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   2106篇
  免费   115篇
  国内免费   18篇
耳鼻咽喉   23篇
儿科学   103篇
妇产科学   23篇
基础医学   225篇
口腔科学   57篇
临床医学   167篇
内科学   531篇
皮肤病学   89篇
神经病学   111篇
特种医学   268篇
外科学   185篇
综合类   64篇
预防医学   173篇
眼科学   36篇
药学   111篇
中国医学   9篇
肿瘤学   64篇
  2023年   3篇
  2022年   21篇
  2021年   36篇
  2020年   38篇
  2019年   34篇
  2018年   51篇
  2017年   29篇
  2016年   25篇
  2015年   49篇
  2014年   81篇
  2013年   114篇
  2012年   107篇
  2011年   109篇
  2010年   87篇
  2009年   84篇
  2008年   96篇
  2007年   101篇
  2006年   80篇
  2005年   82篇
  2004年   56篇
  2003年   44篇
  2002年   59篇
  2001年   34篇
  2000年   37篇
  1999年   38篇
  1998年   84篇
  1997年   60篇
  1996年   71篇
  1995年   45篇
  1994年   54篇
  1993年   47篇
  1992年   19篇
  1991年   20篇
  1990年   17篇
  1989年   48篇
  1988年   33篇
  1987年   33篇
  1986年   24篇
  1985年   18篇
  1984年   22篇
  1983年   16篇
  1982年   14篇
  1981年   23篇
  1980年   14篇
  1979年   12篇
  1978年   12篇
  1977年   16篇
  1976年   9篇
  1975年   12篇
  1968年   5篇
排序方式: 共有2239条查询结果,搜索用时 15 毫秒
71.
We evaluated the influence of allelic frequency of the human leukocyte antigen (HLA) -DRB1 on the acquisition of antibody response against malaria sporozoite and merozoite peptides in patients with Plasmodium vivax malaria acquired in endemic areas of Brazil. IgG antibodies were detected by enzyme-linked immunosorbent assay against four peptides of circumsporozoite protein (CSP) (amino, carboxyl, and VK210 and VK247 repeats) and peptides of merozoite surface protein 1 (MSP-1), apical membrane antigen 1 (AMA-1), and Duffy-binding protein (DBP). We found an association between HLA-DR3 and HLA-DR5 alleles and lack of antibody response to CSP amino terminal, as well as an association between HLA-DR3 and the highest antibody response to MSP1 (Pv200L). In conclusion, we suggest a potential regulatory role of the HLA-DRB1 alleles in the production of antibodies to a conserved region of P. vivax CSP and MSP1 in Brazilian population exposed to malaria.  相似文献   
72.
The Wiskott-Aldrich syndrome protein (WASP) is a key cytoskeletal regulator of hematopoietic cells. Although WASP-knockout (WKO) mice have aberrant B-cell cytoskeletal responses, B-cell development is relatively normal. We hypothesized that N-WASP, a ubiquitously expressed homolog of WASP, may serve some redundant functions with WASP in B cells. In the present study, we generated mice lacking WASP and N-WASP in B cells (conditional double knockout [cDKO] B cells) and show that cDKO mice had decreased numbers of follicular and marginal zone B cells in the spleen. Receptor-induced activation of cDKO B cells led to normal proliferation but a marked reduction of spreading compared with wild-type and WKO B cells. Whereas WKO B cells showed decreased migration in vitro and homing in vivo compared with wild-type cells, cDKO B cells showed an even more pronounced decrease in the migratory response in vivo. After injection of 2,4,6-trinitrophenol (TNP)-Ficoll, cDKO B cells had reduced antigen uptake in the splenic marginal zone. Despite high basal serum IgM, cDKO mice mounted a reduced immune response to the T cell-independent antigen TNP-Ficoll and to the T cell-dependent antigen TNP-keyhole limpet hemocyanin. Our results reveal that the combined activity of WASP and N-WASP is required for peripheral B-cell development and function.  相似文献   
73.
The last decades of life have been traditionally viewed as a time of inevitable disease and frailty. Sedentary living and physical activity may influence capacity to perform activities that are needed to maintain physical independence in daily living. A total of 117 males and 195 females, aged 65–103 years, were assessed for physical activity and sedentary time with accelerometers and for functional fitness with the Senior Fitness Test battery. Based on the individual scores for each fitness item, a Z-score was created. Associations between functional fitness with sedentary time and moderate-to-vigorous physical activity (MVPA) were analyzed. A negative association was found between the composite Z-score for functional fitness and the sedentary time, even adjusting for MVPA and other confounders. On the other hand, MVPA was positively associated with the composite Z-score for functional fitness, independently of the sedentary time. In conclusion elderly who spend more time in physical activity or less time in sedentary behaviors exhibit improved functional fitness and other confounders. The results reinforce the importance of promoting both the reduction of sedentary behaviors and the increase of MVPA in this age group, as it may interfere at older ages in order to preserve functional fitness and performance of daily functioning tasks.  相似文献   
74.
Owing to the disparity between the supply of kidney donors and demand, the use of organs from older deceased donors was initiated in recent years. The potentially poor outcome of these grafts is a major concern. This retrospective study compares graft and patient 1-year survivals between recipients from expanded-criteria donors (ECD; n = 30) and standard-criteria donors (SCD; n = 104). Rates of delayed graft function (DGF), acute rejection (AR), and chronic injury in the pre-implantation biopsy were also assessed. Increasing donor age was associated with increased rates of DGF, and DGF correlated with AR. Cold ischemia time >30 hours was associated with worse graft outcomes. Induction with Simulect correlated with better patient survival compared with Timoglobulina. Chronic injury pre-implantation biopsy correlated with worse renal function, but graft survival was similar. Death-censored graft survival at 1 year was 90% and patient survival 82%, and these were similar in ECD and SCD recipients. Selection of transplant candidates for ECD kidneys must be performed with caution. One-year graft survival was similar to that of SCD kidneys, but kidney function was worse during the same period. This may result in poorer graft survival over longer follow-up.  相似文献   
75.
76.
目的探讨金属对金属(金对金)大头径假体微创全髋关节置换术(THA)治疗青中年股骨头坏死Ⅲ、Ⅳ期的临床疗效。方法本组32例(35髋)青中年股骨头缺血性坏死Ⅲ、Ⅳ期患者,年龄24~59岁,平均45岁,术前髋关节Harris评分平均(37.9±7.5)分;以改良后外侧小切口、肌间隙人路、充分保留关节动力性组织结构为特征的金对金大头径微创THA治疗。术中严格采取正确的假体植入技术,术中保留完整的软骨下骨和髋臼横韧带,击入臼杯时一次性安装成功,正确运用万古霉素预防感染。术后口服利伐沙班片抗凝,术后12h开放负压引流及卧床行功能锻炼,术后第2天拔除引流管后扶拐下地部分负重行走,术后2—3周患者即可弃拐完全负重行走。结果本组32例35髋患者均获随访,随访时间为12个月~6年,平均为4年。所有患者切口均一期愈合,无深静脉血栓形成、关节脱位、坐骨神经损伤、髋臼及股骨疲劳骨折、关节疼痛等严重并发症,X线片示髋关节假体位置均良好,无松动、移位、股骨柄下沉、假体周围骨折等表现。末次随访Harris评分由术前平均(37.9±7.5)分,提高至术后平均(92.2±4.6)分,前后比较有统计学意义(t=44.341,P〈0.05)。所有患者末次随访时髋关节功能明显优于术前,均对治疗效果满意,完全恢复正常生活及工作。结论采用金对金大头径微创THA治疗青中年股骨头坏死Ⅲ、Ⅳ期患者,能够明显降低手术风险,缩短卧床时问,迅速恢复髋关节功能,减少手术并发症,取得了满意的近期临床疗效。随着基础和临床研究的不断深入,金对金大头径髋关节假体的长期疗效还需要进一步探讨。  相似文献   
77.
目的提高对巨大前列腺囊腺瘤的认识。方法回顾性分析收治的1例巨大前列腺囊腺瘤并成功进行腹腔镜切除的临床资料,结合文献复习进行讨论。结果本例患者成功行腹腔镜完整切除,手术时间125min,出血量60ml,术中双侧精囊输精管完整保留,术后会阴部坠胀不适消失,复查精液常规精子数目及活动度正常。已随诊12个月,肿瘤无复发。结论巨大前列腺囊腺瘤罕见,最终确诊要依靠病理诊断,其最有效的治疗是手术完整切除,而腹腔镜途径可作为完整切除的微创手段。  相似文献   
78.
AIM:To examine surgical and medical outcomes for patients with cholangiocarcinoma using a populationbased cancer registry.METHODS:Using the California Cancer Registry’s Cancer Surveillance Program,patients with intrahepatic cholangiocarcinoma treated in Los Angeles County from 1988 to 2006 were identified and evaluated for clinical and pathologic factors and therapies received(surgery,radiation,and chemotherapy).The surgical cohort was further categorized into three treatment groups:patients who received adjuvant chemotherapy,adjuvant chemoradiation,or underwent surgery alone(no chemotherapy or radiation administered).Survival was assessed by Kaplan-Meier method;and Cox proportional hazard modeling was used in multivariate analysis.RESULTS:Of 825 patients,60.2% received no treatment.Of the remaining 328 patients,18.5% chemotherapy only,7.4% chemoradiation,and 13.8% underwent surgery.More male patients underwent surgical resection(P = 0.004).Surgical patients were younger than the patients receiving chemotherapy or chemoradiation(P < 0.001).Of the surgical cohort(n = 114),60.5% underwent surgery alone while 39.5% underwent surgery plus adjuvant therapy(chemotherapy n = 20;chemoradiation,n = 21)(P < 0.001).Median survival for all patients in the study was 6.6 mo.Median survival was highest for patients who underwent surgery(23 mo),whereas both chemotherapy(9 mo) and chemoradiation(8 mo) alone were each less effective(P < 0.001).By multivariate analysis,extent of disease,receipt of surgery,and administration of chemotherapy(with/without surgery) were independent predictors of overall survival.CONCLUSION:This study demonstrates that surgery is a critical treatment modality.Multimodality treatment has yet to be standardized,but play a role in optimal therapy for cholangiocarcinoma.  相似文献   
79.
80.
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