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   5240篇
  免费   340篇
  国内免费   26篇
耳鼻咽喉   18篇
儿科学   85篇
妇产科学   89篇
基础医学   753篇
口腔科学   89篇
临床医学   571篇
内科学   1218篇
皮肤病学   67篇
神经病学   747篇
特种医学   172篇
外科学   690篇
综合类   22篇
预防医学   299篇
眼科学   120篇
药学   353篇
中国医学   14篇
肿瘤学   299篇
  2023年   22篇
  2022年   54篇
  2021年   115篇
  2020年   57篇
  2019年   104篇
  2018年   145篇
  2017年   91篇
  2016年   97篇
  2015年   121篇
  2014年   143篇
  2013年   239篇
  2012年   390篇
  2011年   416篇
  2010年   231篇
  2009年   219篇
  2008年   371篇
  2007年   394篇
  2006年   381篇
  2005年   379篇
  2004年   331篇
  2003年   313篇
  2002年   296篇
  2001年   42篇
  2000年   38篇
  1999年   45篇
  1998年   70篇
  1997年   66篇
  1996年   46篇
  1995年   46篇
  1994年   40篇
  1993年   40篇
  1992年   23篇
  1991年   15篇
  1990年   19篇
  1989年   9篇
  1988年   10篇
  1987年   7篇
  1985年   13篇
  1984年   10篇
  1983年   12篇
  1982年   19篇
  1981年   17篇
  1980年   6篇
  1979年   7篇
  1978年   8篇
  1977年   12篇
  1976年   8篇
  1975年   7篇
  1974年   13篇
  1963年   7篇
排序方式: 共有5606条查询结果,搜索用时 15 毫秒
41.
Background: The association between vitamin D and weight gain remains controversial due to important limitations in the studies. We investigated the relationship between vitamin D levels and 5 and 10 years of weight and waist circumference change in a population-based prospective cohort study. Methods: Prospective study including participants aged between 35 and 75 years living in the city of Lausanne, Switzerland. Weight and waist change at 5- and 10-year follow-up were assessed according to baseline vitamin D status (normal, insufficiency and deficiency). Results: A total of 3638 participants (47.9 % women, mean age 51.6 ± 10.4 years) were included for the 5-year follow-up. No association was found between vitamin D categories and weight change, multivariate-adjusted average ± standard error: 1.6 ± 0.3, 1.5 ± 0.2 and 1.2 ± 0.1 kg for normal, insufficiency and deficiency, respectively, p = 0.159. For waist change, the corresponding values were 3.3 ± 0.4, 3.3 ± 0.2 and 3.4 ± 0.2 cm, p = 0.792. For the 10-year follow-up, data from 2999 participants (45.8% women, mean age 50.8 ± 10.3 years) were used. No association was found for weight 2.3 ± 0.4, 2.3 ± 0.2 and 2.0 ± 0.2 kg, p = 0.588, or for waist 3.7 ± 0.4, 3.6 ± 0.3 and 4.2 ± 0.2 cm for normal, insufficiency and deficiency, respectively, p = 0.259. Conclusion: No association between vitamin D status and weight or waist gain at 5- and 10-year follow-up was found.  相似文献   
42.
IntroductionPotassium para‐aminobenzoate is an agent used in the treatment of sclerotic diseases including Peyronie's disease of the penis. It has been reported that this medication may have been responsible for cases of acute liver injury.AimTo inform clinicians of the possibility of an adverse drug event associated with the oral intake of potassium para‐aminobenzoate by reporting an additional case and compiling information from previous reports.MethodsThe affected patient's medical records were diligently reviewed; all available and relevant information pertaining to this adverse event is reported. Similar case reports were analyzed and compared, and relevant information was compiled in this report.ResultsThe patient enjoyed a full biochemical recovery from his hepatitis 4 months after discontinuation of potassium para‐aminobenzoate.ConclusionTo date, the oral use of potassium para‐aminobenzoate has been reported to be linked to acute liver injury in six individuals. Appropriate management of this adverse drug event is the immediate discontinuation of the offending drug and general patient support measures. Roy J, and Carrier S. Acute hepatitis associated with treatment of Peyronie's disease with potassium para‐aminobenzoate (Potaba). J Sex Med **;**:**–**.  相似文献   
43.
2,5-Bis(hydroxymethyl)furan monoacetate (3) and 2,5-bis(hydroxymethyl)furan diacetate (4) were obtained as new natural products from an ethyl acetate extract of the terrestrial Streptomyces sp. isolate GW11/1695. Another Streptomyces isolate, GW21/1313, delivered a dimer (6) and a trimer (7) of (hydroxymethyl)furfural. The latter strain also produced 4-hydroxy-2-(5-(hydroxymethyl)furan-2-ylmethylene)-5-methylfuran-3-one (5), perlolyrin (8), and two new beta-carboline derivatives, 9 and 10. 2,5-Bis(hydroxymethyl)furan diacetate (4) exhibited weak cytotoxic activity against brine shrimp larvae.  相似文献   
44.
Penicillium herquei isolate GA4 was isolated from the infected Conchocelis of Porphyra yezoensis. A large-scale fermentation using yeast extract sucrose medium and repeated chromatography afforded a new symmetrical urea derivative, hualyzin (1). The structure was determined by detailed NMR spectroscopic investigations and MS fragmentation analysis.  相似文献   
45.
46.
47.
Purpose The aim of the present report is to describe abnormal 18F-fluorodeoxyglucose (FDG) accumulation patterns in the pleura and lung parenchyma in a group of lung cancer patients in whom lung infarction was present at the time of positron emission tomography (PET).Methods Between November 2002 and December 2003, a total of 145 patients (102 males, 43 females; age range 38–85 years) were subjected to whole-body FDG PET for initial staging (n=117) or restaging (n=11) of lung cancer or for evaluation of solitary pulmonary nodules (n=17). Of these patients, 24 displayed abnormal FDG accumulation in the lung parenchyma that was not consistent with the primary lesion under investigation (ipsilateral n=12, contralateral n=9 or bilateral n=3). Without correlative imaging, this additional FDG uptake would have been considered indeterminate in differential diagnosis.Results Of the 24 patients who were identified as having such lesions, six harboured secondary tumour nodules diagnosed as metastases, while in three the diagnosis of a synchronous second primary lung tumour was established. Additionally, nine patients were identified as having post-stenotic pneumonia and/or atelectasis (n=6) or granulomatous lung disease (n=3). In the remaining six (4% of all patients), a diagnosis of recent pulmonary embolism that topographically matched the additional FDG accumulation (SUVmax range 1.4–8.6, mean 3.9) was made. Four of these six patients were known to have pulmonary embolism, and hence false positive interpretation was avoided by correlating the PET findings with those of the pre-existing diagnostic work-up. The remaining two patients were harbouring small occult infarctions that mimicked satellite nodules in the lung periphery. Based on histopathological results, the abnormal FDG accumulation in these two patients was attributed to the inflammatory reaction and tissue repair associated with the pathological cascade of pulmonary embolism.Conclusion In patients with pulmonary malignancies, synchronous lung infarction may induce pathological FDG accumulation that can mimic active tumour manifestations. Identifying this potential pitfall may allow avoidance of false positive FDG PET interpretation.  相似文献   
48.
The usefulness of preoperative radionuclide scanning of the parathyroid glands in patients with primary or secondary hyperparathyroidism was long controversial because available techniques were of limited diagnostic efficacy. Technetium-99m-labeled sestamibi (99Tc-sestamibi) is a new radiopharmaceutical agent easily detected by gamma cameras. The first parathyroid imaging studies done with 99Tc-sestamibi about 10 years ago used a double-phase technique to separate thyroid and parathyroid tissue. Although promising, this method was less than ideal, particularly in multiple gland primary hyperparathyroidism and in secondary hyperparathyroidism. For several years, we have been using subtraction between two images acquired simultaneously, one with 99Tc-sestamibi, which binds to thyroid and parathyroid tissue, and the other with 123-iodine, which binds only to thyroid tissue. The remarkable efficacy of this technique in both primary and secondary hyperparathyroidism invites a reappraisal of the place of radionuclide imaging as a preoperative localization procedure done to reduce the need for repeat surgery. The usefulness of this technique in selecting candidates for unilateral surgery among patients with primary hyperparathyroidism is discussed.  相似文献   
49.
50.
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