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   8217篇
  免费   358篇
  国内免费   67篇
耳鼻咽喉   188篇
儿科学   249篇
妇产科学   106篇
基础医学   1361篇
口腔科学   131篇
临床医学   414篇
内科学   1982篇
皮肤病学   168篇
神经病学   592篇
特种医学   284篇
外科学   1340篇
综合类   22篇
预防医学   141篇
眼科学   107篇
药学   486篇
中国医学   24篇
肿瘤学   1047篇
  2023年   36篇
  2022年   75篇
  2021年   200篇
  2020年   95篇
  2019年   122篇
  2018年   155篇
  2017年   139篇
  2016年   161篇
  2015年   161篇
  2014年   234篇
  2013年   292篇
  2012年   478篇
  2011年   573篇
  2010年   328篇
  2009年   247篇
  2008年   425篇
  2007年   499篇
  2006年   506篇
  2005年   537篇
  2004年   567篇
  2003年   527篇
  2002年   605篇
  2001年   114篇
  2000年   68篇
  1999年   109篇
  1998年   136篇
  1997年   137篇
  1996年   113篇
  1995年   82篇
  1994年   100篇
  1993年   105篇
  1992年   71篇
  1991年   74篇
  1990年   59篇
  1989年   51篇
  1988年   48篇
  1987年   42篇
  1986年   45篇
  1985年   36篇
  1984年   39篇
  1983年   24篇
  1982年   34篇
  1981年   25篇
  1980年   30篇
  1979年   14篇
  1978年   24篇
  1977年   11篇
  1976年   17篇
  1974年   8篇
  1973年   11篇
排序方式: 共有8642条查询结果,搜索用时 15 毫秒
131.
Inverted urothelial carcinoma (UC) without papillary areas is very rare; only 31 cases of three papers have been reported. The author herein reports three additional cases, and proposes the term “inverted variant” (IV) of UC. The materials were 3 cases of IV of UC, 5 cases of inverted papilloma (IP), and two cases of nested variant (NV) of UC. The three cases of IV of UC consisted of 56-year-old woman, 63-year-old man, and 78-year-old man. Presenting symptoms were hematuria in all cases. The cystoscopic findings were elevated tumors without papillary proliferations in all cases. The treatment was transurethral tumor resection (TUR-BT) in all cases. The sizes was 0.6 cm, 0.5 cm, and 3 cm. Microscopically, IV of UC showed inverted growth of atypical cells without papillary proliferations. Compared to IP, the inverted growth pattern was similar, but cytological atypia and thick trabeculae were noted in IV of UP while they were absent in IP. Compared to NV of UC, the growth pattern is different; NV of UC showed nested and vague tubular pattern. The cellular atypia is more pronounced in IV of UC than NV of UC. Immunohistochemically, p53 expression was seen in all the cases of IV of UC and in all the cases of NV of UC, while p53 expression was negative in all the cases of IP. Ki-67 labeling index was 25, 30 and 40% in IV of UC, 15 and 30% in NV of UC, and 3, 5, 6, 7, 9% in IP. Invasive features were seen in 1 case of IV of UC and 2 cases of NV of UC. In all cases of IV of UC, IP, and NV of UC, the TUR-BT, but one case of IV of UC, showed no recurrence after TUR-BT, while one case of IV of UC showed a recurrence. In conclusion, the IV and UC were structurally and cytologically very different from the NV of UC. The IV of UC was structurally similar to IP, but cellular atypia and thickened trabeculae were seen in IV and UC. p53 expression and Ki-67 labeling status were entirely different between in IV of UC and IP. The author proposes the term of IV of UC as a new clinicopathological entity.  相似文献   
132.
133.
134.
135.
Pallister‐Killian syndrome (PKS) is rare genetic disorder caused by tetrasomy 12p mosaicism with supernumerary isochromosome 12p that manifests with intellectual disability, craniofacial dysmorphism, and epilepsy. Although PKS presents as a multisystem morphological defect, respiratory system involvement is rare, except for diaphragmatic hernia. We are the first to report a case of PKS with progressive subglottic stenosis. Subglottic stenosis is a potentially lethal condition due to severe respiratory obstruction and difficult intubation; therefore, further accumulation of cases is required to assess the causal link between PKS and subglottic stenosis.  相似文献   
136.
ObjectivesTo investigate the expression levels of multiple molecular markers in radical nephrectomy specimens from patients with metastatic renal cell carcinoma (RCC) treated with sorafenib in order to identify factors predicting susceptibility to this agent.Materials and methodsThis study included 45 consecutive patients undergoing radical nephrectomy for clear cell RCC who were diagnosed as having metastatic diseases refractory to cytokine therapy and subsequently treated with sorafenib. Expression levels of 19 molecular markers involved in the regulation of apoptosis, cell cycle, signal transduction, and angiogenesis in primary RCC specimens were measured by immunohistochemical staining.ResultsThere was no molecular marker having significant impact on the prediction of response to sorafenib. However, progression-free survival (PFS) was significantly associated with the expression levels of Bcl-xL and platelet-derived growth factor receptor (PDGFR)-α in addition to the presence of bone metastasis and C-reactive protein level on univariate analysis. Of these significant factors, PDGFR-α expression and the presence of bone metastasis appeared to be independently related to PFS by multivariate analysis. Furthermore, there were significant differences in PFS according to positive numbers of these 2 independent risk factors; that is, disease progression occurred in 2 of 7 patients who were negative for risk factor, 19 of 34 positive for a single risk factor, and 6 of 6 positive for both risk factors.ConclusionsCollectively, these findings suggest that it would be useful to consider expression levels of potential molecular markers, particularly PDGFR-α, as well as clinical parameters to select metastatic RCC patients likely to benefit from treatment with sorafenib.  相似文献   
137.
138.
Journal of Gastroenterology - A correction to this paper has been published: https://doi.org/10.1007/s00535-021-01786-z  相似文献   
139.
Infantile hemangioma (IH) is a benign vascular tumor that gradually involutes over several years. Rapidly involuting congenital hemangioma (RICH) is the relatively rare congenital vascular tumor that is fully grown at birth and does not undergo postnatal growth and involutes during the first year. However, after involution of both IH and RICH, some have severe sequelae, such as redundant skin or conspicuous scarring, requiring additional treatment. We present the case of a 6-year-old girl with a concave deformity due to subcutaneous atrophy, skin darkening, and altered skin texture of her left zygomatic region following involution of a hemangioma. We successfully treated this patient by transferring a dermal fat graft. This technique can be beneficial for atrophic sequelae after regression of a hemangioma and is easy to perform and cosmetically effective.  相似文献   
140.
The degree of stenosis in the carotid artery can be predicted using automated carotid lumen diameter (LD) measured from B-mode ultrasound images. Systolic velocity-based methods for measurement of LD are subjective. With the advancement of high resolution imaging, image-based methods have started to emerge. However, they require robust image analysis for accurate LD measurement. This paper presents two different algorithms for automated segmentation of the lumen borders in carotid ultrasound images. Both algorithms are modeled as a two stage process. Stage one consists of a global-based model using scale-space framework for the extraction of the region of interest. This stage is common to both algorithms. Stage two is modeled using a local-based strategy that extracts the lumen interfaces. At this stage, the algorithm-1 is modeled as a region-based strategy using a classification framework, whereas the algorithm-2 is modeled as a boundary-based approach that uses the level set framework. Two sets of databases (DB), Japan DB (JDB) (202 patients, 404 images) and Hong Kong DB (HKDB) (50 patients, 300 images) were used in this study. Two trained neuroradiologists performed manual LD tracings. The mean automated LD measured was 6.35 ± 0.95 mm for JDB and 6.20 ± 1.35 mm for HKDB. The precision-of-merit was: 97.4 % and 98.0 % w.r.t to two manual tracings for JDB and 99.7 % and 97.9 % w.r.t to two manual tracings for HKDB. Statistical tests such as ANOVA, Chi-Squared, T-test, and Mann-Whitney test were conducted to show the stability and reliability of the automated techniques.  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