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   9595篇
  免费   895篇
  国内免费   1305篇
耳鼻咽喉   28篇
儿科学   28篇
妇产科学   18篇
基础医学   534篇
口腔科学   138篇
临床医学   408篇
内科学   1010篇
皮肤病学   293篇
神经病学   451篇
特种医学   500篇
外科学   319篇
综合类   1400篇
现状与发展   2篇
一般理论   1篇
预防医学   599篇
眼科学   109篇
药学   2938篇
  3篇
中国医学   2852篇
肿瘤学   164篇
  2024年   82篇
  2023年   174篇
  2022年   356篇
  2021年   432篇
  2020年   370篇
  2019年   277篇
  2018年   269篇
  2017年   362篇
  2016年   377篇
  2015年   417篇
  2014年   695篇
  2013年   794篇
  2012年   648篇
  2011年   729篇
  2010年   572篇
  2009年   512篇
  2008年   544篇
  2007年   431篇
  2006年   496篇
  2005年   406篇
  2004年   308篇
  2003年   297篇
  2002年   252篇
  2001年   238篇
  2000年   141篇
  1999年   151篇
  1998年   154篇
  1997年   125篇
  1996年   112篇
  1995年   98篇
  1994年   103篇
  1993年   92篇
  1992年   105篇
  1991年   74篇
  1990年   69篇
  1989年   54篇
  1988年   55篇
  1987年   56篇
  1986年   41篇
  1985年   50篇
  1984年   42篇
  1983年   48篇
  1982年   37篇
  1981年   37篇
  1980年   29篇
  1979年   21篇
  1978年   15篇
  1977年   14篇
  1976年   12篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
1.
Antiandrogen withdrawal syndrome (AWS) is a well-established phenomenon in prostate cancer. However, responses to AWS are usually of limited duration, and a complete response (CR) is extremely rare. We present two patients who exhibited a chemical CR for more than 2 years after the discontinuation of steroidal antiandrogen chlormadinone acetate use. Whether patients who respond to antiandrogen withdrawal include a group of patients with a better prognosis remains uncertain. However, considering that the usual survival period of patients with hormone-resistant prostate cancer is approximately 12 months, both of the patients reported here, who are present in excellent physical condition, exhibiting an improved quality of life, and attending their hospital as outpatients, obviously acquired a prolonged survival because of AWS.  相似文献   
2.
Skeletal muscle extracellular carbonic anhydrase III was investigated in anesthetized rats by a microdialysis technique. A small dialysis probe was inserted into the tibialis anterior (TA) muscle and perfused continuously. Perfusates were collected before and during muscle contraction, induced by electrical stimulation of the muscle or of the sciatic nerve. In the perfusate of resting normal and denervated muscle, the concentration of CA III was 10 to 12 ng/mL, as measured by a radioimmunosorbent technique. During contractile activity, the concentrations of CA III increased markedly in the normal and denervated muscle. A TA muscle suspended in physiological saline behaved similarly, even though the leakage before and during contraction was higher than in vivo. The results show that skeletal muscle leaks CA III both in vivo and in vitro, a leakage which was markedly increased by contractile activity. The microdialysis technique should also be useful in humans to study the efflux of various proteins from different kinds of diseased or fatigued muscles.  相似文献   
3.
BACKGROUND: Allergoids are widely used in specific immunotherapy (SIT) for the treatment of IgE-mediated allergic diseases, but all techniques for standardization of conventional allergic extracts may not be appropriate for standardization of a glutaraldehyde (GA)-modified extract because of the unique characteristics of these extracts. OBJECTIVE: To assess an accurate methodology for standardization of chemically modified extracts. METHODS: GA-modified extracts from Parietaria judaica pollen were purified by diafiltration. Biochemical properties were investigated by determination of amino groups, chromatography, and SDS-PAGE. The IgE-binding activity was determined by skin prick test, enzyme allergosorbent test inhibition, basophil activation, and histamine release tests. Peripheral blood mononuclear cells (PBMCs) from P. judaica pollen-allergic subjects were stimulated with either native or allergoid extracts, and proliferation was measured. RESULTS: Biochemical data indicated a high degree of allergen polymerization resulting in extract components higher than 100 kDa. IgE-binding activity, both in vivo and in vitro, was reduced by more than 99.8%. Both allergen and allergoid induced PBMC proliferation and synthesis of blocking IgG antibodies at similar rates. Moreover, no evidence of introduction of new determinants by chemical modification was found. CONCLUSIONS: The preparation of GA-modified extracts by diafiltration is faster and more reliable than previous chromatographic methods. These modified extracts have drastically reduced their allergenicity while maintaining their immunogenicity, and therefore they can be used in safer and shortened schedules of SIT.  相似文献   
4.
5.
Thirty-six Australian Aboriginal children with urolithiasis were reviewed. Males dominated the series. The age distribution ranged from 8 months to 12 years and nearly 70% were 2 years or younger. Thirty-five patients had upper tract stones. Ultrasound was diagnostic in 35 patients and was falsely negative in one. Dietary factors, dehydration and recurrent diarrhoea are incriminated in the aetiology, because ammonium urate and oxalate were the main constituents of the stones. Malformations of the urinary tract were rare and known metabolic disorders were not seen. Chemical dissolution of the stones was found to be a safe and effective adjuvant in the management of urate stones.  相似文献   
6.
Studies using magnetic resonance spectroscopy in human volunteers to evaluate their livers in vivo and to analyze their blood in vitro suggest that there are measurable amounts of silicon compounds in the blood of some women with implants and that there is migration of silicone to other organs such as the liver.  相似文献   
7.
[目的]探讨顺铂引起恶心呕吐的有效治疗途径。[方法]对肺癌患者64例,随机分2组。自拟人参二苓解毒汤联合盐酸恩丹西酮注射液(以下简称商品名欧贝)(B组)和单独使用欧贝(A组)对顺铂为主的静脉化疗后镇吐疗效。[结果]B组(78·13%,93·75%)较A组(59·38%,75·00%)在近期镇吐治疗(指化疗后24-48h出现恶心呕吐)有明显差异(P<0·05),并在副作用方面,如便秘,乏力症状和血三系下降有明显差异(P<0·05)。[结论]辅以自拟人参二苓解毒汤确有增效解毒功能。  相似文献   
8.
Three-point Dixon techniques achieve good lipid-water separation by estimating the phase due to field inhomogeneities. Recently it was demonstrated that the combination of an iterative algorithm (iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL)) with a fast spin-echo (FSE) three-point Dixon method yielded robust lipid-water decomposition. As an alternative to FSE, the gradient- and spin-echo (GRASE) technique has been developed for efficient data collection. In this work we present a method for lipid-water separation by combining IDEAL with the GRASE technique. An approach to correct for errors in the lipid-water decomposition caused by phase distortions due to the switching of the readout gradient polarities inherent to GRASE is presented. The IDEAL-GRASE technique is demonstrated in phantoms and in vivo for various applications, including pelvic, musculoskeletal, and (breath-hold) cardiac imaging.  相似文献   
9.
单甲氧聚乙二醇化学修饰药物酶的研究进展   总被引:4,自引:0,他引:4  
用单甲氧基聚乙二醉(1)化学修饰药物酶是生化药物研究开发的重要手段之一。本文综述了1化学修饰药物酶的一般方法及修饰后酶在生物和理化性质方面的变化,同时对1研究前景进行展望,并指出了尚待解决的问题。  相似文献   
10.
Clinically, phenol is used often as a neurolytic agent to treat pain and spasticity. The purpose of this study was to examine the time course of denervation and recovery in several hindlimb muscles following application of a 5% aqueous solution of phenol to the sciatic nerve. Phenol was applied to the sciatic nerve of adult female rats either by intraneural or perineural injection. Axonal degeneration was evident within the sciatic nerve 2 days following phenol application, although variable amounts of damage were observed. By 2 weeks, the soleus and tibialis anterior had atrophied to 63% and 51% of control. Reinnervation of hindlimb muscles occurred between 2 and 4 weeks following the nerve block. Following denervation, the soleus became slower in that all of the fibers expressed the slow myosin heavy chain (MHC). At 5 months, maximum tension of the soleus was 74% of control and the muscle consisted of more fast fibers on average, some of which expressed IIx MHC. These data suggest that 5% phenol causes an injury to the nerve that is more severe than a crush injury, and that reinnervation of denervated muscles may be by motoneurons other than those that originally innervated the muscles. © 1996 John Wiley & Sons, Inc.  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