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   6386篇
  免费   490篇
  国内免费   19篇
耳鼻咽喉   72篇
儿科学   162篇
妇产科学   165篇
基础医学   987篇
口腔科学   103篇
临床医学   620篇
内科学   1435篇
皮肤病学   145篇
神经病学   373篇
特种医学   373篇
外国民族医学   1篇
外科学   1156篇
综合类   49篇
一般理论   3篇
预防医学   246篇
眼科学   156篇
药学   405篇
中国医学   12篇
肿瘤学   432篇
  2022年   38篇
  2021年   73篇
  2020年   54篇
  2019年   72篇
  2018年   96篇
  2017年   87篇
  2016年   116篇
  2015年   155篇
  2014年   170篇
  2013年   209篇
  2012年   309篇
  2011年   330篇
  2010年   174篇
  2009年   190篇
  2008年   307篇
  2007年   327篇
  2006年   302篇
  2005年   303篇
  2004年   250篇
  2003年   258篇
  2002年   230篇
  2001年   186篇
  2000年   213篇
  1999年   203篇
  1998年   100篇
  1997年   93篇
  1996年   72篇
  1995年   74篇
  1994年   60篇
  1993年   67篇
  1992年   110篇
  1991年   113篇
  1990年   108篇
  1989年   132篇
  1988年   74篇
  1987年   75篇
  1986年   80篇
  1985年   66篇
  1984年   54篇
  1983年   43篇
  1982年   41篇
  1981年   36篇
  1980年   39篇
  1979年   77篇
  1978年   41篇
  1976年   36篇
  1974年   52篇
  1973年   40篇
  1972年   47篇
  1971年   49篇
排序方式: 共有6895条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
5.
6.
Objective: Electroporation mediated transfer of plasmid DNA into peripheral muscle results in high transfection efficiency. The aim of this study was to investigate the effect of gene transfer of human IL-10 (hIL-10) into the tibialis anterior muscle (MTA) in combination with low dose Cyclosporine A (CsA) on acute rejection of lung allografts in the rat. Methods: Lung allotransplantation was performed from male BN donor to male Fisher F344 rats. Gene transfer was achieved by intramuscular injection into the MTA of the recipient followed by electroporation (4×20 ms impulses at 200 V/cm) 24 h prior to the transplantation. Group A (n=5) received CsA (2.5 mg/kg bw ip) for 5 days post-transplant and group B (n=5) 2.5 μg of PCIK hIL-10 (plasmid expression vector containing human CMV immediate early gene promoter and enhancer) and a low dose CsA (2.5 mg/kg bw i.p.). Graft function was assessed by blood gas at day 5 after exclusion of the native lung. Animals were sacrificed and blood was drawn to measure serum hIL-10 levels (ELISA) and tissue was sampled for histological grading of rejection. Results: Local expression of hIL-10 was confirmed at the mRNA level by in situ hybridization. All group A control animals showed severe signs of rejection. At day 5 all grafts in group B showed good gas exchange mean PaO2 233±123 mmHg, vs 44±8 mmHg in group A. Histological examination revealed moderate to severe rejection in all animals in group A (IIIB, ISHLT) in contrast to low moderate rejection in group B (II–IIIA). hIL-10 serum levels on day 5 were 14±7 pg/ml in group B vs. 0 in group A. Conclusions: Electroporation mediated hIL-10 overexpression in a peripheral muscle of the recipient in combination with low dose CsA reduces acute rejection in this model of rat lung allotransplantation.  相似文献   
7.
8.
The effect of ciclosporin (CS) and methotrexate (MTX) on the development of graft-versus-host (GvH) disease was examined after small bowel allotransplantation in the rat. The drugs were tested either alone or in combination. Lewis small bowel allografts were transplantated into Brown Norway recipients in a heterotopic position. The native small bowel, spleen, liver, skin, mesenteric lymph nodes and the kidney of the recipients were examined histologically 5, 10 and 20 days after allotransplantation. Intraepithelial lymphocyte numbers were determined quantitatively in the native small bowel. The relative spleen weight of the host was determined after sacrifice for estimation of the severity of GvH disease. Grade I GvH reaction of the native small bowel occurred in the animals without immunosuppression, but graft rejection predominated in this group. Treatment with CS was effective in the early postoperative periods; after 10 and 20 days GvH lesions in the native small bowel were comparable to those observed in the allogeneic combinations. MTX had a detrimental effect on the allografts and the GvH reaction was augmented. When CS and MTX were combined, GvH lesions were comparable to those in the animals treated solely with CS. Animals, however, suffered from heavy side effects. The spleen, liver, lymph nodes and kidney exhibited only unspecific histologic changes, which could not unequivocally be recognized as a GvH reaction. This was true for all groups. As a conclusion it can be said that GvH reaction occurs in the early postoperative period in a fully allogeneic model and cannot be prevented by CS in the dosae used. MTX was not seen to be of any value in this regard.  相似文献   
9.
10.
A H Schmid 《Psychiatry》1991,54(4):358-367
Many of the terms used to describe conditions in elderly individuals, whether medical (deterioration, involution, degeneration) or neurobehavioral (impairment, dysfunction), imply deficiency. The complex of distorted views of real impairment, illness, or disability may be described as the deficiency model. Although developmental theory has expanded explosively and could offer an alternative frame of reference to dispel denigration of the elderly condition, late life continues to be viewed as lacking all redeeming aspects, while mortality is considered an obstacle to prolonging life rather than one of its determinants. Deficiency-model thinking has influenced the conduct of epidemiologic, neurobiologic and clinical research, whose results in turn have often been interpreted to reinforce such thinking. It can also distort clinical approaches to diagnosis and treatment of late-life disorders. This paper offers instead an alternative approach that focuses on late life as a developmental task.  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