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   17965篇
  免费   904篇
  国内免费   113篇
耳鼻咽喉   215篇
儿科学   334篇
妇产科学   274篇
基础医学   2082篇
口腔科学   298篇
临床医学   1161篇
内科学   4994篇
皮肤病学   345篇
神经病学   1124篇
特种医学   799篇
外科学   3203篇
综合类   69篇
预防医学   440篇
眼科学   142篇
药学   1268篇
中国医学   66篇
肿瘤学   2168篇
  2023年   103篇
  2022年   107篇
  2021年   448篇
  2020年   259篇
  2019年   342篇
  2018年   418篇
  2017年   325篇
  2016年   393篇
  2015年   430篇
  2014年   536篇
  2013年   610篇
  2012年   1127篇
  2011年   1168篇
  2010年   665篇
  2009年   602篇
  2008年   1035篇
  2007年   1060篇
  2006年   1103篇
  2005年   1064篇
  2004年   1051篇
  2003年   1014篇
  2002年   998篇
  2001年   369篇
  2000年   333篇
  1999年   390篇
  1998年   250篇
  1997年   180篇
  1996年   171篇
  1995年   126篇
  1994年   125篇
  1993年   99篇
  1992年   222篇
  1991年   184篇
  1990年   175篇
  1989年   163篇
  1988年   144篇
  1987年   144篇
  1986年   139篇
  1985年   128篇
  1984年   106篇
  1983年   67篇
  1982年   37篇
  1981年   41篇
  1980年   41篇
  1979年   67篇
  1977年   54篇
  1974年   31篇
  1971年   38篇
  1969年   31篇
  1968年   30篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
991.
Celiac axis stenosis is found at an incidence of 2%–24% in the general population. During pancreatoduodenectomy in patients with celiac axis stenosis, division of the gastroduodenal artery from the common hepatic artery may cause acute ischemia of the upper abdominal organs, such as the liver, stomach, or spleen. Under these circumstances, the clinical indications of arterial reconstruction remain controversial. Between 1994 and 2003, seven patients with celiac axis stenosis (n = 4) or occlusion (n = 3) underwent pancreatoduodenectomy at our hospital. Arterial reconstruction, including division of the median arcuate ligament, was conducted in two patients; the replaced right hepatic artery was preserved in one patient, and no vascular refinement was undertaken in the remaining four of the seven patients. In two of the four patients without arterial reconstruction or preservation, the serum levels of liver enzymes were markedly elevated (> 800 IU/l) on postoperative day 1, and these patients subsequently developed liver abscesses. Two patients who underwent arterial reconstruction and three patients who showed no decrease in intrahepatic arterial flow under Doppler ultrasonography after clamping of the gastroduodenal artery developed no ischemic complications. Although our experience is limited, when intraoperative Doppler ultrasonography indicates a decrease in the hepatic arterial signals, we believe that reconstruction of the hepatic artery will be necessary to minimize ischemic complications in the liver in patients with celiac axis stenosis.  相似文献   
992.
The anterior band of the inferior glenohumeral ligament is the most important restraint for preventing traumatic anterior glenohumeral instability. The condition of this ligament markedly affects the results of arthroscopic Bankart repair. We compared non-arthrographic magnetic resonance imaging (MRI) in abduction and external rotation and arthroscopic findings of the ligament in 51 shoulders with traumatic anterior glenohumeral instability. The condition of the ligament was evaluated based on the presence of a thick low-signal band between the anterior labrum and the head of the humerus in all magnetic resonance images obtained from the 3- to 5-o'clock position of the glenoid rim (right shoulder). The sensitivity and specificity of the MRI evaluation were 94% and 82%, respectively. MRI in abduction and external rotation is fairly useful for predicting the condition of the ligament in advance of invasive measures (ie, arthroscopy).  相似文献   
993.
A 69-year-old woman presented with a transethmoidal meningoencephalocele manifesting as gradually developing anosmia. Examinations revealed a mass in the nasal cavity associated with multiple angiomas in her lip and orbit. Neuroimaging showed meningoencephalocele extending via the ethmoid sinus to the nasal cavity. She had no history of craniofacial trauma and intranasal or intracranial operation, and no skull base tumor was detected. Frontal base reconstruction was performed with a two-layer vascularized flap to prevent cerebrospinal fluid leakage. The dural defect was repaired with the pericranial flap, and the bony defect of the cribriform plate was reconstructed using the reversed U-shaped split temporalis musculofascial flap. Transethmoidal meningoencephalocele is a rare congenital malformation and almost half of the cases are identified in the first year of life. We should be aware of this clinical pathology and avoid unexpected rhinorrhea in elderly patients. The most important aspect of the operation is watertight closure of the patent passage to the intracranial compartment. The reversed U-shaped split temporalis musculofascial flap is useful to reconstruct the midline frontal base defect.  相似文献   
994.
The influence of hip position on knee flexion angle before total knee arthroplasty (TKA) and that after TKA were investigated and compared. Sixty-six patients (70 knees) with osteoarthritis who were undergoing TKA were examined using lateral radiographs of maximum knee flexion angle with the hip joint at 0 degrees extension and 90 degrees flexion. The postoperative rate of decrease in knee flexion angle caused by hip extension was significantly larger compared with the value before surgery. The preoperative rate of decrease in knee flexion angle caused by hip extension showed strong inverse correlation with the preoperative and postoperative knee flexion angle ratio. In conclusion, tightness of the extensor mechanism is present in all knees undergoing TKA and especially has a strong influence on the postoperative flexion angle of the knee.  相似文献   
995.
PURPOSE: Vascular endothelial growth factor (VEGF) is known as a multifunctional protein with roles in angiogenesis stimulation and apoptosis inhibition. We hypothesized that intracavernous administration of VEGF would recover erectile dysfunction due to diabetes by protection from apoptosis in the penile cavernosum. MATERIALS AND METHODS: A total of 30, 6-month-old male Sprague-Dawley rats were divided into 2 large groups, namely 20 with diabetes and 10 healthy controls. The diabetic group received intraperitoneal injection of streptozotocin (STZ) to induce diabetes. Intracavernous injection of VEGF was administered to randomly selected STZ diabetic rats 6 weeks after STZ injections. Erectile functional studies were performed in 10 STZ and 10 STZ plus VEGF rats at 12 weeks. After completion of the functional study the penile crura were collected for molecular and immunohistochemical studies. RESULTS: Mean intracavernous pressure in the diabetic group was significantly lower than in controls and low pressure was significantly recovered by VEGF treatment. Gene expression of pro-apoptotic and anti-apoptotic factors were present in the control, diabetic and VEGF treated groups. However, anti-apoptotic protein expression was lacking in the diabetic group and it was recovered by VEGF treatment. The apoptotic index in the diabetic group was significantly higher than in controls and this index was significantly decreased in the VEGF treated group. CONCLUSIONS: The decrease in and recovery of intracavernous pressure correlated significantly with a variation in anti-apoptotic protein expression in the diabetic and VEGF treated groups. To our knowledge this is the first study to show that intracavernous injection of VEGF restores erectile dysfunction through the inhibition of apoptosis in diabetic rats.  相似文献   
996.
PURPOSE: We assayed whether high serum carotenoids and antioxidative substances decrease the risk of urothelial cancer in a case-control study nested in a community based cohort in Japan, that is the Japan Collaborative Cohort Study. MATERIALS AND METHODS: Information on subject life-styles and serum were collected in 1988 to 1990 and subjects were followed as late as 1999. Individuals who had or died of urothelial cancer and controls were matched for study area, sex and age. Serum was stored at -80C and analyzed in 2003. Of 14,097 male and 25,662 female subjects 40 to 79 years old there were 42 cases, which were matched to 124 controls. RESULTS: The OR for the highest to lowest tertile of serum concentration was 0.28 (95% CI 0.07 to 1.15, trend p = 0.08) for beta-carotene, 0.36 (95% CI 0.10 to 1.27, trend p = 0.10) for total carotenes and 0.31 (95% CI 0.09 to -1.09, trend p = 0.09) for total carotenoids after adjustment for smoking in addition to matching variables. High concentrations of tocopherols and xanthophylls slightly tended to decrease the risk of urothelial cancer. In contrast, serum retinol, oxidized low density lipoprotein and Cu/Zn-superoxide dismutase were not associated with urothelial cancer risk. CONCLUSIONS: Our results suggest that high serum carotenoids may decrease the risk of urothelial cancer with carotenes more effective than xanthophylls.  相似文献   
997.

Purpose:

We report the difference in quality of life (QOL) between patients with an orthotopic neobladder and normative values in the age matched Japanese population.

Materials and Methods:

Between November 1996 and June 2003, 75 patients underwent orthotopic neobladder construction at our institution, of whom 47 males and 9 females were enrolled in this study. A total of 19 patients were excluded because of death or insufficient followup (less than 6 months). Two types of questionnaire, namely the RAND 36-Item Health Survey, version 2 and the Functional Assessment of Cancer Therapy-Bladder Cancer, were mailed to all 56 patients. The 48 patients (86%) who returned the completed forms were included in our analysis. Postoperative QOL was compared with age matched normative values in the control Japanese population.

Results:

Overall there was no significant difference in any scale between patients with a neobladder and the age matched control Japanese population. The patient bodily pain score in the seventh decade of life and the role-physical score in those older than 70 years were better than age matched normative values in the Japanese population (p <0.005 and p <0.05, respectively). Male patients in the seventh decade of life were more likely to have better QOL in the physical functioning, role-physical and role-emotional subscales in addition to the bodily pain subscale compared to age matched control values (p <0.05, <0.05, <0.001 and <0.001, respectively). Likewise in male patients older than 70 years role-physical scores remained better than age matched normative values in the Japanese population (p <0.01). Further analysis of bladder cancer related QOL showed that patients followed more than 24 months were more likely to have a lower incontinence score than those followed less than 24 months (p <0.05). In addition, the continence related QOL change alone did not affect any health related QOL scales, as analyzed by RAND 36-Intem Health Survey.

Conclusions:

Our study shows that there is no essential difference in health related QOL between patients with a neobladder and the age matched Japanese control population. The current results provide some primary evidence to help in decision making and eliminate potential anxiety about worse QOL after cystectomy.  相似文献   
998.
Background Messenger RNA of liver fatty acid-binding protein (L-FABP) is expressed in proximal tubules of the kidney, and a certain amount is excreted into urine. We analyzed factors relating to the urinary L-FABP excretion in health-check participants.Methods We measured L-FABP in the first morning urine by ELISA in 715 men and 193 women 30–79 years of age who entered a 2-day hospitalized health checkup program. In addition to the routine physical examination and laboratory tests, plasma high-sensitivity C-reactive protein (HSCRP) was assayed.Results In 150 healthy subjects, urinary L-FABP averaged 3.6 ± 0.2µg/g creatinine, whereas the values were significantly increased in patients with hypertension (5.2 ± 0.4, P = 0.010), diabetes mellitus (5.5 ± 0.5, P < 0.001), and chronic hepatitis (5.8 ± 1.0, P = 0.022). Urinary L-FABP excretion was significantly greater in women than in men when the value was related to creatinine. In regression analysis in men, urinary L-FABP was positively correlated with fasting plasma glucose (r = 0.103, P = 0.033) and plasma HSCRP (r = 0.135, P = 0.006).Conclusions It is suggested that renal production and urinary excretion of L-FABP are increased in situations in which arteriosclerosis is promoted, such as hypertension, diabetes mellitus, and cardiovascular inflammation.  相似文献   
999.
1000.
Purpose We compared the clinicopathologic features affecting outcome after surgery for hepatocellular carcinoma (HCC) between patients with concurrent and previous chronic hepatitis B.Methods Group A consisted of 58 patients with concurrent chronic hepatitis B, defined by seropositivity for the hepatitis B surface antigen (HBsAg), and group B consisted of 18 patients whose HCC was detected after disappearance of the HBsAg. We assessed the influence of various characteristics on outcome.Results The mean age and percentage of patients suffering from alcohol abuse or diabetes mellitus were significantly greater in group B than in group A, whereas histologic hepatitis activity, hepatic fibrosis, and alanine aminotransferase activity were significantly lower in group B than in group A. The tumor-free survival rates were similar between the two groups, but the risk factors of recurrence differed. In group A, relative youth, high aspartate aminotransferase activity, low platelet count, multiple tumors, large tumor size, portal invasion, cirrhosis, nonanatomic resection, and positive surgical margin were risk factors. In group B, large tumor size and poor differentiation were risk factors.Conclusion Hepatitis B status, tumor factors, and the type of operation affected cancer recurrence after surgery for HCC in patients with concurrent chronic HBV, as opposed to only tumor factors in patients with previous chronic hepatitis B.  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