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   1433篇
  免费   75篇
  国内免费   6篇
耳鼻咽喉   12篇
儿科学   31篇
妇产科学   17篇
基础医学   130篇
口腔科学   23篇
临床医学   130篇
内科学   526篇
皮肤病学   9篇
神经病学   90篇
特种医学   18篇
外科学   231篇
综合类   7篇
预防医学   88篇
眼科学   6篇
药学   83篇
中国医学   2篇
肿瘤学   111篇
  2023年   11篇
  2022年   23篇
  2021年   36篇
  2020年   22篇
  2019年   15篇
  2018年   27篇
  2017年   18篇
  2016年   27篇
  2015年   23篇
  2014年   43篇
  2013年   54篇
  2012年   60篇
  2011年   97篇
  2010年   48篇
  2009年   49篇
  2008年   71篇
  2007年   102篇
  2006年   75篇
  2005年   73篇
  2004年   77篇
  2003年   65篇
  2002年   59篇
  2001年   41篇
  2000年   32篇
  1999年   20篇
  1998年   12篇
  1997年   5篇
  1996年   6篇
  1995年   11篇
  1994年   9篇
  1993年   12篇
  1992年   24篇
  1991年   15篇
  1990年   26篇
  1989年   23篇
  1988年   24篇
  1987年   19篇
  1986年   21篇
  1985年   10篇
  1984年   8篇
  1983年   20篇
  1982年   5篇
  1980年   6篇
  1979年   9篇
  1978年   19篇
  1977年   15篇
  1975年   6篇
  1970年   4篇
  1968年   5篇
  1966年   5篇
排序方式: 共有1514条查询结果,搜索用时 15 毫秒
101.
Carcinosarcoma is a rare and aggressive disease characterized by biphasic neoplasms with distinct mesenchymal and epithelial components. We report a case of ureteral carcinosarcoma with malignant necrotic polyps. The patient was a 58-year-old woman with painless hematuria, who was later diagnosed as having ureteral carcinosarcoma. Three long pendulous polypoid-shape tumors consisting of high-grade transitional cell carcinoma with chondrosarcomatous and osteosarcomatous elements were found. Two months after nephroureterectomy, the tumor relapsed in the bladder. Despite anterior exenteration, the patient died of local recurrence 6 months after her initial visit. To our knowledge, only 10 cases of this disease have been reported in the literature.  相似文献   
102.
103.
104.
Airway eosinophilia is one of the key pathophysiologic features in asthma. The endothelial adhesion molecules, vascular cell adhesion molecule (VCAM-1) and intercellular adhesion molecule (ICAM-1), have previously been shown to play a crucial role in eosinophil recruitment into the inflamed airway. We have investigated the effects of dexamethasone on eosinophilia into the bronchoalveolar lavage fluid, and the upregulation of VCAM-1 and ICAM-1 expression, measured by immunoblotting, induced by i.v. injection of Sephadex beads into rats. The beads significantly increased the lung eosinophilia, and expression of VCAM-1 and ICAM-1 in the lung. Pretreatment with dexamethasone (0.1 to 2 mg/kg i.p.) strongly inhibited all the airway inflammatory events in a dose-dependent manner. In conclusion, glucocorticoids may be potent inhibitors of lung eosinophilia, at least in part, due to the prevention of the upregulation of VCAM-1 and ICAM-1 expression.  相似文献   
105.
The arginine-specific cysteine proteinase (Arg-gingipain, Rgp) and lysine-specific cysteine proteinase (Lys-gingipain, Kgp) are produced by Porphyromonas gingivalis, an etiological bacterium of periodontal disease. Rgp and Kgp have been implicated as the major virulent factors because of their degrading activity to a broad range of host proteins and of the essential roles in bacterial cell viability. Recent studies have demonstrated the association of P. gingivalis with systemic diseases such as cardiovascular diseases, preterm birth, and low birth weight. The majority of gingipains exist as the membrane-associated complexes composed of the proteinase domains of both Rgp and Kgp, the C-terminal adhesin domains of RgpA and Kgp, phospholipids, and LPS. The complex induced potent viability loss of human endothelial cells and fibroblasts. As the suppression of Rgp and Kgp seems to be the most important to overcome the P. gingivalis-induced systemic disorders as well as the periodontal disease, we have thus designed and synthesized novel proteinase inhibitors specific to Rgp and Kgp on the basis of cleavage sites. Some of them suppressed the characteristic features of P. gingivalis associated with its pathogenicity such as degradation of host proteins, hemagglutination, enhancement of vascular permeability, disruption of leukocytes function, and induction of host cell death.  相似文献   
106.
OBJECTIVE: Report of a remnant tubal pregnancy after cloacal malformation repair. DESIGN: Case report. SETTING: A university hospital. PATIENT: A woman with cloacal malformation repair. INTERVENTION: Laparoscopic surgery. MAIN OUTCOME MEASURE: Remnant tubal pregnancy. RESULT: Laparoscopic right salpingectomy. CONCLUSION(S): In this patient, ectopic pregnancy was caused by contralateral sperm transmigration to the remnant right tube, which was not connected with the left uterus.  相似文献   
107.
The effectiveness and safety of mutant Escherichia coli heat-labile enterotoxin, LT H44A (His to Arg substitution at position 44 from the N-terminus of the A1 fragment of the A subunit) as an adjuvant for nasal influenza vaccine were examined. (1) When 0.2 microg of LT H44A, together with 0.2 microg of influenza A/PR/8/34 virus (PR8, H1N1) vaccine, was administered intranasally into BALB/c mice (twice, 4 weeks apart), anti-PR8 hemagglutinin (HA) IgA and IgG antibody (Ab) responses were induced at levels that were sufficient to provide either complete protection against infection with a small volume of PR8 virus suspension or partial protection against infection with a lethal dose of the suspension. The dose of the mutant LT and vaccine used here (0.2 microg/ 20 g doses mouse) corresponded to the estimated dose per person, i.e. 0.1 mg/10 kg body weight. (2) Using these vaccination conditions, no additional total IgE Ab responses were induced. (3) The mutant was confirmed to be less toxic than the native LT when the toxicity was analyzed either using Y1 adrenal cells in vitro (1/483 EC(50)) or by an ileal loop test. (4) One hundred micrograms of the mutant, administered intranasally or intraperitoneally into guinea-pigs (Heartley strain, 0.3-0.4 kg), caused no body-weight changes 7 days after administration, although 100 microg of the native LT administered intraperitoneally caused death in all guinea-pigs due to diarrhea within 2 days. The intranasal administration of 100 microg of the mutant resulted in almost no pathological changes in the nasal mucosa 3 days after administration. These results suggest that LT H44A, which can be produced in high yields in an E. coli culture (about 5 mg/l), could be used as one of the effective and safe adjuvants for nasal influenza vaccine in humans.  相似文献   
108.
Apoptosis is a morphologically distinct form of programmed cell death that plays a major role in cancer treatments. This cellular suicide program is known to be regulated by many different signals from both intracellular and extracellular stimuli. Here we report that p53 suppressed expression of the cellular FLICE-inhibitory protein (FLIP) that potentially blocks apoptotic signaling in human colon cancer cell lines expressing mutated and wild-type p53. In contrast, the expression of the death receptor KILLER/DR5 (TRAIL-R2) had no effect on FLIP expression, although exogenous p53 is known to induce KILLER/DR5 expression. In line with these observations, FLIP-negative cancer cells were sensitive to both p53- and KILLER/DR5-mediated apoptosis, whereas cells containing high levels of FLIP underwent apoptotic cell death when triggered by ectopic p53 expression but not by KILLER/DR5 expression. Treating the cells with a specific inhibitor of the proteasome inhibited the decrease of FLIP by p53, suggesting that p53 enhances the degradation of FLIP via a ubiquitin-proteasome pathway. Thus, the data indicate that p53-mediated downregulation of FLIP may explain the potent sensitization of human cancer cells to the apoptotic suicide program induced by wild-type p53 gene transfer.  相似文献   
109.
This study was designed to assess whether adenosine A1 receptor antagonists [(R)-1-[(E)-3-(2-phenylpyrazolo[1,5-a]pyridin-3-yl) acryloyl]-piperidin-2-yl acetic acid (FK352) and 8-cyclopentyl-1,3-dipropylxanthine (DPCPX)] reverse dysmotility induced by ischemia-reperfusion in the rat colon. The gene of adenosine A1 receptor was expressed in the colon. Clamping (30 min) of the colonic marginal vessels was followed by reperfusion, and the propulsive colonic motility was evaluated. Propulsion was significantly slowed by ischemia-reperfusion, while FK352 and DPCPX abolished this delay. In contrast, the non-selective adenosine receptor antagonist, 8-phenyltheophylline, failed to affect the dysmotility. Thus, adenosine A1 receptor antagonists have potent therapeutic potential against ischemia-reperfusion-induced dysmotility in the colon.  相似文献   
110.
Two cell-surface markers, rosette formation with sheep erythrocytes (E-rosette) as a T-cell marker and rosette formation with bovine erythrocyte-antibody-complement complex (EAC-rosette) as a B-cell marker were determined on peripheral blood lymphocytes and lymphoblasts from normal and 89 children with acute lymphoblastic leukemia (ALL). In the majority of the patients (12/15 untreated patients and 6/11 patients in relapse), lymphoblasts exhibited neither E- nor EAC-rosette formation. Lymphoblasts from one untreated patient with mediastinal mass displayed E-(50%) and EAC-rosette formation (15%). In 3 of 11 patients in relapse, lymphoblasts displayed an increase in EAC-rosette formation with progressive disease. In the remaining patients with active disease, a small and variable proportion of lymphoblasts expressed E and/or EAC-rosette formation. In 63 patients in remission, percentages of E- and/or EAC-rosette were similar (p > 0.05) to those of control. The results indicate a wide heterogeneity with respect to expression of lymphocyte membrane markers in lymphoblasts and in normal lymphocytes in patients with active ALL.  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