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   606篇
  免费   22篇
  国内免费   26篇
儿科学   21篇
妇产科学   12篇
基础医学   86篇
口腔科学   27篇
临床医学   86篇
内科学   95篇
皮肤病学   3篇
神经病学   31篇
特种医学   63篇
外科学   92篇
综合类   9篇
预防医学   38篇
眼科学   10篇
药学   51篇
肿瘤学   30篇
  2021年   4篇
  2020年   2篇
  2019年   4篇
  2018年   9篇
  2017年   5篇
  2016年   8篇
  2015年   9篇
  2014年   11篇
  2013年   23篇
  2012年   11篇
  2011年   10篇
  2010年   14篇
  2009年   15篇
  2008年   16篇
  2007年   34篇
  2006年   14篇
  2005年   18篇
  2004年   23篇
  2003年   19篇
  2002年   17篇
  2001年   17篇
  2000年   22篇
  1999年   15篇
  1998年   20篇
  1997年   16篇
  1996年   23篇
  1995年   22篇
  1994年   15篇
  1993年   22篇
  1992年   17篇
  1991年   18篇
  1990年   29篇
  1989年   22篇
  1988年   28篇
  1987年   11篇
  1986年   11篇
  1985年   18篇
  1984年   6篇
  1983年   5篇
  1982年   6篇
  1981年   4篇
  1980年   6篇
  1979年   6篇
  1978年   4篇
  1977年   2篇
  1976年   5篇
  1975年   2篇
  1971年   3篇
  1969年   3篇
  1918年   1篇
排序方式: 共有654条查询结果,搜索用时 0 毫秒
91.
The histologic features of prostatic duct-acinar dysplasia have been difficult to analyze ultrastructurally, because of the difficulty in properly selecting and processing such small, randomly situated grossly invisible lesions. We have succeeded in identifying dysplastic foci by examination of the cut surfaces of tissue slices under low magnification. Dysplasia foci were excised from the slices and were compared to adjacent normal tissue by both light and electron microscopy. By electron microscopy (EM), normal secretory cells were filled with myriad tiny clear vacuoles, which were markedly diminished to absent in the cytoplasm of dysplastic cells. Both apocrine and eccrine secretion characterized normal epithelium and were diminished in dysplasia. EM showed striking features of nuclear abnormality more prominently than light microscopy, and qualitative basement membrane abnormalities were revealed. By EM analysis, dysplastic epithelium resembled that of invasive carcinoma more than normal epithelial cells.  相似文献   
92.
Morphological features in radical prostatectomy specimens from 11 stage A and 73 stage B prostatic carcinomas were compared by mapping of tumor locations, and determinations of cancer volumes and histological patterns. Small stage A cancers were located anteromedially, while small stage B carcinomas were concentrated against the posterior capsule at the rectal surface. Small stage A carcinomas commonly invaded the anterior fibromuscular stroma and benign prostatic hyperplasia nodules, features that were uncommon even in large stage B tumors. Stage A cancers often appeared to arise within benign prostatic hyperplasia nodules and had a distinctive histological appearance. Even when large, stage A carcinomas tended not to spread close to the rectal surface of the gland. Stages A and B cancers spanned a roughly comparable volume range, and both showed progressive dedifferentiation with increasing volume. It is proposed that stages A and B cancers are biologically similar malignancies, distinguished only by their site of origin. Prognosis for patients with stage A carcinoma probably is closely related to tumor volume and dedifferentiation, features that are not reliably estimated in tissue samples removed at operation for benign prostatic hyperplasia.  相似文献   
93.
Pinealectomyaffectsthediurnalvariationsin2-[~(125)I]iodomelatoninbindingsitesinchickenbursaofFabriciusZhaoYing(赵瑛);PoonAMS,Pa?..  相似文献   
94.
The prevalence of mitral valve pro.lapse in Chinese was determined by screening 156 heal- thy subjects and by patholobic examination of 86 adult autopsies. Mitral valve prolapse was found in 7.7% in the clinical study and 5.8% in the autopsy study. A slight female preponderance was noted.  相似文献   
95.
The authors describe percutaneous treatment of gallbladder or bile duct stones in 18 patients who were poor surgical candidates or in whom conventional therapy failed. Dissolution was performed in most cases with methyl tert-butyl ether (MTBE) because of its potent dissolution properties; other solvents used included monooctanoin or chelating solutions. Gallbladder stones were eliminated in 11 of 13 patients (six of seven with dissolution alone, four of four with dissolution and basket extraction, one with basket removal alone). In five patients with stones in the common bile duct (n = 3), cystic duct remnant (n = 1), and intrahepatic bile ducts (n = 1), stones were eliminated with dissolution alone in two and with dissolution plus basket extraction in one. In two patients percutaneous therapy failed due to complications (vagal hypotension with bile peritonitis and transient respiratory arrest) that occurred during catheter placement. Preliminary results suggest that MTBE is effective for dissolution of many gallbladder stones and some bile duct stones. Noncholesterol solvents and adjuvant mechanical maneuvers are valuable adjuncts to achieve complete stone elimination.  相似文献   
96.
Ultrasound guided transrectal core biopsies of the palpably abnormal prostate   总被引:11,自引:0,他引:11  
Ultrasound imaging and ultrasound guided transrectal core biopsies were performed in 251 consecutive men with abnormal prostates on digital rectal examination. A hypoechoic defect on ultrasound was identified in 227 of 251 patients (90 per cent) corresponding to the area of palpable nodularity or abnormal firmness. A mean of 6.25 biopsies were obtained per patient using a commercially available spring-loaded gun. Biopsies were positive for cancer in 165 of the 251 prostates (66 per cent). Palpable nodules more often were hypoechoic and more often contained cancer than less distinct areas of abnormal firmness on digital examination. Among the clinical stages B1, B2 and B3 nodules 70, 76 and 88 per cent, respectively, were positive for cancer, as were 100 per cent of the clinical stage C prostates. Of 77 abnormally firm, nonnodular prostates 36 per cent were positive for cancer. Random biopsy of the contralateral normal lobe in 56 men with clinical stage B1 or B2 nodules showed cancer present contralaterally in 42 and 60 per cent, respectively; 20 per cent had positive biopsies despite a contralateral isoechoic ultrasound. In 78 patients with prior digitally guided biopsies, ultrasound guided biopsies confirmed previously diagnosed cancers in 94 per cent. However, in 23 of 43 patients (53 per cent) with previous negative digitally guided biopsies, ultrasound guided biopsies made the new diagnosis of cancer. Complications, including post-biopsy fever and bleeding, occurred in 6 of 251 patients (2.4 per cent). The combination of the new spring-loaded biopsy guns and transrectal ultrasound guidance of biopsies provides the urologist with a tool that allows multiple prostate cores to be obtained safely and painlessly, reducing the sampling error and increasing the accuracy in diagnosing prostate cancer in the man with a palpable abnormality of the prostate.  相似文献   
97.
98.
脑益嗪对实验性脑血栓形成及血小板聚集的抑制作用   总被引:17,自引:0,他引:17  
本文报道脑益嗪对大鼠实验性脑血栓形成及兔血小板聚集的抑制作用。经大鼠颈动脉顺行注射复合血栓诱导剂造成脑血栓模型,测定伊文思兰通过血脑屏障渗入脑实质的量以反映脑血栓的严重程度。结果表明脑益嗪(67 mg/kg,灌胃)有抗脑血栓形成的作用。半体内实验表明脑益嗪(34 mg/kg,灌胃)可抑制兔血小板聚集。  相似文献   
99.
100.
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