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   190314篇
  免费   1688篇
  国内免费   153篇
耳鼻咽喉   1285篇
儿科学   7024篇
妇产科学   3135篇
基础医学   18360篇
口腔科学   1914篇
临床医学   13272篇
内科学   34966篇
皮肤病学   945篇
神经病学   17383篇
特种医学   9553篇
外科学   31235篇
综合类   2363篇
预防医学   18374篇
眼科学   2922篇
药学   10364篇
中国医学   652篇
肿瘤学   18408篇
  2023年   138篇
  2022年   253篇
  2021年   502篇
  2020年   281篇
  2019年   331篇
  2018年   22262篇
  2017年   17611篇
  2016年   19827篇
  2015年   1295篇
  2014年   1279篇
  2013年   1409篇
  2012年   7863篇
  2011年   21992篇
  2010年   19359篇
  2009年   11959篇
  2008年   20339篇
  2007年   22652篇
  2006年   1497篇
  2005年   3153篇
  2004年   4344篇
  2003年   5216篇
  2002年   3404篇
  2001年   429篇
  2000年   546篇
  1999年   330篇
  1998年   454篇
  1997年   386篇
  1996年   258篇
  1995年   260篇
  1994年   255篇
  1993年   217篇
  1992年   143篇
  1991年   193篇
  1990年   213篇
  1989年   163篇
  1988年   120篇
  1987年   101篇
  1986年   71篇
  1985年   77篇
  1984年   63篇
  1983年   58篇
  1982年   73篇
  1981年   35篇
  1980年   73篇
  1978年   39篇
  1976年   34篇
  1974年   42篇
  1938年   60篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Neutrophil gelatinase associated lipocalin (NGAL) is a protein identified in human neutrophil granules. The aim of the study was to assess whether urine level of NGAL (uNGAL) could represent a novel, reliable marker of urinary tract infection (UTI) and to determine the optimal cutoff level for uNGAL to predict UTI in children. Sixty patients with symptomatic UTI and 29 healthy controls were enrolled the study. Urine NGAL was measured by enzyme-linked immunosorbent assay. A dimercaptosuccinic acid (DMSA) radionuclide scan was performed within 7 days in the patients with UTI in an attempt to distinguish pyelonephritis from cystitis. Mean uNGAL level was significantly higher in the UTI group than in the controls (91.02 ng/ml vs 14.29 ng/ml, p = 0.0001) and using a cutoff 20 ng/ml for uNGAL for diagnosis of UTI, sensitivity, and specificity were 97% and 76%, respectively [area under the curve (AUC): 0.979]. Mean uNGAL/creatinine ratio (uNGAL/Cr) was also significantly higher in the UTI group [201.81 ng/mg creatinine (Cr) vs 18.08 ng/mg Cr; p = 0.0001], and using a cutoff 30 ng/mg Cr for uNGAL/Cr for diagnosis of UTI, sensitivity and specificity were 98% and 76%, respectively (AUC: 0.992). In conclusion, both uNGAL and uNGAL/Cr can be used as a novel, sensitive marker for early prediction of UTI in the absence of acute kidney injury and chronic kidney disease, and the optimal cutoff value for prediction of UTI is lower than the values determined for acute kidney injury. Further investigations with larger patient groups are required to confirm our results.  相似文献   
992.
We investigated whether a proximal femoral nail (PFN) having two lag screws can be implanted without distal locking screws in AO/OTA 31-A1 and 31-A2 intertrochanteric femur fractures. Twenty-four patients with AO/OTA 31-A1 and 31-A2 fractures were treated with a PFN without distal interlocking by a single surgeon. The mean follow-up was 12 months (range: 7–23). Clinical and functional outcome was assessed according to the Harris hip score and Barthel’s activity score. The fractures healed in all patients; the average consolidation time was 14 weeks (range: 9–28). Fourteen patients had excellent and good results, nine patients had fair results, and one patient had a poor result according to the Harris hip score; 17 patients had a high range of mobility according to the Barthel activity score. Our results suggested that the PFN can be successfully implanted without distal interlocking in 31-A1 and 31-A2 fractures.  相似文献   
993.
Mucinous cystic neoplasms (MCN) of the pancreas are rare tumors that are almost exclusively located in the body or the tail of the pancreas. A 60-year-old woman with no history of pancreatic disease was referred to our hospital with a chief complaint of dull pain in the upper abdomen. Abdominal computed tomography showed a multilocular cystic mass of 7.0 cm in the head of the pancreas, and endoscopic retrograde cholangiopancreatography showed no communication between the cystic mass and the main pancreatic duct. A pancreatoduodenectomy was performed for the complete resection of the tumor, and an annular pancreas was discovered by accident. The pathological examination of the tumor led to a definitive diagnosis of MCN with ovarian-type stroma. To our knowledge this is the first documented case of MCN occurring in the head of the pancreas and associated with annular pancreas.  相似文献   
994.
To evaluate the diagnostic accuracy of computed tomography (CT)-based imaging methods for assessing renal vascular anatomy, imaging studies, including standard axial CT, three-dimensional volume-rendered CT (3DVR-CT), and a 3DVR-CT movie, were performed on 30 patients who underwent laparoscopic donor nephrectomy (10 right side, 20 left side) for predicting the location of the renal arteries and renal, adrenal, gonadal, and lumbar veins. These findings were compared with videos obtained during the operation. Two of 37 renal arteries observed intraoperatively were missed by standard axial CT and 3DVR-CT, whereas all arteries were identified by the 3DVR-CT movie. Two of 36 renal veins were missed by standard axial CT and 3DVR-CT, whereas 1 was missed by the 3DVR-CT movie. In 20 left renal hilar anatomical structures, 20 adrenal, 20 gonadal, and 22 lumbar veins were observed during the operation. Preoperatively, the standard axial CT, 3DVR-CT, and 3DVR-CT movie detected 11, 19, and 20 adrenal veins; 13, 14, and 19 gonadal veins; and 6, 11, and 15 lumbar veins, respectively. Overall, of 135 renal vascular structures, the standard axial CT, 3DVR-CT, and 3DVR-CT movie accurately detected 99 (73.3%), 113 (83.7%), and 126 (93.3%) vessels, respectively, which indicated that the 3DVR-CT movie demonstrated a significantly higher detection rate than other CT-based imaging methods (< 0.05). The 3DVR-CT movie accurately provides essential information about the renal vascular anatomy before laparoscopic donor nephrectomy.  相似文献   
995.

Purpose  

The purpose of our study was to evaluate and compare the survival in prostate cancer (PCa) patients who underwent radical prostatectomy (RP) < and ≥70 years.  相似文献   
996.
997.
Submitral left ventricular aneurysm is a rare complex disorder, predominently found in African population. We report a case of a 45 year male diagnosed to have a large submitral aneurysm, eroding the left circumflex artery, leading to severe mitral regurgitation, severe tricuspid regurgitation and congestive heart failure. Surgical correction comprising of submitral aneurysmorraphy with Teflon Felt, mitral valve replacement, modified DeVega’s tricuspid annuloplasty and ligation of left distal circumflex was performed successfully in this case.  相似文献   
998.
999.
Arterial stiffness (Ast) individually predicts cardiovascular (CV) mortality. Ast increases via vascular calcification and can be characterized by pulse wave velocity (PWV). We assessed the influence of mineral and bone metabolism on Ast in dialyzed (D) and renal transplanted (Tx) children by measuring fetuin-A and bone markers [bone-specific alkaline phosphatase (BALP); beta-CrossLaps (β)]. Normalized PWV/height (PWV/h) of 11 D and 17 Tx patients was measured by applanation tonometry. Levels of calcium (Ca), phosphate (P), fetuin-A, and bone markers were analyzed. Ca × P/fetuin-A ratio was calculated to characterize the balance of calcification and inhibition. Cumulative dose of calcitriol was also assessed. Fetuin-A was lower in D and Tx compared with healthy controls. Bone markers and Ca × P/fetuin-A of D were significantly higher than those of Tx and controls. In D PWV/h correlated with Ca × P/fetuin-A and BALP (r = 0.8; p = 0.005, r = 0.6, p = 0.05, respectively); BALP correlated with Ca × P/fetuin-A (r = 0.7, p = 0.01). In Tx, there was a correlation between calcitriol administered before transplantation and PWV/h (r = 0.5, p = 0.04). Increased bone turnover was coupled with an increased potential of calcium-phosphate precipitation, as shown by the increased Ca × P/fetuin-A. It might explain the connection between disturbed mineral and bone metabolism and Ast. Tx might be beneficial on Ast, though follow-up studies are needed.  相似文献   
1000.

Objective  

To evaluate [11C]choline positron emission tomography/computed tomography ([11C]choline PET/CT) for the detection of a biochemical recurrence of prostate cancer after radical prostatectomy.  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