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   21422篇
  免费   1379篇
  国内免费   200篇
耳鼻咽喉   246篇
儿科学   728篇
妇产科学   506篇
基础医学   2822篇
口腔科学   255篇
临床医学   1677篇
内科学   3951篇
皮肤病学   380篇
神经病学   1698篇
特种医学   689篇
外国民族医学   1篇
外科学   2641篇
综合类   494篇
一般理论   24篇
预防医学   3314篇
眼科学   519篇
药学   1479篇
  2篇
中国医学   136篇
肿瘤学   1439篇
  2023年   192篇
  2022年   369篇
  2021年   640篇
  2020年   298篇
  2019年   543篇
  2018年   644篇
  2017年   452篇
  2016年   486篇
  2015年   572篇
  2014年   756篇
  2013年   1089篇
  2012年   1571篇
  2011年   1622篇
  2010年   975篇
  2009年   755篇
  2008年   1178篇
  2007年   1302篇
  2006年   1212篇
  2005年   1079篇
  2004年   1001篇
  2003年   923篇
  2002年   813篇
  2001年   449篇
  2000年   386篇
  1999年   340篇
  1998年   140篇
  1997年   134篇
  1996年   107篇
  1995年   94篇
  1994年   98篇
  1993年   73篇
  1992年   223篇
  1991年   193篇
  1990年   213篇
  1989年   232篇
  1988年   216篇
  1987年   195篇
  1986年   171篇
  1985年   174篇
  1984年   123篇
  1983年   99篇
  1982年   56篇
  1981年   51篇
  1980年   55篇
  1979年   82篇
  1978年   48篇
  1975年   48篇
  1974年   41篇
  1973年   48篇
  1972年   42篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Thirty-three patients with primary gastrointestinal lymphoma (GIL) followed at Ankara University Medical School have been evaluated. The most frequent locations of the disease are the small intestine (48.4%) and the stomach (39.3%). The intermediate and high grade lymphomas constitute 84.8% of the cases. The mean age of the patients with small intestinal lymphoma is 28.7 years and 47.1 years for those with gastric lymphoma. The patients treated with surgery and chemotherapy (S+CT) have a longer survival than those treated with chemotherapy (CT) alone. In conclusion: 1) Small intestinal lymphoma occurs more frequently than gastric lymphoma in our study. 2) The median age of the Turkish patients with primary GIL is approximately 10 years less than those in the Western countries. 3) The therapeutic results of S+CT are superior to those of CT in the early stages of the disease.  相似文献   
42.
Dietary fat, beef protein and fibre have been shown to modulatecancer risk in humans and the present study examined the biologicaleffects in human-flora-associated (HFA) rats of altering intakelevels within the normal human range. Two control groups, oneHFA and the other germfree (GF), consumed a human diet low infat, fibre and beef for 4 weeks; three other groups consumedhuman diets similar except for independent 3-fold increasesin fat, beef protein or fibre. After 2 weeks on the diets, magneticallyrecoverable microcapsules were given orally to the rats andsubsequently recovered from the faeces to assess endogenouscross-linking agents. After 4 weeks, measurements were madeof gut microfloral enzyme activities, hepatic activation ofdietary mutagens and hepatic DNA adducts by 32P-postlabelling.Activation in vitro of the dietary mutagens 2-amino-3-methyl-3H-imidazo[4,5-f]quinolline (IQ) and 2-amino-l-methyl-6- phenytimidazo[4,5-b]pyridine(PhIP) by hepatic S9, formation of endogenous hepatic DNA adductsin vivo and the ß-glucuronidase activity of caecalcontents were all increased in the sequence high fat > highfibre > high beef = control. Of the two DNA adducts foundin all HFA rats, only one was present in GF controls, indicatingthat the human gut microflora (subject to human dietary modulation)either releases a DNA-adducting product able to act outsidethe gastrointestinal tract, or stimulates the generation ofsuch a product by mammalian processes. Caecal nitrate reductaseactivity was highest in rats fed the high beef diet, whilstentrapment of cross-linking agents was highest in those fedthe high fibre diet. These results show that risk-related componentsof human diets interact with human gut microflora to modulatethe production of endogenous DNA-adducting and cross-linkingsubstances.  相似文献   
43.
In 1987, die Department of Health in the UK set up a working party to identify reasons contributing to a shortfall in donor organs. One recommendation was reimbursement to the District Health Authorities for costs incurred in providing the donor organs. The figure chosen was not to be seen as an incentive to donate organs, merely as an appropriate compensation for the costs incurred. There would be no direct payment to doctors, trustees or relatives of the donor. With the development of the competitive health care environment in the United Kingdom, the reimbursement of donating hospital costs is being considered with these data.  相似文献   
44.
This 71 years old women without any history of epilepsy had diabetes mellitus. She was admitted for repetitive giratory seizures in relation with non-ketotic hyperglycaemia. The EEG showed right centro-parietal paroxysmal slow activity. Symptomatology disappeared within 48 hours after insulin therapy. One month later, she presented with a left hemiplegia in relation with a right sylvian infraction. The role of focal transitory ischaemia in connection with hyperglycaemia is discussed.  相似文献   
45.
目的总结近20年来孤立性左肝胆管结石并发左肝胆管狭窄的临床治疗体会.方法原发性肝胆管结石1018例,年龄27~72岁,其中孤立性左肝胆管结石133例,手术治疗112例,对其临床资料进行回顾性分析,包括各肝管狭窄并发率,术前各项检查确诊率,手术治疗方式,再狭窄率.结果左肝管狭窄的发生率为598%,左外肝管和左内肝管分别为840%和848%,均以重度狭窄为主.狭窄切开整形后高位胆肠吻合术是处理左肝管狭窄的常用手术方式(522%),远期再狭窄率为171%;左半肝切除术施实率为194%,再狭窄率为00%;狭窄整形术和狭窄扩张术的施实率分别为90%和194%,再狭窄率分别为500%和923%.左外肝管狭窄通常采用肝段或肝叶切除术(787%),而左内肝管狭窄的处理则通常采用非左半肝切除术(848%).左内肝管狭窄的术前/后影像学确诊率明显低于左肝管和左外肝管,平均确诊率依次259%,933%和879%.结论二级肝管狭窄是孤立性左肝管结石的常见并发症,肝叶或肝段切除术是其首选治疗原则.过多依赖非肝叶/段切除术和不适当的肝段切除术是遗留狭窄和远期疗效差的重要原因  相似文献   
46.
Intracellular recordings from neurons were carried out in cortical slices obtained from tissue removed from patients suffering from intractable seizures. The patients were divided into two groups based on the presence or absence of an anatomical abnormality that could be imaged preoperatively. The lesion or its surround was the presumptive epileptogenic area. The tissue removed from the patients without lesions was removed either for biopsy purposes or for access to epileptic tissue and was not considered epileptogenic. All neurons from patients without an imageable lesion, and some (19%) from patients with an imageable lesion, responded to orthodromic stimuli with a sequence of synaptic excitation followed by inhibition; these properties resembled those of normal rodent cortical slices. Different responses, classified as abnormal, were observed in 81% of the neurons in tissue specimens obtained near lesions. The most common was prolonged synaptic excitation with no noticeable inhibition, even at high stimulus strengths. In three resections, long latency all-or-none depolarization shifts were observed that resemble the classic paradoxical depolarization shift seen in in vivo extracellular recordings. Loss of specific inhibitory systems within the cortex may contribute in part to these abnormal responses.  相似文献   
47.
美宝湿润烧伤膏在治疗慢性泪囊炎的应用   总被引:16,自引:8,他引:8  
目的:观察美宝湿润烧伤膏(MEBO)在治疗慢性泪囊炎的应用价值。方法:对87例102只慢性泪囊炎采用泪道探通手术与MEBO置留治疗。常规泪点表面麻醉,扩张泪点,用生理盐水或氯霉素眼水冲洗鼻泪管、泪囊、泪小管,再用无菌注射器装入5ml MEBO,用5号自制泪道冲洗针沿泪道方向插入,直达泪囊推药,使鼻泪管、泪囊、泪小管内充满MEBO,一周后继续上述方法治疗,一般连续治疗2—5次。结果:治疗总有效率为100%,随访6个月,无一例复发。结论:在泪道探通手术后随即留置MEBO治疗慢性泪囊炎,临床效果良好,操作简单方便,经济有效,值得临床推广应用。  相似文献   
48.
49.
【目的】研究拉米夫定对HBsAg阳性孕妇的乙肝病毒 (HBV)宫内阻断作用。【方法】拉米夫定组 43例 ,孕 2 8周起口服拉米夫定 ,每天 10 0mg至产后 30d。对照组 5 2例 ,未予用药。两组孕妇均于孕 2 8周、分娩前 ,其新生儿于生后 2 4h内免疫接种前抽静脉血检测HBsAg、HBeAg及HBV的定量。【结果】拉米夫定组孕妇HBV的DNA水平显著下降 (P <0 0 5 ) ,其新生儿宫内感染率 (16 3% )明显低于对照组 (32 7% ) ,P <0 0 5。两组孕妇及其新生儿未发现有不良反应。【结论】携带HBV孕妇产前服用拉米夫定可有效减少HBV宫内感染发生率。  相似文献   
50.
BACKGROUND. Schwartz-Jampel syndrome is a rare disorder inherited as an autosomal recessive trait and characterized by growth retardation, multiple skeletal abnormalities, myotonia-like muscle disorders and unusual facies. CASE REPORTS. Case n. 1: A boy, aged 3 years 4 months, was admitted for acute respiratory disease. His main abnormalities included rigid facial expression, blepharophimosis, puckered lips, short neck, pectus carinatum, acetabular dysplasia with coxa vara, platyspondyly and marked growth retardation. There was a continuous muscle fiber activity at rest, with abnormal discharges originating in the muscle component of the neuromuscular junction. Blood investigations revealed low values of IgA. The child died at 4 years. Case n. 2: The sister of case n. 1 was examined at 14 months of age. She presented milder facies abnormalities, difficulties of gait because of stiff hips, muscular hypertrophy, coxa vara and growth retardation. X-rays showed skeletal abnormalities and the electromyogram was similar to those of her brother. She had dislocation of her optic lens. CONCLUSION. These 2 sibs have the characteristic manifestations of Schwartz-Jampel syndrome. Parental consanguinity was also present. The IgA deficiency observed in case n. 1 and the lens dislocation in case n. 2 have both been occasionally reported in this 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