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   352篇
  免费   12篇
  国内免费   51篇
耳鼻咽喉   1篇
儿科学   4篇
妇产科学   11篇
基础医学   24篇
口腔科学   15篇
临床医学   50篇
内科学   88篇
皮肤病学   24篇
神经病学   4篇
外科学   63篇
综合类   55篇
预防医学   12篇
药学   54篇
中国医学   8篇
肿瘤学   2篇
  2022年   4篇
  2017年   5篇
  2015年   7篇
  2014年   15篇
  2013年   25篇
  2012年   9篇
  2011年   6篇
  2010年   28篇
  2009年   30篇
  2008年   16篇
  2007年   12篇
  2006年   19篇
  2005年   8篇
  2004年   8篇
  2002年   4篇
  2001年   2篇
  2000年   3篇
  1999年   8篇
  1998年   10篇
  1997年   8篇
  1996年   18篇
  1995年   5篇
  1994年   10篇
  1993年   11篇
  1992年   10篇
  1991年   7篇
  1990年   7篇
  1989年   8篇
  1988年   7篇
  1987年   9篇
  1986年   3篇
  1983年   2篇
  1981年   4篇
  1980年   2篇
  1966年   2篇
  1965年   6篇
  1963年   5篇
  1962年   6篇
  1960年   3篇
  1959年   2篇
  1958年   7篇
  1957年   6篇
  1956年   6篇
  1955年   3篇
  1954年   7篇
  1948年   3篇
  1940年   2篇
  1939年   4篇
  1935年   2篇
  1931年   2篇
排序方式: 共有415条查询结果,搜索用时 31 毫秒
1.
Abstract  Gastrointestinal stromal tumor (GIST) is a recently described mesenchymal tumor that can develop in any portion of the gastrointestinal tract. The occurrence of a GIST in the urinary tract is rare, but GIST can present as tumor of the urinary tract or invade the urinary tract. This is the first reported case of GIST in the ileal neobladder, which presented as a submucosal tumor. The patient underwent an open exploration and partial resection of the neobladder pouch.  相似文献   
2.
3.
AIM: To evaluate the cause of elevated prostate-specific antigen (PSA) in patients with transrectal needle biopsy negative for prostate cancer. METHODS: Serum PSA concentration, prostate volume, and pathologic findings were examined in 223 patients with negative biopsy for prostate cancer. The degree of prostate inflammation was determined by the extent and degree of inflammation shown by biopsy specimens and is expressed as an inflammation score (range: 0-36). RESULTS: A significant correlation was found between PSA concentration and prostate total volume (P=0.0001). Prostate chronic inflammation showed no correlation with PSA concentration (P=0.485, F=0.488). After allocating patients to normal PSA (4 ng/mL) groups, we found that serum PSA concentrations in both groups were predominantly affected by prostate total volume. CONCLUSIONS: An increase in prostate volume appears to be the major contributor to a high serum PSA concentration in patients with negative biopsy for prostate cancer. However, in contrast to previous reports, there was no correlation between the degree of prostate chronic inflammation and serum PSA concentrations.  相似文献   
4.
Different doses of hepatitis B virus vaccine—prepared by Korea Green Cross Corporation, were given to healthy infants born to HBsAg-negative mothers at birth, 1 and 6 months of age. A dose of 2 μg was administered intradermally in Group A and, in the three other groups, the vaccine was given intramuscularly (i.m.). An adequate follow-up observation was possible for 9 months after birth in 22, 25, 23 and 21 infants in Groups A, B, C and D, respecvely.
Group C (5 μg, i.m.) produced seroconversion most rapidly, showing the highest rate (96%) at 9 months of age. The lowest seroconversion rate (5%) was found at the age of 1 month in Group A subjects, but the rate increased to 91% after a booster dose was given at 6 months of age.
While it can be concluded that a 5 μg i.m. dose of vaccine at 0, 1 and 6 months of age is optimum for the immunization of infants in efficacy and economy, a 2 μg intradermal dose can also be considered as an immunogenic and economical regimen, though the immune response is slower and a special technique is required for immunization.  相似文献   
5.
The DL-arylamino acid ethyl ester derivatives of β-(3-pyridyl)-DL-alanine, and β-(3-benzo[b]thienyl)-DL-alanine were synthesized by diethyl acetamidomalonate condensation with the respective arylmethyl halides followed by partial hydrolysis to the monoethyl ester and decarboxylation. Each derivative was enzymatically resolved to a separable mixture of the corresponding N-acetyl-L-amino acid and the unchanged D amino acid derivative. Acidic hydrolysis of the latter gave the corresponding D-amino acid, the optical purity of which was established by HPLC analysis of the 2,3,4,6-tetra-O-acetyl-β-D-glucopyranosyl isothiocyanate (GITC) derivative. The free D amino acids were converted to D-BOC derivatives by reaction with di-tert-butyldicarbonate in tert-butyl alcohol, water and sodium hydroxide.  相似文献   
6.
7.
8.
9.
目的验证反转恢复实时快速小角度激发(IR-rttfl)成像的心肌T1量化方法。方法对仿体、健康志愿者和心肌坏死患者分别进行成像,在3.0T磁场中使用IR-rttfl的扫描方法量化心肌T1值,与MOLLI方法的结果进行对比,并将T1量化的结果用于分析心肌的异常区域。结果 IR-rttfl方法将扫描时间缩短到6s以内,T1量化结果比MOLLI方法更准确,并且能够有效区分患者心肌的异常区域。结论这种方法能够有效抑制心律不齐造成的影响,提高心肌T1量化结果的准确性,对心肌坏死的诊断具有重要意义。  相似文献   
10.
Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012)  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