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   14752篇
  免费   1857篇
  国内免费   159篇
耳鼻咽喉   46篇
儿科学   578篇
妇产科学   844篇
基础医学   623篇
口腔科学   74篇
临床医学   1162篇
内科学   4718篇
皮肤病学   59篇
神经病学   730篇
特种医学   97篇
外国民族医学   1篇
外科学   2239篇
综合类   803篇
一般理论   1篇
预防医学   2803篇
眼科学   27篇
药学   466篇
中国医学   30篇
肿瘤学   1467篇
  2024年   23篇
  2023年   430篇
  2022年   547篇
  2021年   1073篇
  2020年   821篇
  2019年   862篇
  2018年   800篇
  2017年   676篇
  2016年   700篇
  2015年   666篇
  2014年   972篇
  2013年   1254篇
  2012年   631篇
  2011年   713篇
  2010年   524篇
  2009年   593篇
  2008年   629篇
  2007年   606篇
  2006年   577篇
  2005年   444篇
  2004年   423篇
  2003年   342篇
  2002年   287篇
  2001年   247篇
  2000年   182篇
  1999年   165篇
  1998年   165篇
  1997年   156篇
  1996年   142篇
  1995年   125篇
  1994年   117篇
  1993年   112篇
  1992年   99篇
  1991年   77篇
  1990年   72篇
  1989年   60篇
  1988年   72篇
  1987年   55篇
  1986年   71篇
  1985年   64篇
  1984年   50篇
  1983年   32篇
  1982年   27篇
  1981年   17篇
  1980年   9篇
  1979年   18篇
  1978年   10篇
  1976年   7篇
  1974年   5篇
  1971年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The mortality and suicide rates for involuntarily committed patients in Denmark are presented. Two cohorts of psychiatric patients committed to a mental hospital from January 1, 1971 to December 31, 1975 (8322 people) and January 1, 1981 to December 31, 1985 (5253 people) have been followed. The standard mortality rate (SMR) in relation to the total Danish population were 4.9 (4.5–5.4) and 5.2 (4.7–5.8), respectively, for the two cohorts, during the first year after involuntarily commitment to a mental hospital. During the same period, the SMR for suicide among the committed patients were 44.9 (37.1–53.9) and 30.9 (24.2–38.9), respectively. The crude suicide rates among the committed patients during the first year after the commitment were 14.3 and 14.0, respectively, per 1000 years, unchanged between the cohorts. Short length of stay in hospital (< 14 days), a nonpsychotic main diagnosis, male sex, and age 35 years or more were equally related to high risk of suicide in the 1971 cohort as evaluated to proportional hazard methods (Cox regression), and short length of stay and commitment on the danger indication provided the most information in relation to high suicidal risk in the 1981 cohort. Methodological problems and the reasons for the results are discussed.  相似文献   
62.
OBJECTIVE: An association between caseload and outcome has been reported for complex surgical procedures. We systematically reviewed recent literature to determine whether caseload and surgical speciality are associated with short-term outcome following colorectal cancer surgery. METHOD: We searched the MEDLINE and Cochrane Library databases for relevant publications starting in 1992. We selected hospital caseload and type, and surgeon's caseload, education and experience as variables of interest. Measures of outcome were postoperative morbidity, in-hospital and 30-day mortality, and for rectal cancer anastomotic leak. We stratified the 35 reviewed studies by tumor location: colonic cancer, rectal cancer, or colorectal cancer and described the studies individually. A meta-analysis was performed only when it was considered appropriate. RESULTS: For colonic cancer, postoperative morbidity was associated with surgeon's caseload and education. Postoperative mortality was strongly associated with hospital caseload (OR 0.64, 95% CI 0.55-0.73), and surgeon's caseload (OR 0.50, 95% CI 0.39-0.64). It was also influenced by surgeon's education and experience. For rectal cancer, we found no evidence of an association between the selected variables and short-term outcome, including frequency of anastomotic leak. For colorectal cancer, there was evidence for an association between postoperative morbidity and hospital caseload. CONCLUSION: Our review offers evidence for a positive association between high hospital caseload, surgeon's caseload, sub-speciality and experience and improved short-term outcome in colonic cancer surgery. We failed to find evidence of a relationship for rectal cancer surgery, possibly owing to methodological artifacts. No study reported an inverse relation.  相似文献   
63.
Many studies have shown that health conditions experienced in childhood play an important role on an individual's adult mortality. Recent research suggests that past reductions in early life exposure to infectious diseases have been a major contributor to the historical decline in old-age mortality. Drawing on French-Canadian data from cohorts born in the 17th and 18th centuries, we test whether a progressive deterioration in early life conditions (as revealed by an increasing infant mortality rate) translates into a decrease in survival prospects in late life. We use traditional demographic measures such as the age-specific probability of death, and a series of proportional hazard models to control for familial and environmental conditions. Results point toward little evidence of any early life effects. The trend of increasing infant mortality does not correlate with a general increase of mortality in older ages within the same cohorts. Period changes affecting survival at older ages (war, epidemics) as well as demographic and biological characteristics shared within families have a much larger role in old-age mortality than early life characteristics shared within the same cohorts.  相似文献   
64.
65.
Gastric adenocarcinoma is the second leading cause of cancer death worldwide. In Western series, survival rates vary widely and are generally lower than those reported from Eastern series. We performed a retrospective analysis of cases operated on at the Johns Hopkins Hospital over the past 18 years and collected data on demographics, tumor characteristics, pathologic stage, treatment methods, complications, survival time, and other relevant factors. Survival according to stage of disease, Lauren tumor type, tumorlocation,time period, andadministration of adjuvant therapy wasanalyzed, andresultswerecompared with those of other Western series. During this period, 436 patients with gastric adenocarcinoma underwent resection. We have shown a statistically significant association between survival and margin status, stage of disease, and Lauren tumor type. Overall 5-year survival was 26%, and 5-year survival after R0 resection was 33%. No significant difference was detected between survival and tumor location, time period of treatment, or administration of adjuvant therapy. Analysis of various Western series reveals major differences between the cohorts under study, such as stage of disease, extent of resection, tumor type, and tumor location. Many of the reported differences among Western series may be due to cohort differences, such as stage of disease, extent of resection, tumor type, and tumor location.  相似文献   
66.
This paper investigates the association between individually measured socioeconomic status (SES) and all-cause survival in colorectal cancer patients, and explores whether factors related to the patient, the disease, or the surgical treatment mediate the observed social gradient.  相似文献   
67.
1 A 'retrospective' of the development of the drug treatment of hypertension is presented from the early days of ganglion blockers to the present time together with a review of the evidence of benefit from treatment.
2 Current issues and debates are summarised including shortfalls in the control of hypertension in populations, difficulties surrounding the measurement of blood pressure, disagreement on the levels of blood pressure to treat, the goal blood pressures to aim at, issues surrounding lifestyle measures such as the low salt diet and low intensity exercise, and treatment with diuretics and with calcium antagonists.
3 A 'perspective' is presented on some avenues for progress in the years ahead. These will include the identification of genetic markers to determine the hypertensive individuals with the greatest risk of death and of cardiovascular complications.  相似文献   
68.
The mortality profile of female nurses and teachers in British Columbia (BC) was examined using age-standardized proportional mortality ratios (PMRs) calculated for the period 1950–1984. Lowered overall mortality among nurses was seen for degenerative heart disease and for cerebrovascular accidents. Significantly elevated PMR values were observed for cancer of the breast and ovary in nurses of age 20–65 years. PMRs were significantly elevated for cancer of the pancreas and leukemia among those age 20 years and older. Elevated values were also observed for motor vehicle accidents and suicide among nurses in both age groups. Lower than expected mortality from degenerative heart disease and cerebrovascular accidents was seen in working age teachers (age 20–65 years). However, elevated PMRs were detected for carcinoma of the colon, breast, endometrium, brain, and melanoma. Among those 20 years and over, significantly elevated PMRs were also observed for cancers of the ovary and other digestive organs. Elevated PMRs were found for motor vehicle and aircraft accidents. Mortality from cirrhosis of the liver was lower than anticipated in both teachers and nurses. A number of significant PMRs declined when deaths of “homemakers” were withdrawn from the comparison group used to generate PMR values, suggesting that risk of death from various causes among women working outside the home differ from those seen in women who are predominantly in the home.  相似文献   
69.
Minor,moderate and severe head injury   总被引:9,自引:0,他引:9  
Summary The future role of the neurosurgeon in the management of head injury is reviewed in terms of the care of patients with minor, moderate and severe head injuries. In minor head injury it is predicted that there will be increasing pressure on the neurosurgeon to undertake the management and follow-up of all patients who have sustained head injury, and this will place a considerable additional load on each neurosurgical unit. This is based on a survey of 1919 head injuries admitted in one calendar year (1981), consisting of 93 severe injuries (GCS < 8), 210 moderate injuries (GCS 8–12), and 1616 minor injuries (GCS 13/14). In moderate injuries CT will assume a major role in detecting hematoma early and identifying contusions. There may yet be a role for steroids in these cases and there should be a greater use of neurorehabilitation, instead of the current overemphasis on the severely injured. In severe injury future efforts will be to prevent early secondary insults and to find better methods of controlling raised intracranial pressure.  相似文献   
70.
U.S. cancer mortality data derived from information recorded on death certificates are frequently relied upon as an indicator of progress against cancer. A limitation of this measure is the lack of information pertaining to the onset of disease, such as year-of-diagnosis, age-at-diagnosis, stage of disease at diagnosis and histology of lesions. However, population-based cancer registries collect these types of data and allow the calculation of an incidence-file based mortality rate. This incidence-based mortality rate allows a partitioning of mortality by variables associated with the cancer onset. Breast cancer incidence-based mortality measures are created and compared to mortality rates based on death certificates over a comparable time period. Novel mortality measures, such as mortality rates by stage-at-diagnosis, age-at-diagnosis and year-of-diagnosis, are used to illustrate the value of this approach.  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