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   2842篇
  免费   190篇
  国内免费   18篇
耳鼻咽喉   68篇
儿科学   81篇
妇产科学   19篇
基础医学   486篇
口腔科学   44篇
临床医学   301篇
内科学   431篇
皮肤病学   73篇
神经病学   257篇
特种医学   235篇
外科学   314篇
综合类   124篇
一般理论   1篇
预防医学   187篇
眼科学   68篇
药学   176篇
中国医学   3篇
肿瘤学   182篇
  2022年   27篇
  2021年   51篇
  2020年   21篇
  2019年   27篇
  2018年   52篇
  2017年   31篇
  2016年   55篇
  2015年   62篇
  2014年   69篇
  2013年   76篇
  2012年   144篇
  2011年   132篇
  2010年   86篇
  2009年   96篇
  2008年   141篇
  2007年   107篇
  2006年   108篇
  2005年   92篇
  2004年   77篇
  2003年   91篇
  2002年   86篇
  2001年   107篇
  2000年   84篇
  1999年   89篇
  1998年   87篇
  1997年   62篇
  1996年   53篇
  1995年   31篇
  1994年   39篇
  1993年   35篇
  1992年   57篇
  1991年   55篇
  1990年   42篇
  1989年   41篇
  1988年   38篇
  1987年   53篇
  1986年   37篇
  1985年   36篇
  1984年   28篇
  1983年   32篇
  1982年   28篇
  1981年   21篇
  1979年   30篇
  1978年   25篇
  1976年   26篇
  1975年   29篇
  1974年   24篇
  1973年   19篇
  1972年   39篇
  1971年   22篇
排序方式: 共有3050条查询结果,搜索用时 15 毫秒
21.
22.
23.
PURPOSE: While the rare Seckel-Syndrome is defined by clear criteria, clinical and radiologic findings for microcephalic osteodysplastic primordial dwarfism (MOPD) make an exact diagnosis and classification difficult. By comparing our patients to previously described cases of MOPD we evaluate the hypothesis that this disorder has a greater heterogeneity than has been believed up until now. Furthermore the differential diagnosis of the MOPD-complex is discussed. RESULTS: Two cases that show typical growth retardation, microcephalus and facial anomalies as well as osteodysplastic deformities including hip dysplasia are presented. The parents of both children are consanguineous and of Arabic race. In one of the children growth hormone levels were noticeably decreased. In discrepancy to the Seckel-syndrome both children showed no signs of mental retardation, therefore the classification into the heterogeneous group of microcephalic osteodysplastic primordial dwarfism (MOPD) is the most likely diagnosis. CONCLUSION: It is suggested that microcephalic osteodysplastic primordial dwarfism (MOPD) has a greater clinical and radiological expression than has been assumed up until now. Whether our results are merely a variant or suggest a new subtype of the MOPD can only be resolved by further cases. The exact pathogenesis of the disease currently remains unknown but the most probable cause is an autosomal recessive inheritance.  相似文献   
24.
25.
OBJECTIVE: To assess the efficacy of a longer acting preparation of the gonadotrophin releasing hormone (GnRH) analogue goserelin (Zoladex LA, 10.8 mg) in 12 girls with central precocious or early puberty. METHODS: Two girls started treatment de novo; the remainder had been on suppressive treatment for a median duration of 1.5 (range, 0.2-5.6) years. Assessment comprising auxology, pubertal staging, and pelvic ultrasound examination was carried out at weeks 0, 4, 8, 10, and 12 (first cycle) and weeks 8, 10, and 12 (second cycle) to evaluate the required injection frequency. Thereafter, assessment was performed on the day of injection. Zoladex LA was given every 12 weeks unless pubertal progression occurred. RESULTS: Satisfactory control was achieved in eight patients using this regimen, and three patients required more frequent injections. One girl was removed from the study because of clinical progression and extreme mood swings. No serious adverse effects occurred. Mean height velocity during the study period was 4.5 cm/year (range, 3.1-6.6) compared with 6.5 cm/year (range, 3.8-9.6) before treatment in nine patients for whom data were available. CONCLUSIONS: Zoladex LA was effective in controlling precocious puberty in girls when given at intervals of 9-12 weeks and it is recommended that an initial assessment is made eight weeks after beginning treatment.  相似文献   
26.
One hundred patients of Diabetes Mellitus (70 with and 30 without clinical somatic neuropathy) were studied to correlate clinical severity with the magnitude of nerve conduction abnormalities. Age range was 10-79 years (mean 49) with equal number of males and females. Incidence of neuropathy was more in patients over 40 years of age (60 out of 70 patients) with duration of disease over two years (78.33%). The grades of severity were mild in 22 (31.33%), moderate in 25 (35.71%) and severe in 23 (32.86%) patients. Nerve conduction studies were carried out in 48 (27 with and 21 without clinical neuropathy) patients, using the apparatus Dantec (Cantata TM). The nerves (median, peroneal and sural) were stimulated at two points and the recording of latency; amplitude (micro V) and motor and sensory nerve conduction velocities (m/s) were done under identical environmental conditions. Sensory nerve conduction velocity was more affected than motor velocity. In the 21 patients without clinical neuropathy, 14 showed abnormalities indicating early involvement of peripheral nerves. Reduction of motor nerve conduction velocity was more in patients with moderate and severe grades. The reduction was more in lower than in upper limbs. Nerve conduction abnormality helps in diagnosis in diabetic neuropathy even in preclinical state and correlates with severity, in clinical neuropathy.KEY WORDS: Diabetic neuropathy, Nerve conduction abnormality, Peripheral neuropathy  相似文献   
27.
Carbohydrate intolerance to lactose is widely accepted as a cause of gastrointestinal symptoms, but controversy persists on how important dietary fructose intolerance (DFI) is in causing gastrointestinal pain and suffering and if an elimination diet can control the presenting complaints. The objective of this study was to identify a group of well-defined DFI patients and explore whether dietary education followed by dietary compliance could control symptoms and improve quality of life. During a 5-year period, patients referred to a pancreato-biliary clinic were evaluated for dietary carbohydrate intolerances if they presented with gastrointestinal pain and/or gas and/or bloating and/or diarrhea. Patients were tested with a standardized mixture of glucose, fructose, and lactose diluted in sterile water. End-expiratory breath samples were collected for hydrogen and methane measurement. Symptoms were scored using a 9-point symptom questionnaire. The patients underwent in-depth education by a dietician, and were provided with access to a cookbook, a newsletter, and a support group. A dietary questionnaire was used to evaluate compliance with the fructose-restricted diet. DFI can cause significant gastrointestinal symptoms that may not respond to medications or surgical interventions. Symptoms can improve and self-rated health does improve in DFI patients willing to adhere to a low fructose diet.  相似文献   
28.
29.
Background: Per- and polyfluoroalkyl substances (PFAS) are a large class of synthetic (man-made) chemicals widely used in consumer products and industrial processes. Thousands of distinct PFAS exist in commerce. The 2019 U.S. Environmental Protection Agency (U.S. EPA) Per- and Polyfluoroalkyl Substances (PFAS) Action Plan outlines a multiprogram national research plan to address the challenge of PFAS. One component of this strategy involves the use of systematic evidence map (SEM) approaches to characterize the evidence base for hundreds of PFAS.Objective: SEM methods were used to summarize available epidemiological and animal bioassay evidence for a set of 150 PFAS that were prioritized in 2019 by the U.S. EPA’s Center for Computational Toxicology and Exposure (CCTE) for in vitro toxicity and toxicokinetic assay testing.Methods: Systematic review methods were used to identify and screen literature using manual review and machine-learning software. The Populations, Exposures, Comparators, and Outcomes (PECO) criteria were kept broad to identify mammalian animal bioassay and epidemiological studies that could inform human hazard identification. A variety of supplemental content was also tracked, including information on in vitro model systems; exposure measurement–only studies in humans; and absorption, distribution, metabolism, and excretion (ADME). Animal bioassay and epidemiology studies meeting PECO criteria were summarized with respect to study design, and health system(s) were assessed. Because animal bioassay studies with 21-d exposure duration (or reproductive/developmental study design) were most useful to CCTE analyses, these studies underwent study evaluation and detailed data extraction. All data extraction is publicly available online as interactive visuals with downloadable metadata.Results: More than 40,000 studies were identified from scientific databases. Screening processes identified 44 animal and 148 epidemiology studies from the peer-reviewed literature and 95 animal and 50 epidemiology studies from gray literature that met PECO criteria. Epidemiological evidence (available for 15 PFAS) mostly assessed the reproductive, endocrine, developmental, metabolic, cardiovascular, and immune systems. Animal evidence (available for 40 PFAS) commonly assessed effects in the reproductive, developmental, urinary, immunological, and hepatic systems. Overall, 45 PFAS had evidence across animal and epidemiology data streams.Discussion: Many of the 150 PFAS were data poor. Epidemiological and animal evidence were lacking for most of the PFAS included in our search. By disseminating this information, we hope to facilitate additional assessment work by providing the initial scoping literature survey and identifying key research needs. Future research on data-poor PFAS will help support a more complete understanding of the potential health effects from PFAS exposures. https://doi.org/10.1289/EHP10343  相似文献   
30.
Traumatic hyphema in children. Treatment with epsilon-aminocaproic acid   总被引:2,自引:0,他引:2  
Forty-nine patients, ages 3 to 18 years, who sustained nonpenetrating unilateral trauma with hyphemas were assigned randomly to receive either 100 mg/kg of epsilon-aminocaproic acid (EACA), an antifibrinolytic agent, orally every 4 hours for 5 days (maximum 30 g/day) or a placebo. No patients ingested acetylsalicylic acid (ASA)-containing compounds before or during admission. Two patients of 24 treated with EACA and 1 of 25 given placebo had rebleeds. The hyphemas in the EACA-treated group took significantly longer to clear (mean, 5.3 versus 2.6 days; P less than 0.001). Because of the low incidence of rebleeds in the placebo group, the efficacy of EACA in reducing the rate of rebleeds could not be determined. Further studies with this drug, controlling for age, race, sickle trait, and pre-admission antiplatelet agents should be undertaken before its routine use in traumatic hyphema management can be recommended.  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