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   23063篇
  免费   1234篇
  国内免费   98篇
耳鼻咽喉   278篇
儿科学   514篇
妇产科学   423篇
基础医学   2972篇
口腔科学   1318篇
临床医学   1663篇
内科学   5626篇
皮肤病学   479篇
神经病学   1985篇
特种医学   436篇
外科学   3467篇
综合类   219篇
一般理论   9篇
预防医学   1947篇
眼科学   492篇
药学   1400篇
中国医学   108篇
肿瘤学   1059篇
  2023年   149篇
  2022年   268篇
  2021年   791篇
  2020年   437篇
  2019年   656篇
  2018年   818篇
  2017年   503篇
  2016年   521篇
  2015年   677篇
  2014年   987篇
  2013年   1164篇
  2012年   1949篇
  2011年   1981篇
  2010年   1080篇
  2009年   949篇
  2008年   1598篇
  2007年   1678篇
  2006年   1451篇
  2005年   1390篇
  2004年   1167篇
  2003年   974篇
  2002年   966篇
  2001年   204篇
  2000年   140篇
  1999年   176篇
  1998年   204篇
  1997年   141篇
  1996年   98篇
  1995年   88篇
  1994年   93篇
  1993年   73篇
  1992年   104篇
  1991年   79篇
  1990年   67篇
  1989年   63篇
  1988年   55篇
  1987年   42篇
  1986年   44篇
  1985年   44篇
  1984年   45篇
  1983年   43篇
  1982年   44篇
  1981年   37篇
  1980年   22篇
  1979年   25篇
  1978年   35篇
  1977年   33篇
  1976年   19篇
  1974年   18篇
  1973年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Obesity Surgery - Laparoscopic sleeve gastrectomy (LSG) is increasingly playing a key role in obesity management. Such operations, however, carry complications sometimes including leaks. The...  相似文献   
3.
Background: Extracellular matrix molecular components, previously linked to multisystem syndromes include collagens, fibrillins and laminins. Recently, we described a novel multisystem syndrome caused by the c.9418G>A p.(V3140M) mutation in the laminin alpha-5 (LAMA5) gene, which affects connective tissues of all organs and apparatus in a three generation family. In the same family, we have also reported a myopic trait, which, however, was linked to the Prolyl 4-hydroxylase subunit alpha-2 (P4HA2) gene. Results of investigation on vitreous changes and their pathogenesis are reported in the present study.Materials and Methods: Nineteen family individuals underwent complete ophthalmic examination including best-corrected visual acuity (BCVA), fundus examination, fundus photography, intraocular pressure measurement, axial length measurement using ocular biometry, Goldmann visual field examination, standard electroretinogram, SD-OCT. Segregation analysis of LAMA5 and P4HA2 mutations was performed in enrolled members.Results: The vitreous alterations fully segregated with LAMA5 mutation in both young and adult family members. Slight reduction of retinal thickness and peripheral retinal degeneration in only two patients were reported.Conclusions: In this work we showed that PVD is a common trait of LAMA5 multisystem syndrome, therefore occurring as an age-unrelated trait. We hypothesize that the p.(V3140M) mutation results in a reduction of retinal inner limiting membrane (ILM) stability, leading to a derangement in the macromolecular structure of the vitreous gel, and PVD. Further investigations will be necessary to elucidate the role of wild type and mutated LAMA5 in the pathogenesis of PVD.  相似文献   
4.
Gangliocytic paragangliomas are rare tumors that almost exclusively occur within the second portion of the duodenum. Although these tumors generally have a benign clinical course, they have the potential to recur or metastasize to regional lymph nodes. The case report presented here describes a 57-year-old female patient with melena, progressive asthenia, anemia, and a mass in the second-third portion of the duodenum that was treated by local excision. The patient was diagnosed with a friable bleeding tumor. The histologic analysis showed that the tumor was a 4 cm gangliocytic paraganglioma without a malignant cell pattern. In the absence of local invasion or distant metastasis, endoscopic resection represents a feasible, curative therapy. Although endoscopic polypectomy is currently considered the treatment of choice, it is not recommended if the size of the tumor is > 3 cm and/or there is active or recent bleeding. Patients diagnosed with a gangliocytic paraganglioma should be closely followed-up for possible local recurrence.  相似文献   
5.
6.
7.
This meta-analysis focuses on the accuracy of upgrading to clinically significant prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsy (MRI-TB) versus systematic biopsy (SB). We searched the Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and Literatura Latino Americana em Ciências da Saúde databases through January 2020 for comparative, retrospective/prospective, paired-cohort, and randomized clinical trials with paired comparisons. The population consisted of patients with low-risk PCa in active surveillance with at least 1 index lesion on imaging. We evaluated the quality of evidence by using the Quality Assessment of Diagnostic Accuracy Studies-2 score. Group comparisons considered the differences between the area under the curve summary receiver operating characteristic curve in a 2-tailed method. We also compared the positive predictive value of the best single method (MRI-TB or SB) and the referral study test (combined biopsy, a combination of MRI-TB and SB). The meta-analysis included 6 studies enrolling 741 patients. The pooled sensitivity for the 2 groups was 0.79 (95% confidence interval, 0.74-0.83; I2 = 75%) and 0.67 (95% confidence interval, 0.63-0.74; I2 = 55.4%), respectively. The area under the curve for the MRI-TB and SB groups were 0.99 and 0.92 (P < .001), respectively. The positive predictive value for the MRI-TB and combined biopsy groups were similar. The accumulated evidence suggests better results for MRI-TB compared with SB. Therefore, use of MRI-TB alone may be preferable in patients in active surveillance harboring low-risk PCa.  相似文献   
8.
9.
10.
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