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   5553篇
  免费   233篇
  国内免费   44篇
耳鼻咽喉   31篇
儿科学   113篇
妇产科学   66篇
基础医学   484篇
口腔科学   76篇
临床医学   419篇
内科学   1688篇
皮肤病学   85篇
神经病学   345篇
特种医学   266篇
外科学   1042篇
综合类   20篇
预防医学   109篇
眼科学   60篇
药学   309篇
中国医学   17篇
肿瘤学   700篇
  2023年   39篇
  2022年   84篇
  2021年   133篇
  2020年   71篇
  2019年   92篇
  2018年   137篇
  2017年   107篇
  2016年   113篇
  2015年   140篇
  2014年   177篇
  2013年   215篇
  2012年   386篇
  2011年   370篇
  2010年   243篇
  2009年   156篇
  2008年   303篇
  2007年   375篇
  2006年   332篇
  2005年   376篇
  2004年   396篇
  2003年   402篇
  2002年   348篇
  2001年   57篇
  2000年   54篇
  1999年   62篇
  1998年   83篇
  1997年   84篇
  1996年   65篇
  1995年   49篇
  1994年   51篇
  1993年   46篇
  1992年   32篇
  1991年   31篇
  1990年   30篇
  1989年   28篇
  1988年   23篇
  1987年   24篇
  1986年   12篇
  1985年   13篇
  1984年   8篇
  1983年   6篇
  1982年   9篇
  1981年   8篇
  1980年   11篇
  1979年   6篇
  1978年   6篇
  1977年   6篇
  1975年   5篇
  1972年   4篇
  1970年   3篇
排序方式: 共有5830条查询结果,搜索用时 15 毫秒
41.
42.
Open in a separate window OBJECTIVESAlthough reoperation has been increasingly performed in cardiovascular surgery in recent years, preventing surgical adhesions remains an unsolved complication. Therefore, this study aimed to investigate whether gelatine sealing sheets are more effective than fibrin sealing sheets in preventing surgical adhesions.METHODSBilateral femoral arteries of 20 beagle dogs under general anaesthesia were pricked with syringe needles, and gelatine and fibrin sealing sheets were applied on the bleeding points to make canine adhesion models. The femoral artery was harvested after 4 and 12 weeks to evaluate adhesion formations. The adhesive grade was quantified by scoring the area and strength of adhesion tissues. Histological staining was performed to examine the structural features of surgical adhesions.RESULTSSignificantly fewer macroscopic adhesions were observed with gelatine sealing sheets than those with fibrin sealing sheets at 4 and 12 weeks postoperatively. Microscopically, CD3+ T lymphocytes at 4 and 12 weeks postoperatively in gelatine sealing sheets were significantly lower than those in fibrin sealing sheets. Microvessel density determined by CD34 at 4 and 12 weeks postoperatively in gelatine sealing sheets was also significantly lower than those in fibrin sealing sheets.CONCLUSIONSThe gelatine sealing sheets are more effective than the fibrin sealing sheets in preventing surgical adhesions. These findings suggest that the gelatine sealing sheet may help prevent adhesions and thus be a therapeutically effective biomaterial in vascular surgery.  相似文献   
43.
44.
Although the mortality rates of gastric cancer (GC) are gradually declining, gastric cancer is still the fourth leading cause of cancer-related death worldwide. This may be due to the high rate of patients who are diagnosed with GC at advanced stages. However, in countries such as Japan with endoscopic screening systems, more than half of GCs are discovered at an early stage, enabling endoscopic resection (ER). Especially after the introduction of endoscopic submucosal dissection (ESD) in Japan around 2000, a high en bloc resection rate allowing pathological assessment of margin and depth has become possible. While ER is a diagnostic method of treatment and may not always be curative, it is widely accepted as standard treatment because it is less invasive than surgery and can provide an accurate diagnosis for deciding whether additional surgery is necessary. The curability of ER is currently assessed by the completeness of primary tumor removal and the possibility of lymph node metastasis. This review introduces methods, indications, and curability criteria for ER of EGC. Despite recent advances, several problems remain unsolved. This review will also outline the latest evidence concerning future issues.  相似文献   
45.
Acute promyelocytic leukemia (APL) has the best prognosis among acute leukemias, but there is little data about APL in patients on hemodialysis. A 64-year-old hemodialysis patient was successfully treated for APL by induction therapy with all-trans retinoic acid (ATRA), three courses of consolidation therapy with Ara-C, mitomycin?C (MIT), daunorubicin (DNR), and idarubicin (IDR), and maintenance therapy with ATRA. Complete remission has been maintained for 42?months in this patient. With dose modification, ATRA and chemotherapy may be safely given to patients on hemodialysis.  相似文献   
46.
Value of percutaneous transhepatic cholangioscopy (PTCS)   总被引:4,自引:0,他引:4  
Since July 1975, percutaneous transhepatic biliary drainage (PTBD) has been performed in 533 cases, and since April 1977 we have developed percutaneous transhepatic cholangioscopy (PTCS) as a diagnostic and therapeutic endoscopical tool in 198 cases of malignant disease and 195 benign cases. After dilating the sinus tract of PTBD using a 15-Fr catheter about 2 weeks after PTBD, PTCS was carried out through the sinus tract. PTCS has diagnostic advantages: the lesion can be accurately diagnosed histologically and the extent of cancer in the biliary tract can be assessed by taking biopsy specimens before the operation. PTCS has been applied for cholangioscopic lithotripsy in 145 cases of gallstone disease. In 44 cases, the Nd-YAG laser and/or electrohydraulic shock wave has been used to break up the stones. The PTCS morbidity was 6% and mortality was 0.3%.  相似文献   
47.
Miura H  Taira O  Hiraguri S  Maeda J  Kato H 《Surgery today》2002,32(10):891-895
Squamous cell carcinoma of the breast is a rare type of cancer, the origin of which is still uncertain. We report a case of squamous cell carcinoma of the breast with a recurrent tumor that showed undifferentiated features. The patient was a 55-year-old woman who originally presented with a left breast mass in the upper outer quadrant. Echography showed a 46 × 29 × 23-mm mass with cavity formation, and aspiration cytology confirmed a diagnosis of squamous cell carcinoma. A modified radical mastectomy with level III lymph node dissection was performed. Pathologically, the tumor was composed of squamous cell carcinoma and noninvasive ductal carcinoma. A recurrent tumor showing undifferentiated features was detected in the left forechest 3 months after the operation, and tumorectomy with partial resection of the major and minor pectoralis muscles was performed. Despite intensive therapy including chemotherapy (CEF: cyclophosphamide, epirubicin, 5-fluorouracil) and irradiation (50 Gy), the patient died from pulmonary and skin metastases 20 months after her initial operation. The squamous cell carcinoma of the breast in this patient grew rapidly and her prognosis was poor. Immunohistochemical findings indicated the possibility that the squamous cell carcinoma developed from noninvasive ductal carcinoma of the comedo type, and that the undifferentiated cells from the site of recurrence developed from dedifferentiation of the squamous cell carcinoma. Received: August 10, 2001 / Accepted: March 5, 2002  相似文献   
48.
OBJECTIVE: To better determine the role of portal vein resection and its effect on survival, as well as to appreciate the impact of portal vein invasion on prognosis in hilar cholangiocarcinoma. SUMMARY BACKGROUND DATA: Hepatectomy with portal vein resection is sometimes performed for locally advanced hilar cholangiocarcinoma. However, the significance of microscopic invasion of the portal vein has not been determined. METHODS: Medical records of 160 patients with hilar cholangiocarcinoma who underwent macroscopically curative hepatectomy with (n = 52) or without portal vein resection (n = 108) were reviewed. Invasion of the portal vein was assessed histologically on the surgical specimen, and results were correlated with clinicopathologic features and survival. RESULTS: Surgical mortality, including all hospital deaths, was similar in patients who did and did not undergo portal vein resection (9.6% vs. 9.3%), but the primary tumor was more advanced in patients who underwent portal vein resection. Histologically, no invasion was found in 16 (30.8%) of resected portal veins. However, dense fibrosis adjacent to the portal vein was common, and the mean distance between the leading edge of cancer cells and the adventitia of the portal vein was 437 +/- 431 mum. The prognosis was worse in patients with than without portal vein resection (5-year survival, 9.9% vs. 36.8%; P < 0.0001). The presence or absence of microscopic invasion of the resected portal vein did not influence survival (16.6 months in patients with microscopic invasion vs. 19.4 months in those without; P = 0.1506). Multivariate analysis identified histologic differentiation, lymph node metastasis, and macroscopic portal vein invasion as independent prognostic factors. CONCLUSIONS: Microscopic invasion of the portal vein may be misdiagnosed clinically in patients with hilar cholangiocarcinoma. However, the distance between tumor and adventitia is so narrow that curative resection without portal vein resection is unlikely to be possible. Gross portal vein invasion has a negative impact on survival, and hepatectomy with portal vein resection can offer long-term survival in some patients with advanced hilar cholangiocarcinoma.  相似文献   
49.
Abstract

This study aimed to characterize the effect of different running modes on serum irisin concentrations in rats. A total of 18, 10-week-old rats were divided into three groups; control group, 16° uphill running group (concentric exercise; CON) and, ?16° downhill running group (eccentric exercise; ECC). The running group’s rats ran on the inclined treadmill at 16?m/min, for a total of 90?min. Blood was drawn from the rats, 48?h after running, after which the rats were anesthetized. The serum concentrations of irisin were measured using enzyme-linked immunosorbent assays. Vastus intermedius was collected for immunohistochemical analysis. After multiple comparisons, the ECC showed a significantly high serum irisin concentration (ECC: 28.42?±?6.31?ng/ml, CON: 21.27?±?3.03?ng/ml) and a larger irisin antibody reactive cross-sectional area in vastus intermedius compared to the CON (p?<?0.05). This is the first study to reveal that single bout downhill running increases serum irisin concentrations in rats.  相似文献   
50.
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