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   2289篇
  免费   117篇
  国内免费   15篇
耳鼻咽喉   97篇
儿科学   217篇
妇产科学   89篇
基础医学   136篇
口腔科学   51篇
临床医学   216篇
内科学   424篇
皮肤病学   59篇
神经病学   142篇
特种医学   220篇
外科学   431篇
综合类   32篇
预防医学   62篇
眼科学   79篇
药学   74篇
肿瘤学   92篇
  2023年   7篇
  2022年   11篇
  2021年   36篇
  2020年   27篇
  2019年   28篇
  2018年   52篇
  2017年   32篇
  2016年   65篇
  2015年   64篇
  2014年   66篇
  2013年   110篇
  2012年   121篇
  2011年   127篇
  2010年   103篇
  2009年   82篇
  2008年   140篇
  2007年   152篇
  2006年   150篇
  2005年   182篇
  2004年   141篇
  2003年   92篇
  2002年   80篇
  2001年   56篇
  2000年   61篇
  1999年   39篇
  1998年   33篇
  1997年   36篇
  1996年   35篇
  1995年   27篇
  1994年   26篇
  1993年   23篇
  1992年   18篇
  1991年   7篇
  1990年   5篇
  1989年   16篇
  1988年   14篇
  1987年   15篇
  1986年   14篇
  1985年   12篇
  1984年   8篇
  1983年   8篇
  1982年   8篇
  1981年   10篇
  1980年   5篇
  1979年   7篇
  1978年   10篇
  1977年   14篇
  1976年   8篇
  1975年   11篇
  1967年   6篇
排序方式: 共有2421条查询结果,搜索用时 15 毫秒
1.
Liver hemangioma: US-guided 18-gauge core-needle biopsy   总被引:6,自引:0,他引:6  
Heilo  A; Stenwig  AE 《Radiology》1997,204(3):719
  相似文献   
2.
In living donor liver transplantation (LDLT), obtaining the precise volume of the graft is very important to decrease volume-related postoperative complications, especially in cases with suspected small-for size grafts. We used stereology based on the Cavalieri method (CM), a new method to measure liver graft volume, and compared the results with those obtained through intraoperative measurement (IOM) and through multidetector computed tomography (MDCT) measurement. Liver volumes estimated using the 3 methods were well-correlated with each other (r(2) = 0.94 and P < 0.001 for IOM and CM; r(2) = 0.91 and P < 0.001 for IOM and MDCT, and r(2) = 0.95 and P < 0.001 for CM and MDCT); however, they were different from each other (in descending order, 908 +/- 124 cm(2), 861 +/- 121 cm(2), and 777 +/- 168 cm(2) for MDCT, CM, and IOM, respectively). Although MDCT and CM overestimated the volumes, the results of CM were almost similar to those obtained via IOM. In conclusion, our results suggest that CM measured the liver graft volume more reliably. Thus, its use, particularly in cases with suspected small-for-size graft, may prove useful.  相似文献   
3.
OBJECTIVE: We aimed to demonstrate the time-dependent ultrastructural changes in pneumocyte type II cells following brain injury, and to propose an electron microscopic scoring model for the damage. METHODS: Forty Wistar-Albino female rats weighing 170-200 g were used. The rats were allocated into five groups. The first group was the control and the second was the craniotomy without trauma. The others were trauma groups. Weight-drop method was used for achieving head trauma. Samples were obtained from the right and left pulmonary lobes at 2-, 8-, and 24-h intervals after transcardiac perfusion. An electron microscopic scoring model was used to reveal the changes. RESULTS: There were no ultrastructural pathological findings pointing to lung injury in any rat of the control groups. There was intense intracellular oedema in type II pneumocyte and interstitial oedema in the adjacent tissue in trauma groups. Oedema in mitochondria and dilatation in both smooth endoplasmic reticulum and Golgi apparatus was more evident in the 8- and 24-h trauma groups. The chromatin dispersion was disintegrated in the nucleus in all trauma groups. Scores of all trauma groups were significantly different from the controls (P<0.05). All trauma groups were different from each other at significant levels (P<0.05 for each trauma groups). CONCLUSIONS: The data suggested that ultrastructural damage is obvious at 2 h and deteriorates with time. The electron microscopic scoring model worked well in depicting the traumatic changes, which were supported by lipid peroxidation. Further experiments are needed to determine the exact outcome after brain death model.  相似文献   
4.
Ameloblastic carcinoma (AC) is an aggressive malignant epithelial odontogenic tumor. It may appear de novo or originate from a pre-existing ameloblastoma or odontogenic cyst. To our knowledge, an AC that originates from the anterior skull base has not been reported before in the English literature. We report a case of an AC that originated from the anterior skull base and invaded the dura of the anterior fossa and discuss its clinical course and treatment.  相似文献   
5.
6.
BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors.  相似文献   
7.
8.
9.
Severe middle vault deformity with disturbed nasal form and function is one of the most challenging procedures to correct in a secondary rhinoplasty. Reconstructing the deformity with autologous septal cartilage would be the primary choice of most surgeons, if it were always available. However in certain cases the lack of a sufficient quantity of autologous cartilage has forced surgeons to explore other viable options. This paper discusses our experience with the combined use of spreader and dorsal onlay grafts from various materials in the reconstruction of severe middle vault deformity in 110 patients. In follow up, (between 6 and 42 months; mean 21 months) all patients were noted to have improved in both aesthetics and function with no major complications noted. In summary, this study proposes that any engrafting material can be used safely when the proper surgical principals and technique are employed.  相似文献   
10.
Abstract Aggressive behaviour is rarely observed as an ictal semiology. Ictal aggression can occur in lesions of frontal and limbic structures. In limbic structure lesions, the main mechanism of aggressive behaviour is hyperactivity; whereas frontal lesions may cause aggressive behaviour with an indirect mechanism in which the suppression on limbic system is lost. Here we present a patient with ictal aggression. In this case a right frontoparietal epileptiform focus was detected during the postictal period. Magnetic resonance imaging showed cortical dysplasia on the right inferior frontal gyrus. The seizures disappeared completely after pharmacological treatment.  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