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   2491篇
  免费   262篇
  国内免费   3篇
耳鼻咽喉   9篇
儿科学   41篇
妇产科学   90篇
基础医学   400篇
口腔科学   128篇
临床医学   268篇
内科学   403篇
皮肤病学   51篇
神经病学   218篇
特种医学   168篇
外科学   376篇
综合类   45篇
一般理论   6篇
预防医学   259篇
眼科学   38篇
药学   125篇
肿瘤学   131篇
  2023年   14篇
  2022年   15篇
  2021年   36篇
  2020年   21篇
  2019年   43篇
  2018年   46篇
  2017年   45篇
  2016年   38篇
  2015年   45篇
  2014年   51篇
  2013年   76篇
  2012年   102篇
  2011年   110篇
  2010年   78篇
  2009年   62篇
  2008年   105篇
  2007年   105篇
  2006年   89篇
  2005年   100篇
  2004年   86篇
  2003年   79篇
  2002年   75篇
  2001年   72篇
  2000年   71篇
  1999年   65篇
  1998年   36篇
  1997年   31篇
  1996年   32篇
  1995年   22篇
  1994年   27篇
  1993年   27篇
  1992年   86篇
  1991年   62篇
  1990年   71篇
  1989年   66篇
  1988年   53篇
  1987年   54篇
  1986年   44篇
  1985年   59篇
  1984年   52篇
  1983年   31篇
  1982年   25篇
  1981年   21篇
  1980年   20篇
  1979年   35篇
  1977年   14篇
  1975年   18篇
  1974年   14篇
  1971年   20篇
  1970年   14篇
排序方式: 共有2756条查询结果,搜索用时 0 毫秒
101.
The history of the scientific enterprise demonstrates that it has supported gender, identity, and racial inequity. Further, its institutions have allowed discrimination, harassment, and personal harm of racialized persons and women. This has resulted in a suboptimal and demographically narrow research and innovation system, a concomitant limited lens on research agendas, and less effective knowledge translation between science and society. We argue that, to reverse this situation, the scientific community must reexamine its values and then collectively embark upon a moonshot-level new agenda for equity. This new agenda should be based upon the foundational value that scientific research and technological innovation should be prefaced upon progress toward a better world for all of society and that the process of how we conduct research is just as important as the results of research. Such an agenda will attract individuals who have been historically excluded from participation in science, but we will need to engage in substantial work to overcome the longstanding obstacles to their full participation. We highlight the need to implement this new agenda via a coordinated systems approach, recognizing the mutually reinforcing feedback dynamics among all science system components and aligning our equity efforts across them.  相似文献   
102.
Respite care services provided by foster parents to 68 children with severe handicaps between 1976 and 1979 were systematically studied to determine parent satisfaction. A variety of rest options were made available to the parents of handicapped children for purposes of revitalizing themselves to deal with their child's daily needs. The respite options included short periods of time varying from 2 to 15 consecutive days, i. e., taking a much needed vacation, a week-edn or two a month off, a few days off during the week, or time away from the child due to an emergency. Consumer satisfaction was measured by survey questionnaires developed specifically for respite care and mailed to parents of handicapped children who had used the service. Results indicated that consumer opinion acquired via the follow-up questionnaire method was extremely positive, A most important consideration was to collect data on scheduled intervals about children subsequently receiving care from the same program to determine whether ratings increased or decreased. By focusing on specific respite care activities over time, it was possible to align optimum versus actual satisfaction. Through an analysis of observer variance, the modification of documented weaknesses can decrease the difference between optimum and actual consumer satisfaction levels.  相似文献   
103.
BACKGROUND: Because many acute cerebral ischemic events are caused by rupture of vulnerable carotid atheroma and subsequent thrombosis, the present study used both idealized and patient-specific carotid atheromatous plaque models to evaluate the effect of structural determinants on stress distributions within plaque. METHODS AND RESULTS: Using a finite element method, structural analysis was performed using models derived from in vivo high-resolution magnetic resonance imaging (MRI) of carotid atheroma in 40 non-consecutive patients (20 symptomatic, 20 asymptomatic). Plaque components were modeled as hyper-elastic materials. The effects of varying fibrous cap thickness, lipid core size and lumen curvature on plaque stress distributions were examined. Lumen curvature and fibrous cap thickness were found to be major determinants of plaque stress. The size of the lipid core did not alter plaque stress significantly when the fibrous cap was relatively thick. The correlation between plaque stress and lumen curvature was significant for both symptomatic (p=0.01; correlation coefficient: 0.689) and asymptomatic patients (p=0.01; correlation coefficient: 0.862). Lumen curvature in plaques of symptomatic patients was significantly larger than those of asymptomatic patients (1.50+/-1.0 mm(-1) vs 1.25+/-0.75 mm(-1); p=0.01). CONCLUSION: Specific plaque morphology (large lumen curvature and thin fibrous cap) is closely related to plaque vulnerability. Structural analysis using high-resolution MRI of carotid atheroma may help in detecting vulnerable atheromatous plaque and aid the risk stratification of patients with carotid disease.  相似文献   
104.
Acanthocystis turfacea chlorella virus (ATCV-1), a prospective member of the family Phycodnaviridae, genus Chlorovirus, infects a unicellular, eukaryotic, chlorella-like green alga, Chlorella SAG 3.83, that is a symbiont in the heliozoon A. turfacea. The 288,047-bp ATCV-1 genome is the first virus to be sequenced that infects Chlorella SAG 3.83. ATCV-1 contains 329 putative protein-encoding and 11 tRNA-encoding genes. The protein-encoding genes are almost evenly distributed on both strands and intergenic space is minimal. Thirty-four percent of the viral gene products resemble entries in the public databases, including some that are unexpected for a virus. For example, these unique gene products include ribonucleoside-triphosphate reductase, dTDP-d-glucose 4,6 dehydratase, potassium ion transporter, aquaglyceroporin, and mucin-desulfating sulfatase. Comparison of ATCV-1 protein-encoding genes with the prototype chlorella virus PBCV-1 indicates that about 80% of the ATCV-1 genes are present in PBCV-1.  相似文献   
105.
106.
107.
Primary objective : To determine the extent to which participation in a multidisciplinary rehabilitation programme and patient characteristics predict improvement in community integration following mild-to-moderate traumatic brain injury (TBI).

Research design : A non-randomized case-control study was conducted employing a pre-test-post-test multiple regression design.

Methods and procedures : Archival data for 42 patients with mild-to-moderate TBI who completed the Community Integration Questionnaire (CIQ) at intake and again 6-18 months later were analysed. Half the sample participated in an intensive outpatient rehabilitation programme that provided multi-modal interventions, while the other half received no rehabilitation. The two groups were matched on age, education and time since injury.

Results : On the CIQ Home Integration scale, participation in rehabilitation and female gender predicted better outcome. On the Productivity scale, patients with a lower age at injury had better outcome. Outcome on both of these scales, as well as on the Social Integration scale, was predicted by the baseline pre-test score (initial severity).

Conclusions : Overall, multidisciplinary rehabilitation appeared to increase personal independence. It is also concluded that: (1) multivariate analysis can reveal the relative importance of multiple predictors of outcome; (2) different predictors may predict different aspects of outcome; and (3) more sensitive and specific outcome measures are needed.  相似文献   
108.
109.
110.
Santana RB  Xu L  Chase HB  Amar S  Graves DT  Trackman PC 《Diabetes》2003,52(6):1502-1510
The effect of type 1 diabetes on bone healing and bone formation in standardized craniotomy defects created in BALB/cByJ mice was determined. The hypothesis that advanced glycation end products (AGEs) contribute to diminished bone healing in diabetes was evaluated by assessing for the presence of the receptor for advanced glycation end products (RAGE) by immunohistochemistry in healing craniotomy defects in diabetic animals. The effect of local application of a known RAGE protein ligand, N(epsilon)-(carboxymethyl)lysine (CML)-mouse serum albumin (MSA), on craniotomy defect healing in normal animals was then assessed and compared to the effects of control MSA. Finally, evidence in support of the expression of RAGE mRNA and protein in osteoblastic cells was obtained. The results indicated that craniotomy defects in diabetic animals healed approximately 40% of the degree to which they healed in nondiabetic animals (P < 0.05). RAGE was expressed at higher levels in healing bone tissues in diabetic compared to control animals. Further studies in nondiabetic animals indicated that bone healing was reduced by 63 and 42% in lesions treated with 900 and 90 micro g CML-MSA, respectively, compared to in animals treated with MSA alone (P < 0.05). Evidence for the expression of RAGE was obtained in mouse and rat osteoblastic cultures. These results support the contribution of AGEs to diminished bone healing in type 1 diabetes, possibly mediated by RAGE.  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