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   23017篇
  免费   2609篇
  国内免费   432篇
耳鼻咽喉   297篇
儿科学   334篇
妇产科学   344篇
基础医学   1283篇
口腔科学   9530篇
临床医学   1376篇
内科学   1865篇
皮肤病学   476篇
神经病学   307篇
特种医学   209篇
外国民族医学   1篇
外科学   1113篇
综合类   1753篇
现状与发展   3篇
预防医学   1140篇
眼科学   60篇
药学   3308篇
  28篇
中国医学   1182篇
肿瘤学   1449篇
  2024年   58篇
  2023年   504篇
  2022年   663篇
  2021年   969篇
  2020年   1182篇
  2019年   1188篇
  2018年   1110篇
  2017年   1036篇
  2016年   1036篇
  2015年   1002篇
  2014年   1354篇
  2013年   1865篇
  2012年   1193篇
  2011年   1258篇
  2010年   956篇
  2009年   902篇
  2008年   888篇
  2007年   857篇
  2006年   775篇
  2005年   787篇
  2004年   681篇
  2003年   642篇
  2002年   572篇
  2001年   518篇
  2000年   423篇
  1999年   351篇
  1998年   325篇
  1997年   362篇
  1996年   277篇
  1995年   242篇
  1994年   231篇
  1993年   177篇
  1992年   199篇
  1991年   149篇
  1990年   143篇
  1989年   158篇
  1988年   114篇
  1987年   111篇
  1986年   98篇
  1985年   85篇
  1984年   78篇
  1983年   64篇
  1982年   73篇
  1981年   73篇
  1980年   55篇
  1979年   39篇
  1978年   36篇
  1977年   60篇
  1976年   41篇
  1975年   34篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
The mortality of cerebrovascular diseases in Denmark was analysed for men and women 15-44 years of age, in a 14-year period before and after the appearance of oral contraceptives (OC) in 1966. 1,670 deaths were registered over 28 years, during which the female incidence of cerebrovascular deaths increased by 19% (P less than 0.025), while the male mortality was unchanged. Women showed a percentage increase in deaths from cerebral thromboembolic attacks (CTA) of 33%, men a fall of 14%. The increase of female CTA deaths was most pronounced in the young fertile group, the age group with a high OC use. A relative risk of CTA of 3.3-4.5 for OC users compared with non-users could explain the CTA trend difference between women and men. No other single risk factor responsible for the observed trends could be identified. Both women and men had a significant increase in the mortality of subarachnoidal hemorrhages, and a significant fall in the mortality of intracerebral hemorrhages.  相似文献   
72.
目的 研究妊娠期糖尿病与胎儿生长发育中糖代谢特点的关系。方法 选择妊娠期糖尿病25例(GDM组),正常孕妇20例(对照组),分别测孕妇空腹血糖、糖耐量、C肽、IGF-I、新生儿出生2h内空腹血糖,并依据新生儿出生体重分为大于胎龄儿组(LGA组,≥4000g),适于胎龄儿组(AGA组,2500-3999g)。结果 C肽及新生儿出生2h内空腹血糖GDM组与对照组差异有显著性;糖耐量各时点血糖值餐后2h血糖值LGA和AGA组差异有显著性。结论 血糖始终是影响胎儿生长发育的重要因素,孕妇餐后2h血糖水平与巨大儿的发生呈正相关。  相似文献   
73.
联合应用血康口服液和他莫昔芬治疗成人免疫性血小板减少性紫癜(ITP)20例。疗程超过2月。15例患者的血小板(BPC)计数明显上升,有效率为75%(15/20),对于激素治疗无效者,仍有良效。对月经过多者和不适合应用激素者尤为适应。两药合用无明显副作用。治疗起效时间较快,平均13天。疗效持续时间较长,长者已达一年以上。  相似文献   
74.
75.
BACKGROUND: We hypothesise that the density of proliferating cells at the invasive tumour front (ITF) has a positive relationship with prognostic and risk factors in human oral squamous cell carcinoma (SCC). METHODS: Tissues from 47 human oral SCC specimens were collected and stained with a monoclonal antibody directed against the Ki-67 antigen using a horseradish peroxidase based two-step immunostaining method. Counting was performed on two parallel sections at the ITF using an image analyser. The Ki-67 labelling index (LI) was determined by measuring the number of nuclei/mm(2) of epithelium. RESULTS: Our results show that the density of proliferating cells is related to clinical staging, with advanced stage of disease having a significantly higher Ki-67 LI compared with early stage of disease (2111 +/- 905 vs. 1908 +/- 913; P = 0.03). Importantly, this study shows that tumours that have metastasised have a significantly higher Ki-67 LI than tumours where distant metastasis was not detected (3257 +/- 650 vs. 1966 +/- 881; P < 0.0001). CONCLUSIONS: Cell proliferation, as measured by the Ki-67 LI at the ITF, has a positive relationship with clinical staging, tumour thickness, smoking status of the patient and alcohol consumption. Further, we suggest that a multicenter study with a large cohort of patients is indicated to fully elucidate whether cell proliferation at the ITF is directly related to patient survival.  相似文献   
76.
77.
Relative frequency of solitary melanocytic lesions of the oral mucosa   总被引:4,自引:0,他引:4  
Background: Solitary pigmented lesions of melanocytic origin are uncommon in the oral mucosa. These lesions include the oral and labial melanotic macule, oral melanocytic nevus, oral melanoacanthoma, oral melanoma and atypical melanocytic proliferation. The purpose of the study was twofold: to report a large series of solitary melanocytic lesions from one source, and to determine the relative frequency of these lesions. Methods: The study was based on a systematic search of the files of the Pacific Oral and Maxillofacial Pathology Laboratory, University of the Pacific, San Francisco for solitary pigmented melanocytic lesions (benign and malignant) accessed during the years 1984–2002. Results: Of the 89 430 biopsies accessed during the 19‐year period, 773 (0.83%) cases of solitary pigmented melanocytic lesions in the oral mucosa were identified. Oral and labial melanotic macules were the most common melanocytic lesions comprising 86.1% of the entire group and 0.7% of the total number of accessed biopsies. The vermilion border and gingiva were the most common sites (31.1% and 31.0% respectively). Oral melanocytic nevi comprised 11.8% of the entire melanocytic group and 0.1% of the total number of biopsies. The most common site was the palate (44%). Intramucosal nevi were the most common (64%), followed by compound nevi (16.5%) and common blue nevi (16.5%). Junctional nevi were uncommon (3.0%). Oral melanoacanthoma comprised only 0.9% of the entire melanocytic group and 0.008% of the total number of biopsies. Oral melanoma and atypical melanocytic proliferation were the least common lesions each comprising 0.6% of the entire melanocytic group and 0.006% of the total number of biopsies. The most common site for oral melanoma was the palate (60%). Conclusion: The palate was the most common location for both melanocytic nevi and oral melanoma. Thus, all melanocytic lesions in the palate should be viewed with caution and biopsy is recommended to rule out melanoma. Further studies are required to elucidate the entity of oral atypical melanocytic proliferation.  相似文献   
78.
P-glycoprotein, a membrane-associated transport protein, has recently been recognised as an important element of the intestinal epithelium. This paper summarises thein vivodata on the pharmacological role of intestinal P-glycoprotein. These data show that P-glycoprotein contributes to the elimination of many drugs by mediating their direct secretion from the blood into the intestinal lumen. In addition, there is also evidence that this protein can limit oral drug absorption. Hence, inhibition of intestinal P-glycoprotein, e.g. by a reversal agent like cyclosporin A, may be a promising strategy for improving the oral bioavailability of P-glycoprotein substrate drugs. Indeed, several preclinical and clinical studies have shown that coadministration of drugs with a reversal agent can substantially increase oral drug absorption.  相似文献   
79.
OBJECTIVE: To examine the effect of short-term improvements in glycaemic control on brachial artery endothelial function as a marker of cardiovascular health. METHODS: Persons with Type 2 diabetes who were poorly controlled on oral therapy were randomly assigned to monotherapy with repaglinide or combination therapy with repaglinide plus metformin. Brachial artery flow-mediated vasodilation was assessed by ultrasonography at randomization and following 16 weeks of therapy. The primary outcome was change in brachial artery endothelial function from baseline. Comparison of randomized groups was a secondary aim. RESULTS: Eighty-six participants were randomized, and 83 were followed to study completion. Post occlusion brachial artery vasodilation was 3.74% at baseline and 3.82% following 16 weeks of therapy (P = 0.77). The treatment effect was 0.08% (95% CI: -0.48%, 0.64%). No difference was seen between treatment groups (P = 0.69). Overall, A1C was reduced from 8.3% to 7.0%, with a greater reduction in the combination therapy group (from 8.4% to 6.7%) than in the monotherapy group (from 8.3% to 7.3%, p for difference between groups = 0.01). Statistically significant reductions were observed in fasting glucose, and plasminogen activator inhibitor-1. Statistically significant increases were observed for fasting insulin, uric acid, weight and BMI. CONCLUSIONS: Brachial artery endothelial function was not influenced by short-term improvements in glycaemic control. The CONTROL DM group was successful in lowering A1C. Future research should explore more intensive and longer-lasting improvements in glycaemic control on endothelial function. Some data previously published in abstract form (Diabetes 2001; 50 (Suppl. 2): A217).  相似文献   
80.
目的:评价太极通天液治疗血管性痴呆的临床疗效。方法:随机将148例血管性痴呆分为太极通天液治疗组和丹参口服液对照组,另接应用韦氏成人智力量表评分,将血管性痴呆组分为3个亚组:即80-89分组,70-79分组和70分以下组,观察期为3个月。结果:太极通天液治疗前后WAIS-RC评分与对照组比较,80-89分组和70-79分组均有统计学差异(P<0.05),而70分以下组无统计学差异(P>0.05),结论:太极通天液对血管性痴呆有较好的治疗效果,且与痴呆病情程度有关。  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