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   461篇
  免费   20篇
  国内免费   20篇
耳鼻咽喉   1篇
儿科学   14篇
妇产科学   4篇
基础医学   39篇
口腔科学   52篇
临床医学   41篇
内科学   75篇
皮肤病学   6篇
神经病学   19篇
特种医学   164篇
外科学   30篇
综合类   4篇
预防医学   6篇
眼科学   1篇
药学   31篇
肿瘤学   14篇
  2020年   3篇
  2019年   9篇
  2018年   4篇
  2017年   3篇
  2016年   12篇
  2015年   14篇
  2014年   12篇
  2013年   8篇
  2012年   6篇
  2011年   5篇
  2010年   9篇
  2009年   18篇
  2008年   21篇
  2007年   31篇
  2006年   13篇
  2005年   15篇
  2004年   17篇
  2003年   10篇
  2002年   14篇
  2001年   20篇
  2000年   12篇
  1999年   16篇
  1998年   26篇
  1997年   15篇
  1996年   7篇
  1995年   10篇
  1994年   13篇
  1993年   10篇
  1992年   2篇
  1991年   10篇
  1990年   8篇
  1989年   17篇
  1988年   20篇
  1987年   10篇
  1986年   13篇
  1985年   14篇
  1984年   10篇
  1983年   4篇
  1982年   4篇
  1981年   3篇
  1980年   7篇
  1979年   3篇
  1977年   2篇
  1976年   5篇
  1975年   4篇
  1974年   3篇
  1965年   2篇
  1912年   1篇
  1908年   1篇
  1903年   1篇
排序方式: 共有501条查询结果,搜索用时 46 毫秒
91.
92.
Zusammenfassung  Die Geltendmachung von Schadensersatz gegen einen Sachverst?ndigen gem. § 839a BGB setzt eine detaillierte Auseinandersetzung mit dem Inhalt des Gutachtens voraus und erfordert einen substantiierten Sachvortrag zu der vorgetragenen Behauptung einer vors?tzlichen bzw. grob fahrl?ssigen Erstattung eines unrichtigen Gutachtens. Lediglich subjektive Zweifel an der Richtigkeit des Gutachtens begründen noch keinen Anspruch. (Leitsatz der Bearbeiterin)  相似文献   
93.
Early non‐invasive tumour therapy response assessment requires methods sensitive to biological and physiological tumour characteristics. The aim of this study was to find and evaluate magnetic resonance imaging (MRI) derived tumour tissue parameters that correlate with histological parameters and that reflect effects of radionuclide therapy. Mice bearing a subcutaneous human small‐intestine neuroendocrine tumour were i.v. injected with 177Lu‐octreotate. MRI was performed (7 T Bruker Biospec) on different post‐therapy intervals (1 and 13 days) using T2‐weighted imaging, mapping of T2* and T1 relaxation time constants, as well as diffusion and dynamic contrast enhancement (DCE‐MRI) techniques. After MRI, animals were killed and tumours excised. Four differently stained histological sections of the most central imaged tumour plane were digitized, and segmentation techniques were used to produce maps reflecting fibrotic and vascular density, apoptosis, and proliferation. Histological maps were aligned with MRI‐derived parametric maps using landmark‐based registration. Correlations and predictive power were evaluated using linear mixed‐effects models and cross‐validation, respectively. Several MR parameters showed statistically significant correlations with histological parameters. In particular, three DCE‐MRI‐derived parameters reflecting capillary function additionally showed high predictive power regarding apoptosis (2/3) and proliferation (1/3). T1 could be used to predict vascular density, and perfusion fraction derived from diffusion MRI could predict fibrotic density, although with lower predictive power. This work demonstrates the potential to use multiparametric MRI to retrieve important information on the tumour microenvironment after radiotherapy. The non‐invasiveness of the method also allows longitudinal tumour tissue characterization. Further investigation is warranted to evaluate the parameters highlighted in this study longitudinally, in larger studies, and with additional histological methods.  相似文献   
94.
95.
96.
Between January 1980 and July 1983, percutaneous transluminal angioplasty was attempted on 137 stenotic renal arteries in 100 patients. At termination of follow-up studies (3-39 months, mean of 16 months), 70% of those treated for hypertension had benefited from the procedure. Stenosis secondary to fibromuscular dysplasia responded better than stenosis from arteriosclerosis (85% and 65% of the patients, respectively). Benefit was minimal for those with stenosis of the renal artery ostium or renal insufficiency. Determining levels of renal vein renin before angioplasty is helpful in selecting patients; following angioplasty, this has considerable significance in predicting the success of the procedure.  相似文献   
97.
Six healthy subjects in random order underwent gastric bicarbonate secretion investigations, including stimulation with increasing doses of the cholinergic agonist carbachol, sham feeding, fundic distension and gastric instillation of 16,16-dimethyl prostaglandin E2. Bicarbonate secretion was measured by a computer-based system which continuously recorded pH and PCO2 of the effluent in a high-volume gastric perfusion system. The peak 30 min gastric bicarbonate output in response to carbachol, 150 mg subcutaneously, was 114% (P less than 0.05). Vagal stimulation by sham feeding resulted in a corresponding increase of 112% (P less than 0.05), while fundic distension to a volume of 600 ml gave an increase of 114% (P less than 0.05). In comparison, the response to 80 micrograms 16,16-dimethyl prostaglandin E2 was much greater, the peak bicarbonate output being increased by 245% (P less than 0.05). Both sham feeding and fundic distension appear to be either submaximal stimuli of gastric bicarbonate secretion in man or may possess both stimulatory and inhibitory actions.  相似文献   
98.
99.
BACKGROUND: We have previously hypothesized that preterm birth or impaired fetal growth may cause esophageal adenocarcinomas through gastroesophageal reflux early in life. In this study, we aimed to test if there is an association between gestational duration and birth weight on the one hand, and risk of esophageal and cardia adenocarcinoma on the other. METHODS: We conducted a nested case-control study of 67 cases of esophageal adenocarcinoma and 93 cases of cardia adenocarcinoma, whereas 50 cases of squamous cell carcinoma were studied for comparison. Birth records of cases were traced. Three matched controls per case were randomly selected. Perinatal data were extracted from birth records. RESULTS: Long gestational duration was associated with a decreased risk of cardia adenocarcinoma (P(trend) = 0.001) and a nonsignificant decreased risk of esophageal adenocarcinoma (P = 0.07), whereas no such association was found for esophageal squamous cell carcinoma (P = 0.96). Birth weight was not associated with risk of any of the studied cancers. Compared with lower maternal age (相似文献   
100.
Urinary concentrations of interleukin-lα (IL-lα) and interleukin-l receptor antagonist (IL-Ira) standardized to urinary creatinine concentrations were studied. The median standardized IL-1α creatinine quotient in children with first-time acute pyelonephritis was 3.6 pg/μmol, but was non-detectable in children with recurrent pyelonephritis, children with non-renal febrile conditions and children convalescent after acute pyelonephritis ( p < 0.05–0.01). IL-lra levels were also significantly higher in children with acute first-time pyelonephritis (median of 239 pglpmol) compared to these three groups of children ( p < 0.01–0.001). The highest urinary 1L-lra levels, however, were found in the healthy controls (median value 1.019; p < 0.001). Both cytokines were higher among children younger than one year compared to older children. The acute IL-lα creatinine quotients were lowest in children with uptake defects on 99mTC-dimercaptosuccinic acid (DMSA) scintigraphy both during the acute infection (reflecting the acute inflammation) ( p < 0.001) and 1 year after the acute infection (reflecting permanent kidney scarring) ( p < 0.01). In conclusion, persisting high urinary levels of 1L-lα were associated with less renal inflammation and scarring.  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