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   8943篇
  免费   837篇
  国内免费   27篇
耳鼻咽喉   81篇
儿科学   262篇
妇产科学   267篇
基础医学   1328篇
口腔科学   138篇
临床医学   933篇
内科学   1590篇
皮肤病学   98篇
神经病学   675篇
特种医学   400篇
外国民族医学   1篇
外科学   1331篇
综合类   244篇
一般理论   32篇
预防医学   897篇
眼科学   148篇
药学   716篇
中国医学   8篇
肿瘤学   658篇
  2021年   104篇
  2019年   94篇
  2018年   135篇
  2017年   99篇
  2016年   123篇
  2015年   130篇
  2014年   187篇
  2013年   285篇
  2012年   403篇
  2011年   395篇
  2010年   228篇
  2009年   194篇
  2008年   347篇
  2007年   368篇
  2006年   343篇
  2005年   353篇
  2004年   373篇
  2003年   294篇
  2002年   344篇
  2001年   299篇
  2000年   334篇
  1999年   264篇
  1998年   116篇
  1997年   109篇
  1996年   104篇
  1995年   102篇
  1994年   86篇
  1993年   82篇
  1992年   250篇
  1991年   222篇
  1990年   210篇
  1989年   165篇
  1988年   202篇
  1987年   199篇
  1986年   207篇
  1985年   165篇
  1984年   129篇
  1983年   96篇
  1982年   87篇
  1981年   68篇
  1979年   103篇
  1978年   67篇
  1976年   71篇
  1975年   68篇
  1974年   76篇
  1973年   93篇
  1972年   75篇
  1971年   79篇
  1969年   81篇
  1968年   69篇
排序方式: 共有9807条查询结果,搜索用时 31 毫秒
1.
2.
CONTEXT: The physician assistant profession has been moving toward requiring master's degrees for new practitioners, but some argue this could change the face of the discipline. PURPOSE: To see if there is an association between physician assistants' academic degrees and practice in primary care, in rural areas, and with the medically underserved. METHODS: Surveys were sent to 880 graduates of the first 32 University of Washington physician assistant classes through 2000. Respondents noted their academic degree at program entry and the highest degree attained at any time up to the time of survey. Relationships between practice characteristics and academic degree levels were tested by unadjusted odds ratios and logistic regression after controlling for year of graduation and sex. RESULTS: Of the 478 respondents, 54% worked in primary care, about 30% practiced in nonmetropolitan communities, and 42% reported providing care for the medically underserved. Respondents with no degree (33% of total at entry, 24% at survey) were significantly more likely than degree holders to work in primary care and nonmetropolitan areas. Respondents with no degree at program entry were significantly more likely, and those with no degree at the time of the survey were marginally more likely, to self-report work with the medically underserved. CONCLUSION: Respondents with no academic degree are significantly more likely to demonstrate a commitment to primary, rural, and underserved health care. These findings may inform the national debate about the impact of required advanced degrees on the practice patterns of nonphysician providers.  相似文献   
3.
4.
5.
The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.  相似文献   
6.
Between January 1966 and August 1981, 159 patients with previously untreated squamous cell carcinomas of the anterior faucial pillar or retromolar trigone received definitive radiation therapy at The University of Texas M. D. Anderson Hospital and Tumor Institute. All except 11 patients were treated by external radiation including combination of electron beams with high-energy photons or 60Co to doses ranging from 60 Gy to 75 Gy. In the N0 patients, as a rule, only the ipsilateral subdigastric nodes were treated electively to a dose of 50 Gy. The 5-year determinate survival rate for the overall group was 83%. The cumulative recurrence rate showed that 92% of the patients had recurrence by 2 years. Therefore, all patients except those who died with no evidence of local disease less than 2 years after treatment were evaluated for local control. The failure rate for the evaluable patients was 29% for T1 lesions, 30% for T2 lesions, 24% for T3 lesions, and 40% for T4 lesions. After salvage surgery, which consisted of intraoral resection in one-third of the patients and of a composite operation in the other two-thirds, the ultimate failure rate was 0% for T1 lesions, 6% for T2 lesions, 8% for T3 lesions, and 20% for T4 lesions. Whereas stage was a poor indicator for treatment outcome, there was a significantly higher failure rate for infiltrative and/or ulcerated lesions (35%) than for exophytic or superficial lesions (15%). Histologic grade was of no prognostic significance, nor was there any significant difference in the failure rate for lesions originating on the anterior faucial pillar versus that for lesions on the retromolar trigone. Following radiotherapy, 30% of the patients developed some degree of bone exposure but only 5.6% (9 patients) required a segmental mandibular resection. The probability of bone exposure was not dose related and more likely reflected tumor location on the mucoperiosteum. Of the whole group, 16 patients (10%) experienced a neck failure with 8 ultimate failures after salvage surgery. Among the 16 patients who had neck failures, 13 were originally staged N0; 6 of these patients had failures that occurred in the electively treated ipsilateral subdigastric area, but the field was too small to cover the nodes adequately. Aspects of the radiotherapy techniques with combined electron and photon beams that may influence the treatment outcome are discussed.  相似文献   
7.
Perceptions of fever among adults in a family practice setting   总被引:1,自引:0,他引:1  
Febrile illnesses are common clinical problems for the family physician. A questionnaire study was conducted of 100 adult patients in a family practice clinic to gain understanding of their knowledge about fever and its management. Many misconceptions were documented among adult patients about their own fevers and those of children for whom they cared. Misconceptions included the conviction that fever is more dangerous in children than in adults and a distorted concern about bodily damage from fever. Patients demonstrated a poor understanding of normal body temperature, minimum and maximum febrile temperatures, and minimum temperatures warranting antipyresis. Though many owned thermometers, they indicated improper usage and demonstrated inaccurate temperature-reading technique. Questionnaire responses indicated that health care providers had done poorly in educating patients about fever, its consequences, and its proper treatment.  相似文献   
8.
9.
Granulocyte colony-stimulating factor (G-CSF) is being considered as adjuvant treatment for infections in non-neutropenic patients. Normal healthy donors were given rHuG-CSF (Lenograstim) at 2.5, 5.0 and 7.5 μg/kg subcutaneously daily for 5 d. Polymorphonuclear leucocyte (PMN) function tests were carried out on peripheral blood PMN before the first injection and at 24 h and 96 h. Circulating PMN levels were also measured at these time intervals and found to be significantly increased with all doses by 24 and 96 h. Investigation of cell surface antigen expression revealed no changes in β2 integrin (CD11b/CD18) expression. L-selectin (CD62L) expression was reduced with all doses by 96 h, this being significant with the 7.5 μg/kg dose. FcγRI (CD64) levels were significantly up-regulated with the 7.5 μg/kg dose by 96 h whereas FcγRIII (CD16) expression was found to be reduced during G-CSF treatment. Superoxide anion production was significantly increased in response to N -formylmethionylleucylphenylalanine (FMLP) and opsonized Staphylococcus epidermidis stimulation at 24 h and 96 h with the 5.0 and 7.5 μg/kg doses. The initial rate of phagocytosis (0–2 min) appeared to have increased with the 7.5 and 5.0 μg/kg doses at 96 and 24 h compared with PMN responses pretreatment, although these increases were not statistically significant. These results show that G-CSF enhances the functional responses of PMN stimulated by physiological agonists and may help in the treatment of infections.  相似文献   
10.
In conclusion, endopyelotomy has been developed over the past several decades on the basis of sound laboratory and clinical research. The success rates have been similar to those of the standard open pyeloplasty, and the procedure is not associated with undue complications. Endopyelotomy has several distinct advantages over open surgery, including the decreased morbidity and associated expense of an open operation, minimal interference with the blood supply of the ureter, and avoidance of removal of the ureter from its natural sheath, preventing the tendency to adhere to adjacent structures and thus kink. As the instrumentation available for percutaneous renal surgery has improved and been miniaturized, the techniques developed in adults have been progressively applied to younger and smaller children. There seems to be little doubt that a comparison of morbidity and socioeconomic factors associated with a successful endopyelotomy versus an open pyeloplasty in adults heavily favors the percutaneous procedures, and judicious application to children would seem warranted. However, the changing presentation of ureteropelvic junction obstruction in children that has resulted from the widespread use of prenatal ultrasonography may make the question moot. Open infant pyeloplasty is a highly successful procedure, accompanied by minimal morbidity and accomplished in a 2- to 3-day hospital stay. The socioeconomic factors are obviated in the infant, who already requires constant maternal care. However, endopyelotomy deserves consideration in the older child, especially if the obstruction is secondary in nature after a previous open procedure.  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