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   12362篇
  免费   983篇
  国内免费   57篇
耳鼻咽喉   58篇
儿科学   317篇
妇产科学   230篇
基础医学   1794篇
口腔科学   237篇
临床医学   1285篇
内科学   2626篇
皮肤病学   234篇
神经病学   933篇
特种医学   486篇
外科学   1904篇
综合类   134篇
一般理论   5篇
预防医学   1093篇
眼科学   342篇
药学   831篇
中国医学   11篇
肿瘤学   882篇
  2023年   48篇
  2022年   171篇
  2021年   302篇
  2020年   148篇
  2019年   238篇
  2018年   324篇
  2017年   208篇
  2016年   226篇
  2015年   254篇
  2014年   349篇
  2013年   506篇
  2012年   794篇
  2011年   810篇
  2010年   464篇
  2009年   391篇
  2008年   695篇
  2007年   777篇
  2006年   695篇
  2005年   767篇
  2004年   692篇
  2003年   627篇
  2002年   645篇
  2001年   166篇
  2000年   194篇
  1999年   195篇
  1998年   154篇
  1997年   143篇
  1996年   106篇
  1995年   113篇
  1994年   97篇
  1993年   105篇
  1992年   124篇
  1991年   151篇
  1990年   118篇
  1989年   131篇
  1988年   132篇
  1987年   110篇
  1986年   85篇
  1985年   91篇
  1984年   95篇
  1983年   84篇
  1982年   74篇
  1981年   65篇
  1980年   61篇
  1979年   61篇
  1978年   54篇
  1977年   48篇
  1976年   40篇
  1975年   42篇
  1972年   42篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
43.
44.
Surgery in cirrhotic patients is associated with high morbidity and mortality related to portal hypertension and liver insufficiency. Therefore, preoperative portal decompression is a logical approach to facilitate abdominal surgery and hopefully to improve postoperative survival. The present study evaluated the clinical outcomes of 18 patients (mean age 58 years) with cirrhosis (seven alcoholics and 11 nonalcoholics) who underwent transjugular intrahepatic portosystemic shunt (TIPS) placement before antrectomy (n=5), colectomy (n=10), small-bowel resection (n=1), pancreatectomy (n=1) and nephrectomy (n=1). TIPS was performed a mean (+/-SD) of 72+/-21 days before surgery and induced a marked mean decrease in portohepatic gradient from 21.4+/-3.9 mmHg to 8.4+/-3.4 mmHg. Cirrhotic patients (n=17) who underwent elective abdominal surgery without preoperative TIPS placement were used as the control group. Both groups were matched for age, etiology of cirrhosis, indications for surgery, type of surgery and coagulation parameters. The mean Pugh score was significantly higher in the TIPS group (7.7 versus 6.2). No significant differences were observed for operative blood loss, postoperative complications, duration of hospitalization and one-month (83% versus 88%) or one-year (54% versus 63%) cumulative survival rate. Analysis using the Cox proportional hazards model showed that neither TIPS placement nor preoperative Pugh score were independent predictors for survival. The present study suggests that preoperative TIPS placement does not improve postoperative evolution after abdominal surgery in cirrhotic patients with good or moderately impaired liver function.  相似文献   
45.
46.
The research was designed to investigate the moderating effect of some personality traits on subjective distress caused by daily hassles. The traits were internal locus of control, repression, ego strength, and barrier (as studied and defined by S. Fisher). The last two variables were negatively correlated both with the somatic and emotional distress indications and with the frequency of hassles reportED; internal locus of control showed an inverse relationship only with frequency of hassles. The hypothesis is formulated that ego strength and barrier are personality factors influencing not only the outcomes of coping (ie the stress response), but also event appraisal.  相似文献   
47.
Hyperinfestation with Strongyloides is a severe complication in immunodepressed patients. It may present with various clinical signs, notably acute respiratory failure. Diagnosis may be difficult, particularly when the strongyloidiasis is associated with septicaemia caused by Gram-negative organisms. We report a new case of hyperinfestation with Strongyloides in a patient treated for periarteritis nodosa. This case was remarkable on two scores: the diagnosis problem raised by the presence of intrapulmonary haemorrhages, and the favourable outcome of an acute and initially severe respiratory failure which had required assisted ventilation. The role played in the patient's cure by the doses of thiabendazole given and the duration of their administration is discussed.  相似文献   
48.
Objective: Whatever the surgical technique used, false aneurysm formation is one of the long-term complications of repair of aortic coarctation. Conservative management is associated with a 100% rate of rupture. The conventional surgical approach is complex and associated with high morbidity and mortality rates. We report our experience of endovascular management of pseudo-aneurysms after previous surgical repair of congenital aortic coarctation. Methods: Between October 2005 and 2006, stent-grafting of pseudo-aneurysms after previous surgical repair of congenital aortic coarctation was performed in four patients. Median age was 31.5 years (range: 24–38). Two patients had undergone two previous interventions. The last previous surgery consisted of graft interposition (N = 2), subclavian flap aortoplasty (N = 1) and aorto-aortic bypass (N = 1). Median size of the pseudo-aneurysm was 31.5 mm (range: 20–58). Mean time between the last surgery and endovascular treatment was 24 years (range: 3–32). One patient was treated emergently because of hemoptysis in relation with an aorto-bronchial fistula, the three other patients were treated electively. A transfemoral approach was used in all patients. The Zenith TX2® (Cook) thoracic stent-graft was used in all the patients, one patient underwent previous dilatation at the coarctation level. When present, the ostium of the left subclavian artery was always covered (N = 3). Results: No major complication occurred during the procedure and no patient died during the follow-up. One patient presented a type II endoleak which spontaneously healed during the first month. Another patient with his left subclavian artery covered presented claudication of the left arm requiring a carotid-subclavian bypass. After a median follow-up of 7.5 months (range: 1–12.9), the patients were asymptomatic and CT scans demonstrated complete exclusion of all treated postcoarctation aneurysms without recoarctation and without any stent-graft-related complication. Conclusions: The endovascular management of pseudo-aneurysms after previous surgical repair of congenital aortic coarctation is feasible. This approach was safe and effective. Long-term clinic and imaging follow-up is mandatory.  相似文献   
49.
OBJECTIVE: The efficacy of a low-protein diet in the secondary prevention of diabetic nephropathy is not established in patients with type 1 or type 2 diabetes mellitus. To determine whether a low-protein diet slows the decrease in glomerular filtration rate (GFR) and decreases the albumin excretion rate (AER) in diabetic patients with incipient and overt nephropathy, we performed a 2-year prospective, randomized controlled trial comparing the effects of a low-protein diet (0.8 g/kg/day) with a usual-protein diet. SETTING AND PATIENTS: The study was conducted in a University hospital and included 63 type 1 and type 2 diabetic patients with either incipient or overt nephropathy and mild renal failure (prestudy GFR, 80 +/- 20 mL/min). The primary outcome measures were decreased in GFR and 24-hour AER. RESULTS: In the low-protein-diet group, patients were younger (52 +/- 12 versus 63 +/- 9 years old) and more often were type 2 diabetic. During the follow-up period, according to dietary records the low-protein-diet group consumed 16% +/- 3% of total caloric intakes as compared with 19% +/- 4% in the usual-protein-diet group (P < .02), but 24-hour urinary urea excretions did not differ between the two groups. The 2-year GFR decrease was 7 +/- 11 mL/min in the low-protein-diet group and 5 +/- 15 mL/min in the usual-protein-diet group (P = not significant). AER did not increase significantly in the two diet groups during the follow-up period. Blood pressure and glycemic control were similar in the two groups all along the study. The decrease in GFR and AER were also similar in 6 compliant patients according to dietary records and to 24-hour urinary urea excretions from the low-protein-diet group and in 12 patients from the usual-protein-diet group. CONCLUSIONS: A 2-year low-protein diet did not alter the course of GFR or of AER in diabetic patients with incipient or overt nephropathy receiving renin-angiotensin blockers with strict blood pressure control.  相似文献   
50.
Community-acquired viral respiratory tract infections (RTI) in lung transplant recipients may have a high rate of progression to pneumonia and can be a trigger for immunologically mediated detrimental effects on lung function. A cohort of 100 patients was enrolled from 2001 to 2003 in which 50 patients had clinically diagnosed viral RTI and 50 were asymptomatic. All patients had nasopharyngeal and throat swabs taken for respiratory virus antigen detection, culture and RT-PCR. All patients had pulmonary function tests at regular intervals for 12 months. Rates of rejection, decline in forced expiratory volume (L) in 1 s (FEV-1) and bacterial and fungal superinfection were compared at the 3-month primary endpoint. In the 50 patients with RTI, a microbial etiology was identified in 33 of 50 (66%) and included rhinovirus (9), coronavirus (8), RSV (6), influenza A (5), parainfluenza (4) and human metapneumovirus (1). During the 3-month primary endpoint, 8 of 50 (16%) RTI patients had acute rejection versus 0 of 50 non-RTI patients (p=0.006). The number of patients experiencing a 20% or more decline in FEV-1 by 3 months was 9 of 50 (18%) RTI versus 0 of 50 non-RTI (0%) (p=0.003). In six of these nine patients, the decline in FEV-1 was sustained over a 1-year period consistent with bronchiolitis obliterans syndrome (BOS). Community-acquired respiratory viruses may be associated with the development of acute rejection and BOS.  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