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   20296篇
  免费   1313篇
  国内免费   70篇
耳鼻咽喉   233篇
儿科学   733篇
妇产科学   580篇
基础医学   2368篇
口腔科学   249篇
临床医学   3511篇
内科学   3476篇
皮肤病学   201篇
神经病学   1945篇
特种医学   309篇
外科学   1594篇
综合类   198篇
一般理论   85篇
预防医学   3106篇
眼科学   710篇
药学   1017篇
中国医学   11篇
肿瘤学   1353篇
  2023年   81篇
  2022年   133篇
  2021年   292篇
  2020年   208篇
  2019年   357篇
  2018年   404篇
  2017年   313篇
  2016年   368篇
  2015年   447篇
  2014年   587篇
  2013年   1018篇
  2012年   1398篇
  2011年   1466篇
  2010年   806篇
  2009年   688篇
  2008年   1310篇
  2007年   1518篇
  2006年   1483篇
  2005年   1474篇
  2004年   1419篇
  2003年   1319篇
  2002年   1271篇
  2001年   175篇
  2000年   124篇
  1999年   200篇
  1998年   273篇
  1997年   222篇
  1996年   188篇
  1995年   162篇
  1994年   178篇
  1993年   147篇
  1992年   93篇
  1991年   105篇
  1990年   88篇
  1989年   79篇
  1988年   73篇
  1987年   73篇
  1986年   72篇
  1985年   72篇
  1984年   97篇
  1983年   99篇
  1982年   114篇
  1981年   123篇
  1980年   107篇
  1979年   64篇
  1978年   58篇
  1977年   56篇
  1976年   47篇
  1975年   44篇
  1973年   36篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
BACKGROUND: The incidence of adefovir dipivoxil (ADV) nephrotoxicity has been previously reported with the 60 and 120 mg daily dose in human immunodeficiency virus (HIV). We report a complete analysis on the renal tolerance of ADV at the currently approved dose of 10 mg daily for the treatment of chronic hepatitis B. METHODS: To investigate the efficacy, safety, and the tolerability of two dosing regimens of ADV (10 mg daily or 30 mg daily), two double-blind, placebo-controlled studies were performed in patients with chronic hepatitis B and compensated liver disease who were not undergoing current treatment and who had evidence of hepatitis B virus (HBV) replication. RESULTS: There was no overall median change from baseline at week 48 in serum creatinine or serum phosphorus levels in the ADV 10 mg group. In the ADV 30 mg group there was a slight increase of 0.2 mg/dL in median serum creatinine levels, and decrease of 0.1 mg/dL in serum phosphorus levels at week 48. Serum creatinine increase and hypophosphatemia were more frequently observed in patients receiving ADV 30 mg daily compared with ADV 10 mg and placebo. There were no grade 4 proteinuria, hematuria, or glycosuria events. CONCLUSION: Mild nephrotoxicity was demonstrated with the dose of 30 mg daily. Nephrotoxicity, as defined by an increase >/=0.5 mg/dL from baseline in serum creatinine or a serum phosphorus value of <1.5 mg/dL on two consecutive occasions, was not observed in patients treated with ADV 10 mg for a median follow-up period of approximately 64 weeks.  相似文献   
993.
994.
995.
BACKGROUND: Currently available clinical tools for assessing rehabilitation outcomes do not capture both the effort exerted and assistance required for persons with spinal cord injuries to perform a standing pivot transfer using functional electrical stimulation (FES). This study was undertaken to develop and apply a clinical tool to measure the ability to stand and transfer with electrical stimulation. METHODS: The Functional Performance Measure (FPM) methodology was chosen to develop a tool to measure performance. Through an iterative review of videotaped FES transfers, fundamental components of the standing pivot transfer were identified and standardized performance criteria for user effort and helper assistance were developed for every phase using the 8-point FPM scales. RESULTS: Interrater and intrarater reliability were established with a simple kappa coefficient for the effort scale and assistance scale. The final version of the tool has been applied to users of the implanted FES standing neuroprosthesis to describe the effort and assistance required for the transfer. CONCLUSION: The tool has been shown to capture the effort and assistance needed during FES-assisted standing pivot transfers throughout all phases of the transfer.  相似文献   
996.
BACKGROUND: Abnormalities in the structure and function of glomerular endothelial cells play a pivotal role in the development of progressive renal disease. The vascular abnormalities observed in the renal tubulointerstitium, however, correlate more strongly with progressive renal failure. Therefore, the successful isolation and culture of human renal microvascular endothelial cells from both the glomerulus and tubulointerstitium are paramount in studying renal disease models. METHODS AND RESULTS: This study describes a simple and reproducible method for the isolation of human tubulointerstitial and glomerular endothelial cells by using immunomagnetic separation with anti-platelet endothelial-cell adhesion (anti-PECAM-1) Dyna beads, followed by manual weeding of mesangial and fibroblast contamination. No significant changes in morphological or immunohistochemical characteristics were observed up to passage two of culture. The in vitro characteristics of the endothelial cells were compared to the renal cortical endothelial cells in vivo and the standard human umbilical vein endothelial cell model (HUVECs). Similar to HUVECs, both populations of renal microvascular endothelial cells had a classical cobblestone appearance, stained positively for von Willebrand Factor and PECAM-1 and negatively for antifibroblast surface antigen and anticytokeratin. Differences in the expression of von Willebrand Factor, Wiebel Palade bodies and Flk-1 staining were observed between glomerular and tubulointerstitial endothelial cells. These immunohistochemical characteristics suggested that tubulointerstital endothelial cells were more closely aligned to HUVECS than to the glomerular endothelial cells. This observation indicated that HUVECs may be a suitable model for determining the tubulointerstitial endothelial response to systemic injury. CONCLUSION: In conclusion, a unique and novel method for the differential isolation of both glomerular and tubulointerstitial endothelial cells has been developed. Significantly, characterization of these populations suggests a role for HUVECS in the study of renal tubulointerstitial disease.  相似文献   
997.
The Infevers database (http://fmf.igh.cnrs.fr/infevers/) was established in 2002 to provide investigators with access to a central source of information about all sequence variants associated with periodic fevers: Familial Mediterranean fever (FMF), TNF Receptor Associated Periodic Syndrome (TRAPS), Hyper IgD Syndrome (HIDS), Familial Cold Autoinflammatory Syndrome/Muckle-Wells Syndrome/Chronic Infantile Neurological Cutaneous and Articular Syndrome (FCAS/MWS/CINCA). The prototype of this group of disorders is FMF, a recessive disease characterized by recurrent bouts of unexplained inflammation. FMF is the pivotal member of an expanding family of autoinflammatory disorders, a new term coined to describe illnesses resulting from a defect of the innate immune response. Therefore, we decided to extend the Infevers database to genes connected with autoinflammatory diseases. We present here the biological content of the Infevers database, including the introduction of two new entries: Crohn/Blau and Pyogenic sterile arthritis, pyoderma gangrenosum and acne (PAPA syndrome). Infevers has a range of query capabilities, allowing for simple or complex interrogation of the database. Currently, the database contains 291 sequence variants in related genes (MEFV, TNFRSF1A, MVK, CARD15, PSTPIP1, and CIAS1), consisting of published data and personal communications, which has revealed or refined the preferential mutational sites for each gene. This database will continue to evolve in its content and to improve in its presentation.  相似文献   
998.
Orally based diagnostic testing is emerging as an alternative, noninvasive method for analyzing a variety of analytes. These analytes include pathogens, antibodies, drugs, and nucleic acids. In the present study we developed a protocol for evaluation of collectors that could be used in orally based, point-of-care diagnostics. A performance comparison was carried out with a number of commercially available collectors, and their ability to deliver fluid, proteins, bacteria, and nucleic acid from pathogens compatible with PCR was assessed. The collectors were all capable of picking up and delivering test materials, albeit at various levels.  相似文献   
999.
Most research on work-home conflict focuses solely on women. This study compares men and women’s perceptions of the extent to which paid work interferes with family life, and examines associations between work-home conflict and health. Data were collected from 2,176 full-time white-collar employees of a British bank. We did not find any significant gender differences in perceptions of work-home conflict. However, predictors of work-home conflict did vary by gender; having children and being in a senior position were more strongly related to work-home conflict for women than for men, while working unsociable hours was more important for men than for women. Work-home conflict was strongly associated with reporting fair or poor self-assessed health, a high number of reported physical symptoms and minor psychological morbidity (GHQ-12). These associations were equally strong for men and women. Our results suggest that work-home conflict is a problem for men as well as women.  相似文献   
1000.
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