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   4399篇
  免费   245篇
  国内免费   31篇
耳鼻咽喉   80篇
儿科学   108篇
妇产科学   86篇
基础医学   450篇
口腔科学   184篇
临床医学   456篇
内科学   884篇
皮肤病学   57篇
神经病学   269篇
特种医学   215篇
外科学   691篇
综合类   124篇
一般理论   1篇
预防医学   282篇
眼科学   155篇
药学   420篇
中国医学   48篇
肿瘤学   165篇
  2024年   3篇
  2023年   80篇
  2022年   167篇
  2021年   232篇
  2020年   163篇
  2019年   198篇
  2018年   229篇
  2017年   151篇
  2016年   141篇
  2015年   140篇
  2014年   185篇
  2013年   252篇
  2012年   346篇
  2011年   349篇
  2010年   182篇
  2009年   137篇
  2008年   245篇
  2007年   248篇
  2006年   200篇
  2005年   144篇
  2004年   145篇
  2003年   131篇
  2002年   110篇
  2001年   56篇
  2000年   49篇
  1999年   50篇
  1998年   28篇
  1997年   19篇
  1996年   13篇
  1995年   21篇
  1994年   12篇
  1993年   12篇
  1992年   27篇
  1991年   20篇
  1990年   19篇
  1989年   26篇
  1988年   23篇
  1987年   28篇
  1986年   14篇
  1985年   9篇
  1984年   8篇
  1983年   8篇
  1982年   7篇
  1981年   4篇
  1980年   7篇
  1979年   7篇
  1976年   6篇
  1974年   6篇
  1969年   3篇
  1968年   3篇
排序方式: 共有4675条查询结果,搜索用时 15 毫秒
31.
Avascular necrosis (AVN) is a well-recognized complication of patients on high-dose steroids for a long time. Exogenous hypercortisolism is a well known cause of AVN and a number of cases have been reported. Cushing??s syndrome describes hypercortisolism of any cause endogenous or exogenous. A variety of traumatic and non-traumatic factors contribute to the aetiology of AVN although exogenous glucocorticoids administration and alcoholism are among the most common non-traumatic causes. AVN secondary to endogenous hypercortisolism is rare and very few case reports are available describing this complication. No literature is available on AVN presenting post-adrenal surgery. Here we present a young woman who presented with avascular necrosis of both hips 1?year after adrenalectomy for Cushing??s syndrome.  相似文献   
32.
33.
Objectives: Natural products have a potential role on food intake in mammals. It has been reported that phytohormone abscisic acid (ABA) has a regulatory role on metabolic processes. Here, the effects of ABA on feeding behavior and brain oxidative stress were investigated in male Wistar rats.

Methods: ABA was injected intracerebroventricularly. Experimental groups were included (n = 9): control (received no injection), ABA vehicle (received normal saline), and ABA-treated groups were injected with different doses of ABA (2.5, 5, and 10 μg/rat for 7 days). Daily cumulative daytime and nighttime food consumption, meal frequency, meal duration, and alteration in body weight were recorded. At the end of behavioral experiment, catalase and peroxidase activity and malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels were assayed.

Results: The results showed that ABA (5 and 10 μg) increased the meal frequency. Moreover, ABA could decrease body weight and MDA and H2O2 levels and increased the catalase and peroxidase activities in diencephalon. It also decreased the MDA concentration in the brain stem.

Discussion: Taken together, ABA has an important effect on feeding behavior and body weight in rats likely via increasing antioxidant capacity. However, further studies are still required to determine the underlying mechanisms of ABA on the feeding behavior.  相似文献   
34.
ObjectiveWe conducted a systematic review and dose–response meta-analysis of prospective studies to summarize findings on the associations between intakes of soy, soy isoflavones, and soy protein and risk of mortality from all causes, cancers, and cardiovascular diseases.MethodsOnline databases were systematically searched to identify relevant articles published earlier than May 2018. We applied restricted cubic splines using random-effects analysis to assess dose–response associations. Between-study heterogeneity was assessed by I2 value and Cochrane Q test. Potential publication bias was assessed by visual inspection of funnel plots and Begg regression test.ResultsIn total, 23 prospective studies with an overall sample size of 330,826 participants were included in the current systematic review and the meta-analysis. Soy/soy products consumption was inversely associated with deaths from cancers (pooled relative risk 0.88, 95% CI 0.79 to 0.99; P=0.03; I2=47.1%, 95% CI 0.0% to 75.4%) and cardiovascular diseases (pooled effect size: 0.85, 95% CI 0.72 to 0.99; P=0.04; I2=50.0%, 95% CI 0.0% to 77.6%). Such significant associations were also observed for all-cause mortality in some subgroups of the included studies, particularly those with higher quality. In addition, higher intake of soy was associated with decreased risk of mortality from gastric, colorectal, and lung cancers as well as ischemic cardiovascular diseases. Participants in the highest category of dietary soy isoflavones intake had a 10% lower risk of all-cause mortality compared with those in the lowest category. We also found that a 10-mg/day increase in intake of soy isoflavones was associated with 7% and 9% decreased risk of mortality from all cancers and also breast cancer respectively. Furthermore, a 12% reduction in breast cancer death was indicated for each 5-g/day increase in consumption of soy protein. However, intake of soy protein was not significantly associated with all-cause and cardiovascular diseases mortality.ConclusionsSoy and its isoflavones may favorably influence risk of mortality. In addition, soy protein intake was associated with a decreased risk in the mortality of breast cancer. Our findings may support the current recommendations to increase intake of soy for greater longevity.  相似文献   
35.
36.
37.
38.
Rationale:In this report, we present an extremely rare case of recurrent monocular exudative retinal detachment without concomitant ocular metastases. This turned out to be the first symptom of squamous cell lung cancer.Patient concerns:A 63-year-old woman was referred to our ophthalmology clinic by her primary care physician with a complaint of deteriorating vision in her right eye that had started four months prior, without concomitant pain.Diagnoses:We observed a detachment in the lower part of the retina during her ophthalmoscopy. We did not find any tears, holes, or degenerative changes in the periphery of the retina of the right eye during the surgery. In addition, plaques, tumor masses, and metastases were absent. Therefore, we diagnosed her with unilateral paraneoplastic exudative retinal detachment. Imaging tests performed before surgery revealed perihilar density with a visible air bronchogram in the middle field of the left lung. This turned out to be squamous cell carcinoma.Interventions:Patient underwent pars plana vitrectomy and routine laboratory and imaging tests before the procedure that utilized 20-gauge instrumentation. The subretinal fluid and was drained and a tamponade using Densiron (Fluoron Co, Neu-Ulm, Germany) was applied. After ophthalmic treatment, patient underwent complex oncological treatment based on chemotherapy and radiotherapy.Outcomes:Despite the application of heavy silicone oil (Densiron) into the vitreous chamber, we observed a recurrence of retinal detachment in the right eye during the follow-up visit, 13 months after the first ophthalmic surgery. Following subsequent pars plana vitrectomy, the Densiron and subretinal membranes were removed. Despite oncological treatment, the patient died, twenty months after the appearance of the first ocular symptoms.Lessons:Exudative retinal detachment without tumor metastasis to the eyeball can be one of the first signs of lung cancer in rare cases. Multidisciplinary care and imaging methods with greater accuracy will provide comprehensive care to the patients. It will not only facilitate timely detection and treatment of lung tumors but also for a plethora of oncological diseases.  相似文献   
39.
The current research work was conducted to characterize wheat proteins through immunochemical techniques and to find out their relationship with wheat quality traits. The results revealed that wheat variety AARI-11 possessed higher protein content (11.96%), wet gluten (31.39%), dry gluten (9.66%), Pelshenke value (190.52 min), and SDS-Sedimentation value (28.27 ml) than other tested varieties. The chapattis prepared from the wheat variety AARI-11 got significantly higher sensory scores owing to its higher protein contents. The wheat variety AARI-11 also exhibited significantly the highest antibody response against all the assessed protein fractions. The results of the present study suggest that anti-glutenin and anti-high molecular weight glutenin subunits (HMW-GS) antibody response was found positively correlated to the quality characteristics of flours and chapattis. The present study suggests that the use of antibodies response against glutenin and HMW-GS offers good tool for predicting quality and suitability of wheat to chapatti-making quality.  相似文献   
40.
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