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   213624篇
  免费   50593篇
  国内免费   3702篇
耳鼻咽喉   2490篇
儿科学   7231篇
妇产科学   3981篇
基础医学   39265篇
口腔科学   9248篇
临床医学   22301篇
内科学   37381篇
皮肤病学   6163篇
神经病学   24467篇
特种医学   8245篇
外国民族医学   27篇
外科学   22138篇
综合类   15934篇
现状与发展   16篇
一般理论   39篇
预防医学   18209篇
眼科学   3956篇
药学   21191篇
  90篇
中国医学   7839篇
肿瘤学   17708篇
  2024年   193篇
  2023年   1427篇
  2022年   2475篇
  2021年   5316篇
  2020年   9227篇
  2019年   14402篇
  2018年   13839篇
  2017年   15139篇
  2016年   14327篇
  2015年   14260篇
  2014年   16465篇
  2013年   18897篇
  2012年   15802篇
  2011年   16307篇
  2010年   13876篇
  2009年   10057篇
  2008年   10569篇
  2007年   9158篇
  2006年   8523篇
  2005年   7870篇
  2004年   7294篇
  2003年   6769篇
  2002年   5872篇
  2001年   4868篇
  2000年   3394篇
  1999年   2117篇
  1998年   1767篇
  1997年   1702篇
  1996年   1579篇
  1995年   1512篇
  1994年   1290篇
  1993年   1143篇
  1992年   1045篇
  1991年   942篇
  1990年   837篇
  1989年   763篇
  1988年   601篇
  1987年   495篇
  1986年   518篇
  1985年   810篇
  1984年   735篇
  1983年   474篇
  1982年   595篇
  1981年   476篇
  1980年   450篇
  1979年   319篇
  1978年   289篇
  1977年   234篇
  1976年   226篇
  1975年   154篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Matrix metalloproteinase-11 (MMP11) is an enzyme with proteolytic activity against matrix and nonmatrix proteins. Although most MMPs are secreted as inactive proenzymes and are later activated extracellularly, MMP11 is activated intracellularly by furin within the constitutive secretory pathway. It is a key factor in physiological tissue remodeling and its alteration may play an important role in the progression of epithelial malignancies and other diseases. TCGA colon and colorectal adenocarcinoma data showed that upregulation of MMP11 expression correlates with tumorigenesis and malignancy. Here, we provide evidence that a germline variant in the MMP11 gene (NM_005940: c.232C>T; p.(Pro78Ser)), identified by whole exome sequencing, can increase the tumorigenic properties of colorectal cancer (CRC) cells. P78S is located in the prodomain region, which is responsible for blocking MMP11's protease activity. This variant was detected in the proband and all the cancer-affected family members analyzed, while it was not detected in healthy relatives. In silico analyses predict that P78S could have an impact on the activation of the enzyme. Furthermore, our in vitro analyses show that the expression of P78S in HCT116 cells increases tumor cell invasion and proliferation. In summary, our results show that this variant could modify the structure of the MMP11 prodomain, producing a premature or uncontrolled activation of the enzyme that may contribute to an early CRC onset in these patients. The study of this gene in other CRC cases will provide further information about its role in CRC development, which might improve patient treatment in the future.  相似文献   
93.
ObjectivesThis document presents the fundamentals of speech audiometry in noise, general requirements for implementation and criteria for choice among the tests available in French according to the health-professional's needs.Material and methodsThe recommendations are based on a systematic analysis of the literature carried out by a multidisciplinary group of doctors, audiologists and audioprosthetists from all over France. They are graded A, B, C or expert opinion according to decreasing level of scientific evidence.ResultsEight tests of speech audiometry in noise can be used in France.ConclusionTo be complete, evaluation of hearing status requires testing understanding of speech in noise. The examination must begin with a minimum of two measurements familiarizing the subject with the test procedure. For initial diagnosis, adaptive procedures establishing the 50% speech reception threshold (SRT50) in noise are to be preferred in order to obtain a rapid and standardized measurement of perception of speech in noise. When the aim is to measure real-life speech comprehension, tests based on sentences, cocktail-party noise and free-field stimulation are to be preferred. Prosthetic gain is evaluated exclusively in free field. This is the only way to evaluate the contribution of binaurality and to measure perception in noise in an environment as close as possible to real life. In order to avoid acoustic interference in free field, at least five loudspeakers should be used, in particular for evaluating the effectiveness of directional microphones, CROS devices enabling sounds picked up in the damaged ear to be rerouted to the functional ear, or bimodal fitting (i.e., when hearing is enabled by two modalities: for example, hearing aid for one ear, cochlear implant for the other).  相似文献   
94.
邵奇敏  刘虹 《全科护理》2022,20(4):530-532,535
目的:探讨园艺互动干预应用于维持性血液透析病人中的效果。方法:选择本院收治的行维持性血液透析病人157例,按照入院时间先后顺序分为对照组77例,观察组80例。对照组实施常规干预,观察组实施园艺互动干预。对比两组干预前后心理状态、应对方式、生活质量及总体幸福感变化。结果:观察组干预12周后症状自评量表(SCL-90)各维度评分低于对照组(P<0.05);观察组干预12周后积极应对评分高于对照组,消极应对评分低于对照组(P<0.05);观察组生活质量各维度评分高于对照组(P<0.05);观察组总体幸福感评分高于对照组(P<0.05)。结论:园艺互动干预应用于维持性血液透析病人可改善心理状态及应对方式,提升生活质量与总体幸福感。  相似文献   
95.
96.
97.
Objectives:To reassess the long-term camouflage effects of resin infiltration (Icon, DMG, Hamburg, Germany) of white spot lesions (WSL) and sound adjacent enamel (SAE) achieved in a previous trial. The null hypothesis was tested that there were no significantly different CIE-L*a*b*-ΔE-values between WSL and SAE areas of assessment after at least 24 months (T24) compared to those at baseline (T0).Materials and Methods:Of twenty subjects who received previous resin infiltration treatment of nteeth = 111 nonrestored, noncavitated postorthodontic WSL after multibracket treatment during a randomized controlled trial and were contacted 20 months after baseline, eight subjects (trial teeth nteeth = 40; m/f ratio 1/7; age range (mean; SD) 12–17 [15.25; 2.12] years); response rate: 40%) were available for follow-up after at least 24 months (T24). CIE-L*a*b* differences between summarized color and lightness values (ΔEWSL/SAE) of WSL and SAE were assessed using a spectrophotometer and compared to baseline data assessed prior to infiltration (T0), and those after 6 (T6), and 12 (T12) months using paired t tests at a significance level of α = 5%.Results:T24 assessments were performed after a mean 33.86 (SD: 8.64; Min: 24; Max: 45) months following T0. Mean (SD) ΔEWSL/SAE units of available teeth were 8.76 (5.33) at baseline; 5.5 (2.75) at T6; 5.2 (2.41) at T12; and 5.57 (2.6) at T24. Comparisons of T6, T12, and T24 with T0 yielded highly significant differences, whereas T6–T24 and T12–T24 differences were found to be not significant.Conclusions:Assimilation of infiltrated WSL to the color of adjacent enamel by resin infiltration is considered to be suitable for the long-term improvement in the esthetic appearance of postorthodontic WSL.  相似文献   
98.
99.
100.
Fibroepithelial polyps (FEPs) are common, benign intraoral lesions that tend to develop slowly at predictable sites, often in response to local irritation or trauma. Historical precedent often results in referral to oral and maxillofacial surgery (OMFS) departments for biopsy, often irrespective of symptoms, and histological assessment. OMFS and pathology services are struggling to cope with an increasing workload that will potentially lead to widespread delays to diagnosis and treatment. Over the past 20 years, clinical pathways and guidance have been developed to ensure that healthcare interventions, such as the removal of third molars, tonsils, skin tags, and benign moles, are evidence-based, have a net patient benefit, and ensure the best use of finite NHS resources. However, no such guidance exists for intraoral lesions and we regard this as an oversight. We analysed the removal of 682 FEPs over a seven-year period and report sensitivities of 92.4% for a “confirmed clinical suspicion of an FEP” and 99.7% for a “confirmed clinical suspicion of a benign diagnosis”. The incidence of non-benign disease was 0.3%. Primary care dentists should be able to diagnose and monitor FEPs and refer only if symptoms are serious or in high-risk patients or sites. Adopting this practice across the UK could free up to 1825 four-hour OMFS clinics, 405 hours of consultant histopathologists’ time, and recurring savings to the NHS estimated to be in the region of £620 000/annum. We believe that the removal of FEPs should be reclassified as an “intervention not normally funded”, and the time and resources put to better use treating patients with lesions of questionable pathology.  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