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   5743篇
  免费   546篇
  国内免费   229篇
耳鼻咽喉   94篇
儿科学   203篇
妇产科学   102篇
基础医学   565篇
口腔科学   143篇
临床医学   634篇
内科学   1003篇
皮肤病学   118篇
神经病学   205篇
特种医学   182篇
外科学   884篇
综合类   765篇
一般理论   1篇
预防医学   338篇
眼科学   162篇
药学   556篇
  2篇
中国医学   309篇
肿瘤学   252篇
  2024年   31篇
  2023年   101篇
  2022年   223篇
  2021年   324篇
  2020年   231篇
  2019年   183篇
  2018年   203篇
  2017年   228篇
  2016年   199篇
  2015年   265篇
  2014年   324篇
  2013年   369篇
  2012年   486篇
  2011年   438篇
  2010年   315篇
  2009年   289篇
  2008年   364篇
  2007年   334篇
  2006年   297篇
  2005年   274篇
  2004年   206篇
  2003年   233篇
  2002年   172篇
  2001年   95篇
  2000年   80篇
  1999年   49篇
  1998年   28篇
  1997年   35篇
  1996年   19篇
  1995年   19篇
  1994年   22篇
  1993年   16篇
  1992年   4篇
  1991年   11篇
  1990年   7篇
  1989年   4篇
  1988年   4篇
  1987年   7篇
  1986年   2篇
  1985年   6篇
  1984年   2篇
  1983年   2篇
  1982年   3篇
  1976年   2篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
  1965年   3篇
  1957年   1篇
  1943年   1篇
排序方式: 共有6518条查询结果,搜索用时 359 毫秒
31.
32.
We aimed to investigate the association between erectile dysfunction and severity of cardiovascular morbidity and to assess clinical responses to tadalafil of patients in different cardiovascular risk groups. Between November 2019 and August 2020, a total of 258 male patients aged 45–70 years with ED were included. They were divided into three groups according to the Framingham risk score: low-risk (n: 86, 33.3%), intermediate-risk (n: 103, 39.9%) and high-risk (n: 69, 26.8%). At admission, all domains of the International Index of Erectile Function score were worse in high-risk group compared to other risk groups (p < .001). After a 12-week follow-up, a more significant improvement was observed in all domains of erectile function in all risk groups, but high-risk group had lower sexual scores (p < .001). The lowest rate for complete responsiveness to tadalafil was observed in the high-risk group (37.7%). The rate of failure in complete responsiveness was found to be 4.127 times greater with higher Framingham score and 3.102 times greater with higher erectile dysfunction severity at admission. Our preliminary findings show that more severe sexual disorders are observed in high-risk patients with cardiovascular morbidity. Individualised treatment may be important in high-risk group since they may benefit less from tadalafil, and failure in complete responsiveness can be more common in this group.  相似文献   
33.
IntroductionContralateral prophylactic mastectomy has the potential to decrease the occurrence of cancer and reduce psychological burden. However, it is known that complications after bilateral mastectomy are higher compared with unilateral mastectomy. Our goal was to evaluate outcomes of immediate breast reconstruction in patients undergoing bilateral mastectomy and to compare complication rates between therapeutic and prophylactic sides.Patients and MethodsElectronic medical records of patients with unilateral breast cancer who underwent bilateral mastectomy and immediate reconstruction with expanders were reviewed. Postoperative complications were compared between therapeutic and prophylactic mastectomy sides.ResultsSixty-two patients were analyzed. The overall complication rate after both stages was 23.9% on the therapeutic side and 16.5% on the prophylactic side. Infection was the most common complication on both sides. All infections on the prophylactic mastectomy side were successfully treated with intravenous (IV) antibiotics (salvage rate of 100%), whereas 35.7% of infected tissue expander/implants on the therapeutic mastectomy side were explanted despite treatment.ConclusionCareful counselling of patients undergoing elective contralateral prophylactic mastectomy is essential as complications can develop in either breast after reconstruction.  相似文献   
34.
Archives of Sexual Behavior - Previous experiments showed that following acquisition of an association between a terry-cloth object conditioned stimulus (CS) and a live female unconditioned...  相似文献   
35.
[目的 ]通过脂多糖对胆汁分泌的影响实验 ,初步探讨引起肝功能障碍及肝内结石形成的机理 .[方法 ]在麻醉状态下 ,直接往实验动物肝内注入脂多糖等实验药物 ,测定相关数据 .[结果 ]脂多糖对胆汁分泌有抑制作用 ,并对胆汁酸、磷脂浓度有降低作用 ,而对胆红素、钙的浓度无显著作用 .[结论 ]脂多糖对胆汁分泌有明显作用 ,对诱发肝功能障碍及形成肝内胆结石有一定的影响  相似文献   
36.
目的:获得起效快、复原快的肌肉松驰剂。方法:1类化合物以汉防乙甲素为原料,经季铵化制得。Ⅱ类以阿曲库铵的结构为模板,对其1-取代基进行结构改造而得,所有目的化合物的结构经IR、^1HNMR、MS鉴定。结果:设计合成了未见文献报道的11个两类双苄基异喹啉季铵类化合物。结论:初步药理试验表明,目的化合物1c的起效剂量、起效时间与汉肌松相当。  相似文献   
37.
? Objective:To explore the molecular mechanism of G1arrest of thymocytes and splenocytes in mice induced by whole body irradiation(WBI) .Methods:Flow cytometry(FCM) and dotblotwere used to analyze MDM2 m RNA and protein expressions of thymocytes and splenocytes in Kunming mice after whole body irradiation (WBI) with x- rays.Results:The expressions of MDM2 protein of thymocytes in mice increased from 4h to 8h after 2 Gy WBI.There were no significant changes of MDM2 m RNA level of thymocytes and splenocytes from0 to48h after75m Gy or2 Gy WBI.No changes of MDM2 m RNA level were also found in thymocytes or splenocytes of mice4h after0~ 6Gy WBI.Conclusion:These results suggest that ionizing radiation could induce MDM2 protein expression and make G1arrest cells reentering cell cycle. 〔  相似文献   
38.
Background: Solar retinopathy was observed in a total of 86 eyes of 58 patients following the solar eclipse over Turkey in April 1976. The visual prognosis and the presence of late complications were evaluated at the early and late periods. Methods: Of the 58 patients, 34 (51 eyes) presented during the first week and came for follow-up examination in the succeeding week, also after 1, 3, 12 and 18 months. After that they were examined at yearly intervals (mean 4.2 years). Twenty-four patients (35 eyes) presented during the period between 1 and 11 years post-eclipse and were followed up for a mean period of 3.4 years. After a period of 15 years, all of the patients were invited for re-examination and nine patients (14 eyes) attended. Results: The improvement in visual acuity was observed to have taken place mostly during the first 2 weeks to 1 month after the eclipse. Further improvement in visual acuity was not observed in any of the eyes after the 18-month examination. The improvement in visual acuity was more prominent and earlier in the eyes that had visual acuity of 0.2 or better initially. Only the eyes with initial visual acuity equal to or better than 0.4 had a chance to improve their acuity to 10/10. Having observed the 51 eyes for mean period of 4.2 years and the 35 eyes for 3.4 years, no change in visual acuity was observed. Among the total of 86 eyes, 9 were found to have pseudolamellar macular holes. Conclusion: Correlation was found between initial visual acuity and the funduscopic appearance after the 2nd week. Fluorescein angiography was not found to be a conclusive test in solar retinopathy. No late complications were observed.  相似文献   
39.
3-Hydroxy-3-Methylglutaryl coenzyme A lyase (HMG-CoA) deficiency is a rare inborn error of leucine catabolism. The disease is characterized by recurrent episodes of metabolic acidosis, hyperammonemia without ketosis, hypoglycemia, lethargy, hepatomegaly, and seizures. This study has evaluated the magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) findings of three patients with HMG-CoA deficiency. The common findings on all of the MRI scans were multiple, coalescent, marked lesions in periventricular white matter and arcuate fibers, most prominently in frontal or periatrial regions that were superimposed on diffuse, slightly hyperintense subcortical white matter signal. Involvement of the caudate nucleus and the dentate nucleus were observed in the reported patients. MRS studies by both STEAM and PRESS spectra of all patients revealed a decrease in N-acetylaspartate and elevation in both myoinositol and choline. A pathologic peak at 1.33 ppm, which is compatible with lactate, and a particular peak at 2.42 ppm in all patients were also found. The combination of both MRI and MRS findings could be considered as being specific in patients with HMG-CoA lyase deficiency.  相似文献   
40.
The purpose of this study was to investigate the ultrastructural changes taking place in the testicular tissue of adult male Wistar rats following exposure to cigarette smoke. Twenty rats were exposed to smoke in a smoking machine for 2 h daily for 60 days; 10 control rats were placed in the machine for the same amount of time but were exposed to room air. After ether anesthesia and dissection of the animals, the testes were removed and fixed in 2.5% glutaraldehyde. The sections were examined under a transmission electron microscope. Evident degeneration and dissociation of the spermatogenetic cells were common findings. Basal lamina of the tubuli seminiferi contorti was thickened and significantly irregular. Cigarette smoke inhalation damaged the seminiferous epithelium. The primary spermatocytes as well as Sertoli cells appeared to be targets for the smoke. The results indicated that cigarette smoke inhalation could cause specific lesions in the development of spermatozoon, and it might be either directly or indirectly toxic to spermatogenesis.  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