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   752篇
  免费   19篇
  国内免费   1篇
儿科学   129篇
妇产科学   1篇
基础医学   30篇
口腔科学   4篇
临床医学   90篇
内科学   183篇
皮肤病学   6篇
神经病学   56篇
外科学   130篇
综合类   4篇
预防医学   3篇
眼科学   2篇
药学   76篇
中国医学   4篇
肿瘤学   54篇
  2018年   2篇
  2017年   4篇
  2016年   9篇
  2015年   14篇
  2014年   9篇
  2013年   14篇
  2012年   5篇
  2011年   4篇
  2010年   16篇
  2009年   19篇
  2008年   4篇
  2007年   29篇
  2006年   45篇
  2005年   19篇
  2004年   34篇
  2003年   25篇
  2002年   10篇
  2001年   9篇
  2000年   3篇
  1999年   32篇
  1998年   66篇
  1997年   43篇
  1996年   57篇
  1995年   45篇
  1994年   41篇
  1993年   38篇
  1992年   16篇
  1991年   16篇
  1990年   14篇
  1989年   7篇
  1988年   8篇
  1987年   10篇
  1986年   10篇
  1985年   9篇
  1984年   7篇
  1983年   4篇
  1982年   5篇
  1981年   13篇
  1980年   10篇
  1979年   14篇
  1978年   6篇
  1977年   2篇
  1976年   5篇
  1975年   2篇
  1973年   2篇
  1972年   4篇
  1971年   3篇
  1970年   2篇
  1967年   2篇
  1957年   2篇
排序方式: 共有772条查询结果,搜索用时 15 毫秒
51.
An epidemiological survey was carried out to examine the present situation with respect to sudden infant death syndrome (SIDS) in Kanagawa Prefecture. Questionnaires on sudden unexpected death of infants aged < 1 year in 1990-91 were sent to the hospitals and clinics in Kanagawa Prefecture which may take care of such infants. By analysing information from 10 485 replies, 48 out of 73 reported sudden infant deaths were confirmed to be SIDS, although autopsy was not performed in 13 cases (27%). The incidence of SIDS per 1000 live births in Kanagawa Prefecture was 0.29 in 1990 and 0.31 in 1991; and if limited to autopsy cases 0.19 and 0.25, respectively. Sudden infant death syndrome cases in Japan were found to occur more frequently when infants were < 6 months old, at home and sleeping alone, but less in the winter and between midnight and early morning. There was little difference between the numbers in prone and supine sleeping positions at discovery. It was not clear whether SIDS occurred more often to babies sleeping prone than supine, because there were no controls matched with the SIDS cases. In future, continuous epidemiological surveys of SIDS in Japan should be carried out.  相似文献   
52.
BACKGROUND: Retroperitoneal lymph node dissection (RPLND) following induction chemotherapy has been considered a critical component in the comprehensive management of advanced non-seminomatous germ cell tumors (NSGCT). The objectives of the present study were to review the clinical outcome of patients who underwent RPLND and to evaluate the probability of necrosis alone, based on some readily available clinical data for these patients. METHODS: Forty-seven consecutive patients with NSGCT were treated with first-line chemotherapy at our institution between January 1993 and September 2002. Twenty-four of these patients, who underwent RPLND with normal values of tumor markers after induction chemotherapy, were included in the study. The cause-specific survival rate was calculated using the Kaplan-Meier method. Various predictive factors for the histology were analyzed using multivariate analysis. RESULTS: The pathological findings at resection were necrosis alone in 62.5% of cases, teratoma in 25.0%, and viable cancer in 12.5%. The cause-specific 3-year survival rate of patients who underwent complete and incomplete resection was 100% and 50.0%, respectively. Among several clinical factors, prechemotherapy tumor size less than 50 mm was found to be an independent predictor of necrosis alone (hazard ratio = 4.45, P= 0.04). CONCLUSION: Metastatic tumor size before chemotherapy appears to be one of the most important factors for the prediction of necrosis alone in the resected specimens of RPLND. The prognosis of patients might be influenced by the degree to which resection has been completed.  相似文献   
53.
Granular cell tumor is a benign neoplasm which frequently occurs in the oral cavity, skin, and subcutaneous tissue. Granular cell tumor of the bladder is an extremely rare disease, and only nine cases have been reported. We present here an additional case of granular cell tumor occurring in the bladder. Unlike the other tumors reported, this tumor extruded into the Retzius' cavity. Therefore, the tumor was successfully excised through extraperitoneal laparoscopic surgery. The patient was free from recurrence 40 months after surgery. The small tumor located in Retzius' cavity could be managed with extraperitoneal laparoscopic surgery.  相似文献   
54.
A female infant with 21 trisomy syndrome associated with congenital chylothorax was reported. She was born at a gestational age of 34 weeks by Cesarean section because of fetal hydrothorax and hydrops fetus, confirmed by ultrasonography at 32 weeks. Emergent resuscitation and immediate thoracentesis were performed soon after birth. After beginning breast feeding, the serous pleural fluid became opalescent and a diagnosis of congenital chylothorax was made. Feeding was changed to medium-chain triglyceride (MCT) feeding and the production of pleural effusion disappeared after thoracentesis was performed several times. Accumulating evidence suggested that MCT feeding and intermittent thoracentesis under echo guide were effective. Some reports on patients, including this one, suggest that there may be more patients with 21 trisomy associated with congenital hydrothorax. Therefore, congenital hydrothorax might be listed as a complication of 21 trisomy.  相似文献   
55.
Four types of materials, type I collagen coat (Coat), acid-soluble type I collagen gel (Hardgel), pepsin-treated acid-soluble type I collagen gel (Softgel), and an extract of extracellular matrix of the murine Engelbreth-Holm-Swarm sarcoma (Matrigel), were used as matrices to culture rat hepatic parenchymal cells, and their morphological changes and adhesion were compared to the matrices by electron microscopic observations. Hepatic parenchymal cells cultured on Coat and Hardgel were extended and flattened, whereas cells cultured on Softgel and Matrigel assembled and formed aggregates. Such aggregates consisted of several hepatic parenchymal cells, with a recognizable bile duct-like alveolus on the inside. Morphologically, the aggregates were more spherical on Matrigel and oval shaped on Softgel. Microvilli of the cell surface were parallel to the matrix on Matrigel, but invaded into the gel on Softgel. Subsequently, investigation into how these morphological features affected the liver-specific functions, including secretion of albumin and induction of P450 by 3-methylcholanthrene, demonstrated that a high level of liver function was maintained in a long-term culture in hepatic parenchymal cells on Softgel. These results suggest that hepatic parenchymal cell interactions were stronger with Softgel than with Matrigel, and that Softgel appears to closely mimic the in vivo environment.  相似文献   
56.
: Maintaining high levels of intracellular cyclic AMP (cAMP) is known to inhibit the growth of various proliferating cells including hepatocytes. We show here that transient (30 min) elevations of cAMP induced by addition of 8-bromo-cAMP (1 mmol/L) to rat hepatocytes in primary culture at three time points (12h, 16h and 20h) after seeding stimulated DNA synthesis. Sustained levels of cAMP stimulated DNA synthesis to a lesser degree at a lower concentration (1 μmol/L), but inhibited it at concentrations higher than 100μmol/L. We also determined cyclin-dependent kinase 2 (cdk2) activity in the hepatocytes during this incubation period. The transient addition of 8-bromo-cAMP at the late G1 phase increased cdk2 activity. This suggests that transient cAMP elevation in hepatocytes at the late G1 phase has a growth stimulation effect. Up-regulation of cdk2 activity may have a role in this process.  相似文献   
57.
Effects of glycyrrhizin on immune-mediated cytotoxicity   总被引:10,自引:0,他引:10  
Intravenous administration of glycyrrhizin is known to decrease elevated plasma transaminase levels in patients with chronic viral hepatitis, in which immune-mediated cytotoxicity by cytotoxic T lymphocytes and tumour necrosis factor (TNF)-α is considered to play an important pathogenic role. However, the immunological interpretation of the transaminase-lowering action of glycyrrhizin is not known. Studies were performed to elucidate this action immunologically by assessing the effects of glycyrrhizin on immune-mediated cytotoxicity using an antigen-specific murine CD4+ T hybridoma line, which exhibits cytotoxicity against antigen-presenting cells after stimulation with specific antigen, and a murine TNF-α-sensitive fibroblast line. Glycyrrhizin inhibited the cytotoxic activity of the T cells against antigen-presenting cells and also suppressed TNF-α-induced cytotoxicity in the TNF-α-sensitive cell line in vitro. These results suggest that the decrease of elevated transaminase levels by glycyrrhizin in patients with chronic viral hepatitis is mediated in part by inhibition of immune-mediated cytotoxicity against hepatocytes.  相似文献   
58.
Unfolding profiles of two calcium-binding lysozymes, equine milk lysozyme and pigeon egg-white lysozyme, were obtained by circular dichroism and proton NMR measurements. Equine lysozyme unfolds through a stable molten globule intermediate. The molten globule of equine lysozyme was characterized as more ordered than that of bovine α-lactalbumin. On the other hand, pigeon lysozyme unfolds by a two-state mechanism and the intermediate could not be observed in guanidine or thermal unfolding, the same as with conventional non-calcium-binding lysozymes. Thus, from the point of view of the unfolding profile, equine lysozyme belongs to the group of α-lactalbumin, but pigeon lysozyme belongs to the conventional lysozyme group.  相似文献   
59.
60.
Two autopsy cases of Cronkhite-Canada syndrome were reported. The caused of hypoproteinemia, electrolyte imbalance and ectodermal changes were discussed with reference to previously reported cases. The mechanism of protein loss was probably due to outflow into the intestinal lumen of the mucous substance in the cystically dilated glands, directly and/or indirectly followed by loss of mucosal surface. Electrolyte imbalance probably developed from gastrointestinal loss as well as poor substitution. The ectodermal changes were probably not a subsequent part of the emaciation or hypoproteinemis, but an inherent part of this disease. Therapy, whether substitution or surgical procedure, should be selected in order to control the general condition of the patient.  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