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   6753篇
  免费   408篇
  国内免费   11篇
耳鼻咽喉   45篇
儿科学   263篇
妇产科学   135篇
基础医学   741篇
口腔科学   107篇
临床医学   1461篇
内科学   1131篇
皮肤病学   61篇
神经病学   515篇
特种医学   119篇
外科学   561篇
综合类   76篇
一般理论   9篇
预防医学   872篇
眼科学   83篇
药学   346篇
中国医学   1篇
肿瘤学   646篇
  2024年   5篇
  2023年   36篇
  2022年   60篇
  2021年   119篇
  2020年   77篇
  2019年   90篇
  2018年   144篇
  2017年   107篇
  2016年   120篇
  2015年   131篇
  2014年   223篇
  2013年   321篇
  2012年   480篇
  2011年   568篇
  2010年   298篇
  2009年   263篇
  2008年   485篇
  2007年   560篇
  2006年   518篇
  2005年   534篇
  2004年   495篇
  2003年   453篇
  2002年   462篇
  2001年   42篇
  2000年   28篇
  1999年   62篇
  1998年   56篇
  1997年   55篇
  1996年   49篇
  1995年   41篇
  1994年   44篇
  1993年   29篇
  1992年   28篇
  1991年   24篇
  1990年   15篇
  1989年   12篇
  1988年   9篇
  1987年   13篇
  1986年   8篇
  1985年   10篇
  1984年   21篇
  1983年   11篇
  1982年   18篇
  1981年   11篇
  1980年   20篇
  1979年   2篇
  1978年   3篇
  1976年   2篇
  1975年   4篇
  1930年   2篇
排序方式: 共有7172条查询结果,搜索用时 12 毫秒
101.
102.
103.
104.
We report clinical findings that extend the phenotype of the ∼550 kb 16p11.2 microdeletion syndrome to include a rare, severe, and persistent pediatric speech sound disorder termed Childhood Apraxia of Speech (CAS). CAS is the speech disorder identified in a multigenerational pedigree (‘KE'') in which half of the members have a mutation in FOXP2 that co-segregates with CAS, oromotor apraxia, and low scores on a nonword repetition task. Each of the two patients in the current report completed a 2-h assessment protocol that provided information on their cognitive, language, speech, oral mechanism, motor, and developmental histories and performance. Their histories and standard scores on perceptual and acoustic speech tasks met clinical and research criteria for CAS. Array comparative genomic hybridization analyses identified deletions at chromosome 16p11.2 in each patient. These are the first reported cases with well-characterized CAS in the 16p11.2 syndrome literature and the first report of this microdeletion in CAS genetics research. We discuss implications of findings for issues in both literatures.  相似文献   
105.
Background  Personal health records (PHR) provide opportunities for improved patient engagement, collection of patient-generated data, and overcome health-system inefficiencies. While PHR use is increasing, uptake in rural populations is lower than in urban areas. Objectives  The study aimed to identify priorities for PHR functionality and gain insights into meaning, value, and use of patient-generated data for rural primary care providers. Methods  We performed PHR preimplementation focus groups with rural providers and their health care teams from five primary care clinics in a sparsely populated mountainous region of British Columbia, Canada to obtain their understanding of PHR functionality, needs, and perceived challenges. Results  Eight general practitioners (GP), five medical office assistants, two nurse practitioners (NP), and two registered nurses (14 females and 3 males) participated in focus groups held at their respective clinics. Providers (GPs, NPs, and RNs) had been practicing for a median of 9.5 (range = 1–38) years and had used an electronic medical record for 7.0 (1–20) years. Participants expressed interest in incorporating functionality around two-way communication and appointment scheduling, previsit data gathering, patient and provider data sharing, virtual care including visits using videoconferencing tools, and postvisit sharing of educational materials. Three further themes emerged from the focus groups: (1) the context in which the providers'' practice matters, (2) the need for providing patients and providers with choice (e.g., which data to share, who gets to initiate/respond in communications, and processes around virtual care visits), and (3) perceived risks of system use (e.g., increased complexity for older patients and workload barriers for the health care team). Conclusion  Rural primary care teams perceived PHR opportunities for increased patient engagement and access to patient-generated data, while worries about changes in workflow were the biggest perceived risk. Recommendations for PHR adoption in a rural primary health network include setting provider-patient expectations about response times, ability to share notes selectively, and automatically augmented note-taking from virtual-care visits.  相似文献   
106.
107.
BACKGROUND: While several studies have reported on sexual risk behaviours and the prevalence of sexually transmitted infections (STIs) among injection drug users (IDUs), there are fewer prospective studies that have been able to examine populations of IDUs with no history of STIs. Therefore, the authors examined prevalence, correlates and factors associated with time to first STI infection in a prospective cohort of IDUs in Vancouver, British Columbia. METHODS: The authors examined the prevalence and correlates of STIs among IDUs at the time of recruitment into a prospective cohort study. The authors also evaluated the cumulative rate of time to first STI among IDUs with no history of STIs at baseline using the Kaplan-Meier method, and modelled factors independently associated with first STI using Cox regression. RESULTS: Between May 1996 and November 2003, 1560 individuals were recruited into the cohort; of these individuals, 745 reported a history of STI at baseline. Among the 815 who did not report an STI at baseline, 671 (82%) had at least one follow-up visit and were eligible for the analysis of time to first STI. After 36 months of follow-up, the cumulative rate of first STI was 8.2% for men and 15.9% for women (log-rank P<0.001), whereas the cumulative rate of first STI was 8.0% for IDUs who did not report sex trade involvement versus 19.8% for IDUs who reported sex trade involvement (log-rank P<0.001). In multivariate analyses, the risk of first STI remained independently associated with unprotected sex with regular partners (relative hazard=2.04, 95% CI 1.29 to 3.23; P=0.001) and unprotected sex with sex trade clients (relative hazard=2.36, 95% CI 1.46 to 3.82; P=0.005). CONCLUSIONS: In the present study, the authors found that STIs were associated with both regular sex partnerships and sex trade involvement. These findings are of particular concern because both unprotected sex with regular partners and sex trade involvement is common among IDUs. Interventions to encourage condom use among IDUs, particularly those with regular sex partners and those involved in the sex trade, should be further developed.  相似文献   
108.
109.
Cryptococcal antigen screening is recommended among people living with AIDS when entering HIV care with a CD4 count of <100 cells/μl, and preemptive fluconazole monotherapy treatment is recommended for those with subclinical cryptococcal antigenemia. Yet, knowledge is limited of current antimicrobial resistance in Africa. We examined antifungal drug susceptibility in 198 clinical isolates collected from Kampala, Uganda, between 2010 and 2014 using the CLSI broth microdilution assay. In comparison with two previous studies from 1998 to 1999 that reported an MIC50 of 4 μg/ml and an MIC90 of 8 μg/ml prior to widespread human fluconazole and agricultural azole fungicide usage, we report an upward shift in the fluconazole MIC50 to 8 μg/ml and an MIC90 value of 32 μg/ml, with 31% of isolates with a fluconazole MIC of ≥16 μg/ml. We observed an amphotericin B MIC50 of 0.5 μg/ml and an MIC90 of 1 μg/ml, of which 99.5% of isolates (197 of 198 isolates) were still susceptible. No correlation between MIC and clinical outcome was observed in the context of amphotericin B and fluconazole combination induction therapy. We also analyzed Cryptococcus susceptibility to sertraline, with an MIC50 of 4 μg/ml, suggesting that sertraline is a promising oral, low-cost, available, novel medication and a possible alternative to fluconazole. Although the CLSI broth microdilution assay is ideal to standardize results, limit human bias, and increase assay capacity, such assays are often inaccessible in low-income countries. Thus, we also developed and validated an assay that could easily be implemented in a resource-limited setting, with similar susceptibility results (P = 0.52).  相似文献   
110.
Myeloproliferative neoplasms (MPNs) are characterized by the clonal expansion of one or more myeloid cell lineage. In most cases, proliferation of the malignant clone is ascribed to defined genetic alterations. MPNs are also associated with aberrant expression and activity of multiple cytokines; however, the mechanisms by which these cytokines contribute to disease pathogenesis are poorly understood. Here, we reveal a non-redundant role for steady-state IL-33 in supporting dysregulated myelopoiesis in a murine model of MPN. Genetic ablation of the IL-33 signaling pathway was sufficient and necessary to restore normal hematopoiesis and abrogate MPN-like disease in animals lacking the inositol phosphatase SHIP. Stromal cell–derived IL-33 stimulated the secretion of cytokines and growth factors by myeloid and non-hematopoietic cells of the BM, resulting in myeloproliferation in SHIP-deficient animals. Additionally, in the transgenic JAK2V617F model, the onset of MPN was delayed in animals lacking IL-33 in radio-resistant cells. In human BM, we detected increased numbers of IL-33–expressing cells, specifically in biopsies from MPN patients. Exogenous IL-33 promoted cytokine production and colony formation by primary CD34+ MPN stem/progenitor cells from patients. Moreover, IL-33 improved the survival of JAK2V617F-positive cell lines. Together, these data indicate a central role for IL-33 signaling in the pathogenesis of MPNs.  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