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   50974篇
  免费   6450篇
  国内免费   1110篇
耳鼻咽喉   159篇
儿科学   778篇
妇产科学   612篇
基础医学   5389篇
口腔科学   388篇
临床医学   5423篇
内科学   3729篇
皮肤病学   205篇
神经病学   1199篇
特种医学   2813篇
外国民族医学   75篇
外科学   6774篇
综合类   6009篇
现状与发展   6篇
一般理论   1篇
预防医学   2155篇
眼科学   197篇
药学   3090篇
  40篇
中国医学   868篇
肿瘤学   18624篇
  2024年   184篇
  2023年   879篇
  2022年   1782篇
  2021年   2617篇
  2020年   2476篇
  2019年   2195篇
  2018年   2121篇
  2017年   2031篇
  2016年   2108篇
  2015年   2491篇
  2014年   3362篇
  2013年   3595篇
  2012年   2699篇
  2011年   2996篇
  2010年   2238篇
  2009年   2240篇
  2008年   2220篇
  2007年   2353篇
  2006年   2272篇
  2005年   2004篇
  2004年   1666篇
  2003年   1537篇
  2002年   1280篇
  2001年   1139篇
  2000年   917篇
  1999年   816篇
  1998年   701篇
  1997年   679篇
  1996年   552篇
  1995年   493篇
  1994年   404篇
  1993年   372篇
  1992年   323篇
  1991年   294篇
  1990年   257篇
  1989年   241篇
  1988年   230篇
  1987年   179篇
  1986年   189篇
  1985年   224篇
  1984年   197篇
  1983年   146篇
  1982年   187篇
  1981年   152篇
  1980年   88篇
  1979年   89篇
  1978年   83篇
  1977年   59篇
  1976年   63篇
  1975年   27篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Functional parenchymal kidney volume was determined by single-photon emission computed tomography (SPECT) for 99mTc-dimercaptosuccinic acid (DMSA) using a rotating gamma camera in phantom experiments and in patients with insulin-dependent diabetes mellitus (IDDM). The results from the patient examinations were corrected according to the phantom studies and were thereafter set in relation to renal haemodynamics, blood pressure, and urinary albumin excretion. Functional parenchymal kidney volume was significantly greater in diabetic patients compared to that of 11 healthy controls (P < 0.003). Urinary albumin excretion was increased and glomerular filtration rate (GFR) per renal parenchymal volume significantly less in patients with a duration of diabetic disease of more than 15 years compared to patients with shorter duration of disease (P < 0.03 and P < 0.05 respectively). Diabetic patients with a GFR of more than 120 ml/min had greater renal parenchymal volume than patients with lower GFR (P < 0.02). Patients with increased GFR, renal plasma flow (RPF), renal blood flow, or filtration fraction had significantly greater functional parenchymal volume than the healthy subjects (P < 0.01 for all comparisons). We conclude that by application of SPECT for DMSA we were able to show that IDDM patients have greater renal parenchymal volumes than healthy subjects. GFR/kidney volume was increased in IDDM patients with a duration of disease of < 15 years compared to patients with long-standing diabetes. The SPECT technique seems suitable for prospective long-term follow-up studies of functional kidney volume in IDDM patients.  相似文献   
52.
副乳癌的诊断和治疗(附12例报告)   总被引:5,自引:0,他引:5  
我院1978~1996年共收治副乳癌12例,占同期收治的乳癌1065例的113%。12例中,男性副乳癌1例,占同期收治男性乳癌17例的589%。副乳癌多发生于腋下或腹股沟处,这些部位邻近腋窝或腹股沟淋巴结丰富的区域,发生转移较早,预后较差。本组患者5年生存率为3637%,明显低于乳癌术后的5年生存率4583%(P<0.05)。  相似文献   
53.
Primary breast lymphoma.   总被引:2,自引:0,他引:2  
Primary breast lymphoma (PBL) is a rare tumor of the breast. Three cases of PBL are being described. All three cases achieved remission following biopsy, chemotherapy, and/or radiotherapy. The literature is extensively reviewed with emphasis on true incidence of PBL and survival rates.  相似文献   
54.
55.
本文对6例乳腺导管扩张症进行了临床病理报道,6例术前皆被误诊乳腺其他疾病,根据此种情况作了如何正确诊断的阐述.提出了常见误诊病例如何鉴别。  相似文献   
56.
Previous studies have shown that oestrogen receptor content in breast cancer was correlated with qualitative and also, more strongly, with quantitative nuclear features in tissue sections. However, even with the better reproducible quantitative microscopical assessments, the variance in the correlation with oestrogen receptor was considerable. This might be due to the implicit problems of oestrogen receptor determination with the biochemical assay. Therefore, receptor content was studied using monoclonal antibodies in 50 consecutive invasive ductal breast cancers. Oestrogen receptor status was compared with qualitative features and with the mean and standard deviation of the nuclear area, morphometrically evaluated on immunostained and adjacent haematoxylin and eosin stained sections. In agreement with earlier observations, nearly all tumours with prominent elastosis were oestrogen receptor positive; but a minority of negative cases also showed elastosis. The correlation between the other qualitative features and receptor status was weak. A significant inverse correlation (P less than 0.001) existed between the receptor status and the mean and standard deviation of the nuclear area. Even with the highly reproducible morphometrical analysis, correlation between nuclear oestrogen receptor content and quantitative nuclear features was relatively weak. This might indicate that receptor status and nuclear morphometric features reflect different biological characteristics of breast cancers.  相似文献   
57.
Magnetic resonance imaging enhanced with a macromolecular contrast medium (MMCM), albumin-Gd-DTPA, was used to estimate the plasma volume in vivo in the myocardium, lung, liver, and skeletal muscle of 10 normal rats. The plasma volumes of the same tissues in a parallel group of six rats were estimated in vitro by a conventional radioisotopic technique (111In-transferrin). Plasma volumes of myocardium, lung, liver, and skeletal muscle estimated by the MR technique (μl plas. ia cc-1 of tissue) were 101,109,163, and 11.0, respectively, while plasma volumes measured by the In-transferrin radioisotope technique (mg plasma g-1 of tissue) were 78.6, 215,143, and 11-2, respectively. Assuming a ratio of densities of aerated lung to blood of 0.45 and of other tissues to blood of 1.0, correlation between the methods was excellent (R2 = 0.99) indicating that MR imaging enhanced with MMCM permits reliable in vivo estimation of tissue plasma volume in the rat.  相似文献   
58.
59.
In screening programmes it is important to assess a preliminary effectiveness of the screening method as soon as possible in order to forecast survival figures. In March 1981 a controlled single-view mammographic screening trial for breast cancer was started in the south of Stockholm. The population invited for screening mammography consisted of 40,000 women aged 40–64 years, and 20,000 women served as a well-defined control group. The main aim of the trial was to determine whether repeated mammographic screening could reduce the mortality in the study population (SP) compared to the control population (CP).The cumulative number of advanced mammary carcinomas in the screening and the control populations from the first five years of screening have shown a tendency towards more favourable stages in the screened population aged 40–64 years. A breakdown by age suggests an effect in age group 50–59 years, but not yet in age groups 40–49 and 60–64 years.When comparing the rates of stage II+ cancer, an increased number is found in the study group. As the total rate of breast cancer is higher in SP than in CP, there ought to be a concealed group of stage II+ cancers in the CP which makes the comparison biased. A new approach has been designed, where an estimation of the hidden number of stage II+ cancers in CP is added to the clinically detected cases, and in this respect a comparison has shown a decrease in the cumulative number of advanced cancers in the SP in relation to the CP (p<0.05). According to this it could be important to add the estimated number of undetected, hidden cases in the control group in order to utilize the difference in detection rate in the screening- and control group respectively.  相似文献   
60.
The study presents the results from intraoperative frozen section assessment of axillary sentinel lymph nodes (SLNs) in breast cancer. Routine histological frozen sections from one level were used, two sections stained with haematoxylin and eosin. Immunohistochemistry for cytokeratins was applied to the permanent SLN paraffin sections only. Axillary dissection was performed on all SLN-positive cases regardless of the size of the metastatic deposits. With a detection rate of 83%, 272 patients entered the study over a period of 46 months. A total of 61 cases were SLN positive by frozen section analysis. The paraffin sections gave an additional 23 SLN-positive cases. The false-negative rate for frozen sections was then 27% (23/84). Micrometastases were found in 28 of 84 cases, and macrometastases in 56. The false-negative rate of frozen sections for micrometastases was 71% (20/28), and for macrometastases 5% (3/56). A total of 73% (61/84) of the patients underwent axillary surgery as a one-step procedure.  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