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   2735篇
  免费   139篇
  国内免费   9篇
耳鼻咽喉   20篇
儿科学   42篇
妇产科学   38篇
基础医学   335篇
口腔科学   71篇
临床医学   170篇
内科学   659篇
皮肤病学   42篇
神经病学   202篇
特种医学   57篇
外科学   565篇
综合类   8篇
预防医学   123篇
眼科学   26篇
药学   168篇
中国医学   2篇
肿瘤学   355篇
  2023年   21篇
  2022年   24篇
  2021年   51篇
  2020年   31篇
  2019年   43篇
  2018年   38篇
  2017年   37篇
  2016年   30篇
  2015年   43篇
  2014年   54篇
  2013年   75篇
  2012年   137篇
  2011年   156篇
  2010年   90篇
  2009年   56篇
  2008年   147篇
  2007年   161篇
  2006年   134篇
  2005年   160篇
  2004年   141篇
  2003年   118篇
  2002年   100篇
  2001年   86篇
  2000年   96篇
  1999年   111篇
  1998年   23篇
  1997年   21篇
  1996年   17篇
  1995年   23篇
  1994年   18篇
  1993年   20篇
  1992年   59篇
  1991年   61篇
  1990年   46篇
  1989年   39篇
  1988年   50篇
  1987年   47篇
  1986年   42篇
  1985年   28篇
  1984年   27篇
  1983年   17篇
  1979年   19篇
  1978年   15篇
  1974年   14篇
  1973年   14篇
  1971年   11篇
  1969年   13篇
  1968年   15篇
  1967年   17篇
  1966年   19篇
排序方式: 共有2883条查询结果,搜索用时 31 毫秒
1.
Experiments were performed on spinalized rats, transected at the Cl level. The intravenous administration of TRH and its analog YM-14673 (N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate) produced marked increases in the amplitude of mono- and polysynaptic reflex potentials and those of the withdrawal flexor reflexes. The effects of YM-14673 were stronger and longer-lasting than those of TRH. The stimulant action of TRH and YM-14673 on the flexor reflexes was not antagonized by prazosin, chlorpromazine, haloperidol or cyproheptadine, suggesting no involvement of the release of catecholamines or serotonin in the stimulant effects of TRH and its analog. Therefore, YM-14673 may be beneficial for the treatment of several spinal motor neuron diseases.  相似文献   
2.
The significance of preoperative chemoembolization using ethiodized oil, cisplatin and gelatin sponge (Sandwich therapy) for resectable hepatocellular carcinoma (HCC) was evaluated. One hundred and thirteen patients with solitary and less than 10 cm sized HCC who underwent radical hepatic resection were chosen for this study. Fifty-three patients received Sandwich therapy before surgery (Group A), and the remaining 60 patients under-went surgery without any preoperative treatments (Group B). Any background factors between two groups were not significantly different. The anticancer effects of this therapy were evaluated by histologic examination in 31 patients who had preoperative Sandwich therapy. In 22 of 31 patients (71%), the main nodules were completely necrotic. The ratios of patients with complete necrosis in daughter nodules were 7/12 (58%), in portal vein tumor emboli, 7/10 (70%), in intracapsular invasions, 11/21 (52%), in extracapsular invasions, 4/11 (36%). The 4-year disease-free survival rates in Group A and Group B were 56% and 27% respectively, and the rate of the former was significantly higher than that of the latter (p less than 0.05). The 4-year survival rates in Group A and Group B were 83% and 53% respectively. The rate of Group A was also significantly higher than that of Group B (p less than 0.01). We concluded that preoperative Sandwich therapy was very significant to obtain successful long-term disease-free survival and survival in regard to relatively early stage HCC.  相似文献   
3.
4.
Proton pump inhibitors have been reported to have a cytoprotective action in addition to the anti-secretory action of acid. The precise mechanism, however, remains obscure. In this study, the effects of proton pump inhibitors (omeprazole and NC-1300) on gastric mucosa hemodynamics and tissue oxygenation were investigated using organ reflectance spectrophotometry in a hemorrhagic shock-reperfusion model involving anesthetized rats. Neither drug affected gastric mucosa hemodynamics nor tissue oxygenation in the basal state before hemorrhage. During the hemorrhagic shock state, however, these drugs maintained tissue oxygenation and reduced ulcer formation, although they did not show a significant effect on gastric mucosa blood volume. The results suggest that both proton pump inhibitors have an anti-ulcer action by maintaining mucosal oxygenation in addition to the anti-secretory activity of acid.  相似文献   
5.
The distribution of filipin-sterol complexes (FSCs) and intramembranous particles (IMPs) in the plasma membrane of the late spermatid of the boar and of the sperm obtained from the epididymides, ejaculates, and uterus 2 hours after mating was examined by a freeze-fracture replica technique. In the late spermatid, the FSC density was found to be very low. A majority of the FSCs in the acrosomal plasma membrane (APM) appeared as protuberances on the E face in the epididymal, ejaculate, and uterine sperm. The density of the FSCs in the principal segment (PS) of the APM was 291 +/- 44 FSC/microns2 (mean +/- standard deviation, S.D.), 322 +/- 41 FSC/microns2 and 355 +/- 31 FSC/microns2 in the caput, corpus, and cauda epididymidis, respectively. In comparison with the cauda epididymal sperm, the FSC density gradually decreased in the PS of the ejaculated (277 +/- 39 FSC/microns2) and uterine sperm (243 +/- 50 FSC/microns2). The reduction was especially remarkable in the equatorial segment (ES), where the density of FSCs in ejaculated and uterine sperm decreased to about half and less than half of that in the cauda epididymal sperm, respectively. Large (13 nm) and small (8 nm) IMPs were distributed evenly and densely in the P face of the APM in the late spermatid, epididymal, and ejaculated sperm. In the uterine sperm, IMP-free areas were observed in the P face of the plasma membrane, a feature thought to represent one of the capacitation changes of the boar sperm.  相似文献   
6.
7.
A statistic analysis was carried out on the 4,956 inpatients admitted to our Department of Urology from April 1972 to December 1991. The patients included 3,399 males and 1,557 females. A total of 4,105 operations including 255 renal allotransplantations were performed on 3,590 patients. Open surgery for upper urinary tract stones has been replaced by extracorporeal shock-wave lithotripsy (ESWL) in the last three years.  相似文献   
8.
9.
Ectopic cervical or cervico-mediastinal thymomas are very rare and most of them are asymptomatic, except for the presence of a cervical mass. We present the case of a 71-year-old man with an ectopic cervico-mediastinal thymoma threatening superior vena cava syndrome. He had a slight headache and presented with venous dilatation on the chest wall. A computed tomographic scan and magnetic resonance, imaging of the chest demonstrated a mass extending from the right neck to the hilum, that indented the trachea and compressed and displaced the brachiocephalic veins anteriorly. Under a right hemicollar incision and median sternotomy, the mass was resected en bloc together with the thymus. The resected specimen was an encapsulated mass measuring 11×7×4 cm. The pathological diagnosis was type AB, non-invasive thymoma, confirmed by 3-color flow, cytometry of tumor-derived lymphocytes. Flow cytometry using biopsy material may contribute to the preoperative diagnosis of ectopic thymoma.  相似文献   
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