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   1795篇
  免费   190篇
  国内免费   2篇
耳鼻咽喉   17篇
儿科学   73篇
妇产科学   54篇
基础医学   254篇
口腔科学   18篇
临床医学   207篇
内科学   312篇
皮肤病学   11篇
神经病学   229篇
特种医学   96篇
外科学   231篇
综合类   33篇
预防医学   258篇
眼科学   20篇
药学   103篇
中国医学   2篇
肿瘤学   69篇
  2023年   14篇
  2021年   22篇
  2020年   17篇
  2019年   16篇
  2018年   27篇
  2017年   28篇
  2016年   24篇
  2015年   27篇
  2014年   43篇
  2013年   69篇
  2012年   60篇
  2011年   72篇
  2010年   43篇
  2009年   54篇
  2008年   58篇
  2007年   64篇
  2006年   50篇
  2005年   65篇
  2004年   56篇
  2003年   63篇
  2002年   50篇
  2001年   58篇
  2000年   62篇
  1999年   59篇
  1998年   30篇
  1997年   28篇
  1996年   33篇
  1995年   20篇
  1994年   21篇
  1993年   16篇
  1992年   30篇
  1991年   49篇
  1990年   43篇
  1989年   51篇
  1988年   44篇
  1987年   32篇
  1986年   45篇
  1985年   39篇
  1984年   28篇
  1983年   27篇
  1982年   28篇
  1980年   19篇
  1979年   25篇
  1978年   21篇
  1977年   15篇
  1976年   13篇
  1974年   17篇
  1973年   23篇
  1972年   18篇
  1971年   12篇
排序方式: 共有1987条查询结果,搜索用时 15 毫秒
71.

Objective

The role of anxiety in the use of urgent care in people with long term conditions is not fully understood. A systematic review was conducted with meta-analysis to examine the relationship between anxiety and future use of urgent healthcare among individuals with one of four long term conditions: diabetes; coronary heart disease, chronic obstructive pulmonary disease and asthma.

Methods

Electronic searches of MEDLINE, EMBASE, PSYCINFO, CINAHL, the British Nursing Library and the Cochrane Library were conducted These searches were supplemented by hand-searching bibliographies, citation tracing eligible studies and asking experts within the field about relevant studies. Studies were eligible for inclusion if they: a) used a standardised measure of anxiety, b) used prospective cohort design, c) included adult patients diagnosed with coronary heart disease (CHD), asthma, diabetes or chronic obstructive pulmonary disease (COPD), d) assessed urgent healthcare use prospectively. Data regarding participants, methodology, and association between anxiety and urgent care use was extracted from studies eligible for inclusion. Odds ratios were calculated for each study and pooled using random effects models.

Results

8 independent studies were identified for inclusion in the meta-analysis, with a total of 28,823 individual patients. Pooled effects indicate that anxiety is not associated with an increase in the use of urgent care (OR = 1.078, p = 0.476), regardless of the type of service, or type of medical condition.

Conclusions

Anxiety is not associated with increased use of urgent care. This finding is in contrast to similar studies which have investigated the role of depression as a risk factor for use of urgent care.  相似文献   
72.
73.
牛津膝置换是使用最广泛的膝关节单髁置换(UKR)。牛津膝在37年前开始应用,拥有一个全匹配的活动衬垫,因而磨损率非常低。牛津膝最主要的使用指征是膝关节前内侧骨关节炎,这种病人至少占所有需要行膝关节置换术患者的50%。由于这一系统的设计特点,传统UKR的反指征,如年龄、活动量、肥胖、髌股关节损害和软骨钙质沉着症等对于牛津膝均不是反指征。与全膝关节置换(TKR)相比,牛津膝提供更快的康复、更好的功能、更大的活动度和更好的术后满意度,发生并发症更少、程度更轻,病残率和死亡率更低。一个持续超过30年的研究显示在90%的病例中,牛津膝为患者终生提供了优或良的临床结果,且不需要翻修。在最近15年,牛津膝通过微创手术入路植入,涉及6000多例使用该入路牛津膝置换的9个研究报道显示,10年生存率约95%。在许多这样的研究中,医生们在拟行膝关节置换的患者中约50%使用了牛津单髁膝置换。  相似文献   
74.
Journal of Autism and Developmental Disorders - Siblings describe positive and negative aspects of autism and often assume lifelong support roles. Less is known about cultural influences on sibling...  相似文献   
75.
76.
This study tested the proposal that negative appraisals represent a risk factor for developing posttraumatic stress disorder (PTSD) after trauma. Trainee firefighters (N = 68) were assessed during training (before trauma exposure) for PTSD, history of traumatic events, and tendency to engage in negative appraisals. Firefighters were reassessed 4 years later (N = 52), after commencing firefighter duty (after trauma exposure), for PTSD and depression using the Posttraumatic Stress Disorder Scale (E. B. Foa, L. Cashman, L. Jaycox, & K. Perry, 1997) and the Beck Depression Inventory (Version 2; A. T. Beck, R. A. Steer, & G. K. Brown, 1996). At follow-up, 12% met criteria for PTSD. Pretrauma negative appraisals about oneself accounted for 20% of variance in PTSD severity at follow-up. These data provide the first evidence that preexisting negative appraisals are a risk factor for PTSD.  相似文献   
77.
deShazo  RD; Daul  CB; Andes  WA; Bozelka  BE 《Blood》1985,66(4):993-998
Over an average span of one year, we performed a prospective clinical and immunologic evaluation of 30 patients with hemophilia. No patient developed life-threatening opportunistic infection or malignancy; however, the immunologic abnormalities and lymphadenopathy initially present in nine patients (lymphadenopathy group) persisted. In addition, five patients, representing 24% of the initial group without lymphadenopathy, developed generalized lymphadenopathy (converter group). One episode of idiopathic thrombocytopenia (ITP) and one episode of staphylococcal sepsis occurred in this "converter" group; one episode of ITP also occurred in the lymphadenopathy group. Sixteen patients remained asymptomatic. At the time of the follow-up evaluation, those differences in mononuclear cell (MNC) percentages and numbers noted initially among the three hemophiliac groups were no longer present. Natural killer cell function alone or in the presence of biologic response modifiers was not different among hemophiliac and control groups. Before developing lymphadenopathy, the converter group of patients had significantly better lymphocyte mitogenic function than did the other two groups of patients with hemophilia. However, lymphocyte mitogenic responses of all groups of patients with hemophilia significantly deteriorated over the course of the study. The abnormal mitogenic responses noted in these patients was explained in part by higher levels of spontaneous suppressor cell activity in mononuclear cell preparations from patients with hemophilia. We conclude that long-term immunologic studies of this patient population requires both quantitative and qualitative evaluations. Our data show that patients with hemophilia have progressive dysfunction of cell- mediated immunity.  相似文献   
78.
The synthetic peptides DP-107 and DP-178 (T-20), derived from separate domains within the human immunodeficiency virus type 1 (HIV-1) transmembrane (TM) protein, gp4l, are stable and potent inhibitors of HIV-1 infection and fusion. Using a computer searching strategy (computerized antiviral searching technology, C.A.S.T.) based on the predicted secondary structure of DP-107 and DP-178 (T-20), we have identified conserved heptad repeat domains analogous to the DP-107 and DP-178 regions of HIV-1 gp41 within the glycoproteins of other fusogenic viruses. Here we report on antiviral peptides derived from three representative paramyxoviruses, respiratory syncytial virus (RSV), human parainfluenza virus type 3 (HPIV-3), and measles virus (MV). We screened crude preparations of synthetic 35-residue peptides, scanning the DP-178-like domains, in antiviral assays. Peptide preparations demonstrating antiviral activity were purified and tested for their ability to block syncytium formation. Representative DP-178-like peptides from each paramyxovirus blocked homologous virus-mediated syncytium formation and exhibited EC50 values in the range 0.015-0.250 microM. Moreover, these peptides were highly selective for the virus of origin. Identification of biologically active peptides derived from domains within paramyxovirus F1 proteins analogous to the DP-178 domain of HIV-1 gp4l is compelling evidence for equivalent structural and functional features between retroviral and paramyxoviral fusion proteins. These antiviral peptides provide a novel approach to the development of targeted therapies for paramyxovirus infections.  相似文献   
79.
Syngeneic graft-versus-host disease (sGVHD) has been described after hematopoietic cell transplantation (HCT) but remains poorly defined. We retrospectively reviewed adult syngeneic HCTs at our center (1980-2002) for sGVHD to investigate incidence, morbidity, and risk factors with a primary focus on parity. Among 119 transplantations, there were 21 cases of biopsy-proven sGVHD. The cumulative incidence was 18%, with multiorgan involvement in 6 cases and 1 death. sGVHD was more frequent when the donor was parous (32%) than nulliparous (9%) or male (13%; P = .03) and when the recipient was parous (31%) than nulliparous (7%) or male (13%; P = .02). Other univariable risk factors included older age (P < .01), busulfan/melphalan/thiotepa conditioning (P < .01), interleukin-2 (P = .02), HLA-A26 (P = .03), and more recent transplantation year (P < .01). Overall, risk factors were similar to those described in GVHD. Although an independent effect of parity could not be completely separated from other factors, donor and recipient pregnancy history merits further investigation.   相似文献   
80.
Asians and Pacific Islanders (API) are among the fastest growing minority groups within the USA, and this growth has been accompanied by an increase in HIV incidence. Between 2000 and 2010, the API HIV infection rate increased from 4.5% to 8.7%; however, there is a paucity of HIV-related research for this group, and even less is known about the prevalence and correlates of antiretroviral therapy adherence behavior, quality of life, impact of stress, and efficacious self-management among HIV+ API Americans. This paper examines how acculturation and perceived stress affect depression symptomatology and treatment seeking in the HIV+ API population. A series of cross-sectional audio computer-assisted self-interviews were conducted with a convenience sample of 50 HIV+ API (29 in San Francisco and 21 in New York City). The relationship between acculturation and perceived stress was analyzed, and the results indicate that for those HIV+ API who reported low or moderate acculturation (as compared to those who reported high acculturation), stress was significantly mediated by depression symptomology. Interventions to address acculturation and reduce perceived stress among API generally and Asians specifically are therefore needed.  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