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   18659篇
  免费   883篇
  国内免费   141篇
耳鼻咽喉   170篇
儿科学   379篇
妇产科学   141篇
基础医学   2505篇
口腔科学   426篇
临床医学   1205篇
内科学   4828篇
皮肤病学   349篇
神经病学   1694篇
特种医学   701篇
外科学   3039篇
综合类   85篇
预防医学   510篇
眼科学   408篇
药学   1183篇
中国医学   43篇
肿瘤学   2017篇
  2024年   12篇
  2023年   128篇
  2022年   235篇
  2021年   426篇
  2020年   217篇
  2019年   338篇
  2018年   438篇
  2017年   352篇
  2016年   444篇
  2015年   455篇
  2014年   570篇
  2013年   707篇
  2012年   1182篇
  2011年   1335篇
  2010年   716篇
  2009年   601篇
  2008年   1164篇
  2007年   1314篇
  2006年   1229篇
  2005年   1342篇
  2004年   1285篇
  2003年   1274篇
  2002年   1186篇
  2001年   196篇
  2000年   149篇
  1999年   214篇
  1998年   274篇
  1997年   212篇
  1996年   181篇
  1995年   185篇
  1994年   142篇
  1993年   134篇
  1992年   104篇
  1991年   103篇
  1990年   81篇
  1989年   98篇
  1988年   75篇
  1987年   69篇
  1986年   61篇
  1985年   48篇
  1984年   50篇
  1983年   43篇
  1982年   37篇
  1981年   40篇
  1980年   39篇
  1979年   30篇
  1978年   30篇
  1977年   23篇
  1976年   21篇
  1975年   19篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
A case of congenital diaphragmatic hernia successfully treated by extracorporeal membrane oxygenation (ECMO) is reported. A female baby weighing 3.4 kg was admitted 3 h after birth because of respiratory distress. Her left diaphragmatic hernia was repaired 5 h after birth by laparotomy. The AaDO2 levels were higher than 500 mmHg before and after the operation. She was managed by high-frequency ventilation and administration of tolazoine for the first 58 h. These effects were temporary, however, and she reverted into persistent fetal circulation three times. Therefore, ECMO was started at 59 h after birth. When the flow rate of ECMO reached 320 ml/min, the newborn entered a state of complete lung rest. Her general condition improved slowly, and ECMO was successfully terminated after 60 h of bypass. This was the first successful case in Japan. Offprint requests to: M. Nagaya  相似文献   
992.
This paper constitutes an evaluation of 23 patients with signs and symptoms of 4 types of tumors: 6 congenital epidermoids, 3 cases of meningiomas presenting within the temporal bone, 2 cases of jugular fossa schwannomns, 3 cases of glomus tympanicum, and 9 selected cases of glomus jugulare tumors. Since these tumors occur insidiously and are located in an inaccessible region of the skull, they are usually not diagnosed until they reach considerable size and cause multiple cranial nerve deficits or intracranial complications. Assessment of these tumors and subsequent surgical management depend primarily on the preoperative radiographic findings. CT and dynamic CT study have proven to be extremely valuable and accurate in the diagnosis of these lesions. Epidermoids have a characteristic CT appearance. Dynamic CT is often helpful in differentiating glomus tumors from meningiomas and schwannomas. Involvement of the middle ear, labyrinth, intracranial, and extracranial components of these tumors can be best evaluated by CT. This paper places special emphasis on congenital cholcsteatoma (epidermoid) and draws relevant conclusions about the diagnostic work-up.  相似文献   
993.
994.
Growth hormone (GH) is known to accelerate spermatogenesis and maintain gonadal function. In this study, we evaluated the effect of GH on recovery from testicular damage induced by cyclophosphamide (CP). Eleven- to fourteen-week-old GH-deficient Lewis rats (dw/dw) were divided into 4 groups (n = 10 each), with one group serving as controls. In the CP group, CP was intravenously administered in daily doses of 50 mg/kg for 2 days, followed by daily doses of 10 mg/kg for the next 3 days. In the GH group, rat GH was subcutaneously administered at a daily dose of 0.3 mg/kg until the rats were sacrificed. In the CP/GH group, GH and CP administration were started simultaneously. In the CP/preGH group, GH administration was started 14 days before CP administration. Five rats from each group were sacrificed at days 14 and 28 after administration of CP. Spermatogenesis was then evaluated morphometrically by counting numbers of cells at several stages of the spermatogenic cycle. On day 14, there were no significant differences in the numbers of the spermatocytes between CP and CP/GH group. On day 28, the numbers of spermatocytes and motility of spermatozoa in CP/GH group were greater than those of CP group were. In the CP/preGH group, these effects of GH administration were not observed. These results suggested that administration of GH improved testicular function damaged by CP under GH-deficient condition, when GH and CP administration are started simultaneously.  相似文献   
995.
OBJECT: Although previous studies reported that late reperfusion might prevent left ventricular dilation after acute myocardial infarction (AMI), implication of persistent ischemic chest pain on admission remains to be investigated. This study was undertaken to assess the implication of persistent ischemic chest pain on in-hospital outcome and left ventricular function after late reperfused AMI. METHODS AND PATIENTS: We studied 63 patients with a first anterior AMI who underwent percutaneous coronary intervention 6 to 24 hours (11.2+/-4.5 hours) after the onset. Of 63 patients, 48 (76%) had persistent ischemic chest pain on admission. RESULTS: Incidence of in-hospital death, reinfarction or congestive heart failure was similar between the 2 groups. Pretreatment left ventricular ejection fraction and end-diastolic volume were similar between the 2 groups. Predischarge angiography was performed at 17+/-5 days after the onset. Late reperfusion prevented the dilation of left ventricular end-diastolic volume in patients with chest pain (78+/-12 to 75+/-17 ml/m2, p=0.15), but did not in those without (75+/-20 to 93+/-28 ml/m2, p=0.03). A multivariate analysis revealed that absence of persistent ischemic chest pain was an independent predictor of predischarge left ventricular end-diastolic volume >100 ml/m2 (odds ratio 0.10, p=0.04). CONCLUSIONS: Our data demonstrated that absence of persistent ischemic chest pain appears to be a simple and reliable marker which predicts left ventricular dilation after late reperfused AMI.  相似文献   
996.
997.
We have established a method for in situ tissue engineering of the stomach in a canine model using an acellular collagen scaffold graft. The current study was conducted to evaluate the functional aspects of the tissue-engineered stomach wall. The anterior wall of the stomach in beagle dogs was replaced with a collagen sponge scaffold measuring 4 x 4 cm. At 16 weeks after implantation, the animals were sacrificed and the stomach specimens were evaluated immunohistochemically and physiologically. Regeneration of the proton pump and thin muscle layer, which are essential for mechanical and chemical digestion by the stomach, was observed in the tissue-engineered gastric tissue. However, acetylcholine-induced contraction was not observed in the tissue-engineered stomach wall. Although there is still room for improvement, the tissue-engineered stomach wall had a highly organized structure, and it is anticipated that this approach could eventually become an alternative for stomach reconstruction after gastrectomy.  相似文献   
998.
This report concerns a series of 12 patients with simple bone cysts of the calcaneus, who were treated between 1988 and 2000 by a minimal surgical intervention of curettage, multiple drilling and continuous decompression through insertion of a cannulated screw. Inserted screws were made of titanium in 8 cases and ceramics in 4 cases. The mean operative time was 58.8 +/- 25.4 minutes, and complete healing was achieved in 11 cases after 9.2 +/- 6.4 months. One patient needed an additional surgery for replacement of a titanium screw. Final results were excellent after a mean follow up of 91 +/- 52.1 months. This series of patients represents one of the largest reported series of calcaneal simple bone cyst in conjunction with long-term follow-up. Our technique of minimal curettage, drilling and continuous decompression with a cannulated screw insertion is considered to be a good option for management of simple bone cysts of the calcaneus.  相似文献   
999.
OBJECTIVE: The employment of surgical microscopy in the field of neurosurgery has significantly contributed not only to the advancement of surgical technique, but also the operative outcome as well. This technology has allowed surgeons to meet the demands for increasingly difficult levels of surgery, which usually require a long operative time. However, the surgeon and the assistant are restricted in their posture for a long time, leading to excessive muscular and ocular stress. To solve these problems, we have developed and clinically applied a three dimensional video microscope system for surgery, using a two binocular camera method, that allows surgical procedures to be performed over a video monitor. METHOD: Two 3CCD cameras were installed on the assistant's lens attachment and the camera lens attachment of the microscope for neurosurgery, manufactured by Carl Zeiss Co., Ltd. The surgery was performed by viewing the three dimensional picture on the monitor, which was created by processing the images from the cameras by a time-division method. In November 1998, the prototype was completed and, with numerous modifications, its clinical application has become possible. Currently, we have used it in 42 clinical cases. RESULTS: 1) Instead of viewing the surgical field through a conventional surgical microscope, the surgeon and the assistant were able to perform microsurgery by viewing the stereoscopic vision on the video monitor, through polarized glasses. 2) The assistant is provided with a separate video monitor, so that the assistant can freely adjust the angle of vision 90-180 degrees, according to where he stands. 3) The nurses, resident surgeons and students can view the same three dimensional images displayed to the surgeon. This effectively contributes to the educational environment. CONCLUSION: Even during a long surgical procedure, the posture of surgeon and assistant became less restricted since there was no need to look through the eyepiece of the microscope and led to significant decrease in physical fatigue and ocular strain. In the 42 clinical trials, the operation proceeded uneventfully, without any serious complications.  相似文献   
1000.
Aortic arch injections according to Theron's method have been performed in patients with cerebral ischemia. Digital subtraction angiograms with modified windowing (low and narrow) have been used for better visualization of cerebral parenchymal condition. This "cerebral parenchymography" allows much easier understanding of cerebral parenchymal vascularization on angiographic imaging. Although further study is necessary to estimate accurate cerebral blood flow, this technique can enable an easy and quick understanding of the overall cerebral hemodynamics.  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