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   2319篇
  免费   291篇
  国内免费   22篇
耳鼻咽喉   15篇
儿科学   77篇
妇产科学   40篇
基础医学   157篇
口腔科学   75篇
临床医学   319篇
内科学   613篇
皮肤病学   44篇
神经病学   169篇
特种医学   316篇
外科学   244篇
综合类   20篇
预防医学   312篇
眼科学   25篇
药学   61篇
中国医学   1篇
肿瘤学   144篇
  2023年   48篇
  2022年   16篇
  2021年   18篇
  2020年   45篇
  2019年   27篇
  2018年   61篇
  2017年   46篇
  2016年   61篇
  2015年   66篇
  2014年   116篇
  2013年   147篇
  2012年   75篇
  2011年   79篇
  2010年   88篇
  2009年   103篇
  2008年   77篇
  2007年   105篇
  2006年   83篇
  2005年   57篇
  2004年   64篇
  2003年   35篇
  2002年   48篇
  2001年   57篇
  2000年   36篇
  1999年   52篇
  1998年   71篇
  1997年   94篇
  1996年   87篇
  1995年   61篇
  1994年   67篇
  1993年   54篇
  1992年   31篇
  1991年   17篇
  1990年   42篇
  1989年   45篇
  1988年   38篇
  1987年   42篇
  1986年   38篇
  1985年   47篇
  1984年   19篇
  1983年   22篇
  1982年   31篇
  1981年   34篇
  1980年   20篇
  1979年   20篇
  1977年   20篇
  1976年   20篇
  1975年   15篇
  1973年   11篇
  1966年   10篇
排序方式: 共有2632条查询结果,搜索用时 15 毫秒
11.
12.
13.
BACKGROUND. This study was designed to determine the variability in the consultation practices of family physicians and family nurse practitioners in an urban group practice, and to examine the relation between the referring practitioner's diagnostic certainty at the time of the consultation request, the specificity of the request to the consultant, and the frequency with which the practitioner ordered consultations in that specialty. METHODS. This study examined consultations requested by six family physicians and two family nurse practitioners that were directed to nine medical and surgical specialties in connection with 35,218 family practice visits made over a 19-month period in an urban family practice. Requests for consultation were scored based on the level of certainty of the referring practitioner's diagnosis at the time of consultation and the specificity of the consultation request. RESULTS. There was nearly a fivefold variation in the overall specialty consultation rates among providers, with even greater variation in each individual specialty area studied. Referral rate correlated positively with certainty of diagnosis (r = .40). There was no consistent relation between request specificity and referral rate. CONCLUSIONS. Consultation rates vary widely, even among family physicians and nurse practitioners within the same practice. The rate at which a practitioner orders consultations in a specialty area increases in relation to the practitioner's certainty of the diagnosis at the time the consultation was requested. Diagnostic certainty is discussed as a possible indicator of a referring practitioner's knowledge in a specialty area, implying that the greater a practitioner's knowledge in a specialty area, the more he or she consults with specialists in the field. Financial incentives that attempt to decrease specialty consultation should be reexamined in light of these findings.  相似文献   
14.
15.
16.
The shear modulus of the vocal fold is an essential parameter required to enhance our understanding of how the vocal fold operates, to develop mathematical models of phonatation, and to provide benchmarks to quantify the effectiveness of surgical procedures. The authors announced the successful deployment of an instrument to measure vocal fold elasticity in vivo last year, and now present the data taken from eight patients in vivo. The shear modulus was measured at the mid-membranous point, in a transverse direction with respect to the axis drawn between the anterior commissure and vocal process. The range of mean shear modulus results is 701–2,225 Pa, with a mean value of 1,371 Pa.  相似文献   
17.
18.
This paper examines medical malpractice law as it applies to medically necessary oral health care. The basic legal concepts and reported cases involving medically necessary oral health care are reviewed. It is concluded that dental professionals and consumer advocates must advance their educational and legislative advocacy efforts so that health professional colleagues and the public will become aware of the importance of these services and insurers will routinely include coverage of medically necessary oral health care in their medical and dental policies. While failure to provide medically necessary oral health care can be violative of patient rights and legally actionable, medical malpractice litigation should always be the behavior modifier of last resort.  相似文献   
19.
Soft tissue sarcomas are mesenchymal tumors which respond poorly to systemic therapy. Recent studies suggest a higher response rate with an increased doxorubicin dosage. However, this was parallel with a profound hematotoxicity in 75% of patients. Transfer of the human multidrug resistance 1 (MDR1) gene to normal hematopoietic stem cells and transplantation may significantly reduce the hematotoxicity of anthracyclin-based chemotherapy. To test this concept of supportive gene therapy in advance of a clinical study, we transduced mobilized peripheral blood progenitor cells (PBPC) with the retroviral vector SF91m3 containing the human MDR1 gene, transplanted these cells to immune-deficient mice, allowed 6 weeks for engraftment to occur and treated the animals with MDR1-based chemotherapy. In the MDR1-transduced group the human leukocytes were significantly protected from the toxicity of chemotherapy (p < 0.05). While the gene transfer rate was in the range of 10% and thus comparable to recent clinical trials, the gene expression was 59% of transduced cells and thus significantly higher than previously reported for less-advanced vectors. On the other hand, ifosfamide, a drug which has been used successfully for stem cell mobilization, is active in soft tissue sarcoma. Due to these favorable characteristics sarcoma is an attractive target to test the efficacy of MDR1 gene therapy in a clinical setting. Gene therapeutic strategies may also be used to directly target sarcoma cells, e.g. by transfer of suicide genes. We found that adenoassociated virus 2 (AAV-2) vectors efficiently transduce human HS-1 and HT1080 sarcoma cells (>90%) while other tumor cell lines and primary human PBPC were less susceptible. The thymidine kinase (TK) suicide gene was cloned into an AAV-2 vector and a complete kill of TK-transduced HS-1 and HT1080 cells was observed following exposure to aciclovir or ganciclovir (GCV), while >90% of mock-transduced HS-1 cells survived at these dosages. Transplantation of those sarcoma cells to nonobese diabetic (NOD)/LtSz-severe-combined immunodeficient (scid)/scid (NOD/SCID) mice resulted in a survival of >5 months in the AAV-TK-transduced/GCV-treated group, while the mice in the mock-transduced/GCV-treated group had died after 3 weeks. These data show that soft tissue sarcomas are a particularly suitable model system for the development and clinical testing of new gene therapeutic concepts.  相似文献   
20.
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