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   65940篇
  免费   5303篇
  国内免费   983篇
耳鼻咽喉   1045篇
儿科学   1257篇
妇产科学   1181篇
基础医学   10450篇
口腔科学   1005篇
临床医学   6325篇
内科学   12567篇
皮肤病学   2082篇
神经病学   5433篇
特种医学   3512篇
外国民族医学   2篇
外科学   7735篇
综合类   1922篇
现状与发展   3篇
一般理论   19篇
预防医学   4250篇
眼科学   1661篇
药学   5737篇
  2篇
中国医学   921篇
肿瘤学   5117篇
  2023年   464篇
  2022年   1236篇
  2021年   1933篇
  2020年   1145篇
  2019年   1608篇
  2018年   1824篇
  2017年   1440篇
  2016年   1974篇
  2015年   2607篇
  2014年   3119篇
  2013年   3569篇
  2012年   5067篇
  2011年   5001篇
  2010年   3064篇
  2009年   2602篇
  2008年   3577篇
  2007年   3478篇
  2006年   3135篇
  2005年   2914篇
  2004年   2508篇
  2003年   2322篇
  2002年   2066篇
  2001年   1417篇
  2000年   1328篇
  1999年   1143篇
  1998年   534篇
  1997年   470篇
  1996年   373篇
  1995年   339篇
  1994年   281篇
  1993年   309篇
  1992年   691篇
  1991年   713篇
  1990年   589篇
  1989年   640篇
  1988年   627篇
  1987年   610篇
  1986年   516篇
  1985年   523篇
  1984年   405篇
  1983年   335篇
  1982年   246篇
  1981年   233篇
  1980年   202篇
  1979年   312篇
  1978年   264篇
  1977年   193篇
  1974年   215篇
  1973年   228篇
  1972年   178篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Vertebral hemangiomas have usually been treated by resection following preoperative arterial embolization. A case is presented in which no feeding tumor vessels were demonstrable angiographically. The tumor was resected by an anterolateral transthoracic approach without preoperative embolization. There was progressive postoperative improvement of the myelopathy.  相似文献   
102.
Multiple sclerosis and the workplace: report of an industry-based cluster   总被引:2,自引:0,他引:2  
E C Stein  R B Schiffer  W J Hall  N Young 《Neurology》1987,37(10):1672-1677
Eleven cases of MS occurred within a 10-year period in a zinc-related manufacturing plant. The observed disease incidence was greater than expected from population data, using multiple approaches to statistical analysis (p less than or equal to 0.01). A case-control study, performed to examine several zinc parameters in blood, failed to indicate specific abnormalities among the MS patients, but all subjects (both MS and controls) working in the plant demonstrated higher serum zinc levels than all subjects (MS and controls) not working there.  相似文献   
103.
We present a stillborn male infant with premaxillary agenesis, bilateral microphthalmos, alobar holoprosencephaly, hydrocephalus, ventricular and atrial septal defects, small penis, bilateral cryptorchidism, and bilateral upper limb postaxial polydactyly.  相似文献   
104.
105.
Extracts of cercariae of the avian schistosome Trichobilharzia ocellata were analysed for the presence of ecdysteroids by radioimmunoassay, high-performance liquid chromatography monitoring fractions by radioimmunoassay, and gas chromatography/mass spectrometry (selected ion monitoring). Both free ecdysteroids and polar conjugated ecdysteroids were detected in the cercarial extracts. The free ecdysteroid fraction, as well as the hydrolysed polar conjugated ecdysteroid fraction, contained both ecdysone and 20-hydroxyecdysone in approximately equal amounts. The amount of ecdysteroids detected is comparable to those found in other platyhelminths. A possible role for the ecdysteroids in the development of the parasite and/or the interactions between the parasite and its intermediate host, the freshwater snail Lymnaea stagnalis, is discussed.  相似文献   
106.
On-site testing of 157 poultry processors disclosed that 50% had three or more abnormal upper extremity findings out of a total of 22 possibles. The average worker had five to six abnormal findings. Impaired pinch strength, decreased vibration sensitivity in the fingertips, and reports of current numbness were the most prevalent. Of workers with signs, 25% reported no symptoms, whereas only 8% of workers reported symptoms but had no signs. The investigators concluded that this measurement method has utility for assessments of worker populations to determine prevalence of CTDs and, potentially, for preclinical detection of these disorders to permit early intervention, reduce medical costs, and minimize disability. The need for accurate measurement to enhance early detection and prevention is discussed.  相似文献   
107.
108.
停跳或不停跳心脏手术对血清 S-100B蛋白表达的影响   总被引:2,自引:1,他引:1  
【目的】研究心脏手术围术期血清S-100B蛋白表达及其与停跳或不停跳心肺转流方式和时间的关系。【方法】体外循环心脏手术患者23例,测转流前、转流10min、转流末、转流后24h的血清S-100B蛋白表达水平。【结果】①血清S-100B蛋白质量浓度在体外循环前后动态变化:转流前(M)为0.27μg/L,转流10min后升至0.57μg/L(P<0.01),转流末达峰值1.80μg/L(P<0.01),转流后24h降为0.22μg/L(P>0.05)。转流末的血清S-100B蛋白质量浓度与转流时间呈正相关(r=0.488,P<0.05)。②停跳组(n=6)转流前、转流10min、转流末、转流后24h平均血清S-100B蛋白质量浓度分别为(0.17±0.09)μg/L、(0.48±0.13)μg/L、(1.65±0.52)μg/L和(0.19±0.04)μg/L,不停跳组(n=6)分别为(0.26±0.14)μg/L、(0.71±0.41)μg/L、(1.59±0.84)μg/L和(0.23±0.11)μg/L,两组差别无统计学意义(P>0.05)。【结论】体外循环可导致血清S-100B蛋白表达增高,其表达水平与心肺转流时间呈正相关,但与停跳或不停跳转流方式无关。  相似文献   
109.
BACKGROUND AND PURPOSE: Etanercept (Enbrel), a recombinant tumor necrosis factor receptor fusion protein, has been shown to be effective in the treatment of patients with rheumatoid arthritis (RA). The purpose of this study was to compare the efficacy and safety of etanercept in combination with methotrexate (MTX) and MTX alone in Taiwanese patients with active RA. METHODS: In this double-blind study, 58 patients with active RA who were maintained on MTX therapy at a stable dose of 12.5 to 20 mg per week for 4 weeks were randomized to receive either etanercept 25 mg (n = 29) or placebo (n = 29) by subcutaneous injection twice weekly over a period of 12 weeks. The primary endpoint was the reduction of tender and swollen joint counts by 20% (ACR 20), 50% (ACR 50), and 70% (ACR 70) as determined by the American College of Rheumatology criteria at the 12th week. RESULTS: The addition of etanercept to MTX resulted in a greater reduction in the number of tender (7.00 vs 2.45, p = 0.012) and swollen joints (8.55 vs 3.86, p = 0.017), and in serum levels of C-reactive protein (1.26 mg/dL vs 0.45 mg/dL, p = 0.014) compared to MTX alone after 12 weeks of therapy. In addition, the global assessment of disease activity by both physicians and patients, duration of morning stiffness, pain visual analog scale score, and Health Assessment Questionnaire were all improved by etanercept plus MTX therapy. Results for the overall improvement in disease activity assessed by ACR 20 (90% vs 34%), ACR 50 (66% vs 10%) and ACR 70 (24% vs 0%) all favored the etanercept plus MTX group. However, the adverse events were comparable between the 2 treatment groups. CONCLUSION: Etanercept in combination with MTX was well tolerated and provided significantly more clinical benefit than MTX alone in Taiwanese patients with active RA.  相似文献   
110.
Anti-hepatocyte antibody, hepatocyte paraffin 1, is a monoclonal antibody that is highly specific for normal and neoplastic hepatocytes and that can differentiate hepatocytic from nonhepatocytic tumors. This marker has been rarely studied in extra-hepatic tumors and to our knowledge has not been investigated in ovarian tumors with hepatoid differentiation. We studied hepatocyte paraffin 1 immunoreactivity in a series of ovarian hepatoid carcinomas, ovarian hepatoid yolk sac tumors (YSTs), and hepatocellular carcinomas metastatic to the ovary to assess the potential utility of hepatocyte paraffin 1 in differential diagnosis. Hepatocyte paraffin 1 positivity was seen in three of seven ovarian hepatoid carcinomas, five of eight hepatoid yolk sac tumors, and six of eight metastatic hepatocellular carcinomas. The extent of positivity ranged from <25% to >50% of the tumor cells. There was strong coarsely granular cytoplasmic staining in all three tumor types without a distinctive staining pattern in any group. The degree of hepatic differentiation correlated with hepatocyte paraffin 1 positivity in the three groups: 83% of the well differentiated tumors, 50% of the moderately differentiated tumors, and none of the poorly differentiated tumors were positive. All ovarian hepatoid carcinomas were either immunoreactive for alpha-fetoprotein or had an elevated serum alpha-fetoprotein level; more than half of these tumors were hepatocyte paraffin 1 negative. All but one hepatocyte paraffin 1 negative hepatoid yolk sac tumor and ovarian hepatocellular carcinoma were also negative for alpha-fetoprotein. In conclusion, hepatocyte paraffin 1 is positive in primary ovarian tumors with hepatoid differentiation, with the degree of hepatocyte paraffin 1 positivity correlating with the degree of hepatoid differentiation. Hepatocyte paraffin 1, however, is not useful in distinguishing metastatic hepatocellular carcinoma from primary ovarian hepatoid carcinoma or hepatoid yolk sac tumor.  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