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   40437篇
  免费   2773篇
  国内免费   543篇
耳鼻咽喉   770篇
儿科学   707篇
妇产科学   846篇
基础医学   5686篇
口腔科学   568篇
临床医学   3295篇
内科学   9212篇
皮肤病学   1165篇
神经病学   2844篇
特种医学   2208篇
外科学   5607篇
综合类   582篇
现状与发展   1篇
一般理论   16篇
预防医学   1678篇
眼科学   1125篇
药学   3492篇
中国医学   435篇
肿瘤学   3516篇
  2023年   267篇
  2022年   807篇
  2021年   1318篇
  2020年   672篇
  2019年   1048篇
  2018年   1255篇
  2017年   914篇
  2016年   1248篇
  2015年   1601篇
  2014年   1913篇
  2013年   2205篇
  2012年   3165篇
  2011年   3240篇
  2010年   1953篇
  2009年   1632篇
  2008年   2308篇
  2007年   2202篇
  2006年   1995篇
  2005年   1899篇
  2004年   1592篇
  2003年   1534篇
  2002年   1362篇
  2001年   893篇
  2000年   817篇
  1999年   742篇
  1998年   292篇
  1997年   267篇
  1996年   237篇
  1995年   212篇
  1994年   178篇
  1993年   120篇
  1992年   366篇
  1991年   280篇
  1990年   319篇
  1989年   302篇
  1988年   297篇
  1987年   252篇
  1986年   212篇
  1985年   211篇
  1984年   174篇
  1983年   145篇
  1982年   100篇
  1981年   91篇
  1980年   86篇
  1979年   173篇
  1978年   113篇
  1977年   87篇
  1975年   82篇
  1974年   82篇
  1973年   81篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Y H Ho  C J Pritchett 《Injury》1990,21(2):119-120
A case of an unusual degloving injury of the descending colon resulting from a crushing injury to the mid-torso is reported. The diagnosis was made at laparotomy for associated injuries. The colon was stripped of its muscle layers and mesentery for 10 cm without perforation.  相似文献   
73.
The effects of a variety of detergents (non-ionic, ionic and bile derivatives) on B16 melanoma cells have been examined. Two main effects can be clearly differentiated: loss of cell viability and cell lysis. Under our conditions, cell-surfactant interaction is highly dependent on the nature of the amphiphile (more specifically, on its critical micellar concentration). Loss of cell viability occurs at surfactant concentrations below the critical micellar concentration, i.e. the incorporation of detergent monomers into the cell membranes is enough to impair their barrier function, so that Trypan Blue is no longer actively secreted outside the cell. On the other hand, cell lysis only occurs at or near the critical micellar concentration of the detergent, i.e. when the bilayer-micelle transition may take place. Comparative studies using B16 cells and phospholipid vesicles indicate that the amount of detergent required to induce cell lysis is the same that produces disruption of the lipid bilayer. Thus, our results suggest that membranes are the primary target for the toxicologic effects of surfactants on cells. Moreover, they provide a rationale for the interpretation of other studies in this field: previous results from different laboratories are shown to fit very well our data.  相似文献   
74.
75.
OBJECTIVE: To justify the application of medialization thyroplasty in Chinese patients with symptomatic cancer-related unilateral vocal fold paralysis (UVFP). STUDY DESIGN AND SETTING: Retrospective chart review from February 2000 to March 2006. RESULTS: Eighty-seven Chinese patients undergoing medialization thyroplasty for UVFP were included; there were no significant differences between the cancer-related and benign groups in terms of the speech and swallowing rehabilitation outcome and the perioperative complication rate (P > 0.05). The median survival time of cancer-related UVFP patients from the date of medialization to death was 129 days. Age more than 65 years was identified as the only factor for a shorter survival period after medialization (P = 0.040). CONCLUSION: Medialization thyroplasty restores satisfactory speech and swallowing and has a low perioperative complication rate in Chinese patients with cancer-related UVFP. Postmedialization survival period was also reasonable. SIGNIFICANCE: Medialization thyroplasty is a justifiable treatment option for cancer-related UVFP.  相似文献   
76.
77.
Nasopharyngeal angiofibromas occur predominantly in males in their puberty and adolescence; the incidence in other age groups and in women is exceptional. This report describes a case of a 57-year-old woman with nasopharyngeal angiofibroma presenting typical radiological findings in computed tomography, MR imaging and angiography. The tumour was successfully removed and histopathological examination confirmed the diagnosis. In 6 years follow-up the patient is free of symptoms.  相似文献   
78.
Intravaginal misoprostol has been shown to be effective forcervical priming before a surgically induced abortion. The objectivewas to investigate the effectiveness of oral misoprostol incervical dilatation prior to vacuum aspiration between the 6thand 12th weeks of pregnancy. The results showed that in nulliparouspatients, the median cervical dilatation in the treatment group(7.8 mm) was significantly greater than that in the placebogroup (3.7 mm). In multiparous patients, the difference wasalso statistically significant (9.8 versus 6.0 mm). The easeof dilatation, assessed subjectively by the operating surgeons,was significantly improved in the treatment group. There wasalso a significant reduction in the duration of the operationand in the mean blood loss in the treatment group. The side-effectsencountered in the treatment group were mild and well acceptedby the women. Oral misoprostol is an effective and safe methodfor cervical dilatation prior to vacuum aspiration in firsttrimester pregnancy.  相似文献   
79.
To establish test specific normal limits for quantitative analysis of uptake and washout of 201Tl after dipyridamole infusion combined with low level exercise, 20 healthy volunteers were studied with low likelihood of coronary artery disease (CAD) assessed by a stepwise probability analysis based on age, sex, symptoms, resting electrocardiogram, and exercise electrocardiography. Likelihood of CAD in these volunteers was calculated as 1%. After dipyridamole infusion combined with low level exercise, one volunteer complained of headache; no other side effects were observed. There were no chest pain complaints. Maximal hemodynamic changes were achieved during the 6th and 7th min of the test. No ST segment depression was recorded. Visual analysis of the 201Tl scintigrams was normal in all volunteers. Mean regional washout at 4 h was 44.37%±2.11%. The regional washout in the 70° LAO view (46.65%±1.10%) was significantly higher than in the anterior and 30° LAO views (43.44%±1.50% and 43.02%±1.45%, respectively). Profiles of uptake and washout of 201Tl were different after dipyridamole infusion combined with low level exercise as compared to maximal exercise. Thus, in quantitative analysis of 201Tl scintigraphy after dipyridamole infusion in conjunction with low level exercise as applied in the present study, it is mandatory to use normal limits of uptake and washout of 201Tl derived from healthy volunteers who underwent the same combined protocol.  相似文献   
80.
Kim J  Yin FF  Zhao Y  Kim JH 《Medical physics》2005,32(4):866-873
A rigid body three-dimensional/two-dimensional (3D/2D) registration method has been implemented using mutual information, gradient ascent, and 3D texturemap-based digitally reconstructed radiographs. Nine combinations of commonly used x-ray and computed tomography (CT) image enhancement methods, including window leveling, histogram equalization, and adaptive histogram equalization, were examined to assess their effects on accuracy and robustness of the registration method. From a set of experiments using an anthropomorphic chest phantom, we were able to draw several conclusions. First, the CT and x-ray preprocessing combination with the widest attraction range was the one that linearly stretched the histograms onto the entire display range on both CT and x-ray images. The average attraction ranges of this combination were 71.3 mm and 61.3 deg in the translation and rotation dimensions, respectively, and the average errors were 0.12 deg and 0.47 mm. Second, the combination of the CT image with tissue and bone information and the x-ray images with adaptive histogram equalization also showed subvoxel accuracy, especially the best in the translation dimensions. However, its attraction ranges were the smallest among the examined combinations (on average 36 mm and 19 deg). Last the bone-only information on the CT image did not show convergency property to the correct registration.  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