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   7742篇
  免费   538篇
  国内免费   23篇
耳鼻咽喉   158篇
儿科学   252篇
妇产科学   153篇
基础医学   1051篇
口腔科学   448篇
临床医学   566篇
内科学   1702篇
皮肤病学   167篇
神经病学   573篇
特种医学   188篇
外科学   1197篇
综合类   27篇
一般理论   2篇
预防医学   678篇
眼科学   232篇
药学   482篇
中国医学   49篇
肿瘤学   378篇
  2023年   48篇
  2022年   110篇
  2021年   222篇
  2020年   151篇
  2019年   199篇
  2018年   274篇
  2017年   179篇
  2016年   195篇
  2015年   227篇
  2014年   307篇
  2013年   365篇
  2012年   578篇
  2011年   560篇
  2010年   334篇
  2009年   238篇
  2008年   439篇
  2007年   418篇
  2006年   396篇
  2005年   379篇
  2004年   368篇
  2003年   361篇
  2002年   262篇
  2001年   188篇
  2000年   203篇
  1999年   186篇
  1998年   46篇
  1997年   42篇
  1996年   43篇
  1995年   46篇
  1994年   36篇
  1993年   29篇
  1992年   93篇
  1991年   84篇
  1990年   87篇
  1989年   54篇
  1988年   72篇
  1987年   61篇
  1986年   57篇
  1985年   57篇
  1984年   35篇
  1983年   25篇
  1982年   19篇
  1981年   17篇
  1979年   24篇
  1975年   15篇
  1974年   18篇
  1973年   17篇
  1972年   15篇
  1970年   13篇
  1969年   13篇
排序方式: 共有8303条查询结果,搜索用时 31 毫秒
91.
92.
This is a prospective interventional clinical study evaluating intraocular inflammation developed after Ultrasound Cyclo Plasty (UCP) for the treatment of glaucoma. Eighteen eyes of 18 patients were treated with UCP second-generation probes (Eye OP1). After treatment, the mean intraocular pressure (IOP) significantly decreased from 26.8±7.2 to 18.8±6.1 mm Hg at day 1 and to 14.7±3.4 mm Hg at month 6 (all P<0.001). Mean laser flare-cell photometry value steeply increased after surgery from 12.1±7.5 to 64.1±53.9 ph/ms (P=0.001) at day 1, and then progressively decreased to respectively 60.6±49.7 at day 7, 43.5±38.5 at day 14 and 28.2±18.3 at month 1 (all P<0.05), returning at levels similar to baseline ones at month 3 and month 6 (respectively 16.7±6.2 and 12.8±10.2, both P>0.05). A significant negative correlation was found between postoperative increase of aqueous flare values and anterior chamber depth (R=-0.568, P=0.014). This timeframe may be considered reasonable for repeating UCP treatment, when required.  相似文献   
93.
Fibrin sealants or fibrin glue are products made from human plasma proteins, which mimic the final pathway of the coagulation cascade. Its application to stimulate the healing process has been a topic of debate in the literature. The use of fibrin sealants in phonosurgery has been empirical; there have been no studies that investigate the action of fibrin sealant in Reinke's space.AimTo evaluate the effect of fibrin glue in healing of the vocal folds of pigs after surgical manipulation.Materials and MethodsThis was a prospective and experimental study. Six animals had both vocal folds incised. Sealant was applied in one of them; the other served as a control. After three months, the animals were sacrificed and a collagen count was carried out.ResultsThe side on which glue was applied had an average of 27.8% against 20.4% of the side without glue.ConclusionThe collagen concentration in the samples where the fibrin sealant was applied was significantly higher compared to samples without glue. Thus, the presence of a fibrin sealant stimulates fibrogenesis in this tissue.  相似文献   
94.
95.
This report describes a rare case of coexistence of benign phyllodes tumor, which measured 9 cm in the right breast, and invasive ductal carcinoma of 6 cm in the left breast, synchronous and independent, in a 66-year-old patient. The patient underwent a bilateral mastectomy due to the size of both lesions. Such situations are rare and usually refer to the occurrence of ductal or lobular carcinoma in situ when associated with malignant phyllodes tumors, and more often in ipsilateral breast or intra-lesional.  相似文献   
96.
A long-term comparison was done between the manufacturer-stated 192Ir activity and the measured 192Ir activities determined with a well-type ionization chamber. Sources for a Nucletron Micro Selectron high-dose-rate (HDR) unit were used for this purpose. The radioactive sources reference activities were determined using a PTW well-type ionization chamber traceable to the National Institute of Standards and Technology Primary Calibration Laboratory. The measurements were taken in a period of 56 months with 17 different radioactive sources. The manufacturer stated activities were taken from the source calibration certificate provided by the manufacturer. These values were compared with the measured activities. The results have shown that both the percentage deviation of the monthly control measurements with the well-type chamber and the ratio between the measured activities to the manufacturer-stated value lie within ± 2.5%. These results were compared with similar published data and with uncertainty level (3% of the mean and 5% maximum deviation from mean) for brachytherapy sources calibration recommended by the AAPM. It was concluded that a threshold level of ±2.5% can be used as a suitable quality assurance indicator to spot problems in our department. The typical ±5% uncertainty as provided by the manufacturers may be tightened to ±3% to be more in line with published AAPM reports.  相似文献   
97.
Parkinson''s disease is the second most frequent neurodegenerative disorder in the world, affecting 1-2% of individuals over the age of 65. The etiology of Parkinson''s disease is complex, with the involvement of gene-environment interactions. Although it is considered a disease of late manifestation, early-onset forms of parkinsonism contribute to 5–10% of all cases. In the present study, we screened mutations in coding regions of PARK2 and PINK1 genes in 136 unrelated Brazilian patients with early-onset Parkinson''s disease through automatic sequencing. We identified six missense variants in PARK2 gene: one known pathogenic mutation, two variants of uncertain role, and three nonpathogenic changes. No pathogenic mutation was identified in PINK1 gene, only benign polymorphisms. All putative pathogenic variants found in this study were in heterozygous state. Our data show that PARK2 point mutations are more common in Brazilian early-onset Parkinson''s disease patients (2.9%) than PINK1 missense variants (0%), corroborating other studies worldwide.  相似文献   
98.
99.
100.
Carboplatin is commonly used to treat a variety of tumors. We investigated the effects of carboplatin (100 mg/kg) in the development and metastatic dissemination of the 4T1 mice mammary carcinoma. Carboplatin was able to reduce tumor volume and the number of lung metastases in 50% compared to the control animals. Mitotic and apoptotic indices were also decreased by the treatment. Assessment of the vascularization of the tumors revealed a significant decrease in blood vessel formation by carboplatin. A decrease in nuclear positivity of CDC47 and cyclin D1 was observed in the group treated with carboplatin when compared to the control group. Positivity for p53 was observed in the control group (2/28; 5%) and the treated group (5/71; 4%). Carboplatin has been demonstrated to be an efficient regulator of 4T1MMT growth and dissemination. The action of this chemotherapeutic agent seems to be related to the induction of apoptosis and inhibition of angiogenesis and cell proliferation.  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