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   1875篇
  免费   91篇
  国内免费   10篇
耳鼻咽喉   16篇
儿科学   77篇
妇产科学   214篇
基础医学   235篇
口腔科学   18篇
临床医学   121篇
内科学   348篇
皮肤病学   18篇
神经病学   81篇
特种医学   69篇
外科学   280篇
综合类   43篇
一般理论   1篇
预防医学   71篇
眼科学   73篇
药学   91篇
中国医学   3篇
肿瘤学   217篇
  2022年   19篇
  2021年   23篇
  2020年   25篇
  2019年   40篇
  2018年   38篇
  2017年   38篇
  2016年   48篇
  2015年   60篇
  2014年   53篇
  2013年   74篇
  2012年   104篇
  2011年   101篇
  2010年   59篇
  2009年   55篇
  2008年   79篇
  2007年   78篇
  2006年   74篇
  2005年   75篇
  2004年   69篇
  2003年   48篇
  2002年   50篇
  2001年   53篇
  2000年   59篇
  1999年   71篇
  1998年   30篇
  1997年   30篇
  1996年   25篇
  1995年   10篇
  1994年   18篇
  1993年   33篇
  1992年   28篇
  1991年   38篇
  1990年   34篇
  1989年   40篇
  1988年   20篇
  1987年   18篇
  1986年   20篇
  1985年   24篇
  1982年   11篇
  1981年   13篇
  1979年   21篇
  1977年   9篇
  1974年   13篇
  1973年   12篇
  1972年   16篇
  1970年   9篇
  1969年   9篇
  1968年   9篇
  1967年   9篇
  1966年   11篇
排序方式: 共有1976条查询结果,搜索用时 0 毫秒
101.
102.
It is a fundamental principle of continuous quality improvement (CQI) that processes should be the objects of quality improvement. The objective of this study was to improve process quality concerning the prevention of hospital-acquired infections in surgical departments and intensive care units by a continuous quality improvement (CQI) approach based mainly on quality circles. This approach was evaluated in a prospective controlled intervention study in medium-size acute care hospitals (four intervention and four control hospitals). During two intervention periods (each 10 months) four external physicians with training in hospital epidemiology and infection control introduced and supervised quality circles in the intervention hospitals. Process quality was assessed by interviewing senior staff members before the first and after the second intervention period using standardized questionnaires. The gold standard process quality was defined on the basis of the CDC/HICPAC-guidelines for the prevention of hospital-acquired infections. Most of the evaluated aspects of process quality belonged to the HICPAC-categories IA and IB respectively, the CDC category I. Fifty quality circle sessions were performed in the four intervention hospitals of which 28 were dealing directly with key subjects in infection control. In the intervention hospitals, 19.8% of evaluated aspects of process quality which concerned the prevention of hospital-acquired infections were improved compared to only 6.9% in the control hospitals (P<0.05). Sixty-six point seven percent of positive changes in process quality were initiated by the results of the quality circles. Our study demonstrates that a CQI approach based on infection control quality circles can lead to a substantial improvement of process quality regarding the prevention of hospital-acquired infections.  相似文献   
103.
Primary lymphoma is the most common nonepithelial malignant tumour arising from the paranasal sinus region. It occurs mostly in middle aged and elderly patients with a nonspecific clinical profile resembling that of commoner epithelial sinonasal malignancies. Modified Rappaport’s and the Working Formulation are the frequently used histopathological classification systems. Radiation therapy is the mainstay of treatment with excellent local control of the disease. Most of the failures occur at distant sites outside the treatment area or in the form of disseminateed disease. Chemotherapy, though used in limited number of patients in some series, seems to have a better role to play in the management of these tumours in future as most of the sinonasal lymphomas are of poorly differentiated variety or of unfavourable histology.  相似文献   
104.
The present prospective preliminary study is based on treatment of stage III and IV cancers of the larynx and hypopharynx with a planned combined regimen of radiotherapy and radical surgery. There is a reduction in the failure rate in these cases as compared to those treated in this centre with a single modality of therapy like radiotherapy or surgery alone. 69% of the patients thus treated are surviving disease-free for follow ups varying 18–30 months with a median follow up of 24 months following combined treatment.  相似文献   
105.
In 265 Canadian women, with and without tubal factor infertility (TFI), we compared Chlamydia trachomatis cultures of endocervical swabs, endotubal swabs and biopsies, serology, and past history. A history of pelvic inflammatory disease (PID) was absent in 69.2% of TFI women, despite visual evidence of tubal damage. C. trachomatis was not isolated in any of 52 patients with TFI (TFI group), 114 having tubal ligation (STER group), or 99 patients having hysterectomy (HYST group). However, chlamydial antigen was detected with an immunochemical method in 1 of 16 tubal biopsy specimens from TFI women. The prevalence of chlamydial IgM or IgG antibody in serum was significantly higher (P less than 0.0001) in the TFI group (79.1%) than in the other two groups (relative odds, 6.3; 95% confidence interval: 2.5, 16.8). In seropositive (IgG or IgM) subjects, there was a significant (P = 0.003) and strong (relative odds, 5.1; 95% confidence interval: 1.5, 18.1) association between chlamydial IgA antibody and TFI. In women with TFI, there was no significant association between IgM or IgG seropositivity (P = 0.56). or IgA seropositivity (P = 0.53), and a negative history for PID. These findings are consistent with the hypothesis that C. trachomatis is a major cause of TFI following PID, which may or may not be asymptomatic.  相似文献   
106.
107.
Prognostic factors influencing the outcome of thalamic glioma   总被引:5,自引:0,他引:5  
Retrospective analysis of 27 patients of thalamic glioma including adults and children treated over a period of 7 years from 1991-1997 was done. The study group included 19 males and 8 females; 9 patients were less than 15 years and 18 patients more than 15 years of age at the time of diagnosis. The commonest symptoms were headache and vomiting. 12 patients underwent VP shunt as an initial procedure and 7 underwent total or partial surgical resection. Confirmed histopathological examination was possible in 16 patients; while 12 had low grade astrocytoma, 4 cases had high grade histology. All patients were treated with radiotherapy to a total dose of 50-60 Gy in 25-30 fractions. Median follow up was 9.63 months. The disease free survival in these patients was 28% at 2 years. Prognostic factors which included age, sex, duration of symptoms, surgical procedures, histology and radiotherapy dose were evaluated for significance. A subtotal resection conferred a better prognosis.  相似文献   
108.
OBJECTIVE: A case of ovarian fibrosarcoma associated with a benign cystic teratoma is described. METHODS: A 32-year-old patient with an ovarian tumor detected by routine gynecological examination was referred to our hospital. In addition to histopathological examination of the resected tumor, immunohistochemical studies as well as a cytogenetic analysis by comparative genomic hybridization were carried out. RESULTS: The 7-cm-sized tumor consisted of two different components: a fibrosarcoma and a benign cystic teratoma. The teratoma contained elements of all three germ layers and lacked any focus of immature teratoma. A fibrosarcoma was immediately connected to the teratoma. The sarcoma cells showed eight mitoses per 10 high-power fields on average and exhibited immunohistochemical reactivity for vimentin only. Cytogenetic analysis of the fibrosarcoma using comparative genomic hybridization revealed imbalances of chromosomes 9, 12, and 16. After a 1-year follow-up, there were no signs of tumor recurrence or systemic disease. CONCLUSION: To the authors' knowledge, this is the second report of an association of ovarian fibrosarcoma and benign cystic teratoma, and the first including a cytogenetic analysis.  相似文献   
109.
OBJECTIVE: Subject of the study was the significance of umbilical artery Doppler velocimetry findings for the further course of pregnancy and fetal outcome in cases of twin pregnancies. METHODS: In 206 cases of twin pregnancy, the umbilical artery was examined using Doppler velocimetry in the median 9 days prior to delivery, and the result was correlated with the further course of pregnancy and fetal outcome. 174 pregnancies showed normal Doppler findings of the umbilical artery (group A), 32 twin pregnancies showed pathological Doppler findings of at least one twin (group B). The median of the maternal age and the parity between the groups were not different. RESULTS: In group B (pathological Doppler findings), intrauterine growth retardation and pre-eclampsia occurred 5 times more often than in group A (normal Doppler findings). The total rate of cesarean sections was not different between the study populations; the rate of deliveries by cesarean section in group B was significantly increased by a factor of 2.4 due to a pathological CTG. The median birth weight and the gestational age at birth were significantly lower in group B (1,660 g; 35 weeks) as compared to group A (2,460 g; 37 weeks; p<0.001). In group B, the rate of premature deliveries up to reaching the 34th week of gestation was 3. 4 times higher; the rate of SGA newborns was 6.3 times higher. Perinatal mortality was increased by a factor of 1.5 in group B compared to group A. CONCLUSION: The Doppler velocimetry findings have considerable effects on the further course of a multiple pregnancy. In case of pathological Doppler findings, early hospitalization and close monitoring of the pregnancy should be performed. In cases of additional pathological findings (maternal illness, pathological Doppler findings of fetal blood vessels), termination of the pregnancy has to be considered.  相似文献   
110.
Schlu?folgerung Bei Beachtung der Indikationsstellung (HE bei Nullparit?t mit enger Vagina bzw. immobilem Uterus mit zu erwartenden Verwachsungen) und vorheriger Sicherung des Ureter-Zervixabstandes, stellt dieses Verfahren durch seine minimale Invasivit?t eine Bereicherung der traditionellen Operationstechniken dar, welches nicht als Konkurrenzmethode zur abdominalen Uterusexstirpation zu sehen ist, sondern als ein Mittel, die Indikation zur vaginalen Operation zu erweitern und die Sicherheit dieses Eingriffes zu erh?hen.  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