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   12994篇
  免费   677篇
  国内免费   104篇
耳鼻咽喉   78篇
儿科学   302篇
妇产科学   207篇
基础医学   1525篇
口腔科学   178篇
临床医学   810篇
内科学   3783篇
皮肤病学   208篇
神经病学   898篇
特种医学   406篇
外科学   2341篇
综合类   46篇
预防医学   254篇
眼科学   86篇
药学   871篇
中国医学   29篇
肿瘤学   1753篇
  2023年   112篇
  2022年   208篇
  2021年   399篇
  2020年   226篇
  2019年   291篇
  2018年   338篇
  2017年   260篇
  2016年   318篇
  2015年   352篇
  2014年   431篇
  2013年   472篇
  2012年   911篇
  2011年   927篇
  2010年   551篇
  2009年   461篇
  2008年   795篇
  2007年   825篇
  2006年   840篇
  2005年   792篇
  2004年   827篇
  2003年   780篇
  2002年   811篇
  2001年   148篇
  2000年   90篇
  1999年   163篇
  1998年   190篇
  1997年   146篇
  1996年   137篇
  1995年   100篇
  1994年   106篇
  1993年   88篇
  1992年   88篇
  1991年   73篇
  1990年   68篇
  1989年   43篇
  1988年   36篇
  1987年   39篇
  1986年   26篇
  1985年   26篇
  1984年   36篇
  1983年   22篇
  1982年   25篇
  1981年   20篇
  1980年   25篇
  1979年   22篇
  1978年   11篇
  1977年   16篇
  1976年   10篇
  1974年   13篇
  1969年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
PURPOSE: We developed an innovative transurethral resection system (TURis) consisting of a uniquely-designed generator and a resectoscope. The obturator nerve is protected from troublesome reflexes during TURis because the high frequency current delivery route is via the resection loop to the sheath of the resectscope and not via a patient plate. After extensive preclinical evaluation and verification of the system using an animal model to ensure efficacy as well as operational safety, TURis was conducted for treatment of superficial bladder cancer and benign prostatic hyperplasia. MATERIALS AND METHODS: In preclinical experiments swine bladder wall was transurethrally resected using the system in a saline environment. The results were compared with data obtained from an identical resection using the conventional system using sorbitol solution irrigation. Electrolytic contents were measured after TUR for comparative evaluation vis-a-vis corresponding pre-TUR data. Also, the depth of heat degeneration was measured in the resected tissue. From December, 2000 to June, 2002, TURis was performed in 25 cases of superficial bladder cancer and 30 cases of benign prostatic hyperplasia (BPH), using saline irrigation. All 55 cases were performed under spinal anesthesia without an obturator nerve block. The output power was set at 280 W for cut and 120 W for coagulation. A smaller electrode than those used in conventional TUR was used to improve the cutting efficacy. Occurrence of obturator nerve reflexes, difference of hematocrit and electrolytic contents before and after TURis, operation time and total volume of irrigated saline were evaluated. RESULTS: TURis in animal model: No adductor contraction of a lower limb was observable except for minimal creeping during the resection of a site close to the urethra. There were no apparent anomalies relative to the blood electrolyte content after TURis. No difference was observed in the mean depth of heat-degeneration tissue change compared with the conventional system. TURis for bladder cancer and BPH: No additional skills were required for TURis compared to conventional TUR. No obturator nerve reflex was observed except for a clinically insignificant thigh movement in one case of bladder cancer. The post-TURis blood tests manifested no significant anomalies in blood electrolyte content. Mean operation time for bladder cancer and BPH were 32 and 42 minutes respectively. Mean volumes of saline consumed during TURis were 6,083 ml for bladder cancer and 16,100 ml for BPH. CONCLUSIONS: TURis worked effectively in a saline-irrigated environment. It does not need a patient plate and obturator nerve block even in cases of bladder cancer on the lateral wall. In addition, saline was both safe and cost-effective compared to non-electrolytic solution as irrigant for TUR of BPH. This suggests that TURis may have more applications than conventional TUR.  相似文献   
992.
PURPOSE: To determine the risk factors of cholangitis and liver abscess occurring after percutaneous ablation therapy for liver tumors. MATERIALS AND METHODS: Between October 1995 and September 2002, 358 patients with 455 liver tumors underwent a total of 683 ablation procedures, such as percutaneous ethanol injection (PEI), percutaneous microwave coagulation (PMC), and radiofrequency (RF) ablation therapy. With a retrospective review of medical records, the rates and outcomes of cholangitis and/or liver abscess occurring after ablation therapy were evaluated. The relationship between cholangitis and/or liver abscess and multiple variables (age, disease, Child-Pugh class, size of nodules, multiplicity of nodules, history of transcatheter arterial embolization, presence of bilioenteric anastomosis, and lack of prophylactic antibiotics administration) were statistically analyzed. RESULTS: Cholangitis and/or liver abscess occurred in 10 sessions (1.5%) in 10 patients: six sessions after PEI, three sessions after PMC, and one session after RF ablation. Both cholangitis and liver abscess were noted in seven sessions, cholangitis was noted in two, and liver abscess was noted in one. Six patients recovered, but two developed recurrent cholangitis and liver abscess, one developed lung abscess complicated with liver abscess, and one died of septic shock associated with cholangitis. On stepwise regression analysis, bilioenteric anastomosis was the sole significant predictor of cholangitis and/or liver abscess formation (P <.001; odds ratio = 36.4; 95% CI = 9.67-136.9). CONCLUSION: Bilioenteric anastomosis strongly correlated with the development of cholangitis and/or liver abscess after percutaneous ablation therapy. Close posttreatment attention should be paid to this subgroup of patients.  相似文献   
993.
Exon 1 of the androgen receptor (AR) gene on the X chromosome contains a polymorphic CAG trinucleotide short tandem repeat. We describe here the rapid and reliable method of typing CAG repeats using electrophoresis, with denaturing polyacrylamide gel and an allelic ladder marker. Twenty-one alleles (the repeat number ranges from 13 to 35) were found using CAG repeat typing in normal Japanese individuals (83 males and 82 females). The allelic diversity (h) calculated was h=0.889, illustrating that CAG repeats at the AR locus is a highly polymorphic system.  相似文献   
994.
We analyzed the single nucleotide polymorphisms (SNPs) in the sixth (C6) and the seventh (C7) component genes of the complement system in a sample of the Japanese population, using polymerase chain reaction (PCR)-based methods and PCR direct sequencing. SNPs in the C6 gene studied here are as follows: A413C in exon 3, T1674C in exon 10, T7145A in exon 13, G[357+32]A in intron 2, and G[503-78]A in intron 3. We confirmed that nt413A and nt413C were associated with C6A and C6B, respectively. The result of the nt2145 typing showed that two subtypes exist in the C6B allotype. The SNP of G[357+32]A in intron 2 could be analyzed by using the PCR-RFLP method with HinfI. Allele frequencies in the Japanese population were found to be *G=0.920 and *A=0.080. SNPs in the C7 gene are as follows: T382C in exon 4, G1166C and A1258C in exon 9, and G[+10]A in intron 13. Nt382C and nt1258C would be responsible for C7-5 (=C7-3) and C7-4 allotypes, respectively.  相似文献   
995.
BACKGROUND: Posttransplant proteinuria and hypertension are difficult to treat after renal transplantation. Therefore, we examined whether candesartan cilexetil is effective in reducing urinary protein excretion or in controlling hypertension in patients with renal allograft dysfunction. METHODS: Sixty-two renal transplant recipients with proteinuria were enrolled in this study. They underwent kidney transplantation under cyclosporine or tacrolimus immunosuppression between February 1983 and December 1998. Causes of proteinuria were chronic rejection in 28, glomerulonephritis in 16, cyclosporine or tacrolimus nephrotoxicity in 9, and unknown in 9 recipients. The dose of candesartan cilexetil ranged from 4 to 12 mg/day. Eleven patients with proteinuria who had not been treated with candesartan cilexetil constituted a matched control population. RESULTS: Hypertension was well controlled by administration of candesartan cilexetil. Both systolic blood pressure and diastolic blood pressure significantly decreased from 141.7+/-14.8 mm Hg to 118.7+/-11.9 mm Hg and 121.2+/-11.6 mm Hg, and from 89.0+/-13.0 mm Hg to 72.0+/-10.4 mm Hg and 74.9+/-9.4 mm Hg, at 2 months and 1 year after administration, respectively. Urinary protein excretion was reduced from 0.93+/-1.2 g/day to 0.34+/-0.7 g/day and 0.43+/-1.2 g/day at 2 months and 1 year after administration, respectively. The levels of creatinine clearance were 55.7+/-28.9 mL/min before treatment, 50.9+/-24.8 mL/min at 2 months, and 52.6+/-24.8 mL/min at 1 year after treatment, respectively. There was no clinically significant difference between them. Regarding the calcineurin inhibitor levels, there was no significant difference between the levels before and 1 year after treatment. There was a significant difference in all examinations (systolic blood pressure, diastolic blood pressure, proteinuria, and renal function) between the patients with and without candesartan at 1 year after treatment. No significant adverse effects occurred. CONCLUSIONS: Candesartan cilexetil can effectively control hypertension and proteinuria without deterioration in renal allograft function. These data suggest that treatment with candesartan cilexetil may be useful for maintaining long-term renal allograft function.  相似文献   
996.
BACKGROUND: We developed an extracorporeal liver perfusion (ECLP) system as a liver-assist device. In this study, we evaluated the safety of the ECLP using human decay accelerating factor (hDAF) transgenic porcine livers in healthy baboons. METHODS: Livers were isolated from five hDAF transgenic pigs and five nontransgenic pigs for the ECLP. Ten cross-circulations between the ECLP and healthy baboons were performed without immunosuppressive agents. Cross-circulation was discontinued in any of the following circumstances: elevated hepatic arterial (>200 mm Hg) or portal (>60 mm Hg) perfusion pressure, massive exudate from the graft liver, mild macroscopic hemolysis, thrombocytopenia, or 24-hr well-conditioned cross-circulation. RESULTS: The cross-circulations with nontransgenic porcine livers were discontinued at 4.4+/-1.2 hr (mean+/-standard deviation) because of high perfusion pressure (n=2) or hemolysis (n=3). Three cross-circulations with hDAF transgenic porcine livers were performed for 24 hr; the other two cross-circulations were discontinued at 13 and 17 hr because of massive exudate and thrombocytopenia, respectively. The duration was 20.4+/-5.1 hr. Deposition of membrane attack complex in the hDAF transgenic porcine liver was less than that in the nontransgenic liver, although immunoglobulin-M deposition was comparable. The porcine livers showed no apparent interlobular bleeding or lobular necrosis. All porcine livers maintained bile production during the cross-circulation. No baboons showed any serious complications after the cross-circulation. CONCLUSION: The hDAF transgenic porcine liver reduced complement activation in xenoperfusion with healthy nonhuman primate blood and led to extended duration of cross-circulation.  相似文献   
997.
BACKGROUND: A large splenorenal collateral must be interrupted during liver transplantation to secure adequate portal perfusion. However, this process increases the complexity of the operative procedure and may cause hazardous bleeding. Recently, renoportal anastomosis in portal reconstruction was reported in cadaveric liver transplantation for patients with surgically created splenorenal shunts. We used this technique in a living-related liver transplantation. METHODS: A 29-year-old female with a large spontaneous splenorenal collateral and a portal venous thrombus underwent a living-related liver transplantation. At surgery, the left renal vein was divided and the distal stump was anastomosed to the portal vein of the graft without interrupting collaterals. RESULTS: Adequate portal venous blood flow was maintained throughout the postoperative course. The patient was discharged 9 weeks after transplantation and remains well. CONCLUSION: The renoportal anastomosis could be used for portal reconstruction in living-related liver transplantation for patients with a large splenorenal collateral. It provides adequate portal perfusion without interrupting collateral circulation.  相似文献   
998.
999.
A no change (NC) status could be maintained in a patient with remnant gastric cancer for more than 500 days with low-dose TS-1. The patient was a 68-year-old woman who was found to have remnant gastric cancer during an endoscopic examination in follow-up on an outpatient basis after surgery for hepatocellular carcinoma in our department. Surgery was rejected as a treatment option because of severe liver dysfunction, and the patient was started on oral TS-1 80 mg/day. Both AST and ALT levels increased immediately after the start of TS-1, and TS-1 was discontinued until these levels improved. It was resumed at 50 mg/day, and there were no subsequent adverse reactions. Endoscopic examination on day 69 after the start of TS-1 showed that a partial response (PR) had not been achieved, but the lesion had shrunk. Endoscopy on day 454 after the start of TS-1 showed it had been possible to maintain a similar state. This was a rare case in which it was possible to achieve prolonged same status with low-dose TS-1.  相似文献   
1000.
The prognosis of advanced hepatocellular carcinoma (HCC) is extremely poor. Patient 1 was a 43-year-old male with major portal tumor thrombi. He received combination therapy consisting of continuous arterial infusion (MTX 30 mg/m2, day 1, CDDP/5-FU 6 mg/m2: 250 mg/m2, day 1-14) and subcutaneous injection of IFN-alpha (500 x 10(4) U, 3 times a week, 4 weeks). Patient 2 was a 66-year-old male with major hepatic venous tumor thrombi. He received combination therapy consisting of continuous arterial infusion (5-FU 6 mg/m2: 250 mg/m2, day 1-14) and subcutaneous injection of IFN-alpha (500 x 10(4) U, 3 times a week, 4 weeks). Decrease in tumor was observed in both patients markers and marked regression of tumor was observed in both patients. They are still in complete response. This combination therapy is an effective strategy for advanced HCC.  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