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   3215篇
  免费   137篇
  国内免费   20篇
耳鼻咽喉   28篇
儿科学   76篇
妇产科学   48篇
基础医学   342篇
口腔科学   85篇
临床医学   211篇
内科学   698篇
皮肤病学   36篇
神经病学   254篇
特种医学   180篇
外科学   637篇
综合类   15篇
预防医学   51篇
眼科学   19篇
药学   326篇
中国医学   26篇
肿瘤学   340篇
  2023年   13篇
  2022年   14篇
  2021年   37篇
  2020年   19篇
  2019年   35篇
  2018年   46篇
  2017年   31篇
  2016年   49篇
  2015年   46篇
  2014年   77篇
  2013年   94篇
  2012年   151篇
  2011年   181篇
  2010年   98篇
  2009年   82篇
  2008年   122篇
  2007年   178篇
  2006年   173篇
  2005年   198篇
  2004年   169篇
  2003年   168篇
  2002年   186篇
  2001年   78篇
  2000年   84篇
  1999年   72篇
  1998年   52篇
  1997年   46篇
  1996年   58篇
  1995年   47篇
  1994年   39篇
  1993年   34篇
  1992年   97篇
  1991年   73篇
  1990年   76篇
  1989年   51篇
  1988年   52篇
  1987年   38篇
  1986年   37篇
  1985年   33篇
  1984年   39篇
  1983年   40篇
  1982年   14篇
  1981年   11篇
  1979年   14篇
  1978年   12篇
  1977年   14篇
  1975年   10篇
  1974年   9篇
  1973年   11篇
  1972年   10篇
排序方式: 共有3372条查询结果,搜索用时 15 毫秒
1.
Anthocyanins, which are responsible for a variety of bright colors (including red, blue, and purple) in fruits, vegetables, and flowers, are consumed as dietary polyphenols. Anthocyanin-containing fruits are thought to decrease coronary heart disease and are used in anti-diabetic preparations. Diabetes is associated with a variety of cardiovascular complications that may be mediated by endothelial dysfunction, and so this study was designed mainly to characterize the influence of a synthesized anthocyanidin derivative (HK-008) over acetylcholine (ACh)-induced relaxation in mesenteric arterial beds isolated from rats. In a glucose-tolerance test in intact rats, HK-008 (30 mg/kg) reduced the glucose level as effectively as the same dose of glibenclamide. The aortic relaxation induced by pinacidil (an ATP-sensitive potassium channel opener) was greatly inhibited by glibenclamide (10 microM), and also significantly inhibited by HK-008 (10 microM). Interestingly, the ACh-induced relaxation in the perfused, preconstricted mesenteric arterial bed was significantly enhanced by HK-008 (10 microM), and this enhancement was significantly attenuated by indomethacin (10 microM). The ACh-induced mesenteric relaxation was impaired by an increase in oxidative stress, viz. superoxide-generating treatment [xanthine oxidase (XO; 0.1 U/ml) plus hypoxanthine (HX; 10 microM)]. However, this impairment was strongly suppressed by HK-008 (10 microM). These results suggest that HK-008 increases endothelium-induced relaxation by suppressing oxidative stress or modulating prostanoids signaling. This compound may therefore be useful against certain cardiovascular disorders.  相似文献   
2.
Aminoglycosides are widely used, and clinicians continue to seek newer and better methods for initial dosing of these agents. Recently, three new methods were introduced: Thomson, Reesor Nimmo, and dosing in Tenopathy by easy-to-use multipliers (DREM). In comparing them with older, traditional dosing methods in patients with various degrees of renal function, the pharmacokinetic variables of gentamicin were determined from steady-state peak (Cmax) and trough (Cmin) serum concentrations using individualized regimens in 88 patients. Dosages were determined in each patient using the method of Hull-Sarubbi, rule of eights, and the three new methods, and the resultant Cmax and Cmin values were calculated from dosages generated by each method. The daily doses and Cmax values derived with the Hull-Sarubbi, Thomson, and Reesor Nimmo methods were not significantly different (p>0.05). The Hull-Sarubbi was the most precise (root mean squared prediction error 1.3) and least biased (mean prediction error −0.05) of the five methods in predicting target gentamicin serum peak concentrations (Cmax 6.5 mg/L). The Hull-Sarubbi (69%), Thomson (86%), and Reesor Nimmo (70%) methods yielded therapeutic Cmax (5–8 mg/L) in a significantly higher percentage of patients than did the rule of eights (32%) and DREM (35%), (p<0.05). Therefore, if gentamicin serum concentrations are not available, the first three appear to be reasonable methods for initiating gentamicin dosage regimens, but the last two may not be desirable to use in a clinical setting. These conclusions are based on the assumption that patients are adults with stable renal function and relatively stable clinical conditions.  相似文献   
3.
We report the results and complications of 103 consecutive patients who underwent percutaneous removal of renal and ureteral stones. The overall clinical success rate was 80.6%. For the recent 33 cases in which UL-arm fluoroscopy was used, however, the success rate was as high as 87.9%, which was considered to be due to easier establishment of percutaneous direct access. The most common complications were bleeding (18.5%), extravasation (15.5%) and fever (9.7%). Four cases with significant bleeding required arteriography, but there were no sign of arteriovenous fistula nor pseudoaneurysms in any cases. To study renal parenchymal damage in the percutaneous procedures, plasma renin activities (PRA) were compared in 54 cases after six months. However, significant elevation of PRA did not occur in any case.  相似文献   
4.
5.
During the course of our studies on dental caries prevention by traditional medicines, fatty acids (myristic and oleic acids etc.) and procyanidins from betel nuts (the seed of Areca catechu L.) were respectively revealed to be the major antibacterial principles against a primary cariogenic bacterium, Streptococcus mutans, and the major inhibitory principles against glucosyltransferase from S. mutans.  相似文献   
6.
Between November 1986 and April 1989, 101 patients with superficial bladder cancer were treated with intravesical instillations of mitomycin C on day 1 and doxorubicin on day 2 of each week for 5 consecutive weeks. Of 61 complete responders, 23 patients with carcinoma in situ and 28 with papillary cancer were randomly assigned to a non-maintenance group or to a group receiving maintenance therapy consisting of monthly instillations of the same drugs for 12 months. The 2-year non-recurrence rate calculated for patients with carcinoma in situ was significantly better in the maintenance group than in the non-maintenance group. A similar tendency was observed for patients with papillary cancer, although the difference was not significant. Side effects were considerable, with moderate to severe bladder irritation occurring in approximately half of the patients. In addition to our previous findings, the present results indicate that this intravesical combination chemotherapy is effective in eliminating superficial bladder cancers and that since the effect is not durable, even in complete responders, maintenance therapy is necessary to reduce subsequent tumor recurrence.Presented at the 4th International Conference on Treatment of Urinary Tract Tumors with Adriamycin/Farmorubicin, 16–17 November 1990, Osaka, Japan  相似文献   
7.
Y Tabuchi  H Deguchi  K Imanishi  Y Saitoh 《Cancer》1992,69(10):2411-2417
Correlations between preoperative carcinoembryonic antigen (CEA) levels of peripheral (p-CEA) and draining blood (d-CEA), the CEA gradient between d-CEA and p-CEA (d-p CEA gradient) levels, and survival after resection of cancer lesions were examined in 94 patients with colorectal cancer. Survival rates of patients with normal p-CEA and d-CEA levels and d-p CEA gradient levels (less than 5 ng/ml) were significantly better than those of patients with abnormal levels (greater than or equal to 5 ng/ml), and the 5-year survival rates were, respectively, 62%, 69%, and 72% in the former and 42%, 41%, and 35% in the latter. The differences in the 5-year survival rates between patients with normal and abnormal d-p CEA gradient, d-CEA, and p-CEA levels were 37%, 28%, and 20%, respectively. Furthermore, the positive rates of d-CEA levels (64%) and d-p CEA gradient levels (48%) were higher than that of p-CEA levels (36%). However, some significant differences in background variables also were found between the respective groups of patients with normal and abnormal p-CEA and d-CEA levels and d-p CEA gradient levels. These results suggest that patients with poor prognoses are examined more effectively by determining their d-p CEA gradient and d-CEA levels than their p-CEA levels, and that CEA may be expressed as a quantitative sum total of various pathophysiologic variables of patients with colorectal cancer but not as an independent prognostic variable.  相似文献   
8.
Antibacterial effects of combination use of arbekacin (ABK) with cefotiam (CTM) or cefuzonam (CZON) were evaluated against methicillin-resistant Staphylococcus aureus (MRSA) and the following results were obtained. 1. Antibacterial effects of combinations of ABK with CTM and with CZON were equally potent against MRSA at clinically expected 1 MIC of ABK in blood. However, at a sub MIC of ABK the different effects were observed between the 2 combinations. The antibacterial effect of the former was strong and that of the latter was a little weak. 2. In either combination the potency of the antibacterial activity was less dependent on the concentration of CTM or CZON, but was strongly dependent on ABK concentrations. These results suggest that antibacterial effects of the combinations were highly dependent on antibacterial potency and concentration of ABK as previously reported for combinations of ABK with other drugs. 3. The combination use of ABK with CTM appears to be useful in cases of infection by MRSA alone while the combination use of ABK with CZON appears to be useful in cases of double infection with MRSA and Gram-negative bacterium.  相似文献   
9.
The vascular type of Ehlers-Danlos syndrome is a genetic disorder of connective tissue and is frequently associated with catastrophic arterial complications. Its surgical treatment is extremely difficult because of the fragility of vessels. This article describes three patients with vascular type of Ehlers-Danlos syndrome who developed mesenteric hemorrhage due to spontaneous arterial rupture. The clinical and molecular characteristics of the disease are briefly reviewed.  相似文献   
10.
AIM OF THE STUDY: Although a bleeding tendency as a first symptom is a critical condition in congenital biliary dilatation (CBD), the clinical details of this symptom remain unclear. We assessed this condition in children with CBD in this paper. MATERIALS AND METHODS: Sixty-five children with CBD were treated at our institute between 1983 and 2004. The children, initially presenting with bleeding manifestations such as intracranial hemorrhage and bloody stools, were defined as the bleeding group, and the remaining children with digestive symptoms such as abdominal pain and vomiting were defined as the digestive group. The clinical features were compared between these two groups. RESULTS: In 6 of the 65 cases, bleeding manifestations were noted (9.2 %). All six had cystic-type choledochal dilatation. The mean age of the bleeding group was significantly younger than that of the digestive group, and bleeding was more frequent, especially in infants less than 12 months of age. In a laboratory study, the bleeding group showed a more prolonged blood coagulation time than the digestive group did. Serum amylase and lipase levels in the bleeding group were almost normal, while those in the digestive group were significantly higher. The direct bilirubin level in the bleeding group was significantly higher than that in the digestive group. CONCLUSIONS: Disturbed blood coagulation due to vitamin K deficiency related to cholestasis results in a bleeding tendency in children with CBD. Therefore, pediatric surgeons should be aware of this rare but critical condition which can be prevented by rapid and precise treatment with vitamin K supplementation.  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