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   1866篇
  免费   185篇
  国内免费   10篇
耳鼻咽喉   20篇
儿科学   114篇
妇产科学   16篇
基础医学   251篇
口腔科学   69篇
临床医学   230篇
内科学   363篇
皮肤病学   40篇
神经病学   164篇
特种医学   210篇
外科学   237篇
综合类   24篇
一般理论   1篇
预防医学   114篇
眼科学   42篇
药学   96篇
中国医学   1篇
肿瘤学   69篇
  2023年   13篇
  2022年   13篇
  2021年   31篇
  2020年   27篇
  2019年   39篇
  2018年   43篇
  2017年   28篇
  2016年   50篇
  2015年   35篇
  2014年   62篇
  2013年   80篇
  2012年   110篇
  2011年   115篇
  2010年   62篇
  2009年   52篇
  2008年   96篇
  2007年   107篇
  2006年   71篇
  2005年   71篇
  2004年   65篇
  2003年   67篇
  2002年   59篇
  2001年   54篇
  2000年   41篇
  1999年   53篇
  1998年   27篇
  1997年   44篇
  1996年   20篇
  1995年   39篇
  1994年   30篇
  1993年   14篇
  1992年   34篇
  1991年   28篇
  1990年   24篇
  1989年   39篇
  1988年   41篇
  1987年   38篇
  1986年   28篇
  1985年   23篇
  1984年   14篇
  1983年   10篇
  1982年   12篇
  1981年   12篇
  1980年   16篇
  1979年   16篇
  1978年   15篇
  1977年   19篇
  1975年   10篇
  1971年   14篇
  1967年   9篇
排序方式: 共有2061条查询结果,搜索用时 15 毫秒
1.
Marijuana, and specifically its psychoactive component, THC, can up or down regulate lymphocyte proliferation in murine spleen cells depending in part on the method used to stimulate the cells. This study identifies a difference in THC induced disregulation using cells derived from two different secondary lymphoid organs, the spleen and the lymph node. It was found that THC treatment of mitogen (concanavalin A or phytohemagglutinin) stimulated cells derived from either organ resulted in suppression of the proliferative response. In contrast, spleen cells stimulated with anti-CD3 antibody and treated with low doses of THC displayed an enhanced proliferation whereas the response in lymph nodes did not change. The cell type involved with this THC immunoenhancement in spleen cells was found to be the Ly2 cell. Further differences in the THC modulation of Ly2 spleen cells as compared to lymph node cells were noted following stimulation with PHA. Proliferation of Ly2 cells of splenic origin was inhibited with low doses of THC whereas the Ly2 cells of lymph node origin were more resistant to this drug induced suppression. This study, therefore, demonstrates differences in the immunomodulatory capability of THC dependent upon the organ source of the lymphocytes.  相似文献   
2.
3.
4.
This study provides an overview of the papers emanating from the experimental trial that evaluated a new cognitive rehabilitation program in older adults who were experiencing normal cognitive decline. The main features of the design are summarized, along with evidence that the training produced long-lasting improvement in memory performance, goal management, and psychosocial status. The benefits were attributed to several factors, including the program's emphasis on techniques that promoted efficient strategic processing. Limitations of the program and directions for future research are discussed.  相似文献   
5.
6.
OBJECTIVE: The authors reviewed renal transplant outcomes in recipients 60 years of age or older. BACKGROUND: Before cyclosporine, patients older than 45 years of age were considered to be at high risk for transplantation. With cyclosporine, the age limits for transplantation have expanded. METHODS: The authors compared patient and graft survival, hospital stay, the incidence of rejection and rehospitalization, and the cause of graft loss for primary kidney recipients 60 years of age or older versus those 18 to 59 years of age. For those patients > or = 60 years transplanted since 1985, the authors analyzed pretransplant extrarenal disease and its impact on post-transplant outcome. In addition, all surviving recipients > or = 60 years completed a medical outcome survey (SF-36). RESULTS: Patient and graft survival for those > or = 60 years of age versus those 18 to 59 years of age were similar 3 years after transplant. Subsequently, mortality increased for the older recipients. Death-censored graft survival was identical in the two groups. There were no differences in the cause of graft loss. Those 60 years of age or older had a longer initial hospitalization, but had fewer rejection episodes and fewer rehospitalizations. Quality of life for recipients 60 years of age or older was similar to the age-matched U.S. population. CONCLUSION: Renal transplantation is successful for recipients 60 years of age or older. Most of them had extrarenal disease at the time of transplantation; however, extrarenal disease was not an important predictor of outcome and should not be used as an exclusion criterion. Post-transplant quality of life is excellent.  相似文献   
7.
OBJECTIVE: The aim of this study was to assess the relationships between specific personality disorders and DSM-III axis I conditions in a community sample. METHOD: A total of 810 subjects were examined by psychiatrists in the second stage of the Eastern Baltimore Mental Health Survey, part of the Epidemiological Catchment Area Program of the National Institute of Mental Health. A semistructured examination, the Standardized Psychiatric Examination, was employed to assess axis I and axis II conditions. Scales for compulsive and antisocial personality disorders were derived from DSM-III criteria. The relationships between scores on these personality disorder scales and the presence of generalized anxiety disorder, alcohol use disorders (alcohol abuse and alcohol dependence), and simple phobia were evaluated by using logistic regression. RESULTS: Higher compulsive personality scores were associated with a greater odds of generalized anxiety disorder and simple phobia but a smaller odds of alcohol use disorders. In contrast, higher antisocial personality scores were associated with a greater odds of alcohol use disorders but a smaller odds of generalized anxiety disorder. There was no relationship between antisocial personality scores and simple phobia. CONCLUSIONS: Personality disorders have specific relationships to axis I conditions, which suggests different vulnerabilities but also different protective influences.  相似文献   
8.
In the last years, granulocyte and granulocyte-macrophage colony-stimulating factors (G-CSF and GM-CSF) are being increasingly used and several cutaneous eruptions have been reported in relation to these treatments. In 1991 Horn et al. described three patients with maculopapular eruption that paralleled the time of infusion of GM-CSF. Two of the cases showed an increase in the number and size of macrophages in the biopsy specimen. Since then, several cases have been reported showing this histopathological alteration that has been considered characteristic of reaction to G-CSF or GM-CSF. Although maculopapular eruption with enlarged macrophages can appear after chemotherapy treatment, we have found that the presentation of this eruption after the beginning of cytokine treatment is suggestive of the involvement of G-CSF and GM-CSF in the eruption. We described eight cases of patients treated with G-CSF or GM-CSF that developed maculopapular eruptions with enlarged macrophages.  相似文献   
9.
Irradiation of rabbit retina with diode and Nd:YAG lasers.   总被引:2,自引:0,他引:2       下载免费PDF全文
AIMS--This study was carried out to compare the effects of continuous wave infrared laser radiation on pigmented and albino rabbit retinas at two wavelengths: 810 nm (diode) and 1064 nm (Nd:YAG). METHODS--Transpupillary laser pulses were applied with a spot size of 200 microns and durations of 200 ms (pigmented rabbits) and 0.5-1 s (albino rabbits). Light and electron microscopic analyses were performed immediately after exposure. RESULTS--In pigmented rabbits, threshold lesions were induced using a power of 100 mW with the diode and 200 mW with the Nd:YAG lasers. Damage was incurred by the retinal pigment epithelium with extension into the superficial and mid choroid posteriorly and into the outer retina anteriorly. In albino rabbits, lesions of comparable anteroposterior extension were identified using a power of 10 W with the Nd:YAG laser. Using diode laser irradiation, a maximum power output of 1.2 W failed to produce discernible lesions. CONCLUSIONS--The observed patterns of morphological damage are produced by complex tissue radiation interactions. In pigmented animals, this was primarily related to absorption of radiant energy by melanin within the retinal pigment epithelium and the choroidal melanocytes. In albino rabbits, laser induced effects occurred as a consequence of multiple scattering, together with absorption within haemoglobin and possibly also within tissue water. The data obtained provide further insight into the biological mechanisms arising from retinal photocoagulation with near infrared lasers.  相似文献   
10.
Prednisone-Free Maintenance Immunosuppression—A 5-Year Experience   总被引:1,自引:0,他引:1  
Concern persists that prednisone-free maintenance immunosuppression in kidney transplant recipients will be associated with an increase in late allograft dysfunction and graft loss. We herein report 5-year follow-up of a trial of prednisone-free maintenance immunosuppression. From October 1, 1999, through January 31, 2005, at our center, 589 kidney transplant recipients were treated with a protocol incorporating discontinuation of their prednisone on postoperative day 6. At 5 years, actuarial patient survival was 91%; graft survival, 84%; death-censored graft survival, 92%; acute rejection-free graft survival, 84% and chronic rejection-free graft survival, 87%. The mean serum creatinine level (+/-SD) at 1 year was 1.6 +/- 0.6; at 5 years, 1.7 +/- 0.8. In all, 86% of kidney recipients with functioning grafts remain prednisone-free as of April 30, 2005. As compared with historical controls, recipients on prednisone-free maintenance immunosuppression had a significantly lower rate of a number of complications, including cataracts (p < 0.001), posttransplant diabetes mellitus (p < 0.001), avascular necrosis (p = 0.001), and fractures (p = 0.004). We conclude that prednisone-related side effects can be minimized in a protocol incorporating prednisone-free maintenance immunosuppression. Five-year graft outcome remains good.  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