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   55501篇
  免费   5035篇
  国内免费   3609篇
耳鼻咽喉   539篇
儿科学   665篇
妇产科学   459篇
基础医学   6458篇
口腔科学   851篇
临床医学   6721篇
内科学   8991篇
皮肤病学   686篇
神经病学   3100篇
特种医学   2524篇
外国民族医学   19篇
外科学   5838篇
综合类   8897篇
现状与发展   14篇
一般理论   7篇
预防医学   3513篇
眼科学   1368篇
药学   5925篇
  52篇
中国医学   2841篇
肿瘤学   4677篇
  2024年   159篇
  2023年   770篇
  2022年   1977篇
  2021年   2703篇
  2020年   1994篇
  2019年   1778篇
  2018年   1847篇
  2017年   1702篇
  2016年   1826篇
  2015年   2640篇
  2014年   3150篇
  2013年   3118篇
  2012年   4450篇
  2011年   4743篇
  2010年   3415篇
  2009年   2624篇
  2008年   3180篇
  2007年   3203篇
  2006年   2860篇
  2005年   2815篇
  2004年   2041篇
  2003年   2127篇
  2002年   1794篇
  2001年   1317篇
  2000年   1020篇
  1999年   971篇
  1998年   582篇
  1997年   569篇
  1996年   377篇
  1995年   439篇
  1994年   314篇
  1993年   189篇
  1992年   276篇
  1991年   198篇
  1990年   168篇
  1989年   176篇
  1988年   119篇
  1987年   123篇
  1986年   119篇
  1985年   61篇
  1984年   40篇
  1983年   21篇
  1982年   25篇
  1981年   17篇
  1980年   15篇
  1979年   15篇
  1974年   8篇
  1973年   13篇
  1972年   9篇
  1969年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
目的:观察蓖麻油餐用于晚期妊娠引产的疗效。方法:随机选择118例服用蓖麻油餐引产与同期106例催产素引产作对照,观察引产效果、产程、产后出血及新生儿评分。结果:观察组引产效率明显高于对照组(P<005),剖宫产率明显低于对照组(P<005),两组的产后出血和新生儿阿氏评分无显著性差异(P>005)。结论:蓖麻油引产优于催产素引产。  相似文献   
92.
采用细胞生物学方法测定类风湿性关节炎( R A)14 例血清 I L- 6 、 T N F 水平,均显著高于正常对照组( P< 0 .001) 。相关分析显示 I L- 6 与 T N F 水平变化呈正相关( P< 0 .01) , I L- 6 、 T N F 与血沉亦呈正相关( P<0 .05) 。认为, I L- 6 、 T N F 参与 R A 的发病,两者在致病中有协同相同;其水平变化与 R A 的活动性及血沉相关。  相似文献   
93.
In 1978, China decided to reform its economy and since then has gradually opened up to the world. The economy has grown rapidly at an average of 9.8% per year from 1978 to 1994. Medical expenditure, especially for drugs, has grown even more rapidly. The increase in medical expenditure can be attributed to changing disease patterns, a higher proportion of older people in the population and fee-for-service incentives for hospitals. Due to the changing economic system and higher cost of health care, the Chinese government has reformed its health care system, including its health and drug policy. The drug policy reform has led to more comprehensive policy elements, including registration, production, distribution, utilization and administration. As a part of drug policy reform, the drug distribution network has also been changed, from a centrally controlled supply system (push system) to a market-oriented demand system (pull system). Hospitals can now purchase drugs directly from drug companies, factories and retailers, leading to increased price competition. Patients have easier access to drugs as more drugs are available on the market. At the same time, this has also entailed negative effects. The old drug administrative system is not suitable for the new drug distribution network. It is easy for people to get drugs on the market and this can lead to overuse and misuse. Marketing factors have influenced drug distribution so strongly that there is a risk of fake or low quality drugs being distributed. The government has taken some measures to fight these negative effects. This paper describes the drug policy reform in China, particularly the distribution of drugs to health care facilities.  相似文献   
94.
Manufacture of VAQTA, an inactivated hepatitis A virus vaccine, includes extensive purification of the intact virus particle to remove endogenous components from the host cell culture lysate as well as compounds introduced in the upstream purification process. Analysis of the final purified hepatitis A virus product by SDS-PAGE prior to inactivation shows that greater than 95% of the protein in the preparation is found in four protein bands, which have been confirmed to be hepatitis A virus capsid proteins VP0, VP1, VP2 and VP3 based on Western blot and mass spectrometry analyses. Validation of the manufacturing process and direct analysis of the final product were used to demonstrate that no other specific host cell-derived components are detected and that process residuals are all below the limits of detection of the assays used. Establishment of a rigorous standard of high purity for this product was pursued to minimize the impact of impurities during clinical development of this product and will facilitate the incorporation of this product into combination vaccines.  相似文献   
95.
针对用于上海污水外排的黄浦江底隧道工程,通过土工离心模拟试验,探讨了上海粘土的成拱能力.对于无支护的情况,开挖双孔隧道时,洞底以上约8 m厚的灰色砂质粉土或粘土中不能形成稳定的天然拱.进一步研究表明,该层土所需的成拱厚度至少为12 m;对于有混凝土管支护的情况,由于支护刚度较大,管顶上土压力基本上等于管顶以上土层的自重应力.  相似文献   
96.
PURPOSE: To define the effect of scatter laser photocoagulation on foveal retinal thickness. METHODS: A commercial scanning retinal thickness analyzer was used to measure retinal thickness. The foveal retinal thickness was measured at the central area of the fundus (0.4 x 0.4 mm). The method was applied to 20 consecutive patients (mean age, 52.4 +/-16.9 years) with diabetic retinopathy. Measurements were performed before and 6 weeks after scatter photocoagulation. Patients were examined by fluorescein angiography and slit-lamp biomicroscopy to detect macular edema. RESULTS: Mean foveal thickness before scatter photocoagulation was 187+/-45 microm, increasing to 221+/-46 microm after the treatment (P = 0.0001). The foveal thickness increased in 12 eyes (60%). Laser treatment increased macular permeability in two eyes (10%). Biomicroscopic examination revealed central macular thickening in one eye (5%). Visual acuity was reduced in four eyes (20%). CONCLUSIONS: Our results suggest that subclinical macular edema occurs after scatter laser photocoagulation. The retinal thickness analyzer is a sensitive tool for early detection of macular edema after laser treatment, because increases in retinal thickness as small as 34 microm cannot be assessed by slit-lamp biomicroscopy.  相似文献   
97.
应用视神经纤维分析仪检测正常人视网膜神经纤维层厚度   总被引:3,自引:0,他引:3  
Xie L  Wang W  Dong X  Yao Z  Ying L  Wang Y 《中华眼科杂志》1999,35(4):312-314
目的 探讨正常人的视网膜神经纤维层厚度及其象限比值与年龄的关系。方法 应用视神经每人义检测198例(198只眼)正常志愿者,并按年龄分组进行统计分析。结果 RNFLT与年龄成负相关,上、下方象限厚度较鼻、颞侧大,与年龄相关、鼻、颞侧无此特点。上、下方象限厚度比值平均为1.041。结论 NFA是测量RNFLT的可靠方法,正常人的RNFLT随年龄的增长而减少。  相似文献   
98.
本文回顾分析26 例 (26 眼) 5~14 岁儿童角膜穿通伤合并外伤性白内障植入后房型人工晶体的临床结果。对麻醉、人工晶体植入、后囊纤维膜样混浊进行了分析讨论。提示 8 周岁以上儿童常能在眼局部麻醉下顺利地完成手术。认为对儿童角膜穿通伤合并外伤性白内障植入人工晶体, 应视眼部伤情及术中情况, 权衡利弊, 区别选择Ⅰ期或Ⅱ期植入。作者观察到, 这类联合手术的后囊纤维膜样改变, 在术后一至二周即在不同程度上有所表现。  相似文献   
99.
Cytotoxicities of four urushiols, congeners isolated from the sap of Korean lacquer tree (Rhus vernicifera Stokes), to 29 human cancer cell lines originated from 9 organs were evaluated. Their values of 50% growth inhibition were below 4 microg/ml, and showed cell line specific cytotoxicity. The present result is the first report on the cytotoxicity of urushiols suggesting that they would have an anticancer activity to human cancer cells.  相似文献   
100.
Tissue sections taken from 157 potentially curatively operated lung carcinoma patients (70 epidermoid carcinomas, 68 adenocarcinomas, 15 large cell anaplastic, and 4 small cell anaplastic carcinomas) were examined by a standardized histochemical protocol in a prospective study evaluating the extent of various types of probes to serve as prognostic indicators in lung cancer. Detailed clinical records and survival data (minimum 56 weeks, maximum 96 weeks) were correlated to the results of the histochemical reactions. The study centres on monitoring the expression of galactoside-containing epitopes in tumor cells by human, animal and plant lectins: and with a monoclonal antibody. In addition, affinity-purified subfractions of natural antibodies from human serum with preferential affinity to alpha- and beta-galactosides, respectively, were employed. Significant contributions to the estimation of the survival of patients are given by clinical parameters (pT, pN stage), number of resected and positive lymph nodes and presence of tumor metastases into specific lymph nodes (No. 5 and No. 6 right and left). With respect to the relevance of subsets of beta-galactosides, the galectin from chicken liver (CL-16) and the Le(y)-specific monoclonal antibody unveiled a negative correlation at a statistically significant level. The predictive value of binding of the animal lectin CL-16 was especially pronounced for patients with advanced tumor stages, pointing to a potential role of such lectin-reactive beta-galactosides in late tumor stages or progression.  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