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   17899篇
  免费   756篇
  国内免费   140篇
耳鼻咽喉   176篇
儿科学   372篇
妇产科学   128篇
基础医学   2291篇
口腔科学   309篇
临床医学   1171篇
内科学   4713篇
皮肤病学   462篇
神经病学   1398篇
特种医学   587篇
外科学   2825篇
综合类   52篇
一般理论   4篇
预防医学   409篇
眼科学   621篇
药学   1271篇
中国医学   28篇
肿瘤学   1978篇
  2024年   16篇
  2023年   109篇
  2022年   266篇
  2021年   461篇
  2020年   218篇
  2019年   277篇
  2018年   362篇
  2017年   277篇
  2016年   393篇
  2015年   430篇
  2014年   531篇
  2013年   631篇
  2012年   1136篇
  2011年   1196篇
  2010年   706篇
  2009年   595篇
  2008年   1047篇
  2007年   1195篇
  2006年   1127篇
  2005年   1240篇
  2004年   1237篇
  2003年   1098篇
  2002年   1134篇
  2001年   217篇
  2000年   177篇
  1999年   252篇
  1998年   297篇
  1997年   218篇
  1996年   223篇
  1995年   198篇
  1994年   166篇
  1993年   174篇
  1992年   120篇
  1991年   118篇
  1990年   119篇
  1989年   115篇
  1988年   76篇
  1987年   58篇
  1986年   64篇
  1985年   49篇
  1984年   52篇
  1983年   42篇
  1982年   47篇
  1981年   43篇
  1980年   36篇
  1979年   38篇
  1978年   36篇
  1977年   30篇
  1976年   14篇
  1975年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A method for taking an axial radiograph of the distal femur was developed to see the epicondyles and posterior condyles of the femur. It was hypothesized that these radiographs would be acceptable for evaluating rotational alignment in total knee arthroplasty with comparable reproducibility and good correlation to the results obtained with computed tomography images. Radiographs were obtained of 50 knees in 32 patients having total knee arthroplasty. The radiographs were taken while the patients were with the knee in 90 degrees flexion. The angle between the clinical epicondylar axis and the posterior condylar axis (twist angle) was measured and compared with the results obtained by conventional computed tomography. The interobserver variation in the axial radiography was less than or comparable to the computed tomography method. The mean discrepancy between the two methods (+/- standard deviation) was 0.5 degrees +/- 0.4 degrees (range, 0-1.9 degrees ), and a strong correlation was observed. This plain radiography is acceptable for evaluation of femoral component rotation with comparable reproducibility and correlation to the results with computed tomography. It has several advantages regarding cost, radiation dose, and lack of scatter when used for postoperative assessment.  相似文献   
992.
Two patients with testicular tumors whose serum alpha-fetoprotein (AFP) persisted to show an abnormally high concentration are reported. Case 1 : A 42-year-old male who had been suffering from chronic hepatitis, underwent left high orchiectomy for a left testicular tumor in 1998. Diagnosis was an authentic stage I seminoma. In 2002, chemotherapy was performed for a metastatic seminoma revealed as a solitary mass in the mediastinum by radiographic studies, and histologically confirmed to be a metastatic seminoma. Although lymph nodes were gradually reduced in size, the serum AFP and transaminase levels remained at an abnormally high concentration. The subfraction profile with lens culinaris hemagglutinin (LCA) revealed elevation of only peak 1 which implied that the chronic hepatitis was due to liver dysfunction. After a 10-month follow-up the levels of both AFP and transaminase decreased, and the patient was disease-free. Case 2: In 2002, a 30-year-old male underwent left high orchiectomy for a left testicular tumor, and histological examination revealed seminoma, immature and mature teratoma, embryonal carcinoma. The serum AFP was elevated to 45 ng/ml. Diagnosis was authentic stage I. After 2 courses of chemotherapy, the serum AFP remained at an abnormally high concentration. However, there were no new lesions. The serum AFP level was not elevated in any of the family members. The subfraction profile with LCA revealed elevation of only peak 1, which implied that there were no viable lesions. After a 24-month follow-up AFP was about 20 ng/ml and the patient was disease-free.  相似文献   
993.
Purely intraorbital arteriovenous fistulas (AVFs) are rare, and their clinical management is controversial. The authors successfully treated a patient with an intraorbital AVF by transvenous embolization alone. An accurate distinction between an arteriovenous malformation (AVM), which is characterized by the existence of a nidus, and an AVF, which has no nidus, is important and requires superselective ophthalmic artery angiography. Treatment of an intraorbital AVF by transvenous embolization can improve visual function.  相似文献   
994.
BACKGROUND: The appropriate treatment strategy for transplantable hepatocellular carcinoma (HCC) patients with compensated cirrhosis remains controversial. METHODS: Surgical outcomes were reviewed in 136 cirrhotic patients with transplantable HCC who had undergone partial hepatectomy. Transplantable HCC was defined as that corresponding to Milan's criteria. RESULTS: The adverse prognostic factors for both survival and disease-free survival were histologic surgical margin of 5 mm or less, Child-Pugh B, and the presence of hepatitis C virus infection. The overall 5-year survival and disease-free survival rates of patients with 1 or none of the adverse prognostic factors were 73% and 33%, respectively, whereas those of patients with 2 or 3 adverse prognostic factors were 36% and 17%, respectively. CONCLUSIONS: Transplantable HCC patients with 2 or 3 adverse prognostic factors should be considered candidates for liver transplantation, whereas patients with only 1 or none of the adverse prognostic factors are good candidates for partial hepatectomy.  相似文献   
995.
Coronary artery occlusion during off-pump coronary artery bypass grafting may lead to mechanical trauma of the arterial wall. My colleagues and I describe a safe coronary artery occlusion technique in off-pump bypass grafting that uses a new spring-equipped tourniquet, which enables precise adjustment of the least force necessary to occlude the coronary flow. This prevents snare-induced vessel wall damage.  相似文献   
996.
BACKGROUND: It is sometimes difficult to determine the extent of resection in patients with endobronchial carcinoma because preoperative white-light bronchoscopic (WLB) examination is not sensitive enough to examine the extent fully. Light-Induced Fluorescence Endoscopy (LIFE) is recognized as a useful modality for the diagnosis of early staged bronchial carcinoma, but there have been no reports of its significance in surgical treatment. We have studied the influence of LIFE upon the selection of surgical procedures or other treatments in patients with endobronchial carcinoma preoperatively. METHODS: Conventional WLB and LIFE were performed within 7 days of operation. Biopsy specimens were taken from the marginal regions of the areas that were suspicious for malignancy on LIFE examination and WLB. We decided the resection line before operation and kept the resected central margin 1 cm apart from the area revealed as suspicious by LIFE. RESULTS: From January 1999 to March 2003, 75 patients underwent LIFE. LIFE was performed to decide the surgical procedures for 12 patients (16.0%). Surgical therapy was performed in 8 (66.7%). LIFE findings dramatically changed the surgical procedures for 3 patients, lobectomy changed to sleeve lobectomy in 2 and laser therapy to segmentectomy in 1. LIFE revealed larger abnormal areas of bronchial cancer compared to WLB in 7 (58.3%). Conversely, WLB overestimated the extent of abnormal area in 1 (8.3%). WLB revealed the same cancer area as LIFE in 4. In all patients, the resected bronchial margins were cancer free intraoperatively and postoperatively. CONCLUSION: LIFE can be more sensitive than WLB and be more beneficial for judging the extent of neoplastic bronchial changes for some patients. LIFE may be a useful modality for the preoperative selection of surgical procedures, especially whether sleeve resection is needed or not, for some centrally located superficial endobronchial carcinoma.  相似文献   
997.
A 54-year-old woman with subvalvular aortic stenosis was admitted to our hospital. The pressure gradient across the left ventricular outflow tract was estimated as 88 mmHg (peak) and 45 mmHg (mean) by Doppler echocardiography, but only 14 mmHg (peak to peak) and 31 mmHg (mean) by cardiac catheterization. We considered this discrepancy attributable to the presence of moderate aortic regurgitation and the pressure recovery phenomenon. Pressure recovery has clinical relevance particularly in a patient with tunnel-like stenosis, with gradual lumen re-expansion beyond the limiting orifice. Therefore, if Doppler echocardiography shows significant left ventricular outflow tract gradient, precise evaluation of the stenosis geometry is required to investigate the effect of pressure recovery.  相似文献   
998.
A 49-year-old man presented with fever and uremic symptoms such as general malaise, leg edema and decreased urine output. He was diagnosed as having infective endocarditis (IE) accompanied by renal failure. Although he had been receiving hemodialysis for a long time, renal function dramatically improved after heart valve replacement. This case suggests that uremia can develop as an initial manifestation of IE and removal of an infected heart valve can improve renal function despite persistent renal failure. From the perspective of recovery of renal function, early surgery should be considered in patients with renal failure following IE.  相似文献   
999.
Although it has been reported that chronic obstructive pulmonary disease (COPD) is frequently associated with systemic immune disturbances, negative impact of these disturbances on the increased prevalence of acute respiratory tract infections (aRTIs) has remained unclear. We evaluated circulating levels of interferon-gamma (IFN-gamma), soluble interleukin-2 receptor (sIL-2R), neopterin, and soluble intercellular adhesion molecule-1 (sICAM-1) in 35 clinically stable patients with COPD and in 22 age-matched healthy controls, since these molecules are considered to reflect the in vivo status of systemic cell-mediated immunity (CMI). We found that circulating levels of sIL-2R (1.52+/-1.25 vs. 0.97+/-0.48 ng/ml; P<0.05), neopterin (7.23+/-4.24 vs. 4.95+/-1.52 nmol/l; P<0.05), and sICAM-1 (665+/-302 vs. 328+/-164 ng/ml; P<0.0001), but not IFN-gamma (7.55+/-4.72 vs. 6.65+/-1.13 pg/ml; P=NS) were significantly higher in patients with COPD than in the controls. Importantly, follow-up study for 12 months demonstrated that patients in subgroup with relatively higher circulating levels of sIL-2R (2.20+/-1.44 ng/ml, n=18) had significantly higher risk of developing aRTIs (P=0.0204) than those in subgroup with relatively lower circulating levels of sIL-2R (0.80+/-0.23 ng/ml, n=17). These results may suggest that impaired systemic CMI observed in COPD patients is associated with the increased susceptibility to aRTIs in these patients.  相似文献   
1000.
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