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   3532篇
  免费   400篇
  国内免费   13篇
耳鼻咽喉   29篇
儿科学   220篇
妇产科学   61篇
基础医学   448篇
口腔科学   145篇
临床医学   364篇
内科学   841篇
皮肤病学   45篇
神经病学   370篇
特种医学   230篇
外科学   323篇
综合类   93篇
一般理论   4篇
预防医学   305篇
眼科学   31篇
药学   270篇
中国医学   7篇
肿瘤学   159篇
  2021年   41篇
  2019年   37篇
  2018年   49篇
  2017年   36篇
  2016年   33篇
  2015年   47篇
  2014年   46篇
  2013年   93篇
  2012年   120篇
  2011年   123篇
  2010年   74篇
  2009年   67篇
  2008年   130篇
  2007年   122篇
  2006年   124篇
  2005年   118篇
  2004年   121篇
  2003年   118篇
  2002年   113篇
  2001年   115篇
  2000年   87篇
  1999年   101篇
  1998年   47篇
  1997年   65篇
  1996年   52篇
  1995年   50篇
  1994年   39篇
  1993年   39篇
  1992年   76篇
  1991年   95篇
  1990年   78篇
  1989年   100篇
  1988年   93篇
  1987年   114篇
  1986年   93篇
  1985年   96篇
  1984年   69篇
  1983年   60篇
  1982年   47篇
  1980年   43篇
  1979年   74篇
  1978年   59篇
  1977年   53篇
  1976年   38篇
  1975年   45篇
  1974年   46篇
  1973年   40篇
  1972年   36篇
  1970年   38篇
  1969年   40篇
排序方式: 共有3945条查询结果,搜索用时 15 毫秒
41.
Davis  GD; Fulton  RE; Ritter  DG; Mair  DD; McGoon  DC 《Radiology》1978,128(1):133-144
Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.  相似文献   
42.
The feasibility of using Travenol regular and minidrip sets to deliver intravenous solution with IVAC 230 controllers was investigated. Intravariability within Travenol regular sets proved to be negligible. Likewise, intervariability among IVAC controllers is negligible. The least squares fit obtained from drops per minute (dpm) versus flow rate (ml/hr) for Travenol regular sets using dextrose 5% in water was y = 4.50x + 0.8 (r greater than 0.99). Similarly, the least squares fit for sodium chloride 0.9% was y = 4.50x - 0.6 (r greater than 0.99). Therefore, the calculated dpm for the required flow rate for both solutions is similar using Travenol regular sets. Also, no significant difference is found between the drip rate of dextrose 5% in water and sodium chloride 0.9% with Travenol minidrip at 5, 30, and 60 dpms. This study shows that interchangeability of IVAC administration sets with Travenol regular and minidrip sets is possible for dextrose 5% in water and sodium chloride 0.9% solutions.  相似文献   
43.
44.
The clinical features of 78 patients with SLE seen in Cairo and Glasgow are reviewed. Raynaud's phenomenon was recorded more frequently here than in previous series. The value of serial measurements of anti-DNA antibodies, C3 and C4 in the management of SLE is discussed. Although antibodies to native DNA paralleled the disease course in only a minority of SLE patients anti-DNA antibodies were present during all major SLE exacerbations and could be diagnostically useful. Serious systemic infections complicating the management of SLE patients could occur and their diagnosis is discussed.  相似文献   
45.
46.
Increased dietary fat intake and rate of breastepithelial cell proliferation have each been associated withthe development of breast cancer. The goal ofthis study was to measure the effect ofa low fat, high carbohydrate diet on therate of breast epithelial cell proliferation in womenat high risk for breast cancer. Women wererecruited from the intervention and control groups ofa randomized low fat dietary intervention trial, breastepithelial cells were obtained by fine needle aspiration,and cell proliferation was assessed in these samplesusing immunofluorescent detection of Ki-67 and PCNA. Theeffects of needle size and study group oncell yield and cytologic features of the cellswere also examined. Fifty three women (20 inthe intervention group and 33 in the controlgroup) underwent the biopsy procedure. Slides from 38subjects were stained for Ki-67 and from 14subjects for PCNA. No cell proliferation (fluorescence) wasdetected for either Ki-67 or PCNA in anyof the slides. Epithelial cell yield and numberof stromal fragments were greater with a largerneedle size. Numbers of stromal fragments and bipolarnaked nuclei were greater in the low fatas compared to the control group but nodifferences in epithelial cell yield were observed betweenthe two groups. This study confirms that fineneedle aspiration biopsy is a feasible method ofobtaining epithelial cells from women without discrete breastmasses, but suggests that cell proliferation cannot beassessed using Ki-67 and PCNA in such samples.  相似文献   
47.
Objective: To explore scepticism and resistance towards changes in working practice designed to achieve service improvement. Two principal questions were studied: (1) why some people are sceptical or resistant towards improvement programmes and (2) what influences them to change their minds.

Methods: Semi-structured qualitative interviews were conducted with 19 clinicians and 19 managers who held national and regional roles in two national programmes of service improvement within the NHS involving systematic organisational changes in working practices: the National Booking Programme and the Cancer Services Collaborative (now the Cancer Services Collaborative Improvement Partnership).

Results: Scepticism and resistance exist in all staff groups, especially among medical staff. Reasons include personal reluctance to change, misunderstanding of the aims of improvement programmes, and a dislike of the methods by which programmes have been promoted. Sceptical staff can be influenced to become involved in improvement, but this usually takes time. Newly won support may be fragile, requiring ongoing evidence of benefits to be maintained.

Conclusions: The support of health service staff, particularly doctors, is crucial to the spread and sustainability of the modernisation agenda. Scepticism and resistance are seen to hamper progress. Leaders of improvement initiatives need to recognise the impact of scepticism and resistance, and to consider ways in which staff can become positively engaged in change.

  相似文献   
48.
49.
50.
PURPOSE: To assess current physician self-reported practices regarding initial management of childhood idiopathic thrombocytopenic purpura (ITP) and to determine physician self-reported willingness to participate in randomized clinical trials comparing different initial management strategies. PATIENTS AND METHODS: A questionnaire was mailed in November 1997 to all 720 members of the American Society of Pediatric Hematology/Oncology asking how they would diagnose and manage ITP in children 18 months, 5 years, and 15 years of age who were experiencing either dry purpura (cutaneous hemorrhage only) or wet purpura (active mucous membrane hemorrhage). Specific questions dealt with bone marrow aspiration, hospital admittance, treatment strategy, and specific doses of corticosteroids and intravenous immunoglobulin. RESULTS: The response rate to the questionnaire was 57%. Most respondents indicated they usually perform a bone marrow aspirate when corticosteroids are to be prescribed and administer drug therapy to patients with newly diagnosed ITP with wet or dry purpura. Only 16% of respondents would administer no drug therapy to a child with dry purpura. Intravenous immunoglobulin (IVIG) was preferred to steroids, with anti-D immunoglobulin prescribed less frequently. Hospital admittance often was used for patients with dry purpura and usually recommended for patients with wet purpura. Most respondents expressed willingness to randomize patients with dry purpura to IVIG versus no therapy and those with wet purpura to IVIG versus prednisone as part of a randomized controlled clinical trial. CONCLUSIONS: The self-reported care of the patient with ITP was influenced by the severity of presentation (dry versus wet purpura). Most physicians reported they would administer specific drug treatment in both scenarios. This survey illustrates the diverse diagnostic and management strategies currently used in childhood ITP. Because no one therapeutic approach is predominant and a scientific basis for decision making in childhood ITP has not been developed, future randomized trials are warranted. On the basis of these survey results, such trials are desired by most pediatric hematology/oncology specialists.  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