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   3834篇
  免费   284篇
  国内免费   25篇
耳鼻咽喉   9篇
儿科学   207篇
妇产科学   51篇
基础医学   363篇
口腔科学   90篇
临床医学   394篇
内科学   894篇
皮肤病学   48篇
神经病学   128篇
特种医学   359篇
外科学   421篇
综合类   58篇
一般理论   5篇
预防医学   188篇
眼科学   63篇
药学   329篇
  1篇
中国医学   2篇
肿瘤学   533篇
  2022年   14篇
  2021年   44篇
  2020年   25篇
  2019年   55篇
  2018年   54篇
  2017年   43篇
  2016年   70篇
  2015年   76篇
  2014年   70篇
  2013年   136篇
  2012年   134篇
  2011年   139篇
  2010年   102篇
  2009年   142篇
  2008年   142篇
  2007年   134篇
  2006年   183篇
  2005年   153篇
  2004年   109篇
  2003年   142篇
  2002年   116篇
  2001年   113篇
  2000年   100篇
  1999年   104篇
  1998年   123篇
  1997年   145篇
  1996年   142篇
  1995年   99篇
  1994年   103篇
  1993年   120篇
  1992年   79篇
  1991年   71篇
  1990年   86篇
  1989年   103篇
  1988年   88篇
  1987年   82篇
  1986年   75篇
  1985年   67篇
  1984年   40篇
  1983年   31篇
  1982年   33篇
  1981年   43篇
  1980年   24篇
  1979年   23篇
  1978年   21篇
  1977年   31篇
  1976年   24篇
  1975年   16篇
  1974年   10篇
  1970年   10篇
排序方式: 共有4143条查询结果,搜索用时 0 毫秒
1.
Birth weight on 12,644 singleton infants from 6,196 sibships born in Maryland between 1980 and 1984 were used to estimate the effects of nine maternal and infant covariates on the sibship correlation in birth weight. Assuming a homogeneous correlation across all families, the estimated intraclass correlation was 0.4664 (+/- 0.0099). This high sibship correlation makes it possible to predict, with reasonable accuracy, the birth weight of a child given information on previous sibs, as well as covariates on the mother and/or infant pertinent to a given pregnancy. The reduction in variance associated with incorporating information on the nine covariates used here was approximately equal to that obtained by conditioning on a single previous sib. Testing for heterogeneity in correlation among different groups of families showed that a crude measure of parity (first live birth vs. other), time between births, mother's marital status, and maternal age at the birth of the last child significantly influenced the sibship correlation in birth weight.  相似文献   
2.
Bladder mucosa in urethral reconstructions   总被引:6,自引:0,他引:6  
  相似文献   
3.
An area analysis is presented of deaths in Auckland that were ostensibly avoidable, by appropriate medical intervention and treatment. Mortality data from the National Health Statistics Centre for the period 1977-85 were used in the analysis. The definition of an avoidable death was based on the International Classification of Diseases (ICD) code using established criteria. Eight percent of deaths of people under 65 years of age met the criteria. The basic spatial entity for the analysis is the census area unit and maps of Auckland are presented to show the distribution of avoidable mortality. It is found that there are significant and consistent spatial variations. Three areas with avoidable mortality that is generally higher than elsewhere are apparent: in south Auckland; to the north-west of the central urban sector centered on Grey Lynn; and in the eastern parts of the central sector from Glenn Innes to Onehunga.  相似文献   
4.
Heterosexual men and homosexual men rated how arousing different sexual fantasies were and how often they had used these fantasies over the previous year. Within each group, sensual and genital same-orientation fantasies were more arousing than either public-sex or dominance-submissive fantasies, which in turn were more arousing than aggressive-sex fantasies. For both heterosexual and homosexual men the extent to which a fantasy was arousing correlated with the person's experience of the activity depicted in the fantasy. The frequency of use of a fantasy correlated positively with its arousal level but not always subtantially so. The results are discussed in the context of the mediating role of fantasy in human sexual arousal.  相似文献   
5.
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.  相似文献   
6.
OBJECTIVE: Interictal spikes in intracranial EEG (iEEG) may correlate with epileptogenic cortex, but review of interictal iEEG is labor intensive. Accurate automated spike detectors are necessary for understanding the role of spikes in epileptogenesis. METHODS: The sensitivity, accuracy and reproducibility of three automated iEEG spike detectors were compared against two human EEG readers using iEEG segments from eight patients. A consensus set of detections was generated for detector calibration. Spike verification was calculated after both human EEG readers independently reviewed all detections. RESULTS: Humans and two of the three automated detectors demonstrated comparable accuracy. In four patients, automated spike detection sensitivity was >70% and accuracy was >50%. In the remaining four patients, EEG background morphology resulted in poorer performance. Blinded human verification accuracy was 76.7+/-6.6% for computer-detected spikes, and 84.5+/-4.1% for human-detected spikes. CONCLUSIONS: Automated iEEG spike detectors perform comparably to humans, but sensitivity and accuracy are patient dependent. Humans verified the majority of computer-detected spikes. SIGNIFICANCE: In some patients automated detectors may be used for mapping spike occurrences in epileptic networks. This may reveal associations between spike distribution, seizure onset, and pathology.  相似文献   
7.
Pediatric knee MR imaging: pattern of injuries in the immature skeleton   总被引:3,自引:0,他引:3  
  相似文献   
8.
Feline hyperthyroidism bears a strong clinical and pathologic resemblance to toxic nodular goiter in humans. To evaluate whether the observed thyroid growth might be due to circulating thyroid antibodies, as has been postulated in humans, we studied the effect of purified immunoglobulin (Ig) G preparations on a rat thyroid follicular (FRTL-5) cell line. When compared with control, hyperthyroid cat IgG caused significantly increased [3H]-thymidine (Tdr) incorporation into DNA (p less than 0.02) and stimulated cellular proliferation 15-fold. Stimulation of 3H-Tdr incorporation tended to be biphasic and could be inhibited completely by a potent, specific TSH receptor blocking antibody. Hyperthyroid cat IgG also significantly inhibited 125I-bTSH binding to porcine thyroid membranes, an effect that could be reproduced using electrophoretically pure IgG and normal cat thyroid membranes. Unlike its effect on growth, hyperthyroid cat IgG did not stimulate intracellular cAMP, and there was no correlation between thyroid function in vivo and IgG growth-promoting activity in vitro. These data suggest that elevated titers of thyroid growth IgGs, probably acting through the TSH receptor, are present in feline hyperthyroidism and may play a role in goiter formation. Unlike growth, the thyroid hyperfunction observed is not IgG dependent. Further study of feline hyperthyroidism may contribute important insights into human nodular goiter and into the mediation of thyroid growth in general.  相似文献   
9.
10.
A high dose combination chemotherapy regimen (CBV) consisting of cyclophosphamide (1.5 gm/m2 day 1 to day 4); BCNU (300 mg/m2 day 1) and etoposide (100 mg/m2 every 12 hours for 6 doses), followed by bone marrow transplant from human leukocyte antigen (HLA) identical sibling donors, was evaluated in 29 patients in whom acute leukemia was in relapse or remission. Engraftment of donor cell type occurred in all but one of 21 patients, in whom marker differences between donor and recipient were established. Two of 11 patients transplanted during relapse of the disease, lived beyond 1 year after bone marrow transplantation. One patient died free of leukemia, 41 months after transplantation of meningitis. Two of seven patients transplanted during the second remission of the disease, are alive and free of leukemia at 42+, and 8+ months. All patients transplanted during the third or fourth remission of the disease have died from either a further relapse, or transplant related causes. The low incidence of organ toxicity with CBV allows for further dose escalation of its drug components.  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