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   5261篇
  免费   455篇
  国内免费   14篇
耳鼻咽喉   37篇
儿科学   191篇
妇产科学   136篇
基础医学   619篇
口腔科学   130篇
临床医学   440篇
内科学   1156篇
皮肤病学   145篇
神经病学   642篇
特种医学   111篇
外科学   610篇
综合类   45篇
一般理论   9篇
预防医学   522篇
眼科学   35篇
药学   353篇
中国医学   17篇
肿瘤学   532篇
  2024年   5篇
  2023年   68篇
  2022年   147篇
  2021年   267篇
  2020年   196篇
  2019年   260篇
  2018年   263篇
  2017年   192篇
  2016年   172篇
  2015年   200篇
  2014年   269篇
  2013年   301篇
  2012年   445篇
  2011年   393篇
  2010年   211篇
  2009年   235篇
  2008年   311篇
  2007年   282篇
  2006年   258篇
  2005年   257篇
  2004年   224篇
  2003年   201篇
  2002年   165篇
  2001年   71篇
  2000年   49篇
  1999年   45篇
  1998年   30篇
  1997年   14篇
  1996年   10篇
  1995年   10篇
  1994年   7篇
  1993年   5篇
  1992年   19篇
  1991年   10篇
  1990年   26篇
  1989年   11篇
  1988年   9篇
  1987年   14篇
  1986年   9篇
  1985年   7篇
  1983年   4篇
  1977年   3篇
  1976年   6篇
  1975年   4篇
  1974年   8篇
  1973年   3篇
  1972年   6篇
  1970年   3篇
  1968年   3篇
  1966年   7篇
排序方式: 共有5730条查询结果,搜索用时 31 毫秒
61.
PURPOSE: To assess whether tumour proliferation as measured by Ki67 immunostaining has any predictive value for local control in bladder cancer patients treated by radiotherapy. PATIENTS AND METHODS: Fifty-five patients suffering from infiltrating bladder carcinoma recommended for radical radiotherapy (66 Gy/6-7 weeks) were included in this study. Paraffin-embedded pre-treatment tumour sections were stained with the Ki67 antibody. The percentage of Ki67-positive nuclei was correlated with established prognostic factors, local control and survival. RESULTS: The Ki67 index was not related to local control in our patients when the median was selected as the cut-off value. Patients with tumours with a very low (<27%) Ki67 index had better local control at 5 years (69%) than patients with tumours with greater (>27%) Ki67 expression indices (31.5%) (P<0.05; log-rank test). CONCLUSIONS: Ki67 immunostaining was a feasible method to estimate tumour proliferation. Patients with very low proliferating tumours seemed to achieve better local control after fractionated radiotherapy compared to other patients. Further studies are needed with a greater number of patients to accurately define the role of Ki67 expression in predicting tumour repopulation during fractionated radiotherapy.  相似文献   
62.
In the mammalian CNS, glutamate and GABA are the principal neurotransmitters mediating excitatory and inhibitory synaptic events, respectively, and have been implicated in the neurobiology of seizures. Guanine-based purines, including the nucleoside guanosine and the nucleotide GMP, have been shown to antagonize glutamatergic activity at the receptor level and the other purine nucleoside adenosine is a well-known modulator of seizure threshold. In the present study we investigated the anticonvulsant effect of i. p. guanosine and GMP against seizures induced by the glutamate agonist quinolinic acid (QA) or the GABA(A) antagonist picrotoxin in mice. Animals were pretreated with an i.p. injection of saline, guanosine or GMP 30 min before either an i.c.v. injection of 4 microliter QA (36.8 nmol) or a subcutaneous injection of picrotoxin (3.2 mg/kg). All animals pretreated with vehicle followed by QA or picrotoxin presented seizures, which were completely prevented by the NMDA antagonist MK-801 and the GABA agonist phenobarbital, respectively. Guanosine and GMP dose-dependently protected against QA-induced seizures, up to 70 and 80% at 7.5 mg/kg, with ED(50)=2. 6+/-0.4 and 1.7+/-0.6 mg/kg, respectively. Conversely, neither guanosine, GMP nor MK-801 affected picrotoxin-induced seizures, indicating some degree of specificity towards the glutamatergic system. This study suggests anticonvulsant properties of i.p. guanosine and GMP, which may be related with antagonism of glutamate receptors.  相似文献   
63.
Trace element determination of Argentine wines using ETAAS and USN-ICP-OES.   总被引:1,自引:0,他引:1  
The objective of this work was to develop a method to determine the metal content in wine samples from the province of Mendoza in Argentina. Ten samples of white wine and 10 samples of red wine available in the supermarket were analyzed for the metals aluminium, cadmium, calcium, chromium, copper, iron, nickel, lead and zinc by electrothermal atomic spectrometry (ETAAS) and ultrasonic nebulization was coupled to inductively coupled plasma optical emission spectrometry (USN-ICP-OES). The aluminium, cadmium, calcium, copper, iron, lead, zinc, chromium concentrations were between 17.0-18.0 microg l(-1), 1.0-4.7microg l(-1), 10.0-15.0 mg l(-1), 23.0-28.0 microg l(-1), 480-790 microg l(-1), 50-90 microg l(-1), 24-130 microg l(-1), and <0.2-6.25 microg l(-1), respectively. The levels compare well with those reported for similar wines from some other parts of the world. A significant aspect in this paper is the samples mineralization step, which allowed the direct determination of the metals. Concerning to the Cd determination, a refluxing digestion system was used for the pretreatment of the samples.  相似文献   
64.
65.
BACKGROUND: UCN-01 (7-hydroxy-staurosporine) is a novel antineoplastic agent targeting cyclin-dependent kinases, which shows potent in vitro and in vivo activity against a broad range of tumor types. Our group has previously shown that UCN-01 potentiates the apoptotic response of agents such as cisplatin in vitro by preventing sequence-specific abrogation of G2 arrest caused by DNA-damaging chemotherapies. PATIENTS AND METHODS: This National Cancer Institute-sponsored phase I trial was designed to determine the safety, maximum tolerated dose, and pharmacokinetics of escalating doses of cisplatin in combination with UCN-01 in patients with advanced malignant solid tumors, as well as to do molecular correlative studies on tumor specimens. Cisplatin was infused over 1 hour before UCN-01 (45 mg/m2/d) given as a 72-hour continuous infusion. Escalation of cisplatin was planned through five dose levels at 20, 30, 45, 60, and 75 mg/m2. RESULTS: Ten patients were accrued. Accrual was halted at dose level 2 (cisplatin, 30 mg/m2) due to dose-limiting toxicities consisting of grade 5 sepsis with respiratory failure associated with grade 3 creatinine (one patient) and grade 3 atrial fibrillation (one patient). Plasma and salivary pharmacokinetics of UCN-01 were unaffected by cisplatin. Pretreatment and posttreatment tumor biopsies showed that UCN-01 was active against a key molecular target, the checkpoint kinase Chk1.CONCLUSIONS: This phase I trial failed to achieve targeted therapeutic dose levels of cisplatin when combined with prolonged infusion UCN-01. However, because preclinical data indicate that UCN-01 potentiates response to platinum, further studies with alternative dose schedules of the combination, or with other platinum analogues, are warranted.  相似文献   
66.
AIM: We report on the design, validation and evaluation of a DVD for patient information in a department of surgical oncology. PATIENTS AND METHOD: DVDs provided the patient with information about the anatomy, surgical techniques and post-operative complications on digestive cancers, oral cavity and breast tumours. After surgery a questionnaire was sent to the patients in order to evaluate their level of satisfaction and opinion regarding the pre-operative information they had been given. RESULTS: One hundred and eight patients were invited to watch the DVD. Seventy-one percent of the patients considered that viewing the DVD had been positive and encouraging and 83% of all the patients would recommend its use. Among the 14 patients who experienced complications, only 21% declared having been well informed by the DVD and only 12% considered they were better prepared to face those complications. CONCLUSIONS: DVD based information systems are valuable and acceptable to patients, but the presentation of complications needs to be improved.  相似文献   
67.
68.
69.
70.
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