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   543篇
  免费   25篇
  国内免费   26篇
儿科学   45篇
妇产科学   8篇
基础医学   38篇
口腔科学   24篇
临床医学   57篇
内科学   129篇
皮肤病学   4篇
神经病学   6篇
特种医学   127篇
外科学   38篇
综合类   4篇
预防医学   13篇
眼科学   5篇
药学   72篇
肿瘤学   24篇
  2022年   3篇
  2021年   4篇
  2020年   3篇
  2019年   4篇
  2018年   7篇
  2017年   2篇
  2016年   4篇
  2015年   9篇
  2014年   8篇
  2013年   15篇
  2012年   10篇
  2011年   9篇
  2010年   13篇
  2009年   17篇
  2008年   11篇
  2007年   25篇
  2006年   6篇
  2005年   13篇
  2004年   4篇
  2003年   11篇
  2002年   6篇
  2001年   10篇
  2000年   5篇
  1999年   7篇
  1998年   39篇
  1997年   44篇
  1996年   51篇
  1995年   39篇
  1994年   30篇
  1993年   30篇
  1992年   9篇
  1991年   10篇
  1990年   8篇
  1989年   19篇
  1988年   18篇
  1987年   12篇
  1986年   10篇
  1985年   11篇
  1984年   9篇
  1983年   5篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1979年   4篇
  1978年   2篇
  1977年   6篇
  1976年   6篇
  1975年   8篇
  1954年   1篇
排序方式: 共有594条查询结果,搜索用时 31 毫秒
101.
目的 用重组日本血吸虫22kD表膜蛋白(rSj22)免疫水牛,检测特异性IgG抗体的应答水平,并观察抗血吸虫的保护效果。方法 用抗原(rSj22)加佐剂(Quil-A)肌肉注射免疫水牛,以1000条日本血吸虫尾蚴攻击感染,感染后55d剖杀,计算减虫和减卵率,用免疫印斑和ELISA方法测定抗体反应。结果 免疫组每头牛血清均能特异地识别Quil-A对照组相比,减虫率仅8.5%肝卵EPG减少12.3%,粪卵EPG减少26.8%,但均无统计学意义,结论 用rSj22kD抗原免疫水牛诱导的特异性IgG抗体不能发挥免疫保护作用。  相似文献   
102.
In this article, we describe a relatively simple surgical option that we believe is indicated for use in cases of cervical incompetence. We discuss the advantages of this procedure to the surgeon and patient, and give details of 59 patients who have undergone this procedure one or more times over a 13-year period. A short review of the history of treatment of cervical incompetence and of recent trends for its management is also presented.  相似文献   
103.
Principles and practice of HIV-protease inhibitor pharmacoenhancement   总被引:3,自引:2,他引:1  
GJ Moyle  D Back 《HIV medicine》2001,2(2):105-113
Continually maintaining maximally suppressive drug concentrations represents a key defence against the emergence of resistance. If drug levels fall and replication occurs, the opportunity for mutant virus to be selected occurs. It has been increasingly recognized that variability in the pharmacokinetics of antiretrovirals, particularly protease inhibitors (PIs), means that drug exposure is not always optimal, giving the virus a chance to replicate. A significant number of patients receiving PIs two or three times daily will have trough (Ctrough or Cmin) plasma concentrations, which are close to, or below, the plasma protein binding‐corrected inhibitory concentration (IC50 or IC95) during the dosing interval. It is primarily in this context that therapeutic drug monitoring of PIs has been proposed as an aid to patient management, to ensure that patients maintain adequate drug concentrations throughout the dosing interval. Ideally, an antiretroviral drug will have a pharmacokinetic (PK) profile that maintains drug levels well above the viral inhibitory concentration throughout the entire dosing interval. Beneficial drug–drug interactions have been shown to improve PI pharmacokinetics. Ritonavir (RTV) inhibits the key enzymes that limit the bioavailability or speed the metabolism of other PIs. It is therefore increasingly used for boosting and maintaining PI plasma concentrations. At low (100 mg twice a day) doses it acts as a pharmacoenhancer of indinavir (IDV), amprenavir, saquinavir, lopinavir and to a more limited degree nelfinavir. Using a pharmacoenhancer with a PI results in increased exposure to the PI, higher Cmin levels, and in most cases prolonged elimination half‐lives. The long‐term clinical benefits of PK enhancing are unknown as are the long‐term toxicities, although the incidence of nephrolithiasis with IDV appears increased when IDV is combined with low‐dose RTV in HIV‐infected patients. Head‐to‐head clinical comparisons of boosted PI regimens will help answer some of the questions that remain with regard to PK enhancement.  相似文献   
104.
105.
106.
马蓝的化学成分研究   总被引:15,自引:0,他引:15  
Seven compounds have been isolated from the whole plant of Strobilanthes cusia (Nees) O. Ktze. Three of them are triterpenes (Ⅰ~Ⅲ), two are indole alkaloids (Ⅳ, Ⅴ), two are quinazolinone alkaloids (Ⅵ, Ⅶ). On the basis of spectral analysis and physicochemical properties, their structures were established as lupeol (Ⅰ), betulin (Ⅱ), lupenone (Ⅲ), indigo (Ⅳ), indirubin (Ⅴ), 4 (3H)-quinazolinone (Ⅵ), 2, 4 (1H, 3H)-quinazolinedione (Ⅶ). Ⅵ and Ⅶ were found from natural plant for the first time.The results of the pharmacological tests demonstrate that compound Ⅴ has anticancer activity and compound Ⅵ has hypotensive action. Compound Ⅶ can be quantitatively determined by HPLC, which may serve as a quality control standard for materia medica and its preparations. Compounds Ⅵ and Ⅶ have been confirmed by means of synthesis.  相似文献   
107.
利用硝苯啶溶液对光不稳定的性质,在波长350nm处测其光照前后的吸收度差值(△A),△A与硝苯啶乙醇溶液浓度在10~60μg/ml范围内呈线性关系。使用本法对硝苯啶片进行了含量测定,并对其类似物进行了干扰试验,排除了组分的干扰。该法的精密度日内为1.3%,日间为1.9%,平均回收率为99.96%。方法简便、快速,不需色谱等分离手段即可达到分析目的,专一性、重复性均较好,是分析硝苯啶制剂的一种新途径。  相似文献   
108.
OBJECTIVE: To study the relation between traumatic birth and the development of permanent facial palsy in the newborn. DESIGN: Retrospective case control study of children with 'congenital' facial palsy. SETTING: Two tertiary referral centres for patients with facial palsy. SUBJECTS: 61 children with established facial palsy. MAIN OUTCOME MEASURES: Odds ratios of recognised factors for birth injury: maternal primiparity, high birth weight, and the use of obstetric forceps at delivery. RESULTS: 13.2% of those studied had forceps assisted delivery compared to 10.2% in the normal population (odds ratio 1.34; 95% confidence intervals 0.61 to 2.97) 39.6% were born to primiparae compared to a national rate of 36.7% (1.13; 0.65 to 1.96) and only 18.9% weighed more than 3500 g at birth (0.37; 0.19 to 0.74). CONCLUSIONS: There is no association between the development of permanent 'congenital' facial palsy and recognised risk factors for birth injury. These data suggest an intrauterine rather than a traumatic aetiology.  相似文献   
109.
核磁共振法测定喃氟啶温度敏感性脂质体的相转变温度   总被引:1,自引:0,他引:1  
用核磁共振法测定了喃氟啶温度敏感性脂质体的相转变温度。此法与经典的差热分析法不同,有灵敏度高、准确性好、提供信息全面等优点。用该法测得的DPPC-脂质体和DSPC-脂质体的相转变温度分别为36℃和48℃;DPPC-DSPC-脂质体的相转变温度与DPPC和DSPC的含量有关,随DPPC含量的增加而降低,随DSPC含量的增加而增加;药物的加入及含量不影响相转变温度。同时,制得可供临床前研究用相转变温度为41℃的喃氟啶温度敏感性脂质体。  相似文献   
110.
DESIGN: A case of Nance-Horan syndrome in a male is presented, with some features of the condition in his carrier mother and her mother. It is proposed that Nance-Horan syndrome might be a contiguous gene syndrome mapping to chromosome Xp21.2–p22.3.
SETTING: The proband had congenital cataract micro-phthalmia and dental abnormalities including screwdriver shaped incisors and evidence of enamet pitting hypoplasia. The region Xp2I.2–p22.3 also contains the tooth enamet protein gene, ametogenin (AMGX).
RESULTS: Using molecular genetic techniques, we have shown that there is no evidence that the AMGX gene is deteted in this case of the Nance-Horan syndrome.  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