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   3406篇
  免费   401篇
  国内免费   7篇
耳鼻咽喉   45篇
儿科学   142篇
妇产科学   68篇
基础医学   567篇
口腔科学   77篇
临床医学   426篇
内科学   652篇
皮肤病学   46篇
神经病学   361篇
特种医学   204篇
外科学   361篇
综合类   66篇
一般理论   3篇
预防医学   280篇
眼科学   86篇
药学   265篇
中国医学   1篇
肿瘤学   164篇
  2021年   46篇
  2020年   30篇
  2019年   47篇
  2018年   54篇
  2017年   30篇
  2016年   45篇
  2015年   48篇
  2014年   73篇
  2013年   117篇
  2012年   158篇
  2011年   167篇
  2010年   93篇
  2009年   81篇
  2008年   129篇
  2007年   141篇
  2006年   133篇
  2005年   109篇
  2004年   113篇
  2003年   92篇
  2002年   110篇
  2001年   101篇
  2000年   90篇
  1999年   91篇
  1998年   86篇
  1997年   74篇
  1996年   67篇
  1995年   78篇
  1994年   44篇
  1993年   66篇
  1992年   72篇
  1991年   76篇
  1990年   62篇
  1989年   81篇
  1988年   96篇
  1987年   88篇
  1986年   84篇
  1985年   78篇
  1984年   39篇
  1983年   51篇
  1982年   25篇
  1981年   45篇
  1980年   38篇
  1979年   59篇
  1978年   38篇
  1977年   36篇
  1976年   31篇
  1975年   35篇
  1974年   32篇
  1973年   35篇
  1972年   32篇
排序方式: 共有3814条查询结果,搜索用时 31 毫秒
51.
Summary As part of our studies of the spinal circuitry of the tonic neck reflex, we have recorded extracellularly from Ia reciprocal inhibitory neurons of the decerebrate, labyrinthectomized cat. The activity of a majority of neurons driven by stimulation of the quadriceps nerve was modulated by sinusoidal rotation of the neck; such modulation was much less frequent in the case of neurons driven by stimulation of nerves to more distal muscles. The results suggest that some of the inhibition which is part of the tonic neck reflex is mediated by Ia reciprocal inhibitory neurons, but that other pathways must also play an important role.  相似文献   
52.
53.
SummaryPurpose This study was undertaken to evaluate the radiographie response to two cycles of chemotherapy prior to irradiation in newly diagnosed children with high-grade astrocytomas.Patients and methods. One hundred and thirty children less than 21 years of age with newly-diagnosed highgrade astrocytoma were treated with the eight-drugs-in-one-day chemotherapy regimen as part of a phase III multi-institutional Childrens Cancer Group (CCG) trial. Computerized Tomographic (CT) or Magnetic Resonance Image (MRI) scans, obtained after two cycles of chemotherapy had been administered, were compared with post-operative scans to determine treatment response. Scans were evaluated by institutional radiologists, and were reviewed centrally by a single neuroradiologist.Results Of 79 patients with evaluable post-operative residual tumor on CT or MRI scans, 26 (33%) were determined on institutional evaluation to have had an objective response. However, central review of scans documented responses on only 14/79 (18%). A significantly higher response rate on central review was observed for those children 36 months of age or less at study entry than for older children (33% v 11%; p < 0.001). However, a higher disease progression rate was also observed for those children 36 months of age or less than for older children (21% v 2.6%; p < 0.001).Conclusion In this study, the largest yet reported in newly-diagnosed children with high-grade astrocytomas, the chemotherapy regimen has activity in younger children. The differences in response rates reported by institutional and central review highlight the difficulties inherent in assessing response to brain tumor therapy. However, the study does demonstrate the consistent ability of radiologists to identify disease progression within the institutional and central reviews.  相似文献   
54.
55.
The findings presented in this paper are part of a research project designed to provide a preliminary indication of the support needs of postdiagnosis women with breast cancer in remote and isolated areas in Queensland. This discussion will present data that focuses on the women's expressed personal concerns. For participants in this research a diagnosis of breast cancer involves a confrontation with their own mortality and the possibility of a reduced life span. This is a definite life crisis, creating shock and needing considerable adjustment. Along with these generic issues the participants also articulated significant issues in relation to their experience as women in a rural setting. These concerns centred around worries about how their partner and families cope during their absences for treatment, the additional burden on the family of having to cope with running the property or farm during the participant's absence or illness, added financial strain brought about by the cost of travel for treatment, maintenance of properties during absences, and problems created by time off from properties or self-employment. These findings accord with other reports of health and welfare services for rural Australian and the generic literature on psycho-oncology studies of breast cancer.  相似文献   
56.
Neutral glycolipids and gangliosides were analyzed in 149 astrocytomas (A), 46 oligodendrogliomas (O), and 21 oligoastrocytomas (OA) to determine if specific glycolipids correlate with histologic diagnosis and grade. Positivity for asialoGM1 (GA1) and negativity for paragloboside by immuno-TLC correlated with histological diagnosis of O and OA, whereas the reverse pattern correlated with A. High levels (over 5 microg hexose per mg dry weight) of CMH generally correlated with an O component, but the association was not as strong as for either GA1 presence or paragloboside absence. Pilocytic astrocytomas and pleomorphic xanthoastrocytomas had high proportions (> 15%) of globoside, low ratios (< 0.5) of GD1a: GD1b, and identifiable ceramide trihexoside (CTH). Three gangliosides of the 1b pathway were progressively lost with increasing grade of A, but a similar correlation with grade was not seen in O or OA. A high proportion of cases expressing sialosylparagloboside (3'LM1; 6'LM1) were grade 4 A. Glycolipids are synthesized by glycosyltransferases that add specific sugars to the nascent oligosaccharide. Correlation of specific glycolipids with histological diagnoses and grades indicate that these tumor types express specific patterns of glycosyltransferases, several of which have been cloned. It is possible that critical genes coding for these enzymes are deleted, overexpressed, or mutated in certain tumor types and grades, thus leading to the patterns of glycolipids that we found to be associated with these tumors.  相似文献   
57.

Purpose

We evaluated the effect of exogenous testosterone administration on serum total and free prostate specific antigen (PSA) in healthy young men.

Materials and Methods

Nine volunteers received either 100, 250 or 500 mg. testosterone by intramuscular injection each week for 15 weeks. Blood was drawn every other week for 28 weeks and at week 40. Serum total and free PSA, and total and free testosterone were measured and compared to baseline values.

Results

Significant elevations in total and free testosterone occurred but no significant change in serum total and free PSA was detected.

Conclusions

Serum PSA is not responsive to elevated serum testosterone levels in healthy young men. PSA metabolism in the normal prostate is unclear but our findings may have implications for differentiation of pathological conditions of the human prostate.  相似文献   
58.
The effectiveness and cost of three techniques for obtaining client ratings of their own levels of functioning were assessed in a private, outpatient, mental health clinic. Seventy-five clients were asked to rate the adequacy of their own functioning on vocational, family, social, personal, and overall dimensions. Clients were randomly assigned to (a) mail, (b) telephone, or (c) mail followed (if necessary) by telephone administration of the ratings questionnaire. Mail followed if necessary by phone administration was found to be more cost effective than either mail alone or telephone alone.  相似文献   
59.
60.
Back to basics.     
The basic strength of the AMCA family is the wide range of expertise and "can do" attitude of its diverse membership. The AMCA is currently experiencing problems with federal legislation and fiscal stability because we have not fully utilized member strengths to reevaluate the association's direction and set new goals to address change. However, the AMCA Board of Directors and many committee chairpersons met, reevaluated direction and clarified goals, and initiated major changes to meet the challenges facing the association and its members. Members of the AMCA are encouraged to contribute their individual talents to ensure that the association prosper and serve the needs of the mosquito and vector control family.  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