electron microscopic detection of viral particles within the cells of urinary sediments in three recipients who developed hemorrhagic cystitis after allogeneic bone marrow transplantation. Results of viral cultures of urine and electron microscopic (EM) observations on urinary sediments were consistent in only one recipient. In this recipient, EM observations revealed many viral particles within the cells of urinary sediments with diameter of about 80 nm corresponding to adenovirus, of which type 11 was produced in viral cultures. In one of the other two recipients many viral particles with a mean diameter of 41.6 nm corresponding to papovavirus were observed, but viral cultures using conventional cells were negative. Re-cultures using HEK cells produced polyomavirus BK. EM observation was a clue to the correct diagnosis. In the remaining recipient, no viral particles were observed within the cells of urinary sediments, suggesting the hemorrhagic cystitis to be of non-viral origin, despite a positive result of viral culture. These results suggest that a thin-sectioning technique on the cells of urinary sediments is important for the differential diagnosis between a viral-induced and non-viral hemorrhagic cystitis.  相似文献   
77.
78.
Effects of water extract (UW-ext) from the leaf of Arctostaphylos uva-ursi (L.) Spreng (Bearberry leaf) on the antiallergic and antiinflammatory activities of dexamethasone ointment were investigated. One or 2% UW-ext ointment did not inhibit the ear swelling by picryl chloride-induced contact dermatitis (PC-CD) and carrageenin-induced paw edema. UW-ext augmented the inhibitory effect of dexamethasone ointment (0.005 or 0.025%) on these allergic and inflammatory models, but not the side effect of it. These results suggest that Bearberry leaf increases the inhibitory effect of dexamethasone on the allergic and inflammatory models.  相似文献   
79.
80.
Primary pulmonary artery sarcoma is a rare tumor. We present a case report in which the presumptive diagnosis was made preoperatively with magnetic resonance imaging, Doppler color flow methods, and computer tomography. Surgical treatment was successful.  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