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   200283篇
  免费   15820篇
  国内免费   4846篇
耳鼻咽喉   1478篇
儿科学   2918篇
妇产科学   3325篇
基础医学   25066篇
口腔科学   3611篇
临床医学   14118篇
内科学   27444篇
皮肤病学   2586篇
神经病学   13310篇
特种医学   6943篇
外国民族医学   7篇
外科学   16777篇
综合类   26220篇
现状与发展   33篇
一般理论   8篇
预防医学   15154篇
眼科学   2542篇
药学   30678篇
  61篇
中国医学   12992篇
肿瘤学   15678篇
  2023年   2690篇
  2022年   3574篇
  2021年   7921篇
  2020年   7054篇
  2019年   6997篇
  2018年   7047篇
  2017年   7661篇
  2016年   7538篇
  2015年   7264篇
  2014年   8566篇
  2013年   13386篇
  2012年   10279篇
  2011年   12337篇
  2010年   7912篇
  2009年   8059篇
  2008年   9598篇
  2007年   10515篇
  2006年   9941篇
  2005年   9169篇
  2004年   7824篇
  2003年   7031篇
  2002年   5528篇
  2001年   4938篇
  2000年   4131篇
  1999年   3467篇
  1998年   2595篇
  1997年   2687篇
  1996年   2439篇
  1995年   2300篇
  1994年   2170篇
  1993年   1854篇
  1992年   1660篇
  1991年   1578篇
  1990年   1391篇
  1989年   1126篇
  1988年   1082篇
  1987年   963篇
  1986年   898篇
  1985年   1301篇
  1984年   1054篇
  1983年   785篇
  1982年   818篇
  1981年   679篇
  1980年   651篇
  1979年   507篇
  1978年   329篇
  1977年   278篇
  1976年   264篇
  1975年   197篇
  1974年   156篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
41.
目的 运用科学知识图谱的手段,分析中医药治疗癫痫的研究进程并提炼重点。方法 设置检索时间为1990年至2020年,检索对象为中国知网(CNKI)该领域的相关文献,运用CiteSpace软件科学、准确地分析这些文献的作者信息、研究(发文)机构、关键词情况。结果 共计纳入文献793篇,马融-张喜莲、刘金民、谢炜、王洪图-张丽萍等领导核心作者团队,北京、广州以及广西中医药大学、天津中医药大学第一附属医院、南方医科大学等单位为主要进行相关研究的机构,高频关键词包括大鼠、难治性癫痫、小儿癫痫、海马、脑电图等,作用机制、网络药理学、肠道菌群、氧化应激、分子生物学等为近年来的热点与前沿。结论 通过借用知识图谱的分析能帮助提炼国内中医药治疗癫痫研究领域的重点,全面分析并科学判断近年来该领域的热点及前沿,为未来的研究夯实基础并把握方向。  相似文献   
42.
甲状腺癌是内分泌系统常见的恶性肿瘤之一,其发病率呈逐年上升趋势。甲状腺癌以分化型甲状腺癌(differentiated thyroid carcinoma, DTC)为主,尽管多数DTC患者经规范化治疗后预后良好,但由于部分肿瘤的病理类型侵袭性较高或肿瘤组织分化程度较低,病情进展迅速导致患者总生存时间显著缩短。近年来,有关炎症与肿瘤之间相关性的研究越来越多,炎性微环境的改变在肿瘤发病机制中的作用逐渐被证实,更多的证据表明细胞因子可作为肿瘤的良恶性鉴别、预后判断提示及诊疗方案选择等的重要参考依据。本文就部分细胞因子在DTC诊疗中的应用进展进行论述,旨在为DTC的诊疗与预后判断等提供参考依据。  相似文献   
43.
44.
《Vaccine》2022,40(31):4135-4141
Vaccination, health psychology and mental health make for three well-established and prestigious topoi in medical history. An in-depth look at their historical intersections remains forthcoming, however. Vaccinology’s psychological turns merit historians’ attention, all the more in the light of more recent, post-psychological and infodemiological, perspectives in vaccine acceptance research. Historiography at this point may help appreciating the present, and future, standing of psychological profiling in terms of its explanatory merits and policy uses. Of specific, critical interest is the motif of mental illness historically shared by vaccine advocates and contrarians. Mock-psychiatric nosology was a favored framing device for vaccination polemicists early on, indeed before vaccines were called vaccines and before psychiatry came to be called psychiatry. Though long anticipated, substantive historical-sociological and empirical approaches to vaccine non-acceptance were seen only from the 1920s and 1930s, respectively. Today, spirited animosity over vaccination continues to invite both professional and public debate about the founding concepts, the basic tenets, and the defining boundaries, of the mental health sciences.  相似文献   
45.
目的 探讨糖尿病前期的中医证型及证素分布特点。方法 检索中国知网、万方及维普三大数据库中收录的自建库以来有关糖尿病前期证型的临床研究文献,对中医证型进行规范整理,建立数据库,提取证素,运用数据挖掘技术中的关联分析、聚类分析探究证素分布规律。结果 共纳入10篇文献,总有效病例1620例,证型经规范处理后整理为18个,主要证型为脾虚痰湿证。共提取证素13个,主要病位证素为脾,主要病性证素为气虚、湿和痰,关联分析显示脾—湿支持度和置信度最高,聚类分析结果可得到3个聚类组。结论 糖尿病前期病位在脾,气虚、脾、痰、湿是常见证素,临床诊治糖尿病前期应注重从脾论治,需辨证施治。  相似文献   
46.
The aim of the study was to compare automated and manually conducted (slice-by-slice) virtual orbital wall reconstruction in terms of PSI design, manufacture, and clinical application for orbital fracture management.Patients with orbital wall fractures were evaluated for the potential for treatment with PSI, based on automated virtual wall reconstruction; these formed the main group. The surgical outcomes of these main-group patients' treatments were compared with those of the control group, which comprised patients randomly selected for this study, each of whom had the same orbital trauma patterns and were also managed with PSI. However, the control group patients were treated using ‘slice-by-slice’ virtual orbital reconstruction.Mean volume differences between the intact and reconstructed orbit were 0.65 ± 0.26 cm3 in the main group (n = 23) and 0.57 ± 0.23 cm3 in the control (n = 27; p = 0.837). In both groups, no cases of implant malposition or enophthalmos were detected after surgery. Orbital shape difference was similar for the main group and the control, at ?3.3 ± 3.5% and 3.25 ± 2.5%, respectively (p = 0.929). Diplopia was diagnosed at the 3-month follow-up in 13.0% of the main group and in 11.1% of the control (p = 0.651). The average times spent on computer-aided design (CAD) procedures, including segmentation, virtual orbital reconstruction, and PSI design, were 36.7 ± 6.9 min in the main group and 72.9 ± 7.7 min in the control group (p < 0.001).Within the limitations of the study it seems that PSI based on automated virtual reconstruction is a relevant alternative treatment option for orbital fractures because of its clinical efficacy that is similar to PSI based on a ‘slice-by-slice’ CAD protocol.  相似文献   
47.
《Saudi Dental Journal》2022,34(7):596-603
ObjectiveStudies have shown that gingival crevices may be a significant route for SARS-CoV-2 entry. However, the role of oral health in the acquisition and severity of COVID-19 is not known.DesignA retrospective analysis was performed using electronic health record data from a large urban academic medical center between 12/1/2019 and 8/24/2020. A total of 387 COVID-19 positive cases were identified and matched 1:1 by age, sex, and race to 387 controls without COVID-19 diagnoses. Demographics, number of missing teeth and alveolar crestal height were determined from radiographs and medical/dental charts. In a subgroup of 107 cases and controls, we also examined the rate of change in alveolar crestal height. A conditional logistic regression model was utilized to assess association between alveolar crestal height and missing teeth with COVID-19 status and with hospitalization status among COVID-19 cases.ResultsIncreased alveolar bone loss, OR = 4.302 (2.510 – 7.376), fewer missing teeth, OR = 0.897 (0.835–0.965) and lack of smoking history distinguished COVID-19 cases from controls. After adjusting for time between examinations, cases with COVID-19 had greater alveolar bone loss compared to controls (0.641 ± 0.613 mm vs 0.260 ± 0.631 mm, p < 0.01.) Among cases with COVID-19, increased number of missing teeth OR = 2.1871 (1.146– 4.174) was significantly associated with hospitalization.ConclusionsAlveolar bone loss and missing teeth are positively associated with the acquisition and severity of COVID-19 disease, respectively.  相似文献   
48.
49.
AimTo determine whether convalescent angiotensin (1?7) peptide replacement therapy with plasma (peptide plasma) transfusion can be beneficial in the treatment of critically ill patients with severe coronavirus 2 (SARS-CoV-2) infection.Study designCase series of 9 critically ill patients with laboratory-confirmed COVID-19 who met the following criteria: severe pneumonia with rapid progression and continuously high viral load despite antiviral treatment.Peptide plasma: Plasma with angiotensin (1?7) content 8–10 times higher than healthy plasma donors was obtained from suitable donors. Peptide plasma transfusion was applied to 9 patients whose clinical status and/or laboratory profile deteriorated and who needed intensive care for 2 days.ResultsIn our COVID-19 cases, favipiravir, low molecular weight heparin treatment, which is included in the treatment protocol of the ministry of health, was started. Nine patients with oxygen saturation of 93% and below despite nasal oxygen support, whose clinical and/or laboratory deteriorated, were identified. The youngest of the cases was 36 years old, and the oldest patient was 85 years old. 6 of the 9 cases had male gender. 3 cases had been smoking for more than 10 years. 4 cases had at least one chronic disease.In all of our cases, SARS CoV2 lung involvement was bilateral and peptide plasma therapy was administered in cases when oxygen saturation was 93% and below despite nasal oxygen support of 5 liters/minute and above, and intensive care was required. Although it was not reflected in the laboratory parameters in the early period, 8 patients whose saturations improved with treatment were discharged without the need for intensive care. However, a similar response was not obtained in one case. Oxygen requirement increased gradually and, he died in intensive care process. An increase of the platelet count was observed in all cases following the peptide plasma treatment.ConclusionIn this preliminary case series of 9 critically ill patients with COVID-19, administration of plasma containing angiotensin (1?7) was followed by improvement in their clinical status. The limited sample size and study design preclude a definitive statement about the potential effectiveness of this treatment, and these observations require evaluation in clinical trials.  相似文献   
50.
Frameworks for deriving occupational exposure limits (OELs) and OEL-analogue values (such as derived-no-effect levels [DNELs]) in various regulatory areas in the EU and at national level in Germany were analysed. Reasons for differences between frameworks and possible means of improving transparency and harmonisation were identified. Differences between assessment factors used for deriving exposure limits proved to be one important reason for diverging numerical values. Distributions for exposure time, interspecies and intraspecies extrapolation were combined by probabilistic methods and compared with default values of assessment factors used in the various OEL frameworks in order to investigate protection levels. In a subchronic inhalation study showing local effects in the respiratory tract, the probability that assessment factors were sufficiently high to protect 99% and 95% of the target population (workers) from adverse effects varied considerably from 9% to 71% and 17% to 87%, respectively, between the frameworks. All steps of the derivation process, including the uncertainty associated with the point of departure (POD), were further analysed with two examples of full probabilistic assessments. It is proposed that benchmark modelling should be the method of choice for deriving PODs and that all OEL frameworks should provide detailed guidance documents and clearly define their protection goals by stating the proportion of the exposed population the OEL aims to cover and the probability with which they intend to provide protection from adverse effects. Harmonisation can be achieved by agreeing on the way to perform the methodological steps for deriving OELs and on common protection goals.  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