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:      
  示例: 沙坡头地区,人工植被区,变化  检索词用空格隔开表示必须包含全部检索词,用“,”隔开表示只需满足任一检索词即可!
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   10287篇
  免费   160篇
  国内免费   37篇
耳鼻咽喉   115篇
儿科学   196篇
妇产科学   110篇
基础医学   1134篇
口腔科学   229篇
临床医学   677篇
内科学   2842篇
皮肤病学   174篇
神经病学   601篇
特种医学   362篇
外科学   1740篇
综合类   27篇
一般理论   1篇
预防医学   162篇
眼科学   153篇
药学   536篇
  8篇
中国医学   16篇
肿瘤学   1401篇
  2024年   65篇
  2023年   108篇
  2022年   200篇
  2021年   339篇
  2020年   194篇
  2019年   246篇
  2018年   242篇
  2017年   203篇
  2016年   277篇
  2015年   267篇
  2014年   319篇
  2013年   390篇
  2012年   693篇
  2011年   738篇
  2010年   444篇
  2009年   351篇
  2008年   595篇
  2007年   622篇
  2006年   627篇
  2005年   598篇
  2004年   561篇
  2003年   539篇
  2002年   535篇
  2001年   106篇
  2000年   107篇
  1999年   100篇
  1998年   110篇
  1997年   82篇
  1996年   43篇
  1995年   69篇
  1994年   58篇
  1993年   51篇
  1992年   61篇
  1991年   61篇
  1990年   53篇
  1989年   47篇
  1988年   52篇
  1987年   26篇
  1986年   33篇
  1985年   37篇
  1984年   30篇
  1983年   23篇
  1982年   17篇
  1981年   14篇
  1980年   14篇
  1979年   16篇
  1978年   12篇
  1977年   18篇
  1969年   11篇
  1968年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.

Background

Endoscopic submucosal dissection (ESD) involves dissection of tumors and manipulation of them in an exposed condition for prolonged periods. A large number of tumor cells are exfoliated into the intestinal lumen after colorectal ESD. The aim of this study was to determine whether lavage volume has an influence on tumor cell clearance after colorectal ESD.

Methods

Twenty patients who underwent colorectal ESD at our hospital between July 2013 and December 2014 were studied. Cytological examination of intraluminal lavage samples associated incremental increases in lavage volume was collected. This prospective study was approved by the ethics committee of our hospital.

Results

No patients had exfoliated tumor cells in their samples before ESD. Four patients (20 %) had exfoliated tumor cells in their samples after lavage with 500 ml, while one patient (5 %) had exfoliated tumor cells after lavage with 1000 or 1500 ml.

Conclusion

Tumor cells are exfoliated into the intestinal lumen by tumor manipulation during colorectal ESD. There seems to be a risk for implantation after ESD, as well as rectal surgery. Sufficient intraluminal lavage of more than 1000 ml may be desirable to remove exfoliated tumor cells after colorectal ESD.
  相似文献   
52.
We report a rare case of simultaneous repair for Cor triatriatum (CT), partially unroofed coronary sinus (CS) with persistent left superior vena cava (PLSVC), moderately severe tricuspid regurgitation, and atrial flutter 35 years after radical operation for tetralogy of Fallot (TOF). A 40-year-old woman underwent patch closure of atrial septal defect as to drain blood from left SVC to right atrium (RA), excision of diaphragm in left atrium (LA), tricuspid annuloplasty, and cryoablation. Postoperative course was uneventful with successful anatomical correction.  相似文献   
53.
PURPOSE: We examined the influence of intrathecal or dietary glycine on bladder and urethral activity in rats with spinal cord injury. MATERIALS AND METHODS: A total of 20 female Sprague-Dawley rats were used 4 weeks after lower thoracic spinal cord injury. The rats were divided into standard and 1% glycine diet groups. In the standard diet group isovolumetric cystometry and urethral pressure measurement were performed before and after intrathecal injection of glycine. In the 1% glycine diet group bladder and urethral activity were compared with control recordings in the standard diet group. RESULTS: In the standard diet group intrathecal injection of glycine prolonged the interval and decreased the amplitude of bladder contractions, decreased baseline urethral pressure and altered urethral activity during bladder contraction from a pattern of detrusor-sphincter dyssynergia to detrusor-sphincter synergy at 100 mug glycine. In the 1% glycine diet group the interval and amplitude of bladder contractions were prolonged and decreased, respectively, compared with those in the standard diet group. Baseline urethral pressure was lower than in the standard diet group even after intrathecal injection of 100 mug glycine. Urethral pressure did not change during bladder contraction and it was the same as baseline pressure. Residual urine volume was lower than in the standard diet group. CONCLUSIONS: Intrathecal or dietary glycine inhibits bladder and urethral activity, and improves detrusor hyperreflexia and detrusor-sphincter dyssynergia.  相似文献   
54.
Biliary stricture remains a significant cause of morbidity after liver transplantation. We performed duct-to-duct biliary anastomosis by using an absorbable stent tube with a diameter equal to that of pig common bile duct as an internal stent. The stent tube was constructed using a synthetic biodegradable material-a lactic glycolic acid and epsilon-caprolactone copolymer. Three pigs were alive without cholestasis for 180 d; however, 1 pig died on the 65th postoperative d, and autopsy revealed no cholestasis or biliary sledge in the biliary stent tube. The 3 pigs were euthanized for histological examinations 180 d after surgery; the biliary stent tube was completely absorbed by this time. These experimental results showed the good patency of the absorbable biliary stent tube. In the future, the absorbable biliary stent tube is expected to be clinically developed as a biliary stent for biliary anastomosis, which may protect the biliary anastomotic stricture.  相似文献   
55.
Acinar cell carcinomas (ACCs) of the pancreas are rare neoplasms, accounting for approximately 1% of all exocrine pancreatic tumors. This type of tumor is known to be aggressive, although the survival rates are somewhat better than they are for ductal carcinoma. The tumor tends to present nonspecific symptoms. It occurs in older patients, and jaundice is infrequent. This report presents a case of ACC of the pancreas with intraductal papillary growth and lymph node metastasis.  相似文献   
56.
Hepatic peribiliary cysts are composed of multiple tiny cysts along the larger portal tracts and have been reported to be harmless. On clinical images, peribiliary cysts resemble other diseases such as biliary dilatations, cholangitis, or periportal edema. Therefore, it is important to distinguish peribiliary cysts from these diseases using a combination of several imaging modalities. Herein, we report three cases of peribiliary cysts. The first case underwent laparotomy for the presumptive diagnosis of intrahepatic cholangiocarcinoma. In the remaining two cases, hepatic peribiliary cysts were diagnosed and laparotomy was avoided. Magnetic resonance cholangiography contributed to the diagnosis, owing to their characteristic distribution. In addition, computed tomography during cholangiography (cholangio-CT) demonstrated that the cysts had no communication with the intrahepatic biliary system. Therefore, cholangio-CT is considered to be the most useful modality for the diagnosis of peribiliary cysts.  相似文献   
57.
A case of carcinoma in situ (CIS) in the right renal pelvis in a 71-year-old women is reported. The patient was admitted because of macroscopic hematuria. Drip infusion pyelography showed a filling defect (coagulum) in the right renal pelvis. Other abnormal findings were not made. Malignancy was suspected by cytology examination in both voiding urine and that obtained by catheter from the right pelvis. A right total nephroureterectomy was performed. Macroscopic abnormal findings were only of the coagulum in the renal pelvis. Pathologic examination showed CIS in the renal pelvis. We studied the features, pattern of recurrence, and prognosis of 19 cases of primary CIS in the upper urinary tract in the Japanese literature. A slight higher frequency was reported for women than for men. When the CIS was in the ureter, abnormal roentgenological findings, such as stenosis, filling defects, or a dilated ureter, were common (77%), contrary to expectation. But when the CIS was in the pelvis, such findings were rare. Urine cytology examination was positive in 95% of the patients. In four of the 19 patients, a recurrence was found. In all four patients, the first recurrence was in the bladder within 2 years of surgery. The kind of recurrent bladder tumors varied with the patients. The prognosis with recurrence was poor. If signs of recurrence were not recognized within 2 years of surgery, the prognosis was good.  相似文献   
58.
A 66-year-old man developed a fever of 38 degrees C and generalized pruritic rash about one month after mexiletine hydrochloride administration for ventricular tachycardia. The rash appeared as edematous erythema and papules with purpura on the lower extremities. Liver dysfunction, leukocytosis, and atypical lymphocytes were also present. Elevated antibody titer against human herpes virus 6 (HHV-6) was detected during the course of the disease (1:20 -> 1:640). The patient was diagnosed as having drug-induced hypersensitivity syndrome (DIHS) due to mexiletine. Discontinuation of the mexiletine administration and systemic corticosteroid treatment led to a temporary improvement, but tapering the corticosteroid dose twice led to recrudescence. Simultaneous with the recrudescence, elevated antibody titers against HHV-6 and cytomegalovirus were detected, as well as viral DNA in the blood, suggesting that these two viruses may have been involved in the recrudescence. The patient died of myocarditis, most likely related to cytomegalovirus. Our case indicates that, in addition to HHV-6, other herpes viruses such as cytomegalovirus can be reactivated in DIHS and may modify the clinical disease activity.  相似文献   
59.
The aim of the present study was to assess the response of serotonin (5-hydroxytryptamine; 5-HT) in the preoptic area and anterior hypothalamus (PO/AH) to thermoregulation during exercise in a warm environment. In addition, it was investigated whether a rapid increase in extracellular 5-HT levels in the PO/AH modifies the thermoregulatory response under the same exercise conditions. Rats were made to run for 120 min at 10 m min−1 on a treadmill at the ambient temperature of 30 °C. Body core temperature (Tcore) was monitored using a biotelemetry system, and tail skin temperature (Ttail) was simultaneously measured as an index of heat loss response. Microdialysis in combination with HPLC was used to measure concentrations of monoamines in the PO/AH. Both Tcore and Ttail increased during the first 20 min of exercise and remained stable until the end of the exercise period. Low-intensity exercise did not induce any changes in 5-HT release in the PO/AH, although the levels of norepinephrine and dopamine were increased. Moreover, increased extracellular 5-HT by local perfusion of 1 μM citalopram (selective 5-HT reuptake inhibitor; SSRI) in the PO/AH had no effect on the thermoregulatory response during acute low-intensity exercise in a warm environment. These results suggest that enhanced release of only 5-HT in the PO/AH may not intervene thermoregulation during exercise in a warm environment.  相似文献   
60.
Development of early apoptosis and changes in lymphocyte subsets were examined in lymphoid organs of female BALB/c mice after oral administration of 15 mg/kg b.w. of nivalenol (NIV), the major type B trichothecene mycotoxin, by FACS analysis. Judging from the results of viable cell count and apoptotic cell index, NIV attacked Peyer's patches first and thymus most severely. In thymus, selective damage in CD4(+)CD8(+) cells was observed at 12 and 24 h after inoculation (HAI), following the peak of apoptosis at 9 HAI. CD4(+) cells were clearly suppressed at 3 HAI in Peyer's patches, at and after 9 HAI in mesenteric lymph nodes, and 3 to 12 HAI in spleen, respectively. CD8(+) cells were also suppressed at 24 HAI in mesenteric lymph nodes and at 12 HAI in spleen, respectively. As to changes in B cell subsets, IgG(+) cells significantly decreased from 3 to 12 HAI and all B cell subsets at 24 HAI in mesenteric lymph nodes. In spleen, IgM(+) cells were suppressed at 9 HAI. On the other hand, in Peyer's patches, following clear decrease in the numbers of pan-T and pan-B cells and viable cells at 3 HAI, all B cell subsets, especially IgA(+) cells, showed a significant increase in their numbers at 9 HAI, and the numbers of IgA(+) and IgM(+) cells remained higher values than controls thereafter. Taken together, in the course of recovery from NIV-induced prominent damage in Peyer's patches at 3 HAI, interaction of NIV with Peyer's patches might result in in vivo stimulation of interleukin production at this site and result in increased proliferation and differentiation of IgA-secreting B cells at and after 9 HAI.  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