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   5338篇
  免费   183篇
  国内免费   38篇
耳鼻咽喉   157篇
儿科学   183篇
妇产科学   291篇
基础医学   313篇
口腔科学   323篇
临床医学   402篇
内科学   1263篇
皮肤病学   58篇
神经病学   369篇
特种医学   230篇
外科学   1176篇
综合类   68篇
预防医学   97篇
眼科学   226篇
药学   162篇
中国医学   3篇
肿瘤学   238篇
  2024年   2篇
  2023年   34篇
  2022年   54篇
  2021年   125篇
  2020年   78篇
  2019年   88篇
  2018年   107篇
  2017年   110篇
  2016年   179篇
  2015年   198篇
  2014年   234篇
  2013年   306篇
  2012年   411篇
  2011年   379篇
  2010年   240篇
  2009年   208篇
  2008年   382篇
  2007年   470篇
  2006年   426篇
  2005年   428篇
  2004年   384篇
  2003年   252篇
  2002年   280篇
  2001年   40篇
  2000年   15篇
  1999年   12篇
  1998年   17篇
  1997年   15篇
  1996年   14篇
  1995年   10篇
  1994年   10篇
  1993年   6篇
  1992年   6篇
  1991年   9篇
  1989年   4篇
  1988年   1篇
  1987年   6篇
  1985年   5篇
  1984年   3篇
  1983年   2篇
  1981年   1篇
  1980年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1963年   1篇
排序方式: 共有5559条查询结果,搜索用时 15 毫秒
31.
AIM: The aim of the present study was to compare the use of electrothermal bipolar vessel sealer (EBVS) with harmonic scalpel (HS) during total laparoscopic hysterectomy with respect to operation time, estimated blood loss and related complications. METHODS: A retrospective study was conducted in the university hospital. Forty patients who underwent total laparoscopic hysterectomy and bilateral salpingo-oophorectomy were enrolled. Nineteen hysterectomies were performed with HS and in 21 patients the same surgeons used EBVS. Data about the characteristics of the patients, operation time, estimated blood loss, uterine weights, related complications and length of hospital stay were registered and compared. RESULTS: Mean procedure time and estimated blood loss were significantly less in the EBVS arm (59.57 +/- 3.71 vs 90.95 +/- 5.73 min, P < 0.001; 87.76 +/- 25.48 vs 152.63 +/- 60.90 mL; P < 0.001, respectively). The change in hemoglobin and hematocrit values was found to be more significant in the HS group. CONCLUSION: EBVS was found to be less time-consuming and caused less bleeding when compared with HS.  相似文献   
32.
New quasi-imputation and expansion strategies for correlated binary responses are proposed by borrowing ideas from random number generation. The core idea is to convert correlated binary outcomes to multivariate normal outcomes in a sensible way so that re-conversion to the binary scale, after performing multiple imputation, yields the original specified marginal expectations and correlations. This conversion process ensures that the correlations are transformed reasonably which in turn allows us to take advantage of well-developed imputation techniques for Gaussian outcomes. We use the phrase 'quasi' because the original observations are not guaranteed to be preserved. We argue that if the inferential goals are well-defined, it is not necessary to strictly adhere to the established definition of multiple imputation. Our expansion scheme employs a similar strategy where imputation is used as an intermediate step. It leads to proportionally inflated observed patterns, forcing the data set to a complete rectangular format. The plausibility of the proposed methodology is examined by applying it to a wide range of simulated data sets that reflect alternative assumptions on complete data populations and missing-data mechanisms. We also present an application using a data set from obesity research. We conclude that the proposed method is a promising tool for handling incomplete longitudinal or clustered binary outcomes under ignorable non-response mechanisms.  相似文献   
33.
Meningiomas are the most common primary intracranial tumors. They are usually benign and slowly growing; however, they may show histologically malignant features categorizing them into grade II or III of World Health Organization (WHO) classification. Rhabdoid meningioma (RM) is an uncommon meningioma variant categorized as WHO grade III. The clinical course of RM is determined by local recurrences, invasion of adjacent brain and/or dura, widespread leptomeningeal dissemination, remote metastases and fatal clinical outcome. Herein we report a case with recurrent aggressive left occipital parasagittal region RM in which the patient initially declined radiation treatment. The tumor was resected four times in 5 years. Histopathological examination revealed a rhabdoid meningioma with metaplastic, papillary and chordoid differentiation. Six months after her fourth operation the patient died of progressive disease. RM is a rare subtype of malignant meningioma and the role of different adjuvant therapeutic options are still unknown. Clinical presentation, radiological features and pathologic findings of this uncommon tumor are discussed.  相似文献   
34.
Gastric emptying time measurement by radionuclide study, although quite informative, is rarely remembered in clinical practice. We presented a patient with brittle diabetes who had multiple emergency admissions due to hypoglycemia under routinely prescribed insulin therapy. She had severe gastroparesis, which was determined by scintigraphic gastric emptying study (gastric half-emptying time = 260 min for a mixed meal). She had not presented to the emergency service for two years because of only a slight change the timing of her insulin administration time (after meal instead of before meal) in the light of gastric-emptying study.  相似文献   
35.
36.

Background

Ginger (Zingiber officinale) is a well known and extensively used antioxidant in traditional remedies. In this study, we aimed to investigate the effects of ginger powder on ovarian folliculogenesis and implantation in rats.

Methods

There were two study groups. In the 5-day treatment group (one estrous cycle), 100 mg ginger powder, 200 mg ginger powder or distilled water was given for 5 days to the three subgroups each containing seven rats. In the 10-day treatment group, same doses were given for 10 days (two estrous cycle) to the three subgroups each containing seven rats. At the end of the 5th and 10th days, ovarian volumes, ovarian weights, primordial follicles, antral follicles, atretic follicles, and corpus luteum counts were assessed. To evaluate the angiogenic effects of ginger, vascular endothelial growth factor (VEGF) and for the antioxidant effects of ginger endothelial nitric oxide synthase (eNOS) were examined in the ovaries and in the endometrium immunohistochemically.

Results

In the 5-day treatment group, antral follicle count and ovarian stromal VEGF were significantly high in the 100 mg ginger subgroup in comparison to the control group (p < 0.05). In the 10-day treatment group, endometrial VEGF and ovarian stromal eNOS were significantly high in the 100 mg ginger subgroup in comparison to the control group (p < 0.05). There was no statistically significant difference at 200 mg ginger dose both in 5-day and 10-day treatment groups.

Conclusion

The increases in the antral follicle count and ovarian stromal VEGF in the 100 mg/5-day treatment subgroup indicate that ginger have positive effects on folliculogenesis in short term with low dose. Additionally, ginger may enhance implantation in rats in long term with low dose.  相似文献   
37.
38.
39.
Cor triatriatum dexter (CTD) is an extremely rare congenital anomaly in which the right atrium is divided into 2 chambers by a membrane. The estimated incidence of cor triatriatum has been reported as 0.1% of congenital cardiac malformations. The septation of the right atrium in the setting of CTD is the result of failed resorption of the right valve of the sinus venosus. This results in anterolateral and posteromedial portions of the divided right atrium. CTD can be diagnosed at any age, especially if it is incidentally discovered.  相似文献   
40.
INTRODUCTIONSymtomatic lumbar ligamantum flavum calcification is quite rare in the young age group.PRESENTATION OF CASEThe authors report a case of young adult with diagnosis of lumbar spinal stenosis, presenting with leg pain and neurological deficits. Computerized tomography (CT) scan and magnetic resonance (MR) imaging studies revealed ossification of the ligamantum flavum as the causative factor of the disease and the patient recovered completely after the decompressive operation.DISCUSSIONIt is emphasized that attention should be given to this rare etiological factor of lumbar spinal stenosis.CONCLUSIONComplete relief can be achieved with early and adequate surgery.  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