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   42092篇
  免费   2526篇
  国内免费   568篇
耳鼻咽喉   178篇
儿科学   1304篇
妇产科学   533篇
基础医学   2209篇
口腔科学   845篇
临床医学   4217篇
内科学   4718篇
皮肤病学   348篇
神经病学   2253篇
特种医学   604篇
外国民族医学   1篇
外科学   3058篇
综合类   6633篇
现状与发展   1篇
一般理论   2篇
预防医学   8753篇
眼科学   289篇
药学   2980篇
  82篇
中国医学   4481篇
肿瘤学   1697篇
  2024年   101篇
  2023年   593篇
  2022年   1275篇
  2021年   1693篇
  2020年   1582篇
  2019年   1725篇
  2018年   1561篇
  2017年   1361篇
  2016年   1350篇
  2015年   1355篇
  2014年   3077篇
  2013年   2858篇
  2012年   2535篇
  2011年   2968篇
  2010年   3032篇
  2009年   1830篇
  2008年   1800篇
  2007年   1836篇
  2006年   1529篇
  2005年   1108篇
  2004年   882篇
  2003年   896篇
  2002年   609篇
  2001年   561篇
  2000年   473篇
  1999年   394篇
  1998年   301篇
  1997年   246篇
  1996年   196篇
  1995年   250篇
  1994年   182篇
  1993年   153篇
  1992年   148篇
  1991年   115篇
  1990年   94篇
  1989年   94篇
  1988年   95篇
  1985年   447篇
  1984年   493篇
  1983年   348篇
  1982年   383篇
  1981年   412篇
  1980年   353篇
  1979年   365篇
  1978年   327篇
  1977年   197篇
  1976年   267篇
  1975年   236篇
  1974年   184篇
  1973年   201篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
121.
目的探讨血清B细胞淋巴瘤相关蛋白-2(Bcl-2)和半胱氨酸天冬氨酸蛋白酶-9(Caspase-9)对儿童癫痫持续状态(SE)近期预后的预测价值。 方法选择SE患儿62例为SE组,选择同期体检健康儿童62例为对照组;按照预后将SE患儿分为预后不良组和预后良好组。癫痫持续状态严重程度量表(STESS)评估SE患儿SE严重程度。ELISA检测各组血清Bcl-2和Caspase-9水平。结果SE组Bcl-2和Caspase-9水平高于对照组(P<0.05)。预后不良组和预后良好组STESS评分、Bcl-2和Caspase-9水平比较,差异有显著性(P<0.05)。STESS评分、Bcl-2和Caspase-9是影响SE患儿近期预后的独立影响因素(P<0.05);入院血清Bcl-2和Caspase-9联合检测对SE患者近期预后具有较好的预测效能(P<0.05)。 结论血清Bcl-2和Caspase-9是SE患儿近期预后的有效预测指标。  相似文献   
122.
The origins of the projections of the superior colliculus to the dorsal lateral geniculate nucleus and to the pulvinar in Dutch-belted rabbits were investigated using horseradish peroxidase (HRP) methods. Following injections of HRP in the dorsal lateral geniculate nucleus, retrogradely labeled neurons were found in the upper two-thirds of the stratum griseum superficiale of the ipsilateral superior colliculus. Most of the labeled somata were spindle-shaped, and their major axes tended to be perpendicular to the surface of the superior colliculus. In contrast, following injections of the pulvinar, labeled neurons were found in the lower third of the ipsilateral stratum griseum superficiale. In these cases, the labeled somata were larger than those labeled following dorsal lateral geniculate injections and were multipolar in shape.  相似文献   
123.
Immunologic changes have been reported in the dementing illnesses of mid and late life. The results of two studies of drug-free males meeting research diagnostic criteria for primary neuronal degeneration of the Alzheimer's type suggest that serum IgG levels decrease with the progression of dementia. Serum IgG levels were inversely correlated with duration of illness and the levels of psychiatric symptomatology. Performance on the mini-mental status examination was positively associated with serum IgG concentrations.  相似文献   
124.
Chronic arthritis may have great impact on the patient but also on his or her family, relatives and friends. The assessment of the consequences of chronic arthritis and the effect of therapy not only in terms of physical, but also psychological and social dimensions deserves more attention. Functional ability and health status can be measured using a questionnaire or ‘instrument’, high-lighting important aspects not quantified with more traditional measurements. In this paper, arguments to apply such instruments more frequently are given. Health status instruments can be used not only to assess beneficial but also deleterious (side-)effects of therapeutic interventions. The properties are summarized of the most frequently used instruments assessing functional ability and health status. Many of these instruments have been evaluated sufficiently for validity and reliability; their sensitivity to detect change seems to be satisfactory. Therefore it is advisable to choose an internationally accepted, frequently used instrument, reflecting the area of interest.  相似文献   
125.
目的探讨独生子女首发精神分裂症患者父母的心理健康状况。方法采用SCL-90症状自评量表评定80例首发精神分裂症的独生子女患者父母.所得资料与中国常模比较。结果精神分裂症患者父母的阳性项目数高于全国常模(P〈0.01),各个因子分与常模比较.均明显高于常模(P〈0.05),尤以躯体化、强迫、抑郁、焦虑、人际关系、敌对因子显著。结论精神分裂症患者严重影响了父母的工作、生活,造成父母心理障碍,医护人员在对患者进行治疗时,还应注重对患者父母认知、情绪和行为的改善,提高其社会适应能力,改善对待患者的态度。  相似文献   
126.
Male wild (Cavia aperea) and domestic (C. porcellus) guinea pigs were tested in two-bottle choice tests for preferences between glucose solutions of different concentrations and de-ionized water. Wild males showed significant preferences for concentrations between 0.025 and 0.4 M glucose while domestic males preferred only the 0.2 M glucose solution to de-ionized water. C. aperea males also consumed significantly greater volumes of liquid per kg body wt.34 during the glucose tests than did the C. porcellus males. These comparative results contrast sharply with those obtained by other authors with wild and domestic Norway rats.  相似文献   
127.
HK239: a P2 related temperate phage which excludes rII mutants of T4   总被引:7,自引:0,他引:7  
E K Dhillon  T S Dhillon 《Virology》1973,55(1):136-142
  相似文献   
128.
We report here a case of primary osteoclastoma that despite possessing HLA-DR-positive status and ‘functional’ calcitonin receptors, exhibited aggressive in vitro and in vivo bone resorptive activity. In the osteoclast bone slice assay employing scanning electron microscopy, the giant cell-mediated bone resorption was uninhibited by salmon calcitonin (10 nM) and significantly inhibited by raised extracellular calcium (20 mM). In Fura-2AM based microspectrofluorimetric assays, the presence of the ‘functional’ calcitonin receptors was ascertained by a rise in intracellular calcium induced by calcitonin and high extracellular calcium. These findings provide evidence for a hitherto unrecognized subtype of giant cells that have HLA-DR-positive status, exhibit avid bone resorptive activity, but remain insensitive to calcitonin despite possessing calcitonin receptors.  相似文献   
129.
The ageing process is accompanied by the disregulation of interleukin 2 (IL2) and interleukin 6 (IL6) production. In our paper, we asked whether the age between 60 and 70 years is a turning point for the disregulation of both IL2 and IL6 production. Fifty volunteers 60–70 years old, 25 aged 36–59, and 50 of 20–35 years old were enrolled into the study. Their health status was graded according to the criteria of the Senieur Protocol (SP) as ‘healthy' and ‘almost-healthy'. The cytokines level was determined in the sera of the volunteers. Moreover, the spontaneous release of IL6 by peripheral blood mononuclear cells (PBMC) and the activity of the IL6 gene in non-stimulated PBMC were also analysed. Cytokine levels were measured by biological assays, mRNA for IL6 was detected by RT-PCR method. The results showed that the production of IL2 is not disregulated in the ‘healthy' people until the age of 60–70. People not fulfilling all SP criteria are characterised by a lower level of IL2 in the sera. The overproduction of IL6 into the sera and supernatants from non-stimulated PBMC and PBL as well as the activation of IL6 gene start between the ages 36 and 59 and is more pronounced in the ‘almost-healthy'.  相似文献   
130.
A procedure is described for standardising the determination of adenosine 5-triphosphate and phosphocreatine concentration ([ATP] and [PC], respectively, in absolute arbitrary units) in human muscle by nuclear magnetic resonance (NMR) spectroscopy. The individual 31phosphorus (21P)-NMR spectra obtained on equal hemispherical tissue volumes (muscle plus skin and fat) were corrected for the thickness of the skin and of the subcutaneous fat. The volumes investigated were standardised using an external reference. The procedure described made possible the comparison of high energy phosphate concentrations among different subjects. It was applied to the assessment of [ATP] and [PC] in four groups of sedentary subjects (children, and adults aged 20–35, 35–50 and over 50 years), and in a group of athletes (volleyball players). The [ATP] and [PC] were not statistically different in the groups investigated.  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