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   37017篇
  免费   2946篇
  国内免费   1394篇
耳鼻咽喉   479篇
儿科学   843篇
妇产科学   420篇
基础医学   3368篇
口腔科学   889篇
临床医学   3681篇
内科学   5632篇
皮肤病学   660篇
神经病学   2207篇
特种医学   1519篇
外国民族医学   3篇
外科学   4223篇
综合类   5895篇
现状与发展   8篇
一般理论   3篇
预防医学   3211篇
眼科学   506篇
药学   3627篇
  34篇
中国医学   2014篇
肿瘤学   2135篇
  2024年   123篇
  2023年   352篇
  2022年   820篇
  2021年   1261篇
  2020年   936篇
  2019年   710篇
  2018年   770篇
  2017年   779篇
  2016年   744篇
  2015年   1081篇
  2014年   1415篇
  2013年   1898篇
  2012年   2944篇
  2011年   3010篇
  2010年   2496篇
  2009年   2081篇
  2008年   2566篇
  2007年   2444篇
  2006年   2304篇
  2005年   1951篇
  2004年   1579篇
  2003年   1336篇
  2002年   1073篇
  2001年   1055篇
  2000年   970篇
  1999年   581篇
  1998年   197篇
  1997年   172篇
  1996年   167篇
  1995年   147篇
  1994年   143篇
  1993年   119篇
  1992年   355篇
  1991年   290篇
  1990年   267篇
  1989年   224篇
  1988年   201篇
  1987年   187篇
  1986年   195篇
  1985年   186篇
  1984年   130篇
  1983年   107篇
  1982年   68篇
  1981年   66篇
  1980年   61篇
  1979年   99篇
  1975年   56篇
  1974年   56篇
  1973年   56篇
  1972年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的:探讨肾移植术后发生高尿酸血症的机制及防治策略。方法:分析480例肾移植术后患者的临床资料。结果:肾移植术后移植肾功能正常而血尿酸增高者43例(9%),其中痛风7例,移植肾肾盂或输尿管结石3例。随访1~5年,1例痛风患者血尿酸及症状控制不理想,余血尿酸均控制在正常水平,未见并发症的发生。结论:高尿酸血症是肾移植术后较常见的问题,发生原因较多,但主要与环孢素A的作用有关;长期降尿酸及碱化尿液治疗安全、有效。  相似文献   
42.
目的用新的生活质量量表研究癫痫患儿的生活质量并探讨其影响因素.方法用量表对71例符合标准的癫痫患儿的生活质量进行评估.结果癫痫患儿的生活质量明显低下,总评得分为63.13±18.89.发作频率、发作担忧及抑郁情绪与患儿生活质量呈负相关,相关系数分别为-0.42、-0.25和-0.45,而记忆功能与患儿生活质量呈正相关,相关系数为0.84.结论癫痫患儿的生活质量明显低下,对癫痫患儿进行药物治疗并辅以心理治疗、健康教育,能提高癫痫患儿的生活质量.  相似文献   
43.
开展健康教育实践活动提高护生综合能力   总被引:19,自引:0,他引:19  
季兰芳 《中华护理杂志》2005,40(11):858-860
目的研究健康教育实践活动对护生综合能力培养的影响.方法在实验班中开展读书活动报告会、健康教育主题班会、科普论文书写训练、双休日、假期到医院见习健康教育、社区服务等教学计划外的健康教育实践活动,对照班仅实施教学计划内要求的实践教学.结果实验班护生经读书活动报告会培训后在仪表、精神风貌、内容、脱稿、语音语调、流利程度、表达能力方面比培训前有所提高,差异有统计学意义(P<0.05);实验班和对照班19项综合能力指标得到提高的学生所占比例不同,其中16项差异具有统计学意义(P<0.01).结论以健康教育为主线的一系列校内、校外社会实践活动能有效提高护生综合能力.  相似文献   
44.
目的探讨MR检查在颈静脉球瘤诊断中的应用价值。方法对15例病变进行回顾性分析,重点分析其部位、信号及其侵袭性表现等情况。结果15例患者中,右侧病变8个(8/15),左侧7个(7/15);肿瘤形态为类圆形或不规则形,12例较大病变不同程度侵犯颈静脉孔区、乳突、岩骨、岩尖、斜坡等处骨质;肿瘤信号欠均匀,12个(12/15)肿块在MR平扫出现“盐和胡椒征”,以“胡椒”表现最为显著;13个肿块(13/13)均有明显强化,其中10个肿块出现“盐和胡椒征”。9例行MRA检查,颈内动脉和颈内静脉不同程度移位和包绕。结论根据肿瘤的部位、“盐和胡椒征”等MR表现,可在手术前正确诊断颈静脉球瘤。  相似文献   
45.
Postoperative infection is an important complication after insertion of a ventriculoperitoneal (VP) shunt in children with hydrocephalus. A randomized double-blind placebo-controlled study was performed to determine the efficacy of cephalothin in preventing postoperative shunt infection. Sixty-three children who presented for elective VP shunt insertion between January 1982 and December 1985 and who did not have a history of shunt infections were randomly assigned to receive four doses of prophylactic cephalothin, 25 mg/kg (32 patients), or of a multivitamin placebo (31 patients). Postoperative infection developed in 6% of the treatment group, compared with 10% of the placebo group, a difference that was not statistically significant, although a clinical significance may have been masked by the small sample size. A large multicentre trial is needed to determine the efficacy of antibiotic prophylaxis in reducing the incidence of postoperative VP shunt infections.  相似文献   
46.
Successful pregnancy in primary glomerular disease   总被引:2,自引:0,他引:2  
The course of 66 pregnancies was studied in 48 women with primary glomerular diseases. In all cases diagnoses were established by biopsy before pregnancy. They were: membranoproliferative glomerulonephritis in 16 patients, focal glomeruloesclerosis in 13, IgA nephropathy in 10, membranous nephropathy in seven and focal glomerulonephritis in two women. The clinical status of the nephropathy before conception was that 43 had only mild renal dysfunction, five had moderate renal insufficiency, serum creatinine (1.3 to 1.9 mg%), eight women had hypertension (150/100 mm Hg) and eight had nephrotic range proteinuria. Their clinical course was compared with a control group of 36 women with primary glomerular disease who did not become pregnant, and were matched for similar age, histological type, and status of nephropathy (renal function, blood pressure and proteinuria). After one year and at the end of the five year follow-up period, the incidence of hypertension, proteinuria, and renal failure was similar in the two groups. The fetal survival rate was 92%; 51 pregnancies ended in full-term delivery, with a mean birthweight of 3,242 +/- 320 g. There were seven pre-term deliveries (2,170 +/- 135 g), three small for gestational-age (2,340 +/- 135 g), two stillbirths and three spontaneous abortions. These patients had more pre-term deliveries (10.6%) and perinatal mortality (31%) than a normal population (5.5% and 9.6%, respectively). Blood pressure increased during pregnancy in 13 women; in 10 it was reversible, and in four it persisted after delivery. Ten gravidas developed increased proteinuria (reversible in six of them) and two others developed permanent impairment of renal function.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
47.
The occurrence of transitory cognitive impairment during diffuse subclinical electroencephalographic (EEG) discharges has been widely documented but the role of the parameters influencing the cognitive performance and the involvement of motor or verbal response in the tasks used is still under debate. Fifteen patients suffering from primary generalized epilepsy with frequent bisynchronous EEG epileptic bursts underwent a shape recognition task during EEG monitoring. The test sequence was as follows: memorandum, pause, and multiple choice set. After pressing the response button, the patient was asked to confirm the choice verbally. The following parameters were considered: geometrical complexity of the shape, chronological position of the burst occurring during the single test, and the duration of discharge ranging from 1 to 3 s. Results showed a significant increase in incorrect responses during the test when discharges occurred, with more errors occurring for difficult than for easy shapes. Neither the discharge position nor the duration of the epileptic burst influenced the performance. Diffuse epileptic activity of short duration produced selective effects on the cognitive process regardless of the motor component of the response.  相似文献   
48.
BACKGROUND: Chronic kidney disease patients who are resistant to erythropoietin (EPO) treatment may suffer from malnutrition and/or inflammation. METHODS: In a cross-sectional study of haemodialysis patients, we investigated the relationship between the natural logarithm of the weekly EPO dose normalized for post-dialysis body weight and outcome measures of nutrition and/or inflammation [BMI, albumin and C reactive protein (CRP)] by means of multiple linear regression analysis. On the basis of the decile distribution of weekly EPO doses, we also evaluated four groups of patients: untreated, hyper-responders, normo-responders and hypo-responders. RESULTS: Six hundred and seventy-seven adult haemodialysis patients were recruited from five Italian centres. BMI and albumin were lower in the hypo-responders than in the other groups (21.3+/-3.8 vs 24.4+/-4.7 kg/m(2), P<0.001; and 3.8+/-0.6 vs 4.1+/-0.4 g/dl, P<0.001), whereas the median CRP level was higher (1.9 vs 0.8 mg/dl, P = 0.004). The median weekly EPO dose ranged from 30 IU/kg/week in the hyper-responsive group to 263 IU/kg/week in the hypo-responsive group. Transferrin saturation linearly decreased from the hyper- to hypo-responsive group (37+/-15 to 25+/-10%, P = 0.003), without any differences in transferrin levels. Ferritin levels were lower in the hypo-responsive than in the other patients (median 318 vs 445 ng/ml, P = 0.01). At multiple linear regression analysis, haemoglobin, BMI, albumin, CRP and serum iron levels were independently associated with the natural logarithm of the weekly EPO dose (R(2) = 0.22). CONCLUSIONS: Our findings support a clear association between EPO responsiveness and nutritional and inflammation variables in haemodialysis patients; iron deficiency is still a major cause of hypo-responsiveness.  相似文献   
49.
The present study was designed to examine the effects of a >30kDa fraction of medium conditioned for 2 days by adult rat seminiferoustubules on inhibin secretion by cultured tubules, and on spermatogenesisand fertility of male rats. Inhibin secretion was assayed byadding the >30 kDa fraction to 5 cm segments of adult ratseminiferous tubules and measuring inhibin by radioimmunoassayat 2 day intervals. Fertility was assayed by injecting malerats daily for up to 45 days with the >30 kDa fraction andthen mating them with a proestrus female, or by injecting for15 days and mating them with two female rats. The assay usedto evaluate the in-vivo effect of the >30 kDa fraction onthe testis involved an assessment of frequencies of seminiferoustubule stages scored by transillumination on intact tubules.The addition of the >30 kDa fraction to the adult rat seminiferoustubules cultured for 2 days resulted in an inhibition of inhibinsecretion into the medium. This effect was reversed when thefraction was removed and changed with fresh medium and culturedfor a further 4 days. The >30 kDa fraction administered i.p.to adult male rats resulted in a low fertilization rate comparedto control rats (67%) (P < 0.05). The assessment of frequenciesof seminiferous tubule stages scored by transillumination showedan increased frequency of stage VI and decreased frequency ofstages VII and VIII after treatment. The results of the presentstudy provide additional evidence that local regulation of Sertolicell function is mediated by a >30 kDa component or componentssecreted by adult seminiferous tubules which could arrest spermatogenesis.  相似文献   
50.
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