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   1361篇
  免费   74篇
  国内免费   4篇
耳鼻咽喉   21篇
儿科学   76篇
妇产科学   21篇
基础医学   147篇
口腔科学   93篇
临床医学   101篇
内科学   445篇
皮肤病学   10篇
神经病学   105篇
特种医学   57篇
外科学   99篇
综合类   39篇
预防医学   72篇
眼科学   42篇
药学   64篇
肿瘤学   47篇
  2021年   13篇
  2020年   6篇
  2019年   20篇
  2018年   23篇
  2017年   13篇
  2016年   18篇
  2015年   21篇
  2014年   27篇
  2013年   25篇
  2012年   54篇
  2011年   71篇
  2010年   26篇
  2009年   41篇
  2008年   58篇
  2007年   88篇
  2006年   79篇
  2005年   66篇
  2004年   66篇
  2003年   61篇
  2002年   61篇
  2001年   67篇
  2000年   57篇
  1999年   34篇
  1998年   19篇
  1997年   20篇
  1996年   10篇
  1995年   12篇
  1994年   10篇
  1993年   8篇
  1992年   30篇
  1991年   24篇
  1990年   24篇
  1989年   31篇
  1988年   27篇
  1987年   26篇
  1986年   36篇
  1985年   19篇
  1984年   16篇
  1983年   8篇
  1982年   18篇
  1981年   8篇
  1980年   10篇
  1979年   12篇
  1978年   7篇
  1976年   6篇
  1975年   5篇
  1974年   6篇
  1973年   6篇
  1972年   5篇
  1932年   4篇
排序方式: 共有1439条查询结果,搜索用时 15 毫秒
11.
Summary Question of the study  Sleep logs are common tools in sleep research and clinical routine. Usually sleep logs have to be completed during a 2-week period, with the first week serving as an adaptation to the instrument itself. In the present study, we investigated whether there is indeed such an adaptation bias or not. Patients and methods  A total of 236 chronically sleep-disordered outpatients completed the standardized sleep log ‘Abend-Morgen-Protokoll’ during a 2-week pre-screening period prior to the first visit in our sleep ambulance. Two sets of items were established, the ‘instrumental’ and the ‘therapeutic’ set. The respective ratings of the first and second week (week A, B) were compared to evaluate clinically relevant changes. Results  The ratings of several ‘instrumental’ items significantly differed between week A and B. However, these changes—on average—were only marginal and therefore of little clinical importance. Regarding the ‘therapeutic’ set of items, no systematic variations could be ascertained over the assessment period. Conclusion  The present investigation could not confirm the presence of adaptation biases (instrumental, therapeutic) in a large sample of chronically sleep-disordered outpatients. Therefore, we consider a 1-week pre-screening period via sleep log as sufficient for the diagnostic process in these patients.   相似文献   
12.
Recently we demonstrated an important function of keratinocyte growth factor (KGF) in wound re-epithelialization. As KGF is mitogenic for various epithelial cells, we speculated about a role of KGF in epithelial repair processes of other organs as seen in a variety of inflammatory diseases. Here we demonstrate a strikingly increased expression of KGF in surgical specimens from patients suffering from Crohn's disease and ulcerative colitis. The levels of KGF expression strongly correlated with the degree of inflammation as assessed by histological analysis of adjacent tissue and expression analysis of the pro-inflammatory cytokine interleukin-1 beta. The highest levels of KGF mRNA and protein were found in mesenchymal cells of the lamina propria, particularly in highly inflamed areas. As the KGF receptor is expressed in intestinal epithelial cells, KGF seems to act in a paracrine manner to stimulate proliferation of these cells. These data suggest a crucial role of KGF in epithelial repair after injury caused by inflammatory processes.  相似文献   
13.
Sixty cerebrospinal fluid (CSF) samples were obtained from 28 children with terminal deoxynucleotidyl transferase (TdT) positive acute lymphocytic leukemia (ALL). Cell morphology was evaluated using Wright's stained cytocentrifugation prepared slides. The presence of nuclear TdT was detected by an immunofluorescent (IF) assay. Evaluation of CSF mononuclear cells using these two methods simultaneously allowed us to differentiate between leukemic and nonleukemic pleocytosis. Agreement between cytomorphology and TdT in identifying CNS lymphoblasts was found in 55 of 60 samples. Seventy-two per cent of the TdT-positive samples were obtained from children with CSF cell counts less than 10 WBC/mm3. We recommend that these two methods be used in conjunction when evaluating CSF mononuclear cells from children with TdT positive ALL.  相似文献   
14.
The baseline EEG sleep patterns of 10 young depressed patients, 20 patients with anorexia nervosa, 10 patients with bulimia nervosa, and 10 healthy subjects were found to be indistinguishable, except for an increased REM density in the depressed patients. In eating disorder patients, a concomitant major depressive episode had no influence on EEG sleep. The results of the cholinergic REM sleep induction test revealed a significantly faster induction of REM sleep in the depressed patients when compared with the eating disorder patients and the control subjects. This indicates a subthreshold hypersensitivity of the REM sleep triggering cholinergic transmitter system in depressives, but not in eating disorder patients.  相似文献   
15.
We compared the new Abbott TestPack (TP) respiratory syncytial virus (RSV) enzyme immunoassay (EIA) with cell culture and two commercial RSV EIAs (from Abbott Diagnostics and Kallestad Laboratories) by using split samples of fresh nasal washings from children with suspected RSV disease. Two tubes of HEp-2 cells were inoculated and observed for cytopathic effect for 14 days, and isolates were confirmed by immunofluorescence. The TP EIA was performed by following the manufacturer's instructions. Specimens positive by TP EIA but negative by culture were examined in a competitive inhibition (blocking) assay using the TP EIA, and rabbit anti-RSV serum. Of 218 specimens, 93 were positive by culture, 105 were positive by TP EIA, 80 were positive by the Abbott Diagnostics EIA, and 87 were positive by the Kallestad Laboratories EIA. The sensitivity, specificity, positive predictive value, and negative predictive value of the TP EIA were 92, 86, 81, and 93%, respectively. Of 20 apparently false-positive TP EIAs, 10 of 14 that were positive when retested were neutralized in the blocking assay, indicating that they were truly positive. The recalculated sensitivity, specificity, positive predictive value, and negative predictive value of the TP EIA were 92, 91, 90, and 93%, respectively. We conclude that the TP EIA is easy to perform, rapid (less than 0.5 h), and accurate.  相似文献   
16.
17.
Recombinant Sendai virus vectors (SeVV) have become an attractive tool for basic virological as well as for gene transfer studies. However, to (i) reduce the cellular injury induced by basic recombinant SeV vectors (encoding all six SeV genes as being present in SeV wild-type (wt) genomes) and to (ii) improve SeV vector safety, deletions of viral genes are necessary for the construction of superior SeVV generations. As a strong expression system recombinant replication-incompetent adenoviruses, coding for SeV proteins hemagglutinin-neuraminidase (HN), fusion (F), or matrix (M), were generated and successfully employed for the propagation of single gene deleted (DeltaHN, DeltaF, DeltaM) recombinant SeVV. Further investigations of the propagation procedures required for single gene deleted recombinant SeVV demonstrated (i) modifications of the cell culture medium composition as well as (ii) incubation with vitamin E as crucial steps for the enhancement of SeVV-DeltaHN, -DeltaF, or -DeltaM viral particle yield. Such optimized propagation procedures even led to a successful propagation of HN-deleted viral particles (SeVV-DeltaHN), which has not been reported before.  相似文献   
18.
Objective. To quantify the effect of an induction dose of midazolam on median nerve somatosensory evoked potentials.Methods. We studied 10 patients undergoing lumbar spine surgery. After an induction dose of intravenous midazolam was given, MNEPs were collected for ten minutes. After ten minutes the patients were intubated and their anesthetic was supplemented with 0.5% isoflurane, narcotic, and N2O.Results. We found a clinically significant decrease in amplitude and an insignificant delay in latency.Conclusion. When midazolam is used as an anesthetic induction agent, a decrease in amplitude can be expected.  相似文献   
19.
OBJECTIVE: Although the majority of evidence in rodents does not support the view that weight cycling (consisting of bouts of food restriction and refeeding) promotes obesity, the effects of weight cycling on body weight regulation remain controversial. We have previously demonstrated that some rats within a strain are more susceptible to develop obesity than others when given free access to a high-fat diet. In this study, we tested the hypothesis that rats most susceptible to weight gain on a high-fat diet would also be most susceptible to weight gain as a consequence of weight cycling. RESEARCH METHODS AND PROCEDURES: Rats were provided a low-fat diet (12% corn oil) for 2 weeks, then given a high-fat diet (45% corn oil) for 2 weeks to identify those most (obesity prone) and least (obesity resistant) susceptible to weight gain. Half of each group was then subjected to three 30-day cycles of food restriction (10 days) and refeeding (20 days) [weight cycler (WC) rats]. The other half were allowed free access to the high-fat diet [control (CO) rats]. All rats were then followed for an additional 10 weeks, with free access to the high-fat diet. RESULTS: When considering the entire 160 days of the study, we found no evidence that WC rats relative to CO rats had increased body weight, increased body fat content, or elevated energy efficiency. We found no evidence that rats most prone to dietary obesity were also prone to weight gain after weight cycling. During the weight cycling phase (days 1 to 90), weight cycled groups consumed less energy and gained less weight than controls. During the follow-up phase, WC and CO rats did not differ significantly in weight gain or energy intake. DISCUSSION: In this study, weight cycling did not exacerbate the obesity produced by high-fat diet feeding.  相似文献   
20.
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