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   22850篇
  免费   2399篇
  国内免费   439篇
耳鼻咽喉   152篇
儿科学   537篇
妇产科学   253篇
基础医学   2402篇
口腔科学   840篇
临床医学   2870篇
内科学   3954篇
皮肤病学   393篇
神经病学   1709篇
特种医学   437篇
外国民族医学   11篇
外科学   1909篇
综合类   2475篇
现状与发展   4篇
预防医学   2666篇
眼科学   1233篇
药学   1098篇
  9篇
中国医学   700篇
肿瘤学   2036篇
  2024年   68篇
  2023年   527篇
  2022年   761篇
  2021年   1200篇
  2020年   1019篇
  2019年   1055篇
  2018年   981篇
  2017年   1014篇
  2016年   994篇
  2015年   1008篇
  2014年   1448篇
  2013年   1781篇
  2012年   1197篇
  2011年   1238篇
  2010年   1042篇
  2009年   1004篇
  2008年   986篇
  2007年   992篇
  2006年   868篇
  2005年   806篇
  2004年   677篇
  2003年   605篇
  2002年   560篇
  2001年   449篇
  2000年   386篇
  1999年   341篇
  1998年   288篇
  1997年   249篇
  1996年   237篇
  1995年   197篇
  1994年   191篇
  1993年   191篇
  1992年   156篇
  1991年   164篇
  1990年   129篇
  1989年   92篇
  1988年   90篇
  1987年   74篇
  1986年   76篇
  1985年   127篇
  1984年   83篇
  1983年   64篇
  1982年   76篇
  1981年   56篇
  1980年   44篇
  1979年   26篇
  1978年   28篇
  1977年   14篇
  1976年   11篇
  1975年   11篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
21.
The Depression Scale (DEPS), a new screening instrument for detecting depression in primary health care, was compared with the Hamilton Depression Scale (HDS) among 50 suicide attempters. Using the HDS as a gold standard, the positive and negative predictive values of the DEPS for the diagnosis of depression were 98% and 20%, respectively. The correlation between the total HDS scores and the total DEPS scores was 0.60. The DEPS may help general practitioners to detect depression among suicide attempters, but it should not be used to exclude depression.  相似文献   
22.
A 60-year-old Japanese man was hospitalized because of urinary leakage from the anus on October 3, 1994. Retrograde urethrography detected a fistula between the bulbous urethra and the rectum. Urethrocystoscopy revealed a tumor on the urethrorectal fistula. Tumor biopsy showed a well differentiated adenocarcinoma. Cystourethrectomy with fistulectomy, and ileal conduit urinary diversion were performed. Pathological examination revealed primary adenocarcinoma in the fistula with invasion to the prostatic urethra and bladder wall. The patient showed no evidence of a recurrence as of August, 1996.  相似文献   
23.
24.
原发性强直性脊柱炎的早期临床特点   总被引:2,自引:0,他引:2  
目的 探讨原发性强直性脊柱炎(AS)的早期临床特点。方法 120例AS的早期临床特点。结果 该组病人的发病出现16-20岁和30-35岁两上发作年龄高山峰,初发年龄较低;外周关节受累的频率较脊柱高;下肢大和骶骼关节常易受累,其中髋关节,膝关节、踝关节和胸锁关节受累的频率分别为79%,85%,57%和63%,小关节受累少见,虹膜为和主动脉关闭不全的发生率12.5%和4.5%,未发现有前更炎和类风湿结  相似文献   
25.
Abstract: Fifty -two patients with primary biliary cirrhosis (PBC), 10 of whom were 65 years or older at the time of diagnosis, were investigated by laparo-scopy. Laparoscopic findings in these 10 patients were evaluated and compared with those in younger patients. The 10 cases were composed of nine females and one male, and two had been diagnosed as having symptomatic PBC with skin itching, while the remaining eight had asymptomatic PBC. Two, seven and one case were in Scheuer's stage I, II and III, respectively, and eight had chronic non-suppurative destructive cholangitis (CNSDC) on liver biopsy specimens. The majority of senescent PBC patients had typical findings of the early stage of PBC on the liver surface; mild undulations in nine and reddish patches in eight. The laparoscopic findings in senescent PBC were relatively mild.  相似文献   
26.
The importance of oxygen in maintaining the functional integrity of hepatocytes has been well established in a variety of experimental models, such as in vivo , perfused liver and isolated hepatocytes. However, one of the shortcomings of these systems is their short life span. Therefore, we have examined the effects of long-term hypoxia on cellular adenine nucleotide content and cellular functions, such as albumin production, urea production and DNA synthesis, in adult rat hepatocytes in primary culture. Hepatocytes were cultured at a density of 11 × 104 and 5 × 104 cells/0.18 mL per cm2 for the study of albumin and urea production and DNA synthesis, respectively, at various oxygen tensions (20, 12, 8 and 5%) for 24 h. Cellular ATP content in cultured hepatocytes in hypoxia gradually declined, corresponding to the decrease in oxygen tension, and the cellular ATP level at 5% oxygen was approximately 20% of that at 20% oxygen. Albumin production also decreased in parallel with the decrease in cellular ATP content in cultured hepatocytes in hypoxia. However, even when cellular ATP content gradually declined corresponding with the decrease in oxygen tension in cultured hepatocytes in hypoxia, such as at 8 or 5% oxygen, urea production remained at a high level; in contrast, DNA synthesis was completely suppressed. These results suggest that the cellular ATP content decreases in cultured hepatocytes during long-term hypoxia in relation to oxygen tension and that the relationship between decreased ATP levels and liver function in cultured hepatocytes during hypoxia differs for albumin production, urea production and DNA synthesis.  相似文献   
27.
本文就115例腹会阴直肠切除术,对会阴伤口的两种不同处理方法进行分析比较.在年龄、性别、病理分期及恶性程度无明显差异的情况下,会阴伤口一期缝合组的平均愈合时间为16.90±4.35天,伤口敞开组为37.04±15.44天,差异显著(P<0.002).术后局部复发率分别为3/69例和2/46例,均为4.35%(P>0.05).一期缝合组的平均住院费用约为敞开组的46.87%~76.52%.作者指出,鉴于直肠癌逆行向下的淋巴扩散极为罕见,仅发生于高恶性或伴广泛淋巴转移的病例,因而对癌肿远端需切除2cm~3cm正常肠管而同时切除肛直肠环、不得不作手术者,会阴部清除范围无需太大,会阴伤口可分层完全缝合;对位于肛管内或侵及肛直肠环的癌肿,须彻底清除坐骨直肠窝脂肪结缔组织.本文两组术后局部复发率无差异,进一步表明这一认识的正确性.本组结果充分表明了会阴伤口一期缝合法的合理性与可行性.  相似文献   
28.
The potential for morbidity and mortality in patients who have PID with febrile and nonfebrile illness is extremely high. Familiarity with the clinical manifestations of PID and collaboration with a pediatric immunologist are prerequisites for optimal short-term care of these complex patients. Conservative management with empiric broad-spectrum antimicrobials, early and aggressive surgical debridement of abscesses, and admission at a tertiary pediatric care center are often indicated.  相似文献   
29.
A neuropathological study on 1540 consecutive autopsy brains ranging from 60 to 107 years of age revealed the following points. (1) Of the of the demented cases of the plaque-predominant type, 93% were complicated with multiple tiny cortical infarcts. They showed a tendency for dementia to develop before or after the appearance or worsening of a systemic disorder such as cardiovascular disease, respiratory infection and cancer. However, there was no case showing Alzheimer-type dementia (ATD). (2) The plaque-predominant type might be an extreme condition of brain aging in terms of senile plaques (SP). It is likely that although the pathological appearance of SP alone is not responsible for dementia, its coexistence with multiple cortical infarcts could be the cause of dementia. Therefore, this type should be distinguished from ATD. (3) Primary hippocampal degeneration could also be an extreme condition of brain aging in terms of neurofibrillary tangles. This condition was different pathologically from the hippocampal lesion in ATD. (4) Several characteristics of old-old and oldest-old patients were clarified.  相似文献   
30.
Summary We report a case of a third ventricular neuroblastoma (neurocytoma) in a 66 year old man. A stereotactic needly biopsy was performed to obtain a tissue diagnosis and was followed by total resection. We elected not to give radiation or chemotherapy and to follow the patient closely with serial CT scans. Presently, 48 months postoperatively, the patient is free of tumor by head CT scan and able to live independently. We reviewed the literature of primary cerebral neuroblastomas/neurocytomas occurring in adults (15 years of age) and found 32 cases. Our patient is the oldest of this group with a mean age of 32 ± 14 years (S.D.). The location of the 33 neoplasms was intraventricular in 17 cases (52%) and intraparenchymal in 16 cases. The male to female ratio was 2: 1. Of the 17 patients having a minimal follow-up period of 5 months (mean 51 months), five developed recurrences after 5 to 144 months (mean 50 months) compared to 12 patients without recurrence after a 6- to 72-month follow-up period (mean 52 months). Recurrences occurred statistically significantly more often in parenchymal neuroblastomas/neurocytomas than in intraventricular tumor locations.  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