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   87907篇
  免费   8179篇
  国内免费   5838篇
耳鼻咽喉   600篇
儿科学   1037篇
妇产科学   1317篇
基础医学   10634篇
口腔科学   1728篇
临床医学   11310篇
内科学   13827篇
皮肤病学   901篇
神经病学   4865篇
特种医学   3138篇
外国民族医学   37篇
外科学   8418篇
综合类   14065篇
现状与发展   14篇
一般理论   12篇
预防医学   5950篇
眼科学   2312篇
药学   9390篇
  90篇
中国医学   4762篇
肿瘤学   7517篇
  2024年   358篇
  2023年   1426篇
  2022年   3592篇
  2021年   4511篇
  2020年   3385篇
  2019年   2940篇
  2018年   3133篇
  2017年   2790篇
  2016年   2583篇
  2015年   3910篇
  2014年   4778篇
  2013年   4430篇
  2012年   6718篇
  2011年   7146篇
  2010年   4516篇
  2009年   3598篇
  2008年   4858篇
  2007年   4667篇
  2006年   4259篇
  2005年   4163篇
  2004年   2984篇
  2003年   2665篇
  2002年   2384篇
  2001年   1957篇
  2000年   2043篇
  1999年   2158篇
  1998年   1365篇
  1997年   1376篇
  1996年   1059篇
  1995年   1026篇
  1994年   852篇
  1993年   523篇
  1992年   609篇
  1991年   546篇
  1990年   461篇
  1989年   409篇
  1988年   334篇
  1987年   326篇
  1986年   246篇
  1985年   201篇
  1984年   128篇
  1983年   84篇
  1982年   63篇
  1981年   52篇
  1980年   33篇
  1979年   46篇
  1978年   18篇
  1973年   17篇
  1972年   17篇
  1966年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
OBJECTIVE: To examine the distribution of rat facial motoneurons contributing different branches under normal situation and when nerve reinnervation occurred following facial nerve axotomy. METHODS: The normal distribution of motoneurons innervated both buccal and marginal mandibular branches and its reorganization after facial nerve reinnervation was observed using retrograde labeling with fluorescein. RESULTS: Under normal situation, the motoneurons contributing buccall and marginal mandibular branches were primarily distributed in the intermedial and lateral subnucleus in facial nucleus and almost completely overlapped. The two types labeled neurons organized closely, but there were no double-labeled neurons. Although the motoneurons contributing buccall and marginal mandibular branches were primarily overlapped 4 month post-anastomosis, the number of the labeled neurons obviously decreased and the organization got more scattered. There were 10% of buccall branches, 5% of marginal mandibular motoneurons in the dorsal subnuleus, 1% of buccall and 4% of marginal mandibular in dorsal ventral and medial subnucleus. The distribution pattern of the motoneurons 6 month post-anastomosis was similar to that of 4 month post-anastomosis, but the number of the labeled neurons increased, and there were 1%-2% double-labeled neurons. CONCLUSION: The distribution pattern of motoneurons innervated both buccal and marginal mandibular branches indicates that it should exist wide-spread communicating branches, and its reorganization after facial nerve reinnervation suggests that misdirected regeneration occurs among motoneurons innervating different branches.  相似文献   
62.
静脉输液加药后的微粒变化   总被引:7,自引:1,他引:6  
本文对我院急诊病人常用的供静脉给药的22种药物、42组配伍情况,制成静脉加药输液,在超净工作台条件下,用KF—4型微粒计数器,测定了168次微粒数,结果显示输液加药后微粒虽有增加,但均在药典规定范围内。输液中加1种、2种、3种药物后所产生的微粒数分别为x_1=5.52(n_1=16);x_2=8.17(n_2=18)、x_3=10.25(n_3=8),经统计处理,三组间无显著差异(P<0.05)。本文对产生微粒的药物、注射器、操作环境等因素进行了分析。  相似文献   
63.
Experimental study on the immunosuppressive effects of gui zhi tang   总被引:1,自引:0,他引:1  
X F Lu 《中西医结合杂志》1989,9(5):283-5, 262
In this paper the immunosuppressive effects of Gui Zhi Tang (a famous Chinese medicine) on the murine immune functions are reported. Varying dosages of Gui Zhi Tang administrated orally, i.p. and i.m. were able to inhibit the amounts of PFC, SRFC and the DTH response induced by BSA and the proliferation response of murine spleen cells to Con A and LPS. Further studies showed that Gui Zhi Tang had the inhibitory effect on Interleukin-2 production of murine spleen cells, which might be one of the mechanisms leading to the immunosuppressive effects of Gui Zhi Tang.  相似文献   
64.
Objective To investigate the correlation between TNF-α and IL-6 levels in cervical mucous during follicular development and ovulation stimulation in different protocols.Methods 36 infertile women were set up as experimental groups,divided into CC, HMG, IVF-ET group,each group consisted of 12 infertile women and 15 women with normal menstrual cycles were choiced as control group.Cervical mucous during follicular phase, luteal phase and ovulation phase were collected.TNF-α, IL-6 levels in cervical mucous were measured by radioimmunology assay (RIA).Follicular development were monitored by transvaginal ultrasonagraphy.Results (1) TNF-α levels in cervical mucous of experimental groups and control group were periodically various among the reproductive cycle.It increased during follicular phase, reached to peak during ovulation phase, and decreased during luteal phase (P<0.05).IL-6 levels had no obvious periodical changes.(2) Compared with CC and control group, levels of TNF-α,IL-6 in HMG and IVF-ET group were significantly higher (P<0.05).(3) Levels of TNF-α and IL-6 in cervical mucous were positively correlated with the dominant follicle diameter (r=0.261, r=0.192 respectively,P<0.05).(4) TNF-α and IL-6 showed positive correlation in the reproductive cycle (r=0.782,P<0.05).Conclusions (1) TNF-α level shows a cyclic change in the reproductive cycle and peaks during ovulation,whereas IL-6 level does not.(2) TNF-α and IL-6 may play a certain role in the process of follicular development and ovulation.(3)The levels of TNF-α and IL-6 are up-regulated by gonadotrophic hormone.(4) TNF-α and IL-6 may have coordination properties and participate in the same biological effects.  相似文献   
65.
BACKGROUND: High rates of morbidity and mortality are observed in patients with advanced heart failure (AHF). AHF is now considered the most costly syndrome in cardiology owing to the substantial economic burden associated with hospitalizations for acute decompensation. A management program that involves specialized follow-up by a multidisciplinary team has been suggested as a desirable strategy for improving outcomes for these patients. ObjectivE: To evaluate the impact of a specialized outpatient heart failure (HF) follow-up program for patients with AHF on frequency and duration of hospitalization for HF and functional status. METHODS: We retrospectively studied 167 consecutive patients with AHF who were referred to the outpatient HF follow-up program in our institution between January and November 2002, of whom 147 followed for > or =30 days were included in the analysis. In addition to demographic and baseline clinical characteristics, HF medication and NYHA functional class, the number and duration of hospitalizations for HF during the previous 12 months were recorded and compared at the time of referral and after a follow-up period of 6.5+/-3 months. RESULTS: Of the 147 patients analyzed (aged 60.8+/-13 years; 79% male; left ventricular ejection fraction 27+/-11%), 67% were in NYHA functional class III, 20% in class II and 13% in class IV at the time of referral. There was a significant improvement in functional class during the mean follow-up period: 55% of the patients were in class III, 37% in class II, 5% in class I and 3% in class IV (p<0.0001). The proportion of patients on beta-blockers or spironolactone increased from 33% and 51% at the time of referral to 69% and 71% respectively after referral (p<0.0001). In the 12 months before referral, 39% of the patients had been hospitalized for acute decompensation of HF (87 hospitalizations - mean 7.2/month) versus 13% of the patients during the mean follow-up period (25 hospitalizations - 3.8/month, p<0.0001). No significant differences were found in the proportion of patients on angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, digoxin or diuretics, or in the mean duration of hospitalization before and after referral. ConclusioN: The specialized follow-up of patients with AHF by a team with expertise in HF resulted in significant therapeutic optimization. Increased use of beta-blockers and spironolactone was associated with significant improvement in functional capacity and significant reduction in hospitalizations.  相似文献   
66.
Apical ballooning is a novel clinical entity reported in different contexts of physical and psychological stress, which is more common in middle-aged women. Of unknown etiology, the syndrome is characterized by a sudden and transient dilatation of the left ventricular apex in the absence of obstructive atherosclerotic coronary disease or evidence of myocardial necrosis, with total late recovery of ventricular function. The authors report the case of a 53-year-old woman who was admitted to the emergency room with left arm ischemia and low cardiac output, requiring ventilatory support. Left catheterization showed typical medial and apical myocardial dysfunction, with normal coronary arteries. Transesophageal echocardiography revealed a thrombus attached to the lower face of the aortic arch, which probably explained the thromboembolism of the arm but was unlikely to be the cause of the left ventricular dysfunction since there were no enzymatic or electrocardiographic signs of myocardial necrosis and normal wall motion was fully recovered.  相似文献   
67.
BACKGROUND: Aerobic exercise training has been associated with beneficial effects on the cardiovascular system, improving arterial compliance, possibly related to a positive impact on the endothelium. The effects of competitive aerobic exercise are not so well documented. This prompted us to evaluate the possible modulation of arterial properties in a group of athletes and their response to the aging process. METHODS: 423 healthy males were enrolled in a cross-sectional study, 212 of whom were competitive athletes and 211 were controls. All underwent carotid-femoral pulse wave velocity (PWV) evaluation, and casual blood pressure and other relevant anthropometric data were evaluated. RESULTS: To control the effects of age, each group was divided into two subgroups with an age cut-point of 20 years. PWV was 6.3 +/- 0.9 m/s (athletes) vs. 7.0 +/- 1.0 m/s (controls) for ages <20 years, and 7.6 +/- 1.2 m/s (athletes) vs. 8.1 +/- 0.9 m/s (controls) for ages >20 years, with statistically significant differences in both comparisons. A linear regression model with logarithmic tendency analysis with age as the independent determinant of PWV revealed a different progression of age-related deterioration of aortic compliance between the two groups (athletes and controls). CONCLUSIONS: Our data documented better compliance indices in competition athletes compared with controls, which may reflect optimization of endothelial function. This improvement was age-dependent, being less pronounced as the athletes grow older, which could be due partially to sustained stretching effects on the arterial walls in long-term competitors.  相似文献   
68.
BACKGROUND: Portugal has one of the highest mortality rates from stroke, a high prevalence of hypertension and probably a high salt intake level. AIM: To evaluate Portuguese salt intake levels and their relationship to blood pressure and arterial stiffness in a sample of four different adult populations living in northern Portugal. METHODS: A cross-sectional study evaluating 24-hour urinary excretion of sodium (24 h UNa+), potassium and creatinine, blood pressure (BP), and pulse wave velocity (PWV) as an index of aortic stiffness in adult populations of sustained hypertensives (HT), relatives of patients with previous stroke (Fam), university students (US) and factory workers (FW), in the context of their usual dietary habits. RESULTS: We evaluated a total of 426 subjects, mean age 50 +/- 22 years, 56% female, BMI 27.9+/-5.1, BP 159/92 mmHg, PWV 10.4+/-2.2 m/s, who showed mean 24h UNa+ of 202 +/- 64 mmol/d, corresponding to a daily salt intake of 12.3 g (ranging from 5.2 to 24.8). The four groups were: HT: n = 245, 49 +/- 18 years, 92% of those selected, 69% treated, BP 163/94 mmHg, PWV 11.9 m/s, 24 h UNa+ 212 mmol/d, i.e. 12.4 g/d of salt); Fam: n = 38, 64 +/- 20 years, 57 % of those selected, BP 144/88 mmHg, PWV 10.5 m/s, 24 h UNa+ 194 mmol/d, i.e. 11.1 g/d of salt; US: n = 82, 22 +/- 3 years, 57% of those selected, BP 124/77 mmHg, PWV 8.7 m/s, 24h UNa+ 199 mmol/d, i.e. 11.3 g/d of salt; FW: n = 61, 39 9 years, 47% of those selected, BP 129/79 mmHg, PWV 9.5 m/s, 24 h UNa+ 221 mmol/d, i.e. 12.9 g/d of salt. The ratio of urinary sodium/potassium excretion (1.9 (0.4) was significantly higher in HT than the other three groups. In the 426 subjects, 24h UNa+ correlated significantly (p < 0.01) with systolic BP (r = 0.209) and with PWV (r=0.256) after adjustment for age and BP. Multivariate analysis showed that BP, age and 24h UNa+ correlated independently with PWV taken as a dependent variable. CONCLUSIONS: Four different Portuguese populations showed similarly high mean daily salt intake levels, almost double those recommended by the WHO. Overall, high urinary sodium excretion correlated consistently with high BP levels and appeared to be an independent determining factor of arterial stiffness. These findings suggest that Portugal in general has a high salt intake diet, and urgent measures are required to restrict salt consumption in order to prevent and treat hypertensive disease and to reduce overall cardiovascular risk and events.  相似文献   
69.
10例前置胎盘产后出血改良式宫腔纱布填塞临床分析   总被引:1,自引:0,他引:1  
目的对改良式宫腔填塞治疗前置胎盘产后出血进行疗效分析。方法对我院手术室常规使用大尾纱行子宫下段胎盘附着面出血,填塞压迫止血进行回顾性分析。结果10例患者行子宫下段纱布填塞疗效明显,出血量400~600ml,均未输血,生命体征平稳,无产褥感染和晚期产后出血。结论子宫下段宫腔纱布填塞术治疗产后出血疗效显著。  相似文献   
70.
肝移植术后胆道并发症的介入治疗   总被引:4,自引:1,他引:3  
目的 探讨原位肝移植术后胆道并发症的介入治疗疗效。方法 回顾性分析我院2002年6月至2005年9月诊治的173例原位肝移植患者的临床资料。结果 术后出现胆道并发症14例(8.1%),其中胆管狭窄6例.胆管狭窄合并胆漏1例,胆泥淤积或结石3例,肝断面胆漏2例(劈离式肝移植患者),T管拔除后胆漏1例,Oddi括约肌功能失常1例。除1例胆道狭窄再次行肝移植,因发生严重感染导致肝功能衰竭死亡外.其余患者经介入治疗均获得满意的效果。结论 介入治疗是诊断和治疗肝移植术后胆道并发症的首选方法。  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