全文获取类型
收费全文 | 5224篇 |
免费 | 236篇 |
国内免费 | 41篇 |
专业分类
耳鼻咽喉 | 55篇 |
儿科学 | 41篇 |
妇产科学 | 78篇 |
基础医学 | 607篇 |
口腔科学 | 115篇 |
临床医学 | 385篇 |
内科学 | 1365篇 |
皮肤病学 | 90篇 |
神经病学 | 283篇 |
特种医学 | 366篇 |
外科学 | 909篇 |
综合类 | 17篇 |
预防医学 | 150篇 |
眼科学 | 40篇 |
药学 | 282篇 |
中国医学 | 7篇 |
肿瘤学 | 711篇 |
出版年
2023年 | 57篇 |
2022年 | 92篇 |
2021年 | 193篇 |
2020年 | 120篇 |
2019年 | 135篇 |
2018年 | 146篇 |
2017年 | 104篇 |
2016年 | 116篇 |
2015年 | 136篇 |
2014年 | 169篇 |
2013年 | 214篇 |
2012年 | 342篇 |
2011年 | 341篇 |
2010年 | 206篇 |
2009年 | 173篇 |
2008年 | 299篇 |
2007年 | 338篇 |
2006年 | 291篇 |
2005年 | 308篇 |
2004年 | 262篇 |
2003年 | 246篇 |
2002年 | 256篇 |
2001年 | 66篇 |
2000年 | 78篇 |
1999年 | 68篇 |
1998年 | 46篇 |
1997年 | 51篇 |
1996年 | 38篇 |
1995年 | 45篇 |
1994年 | 31篇 |
1993年 | 15篇 |
1992年 | 57篇 |
1991年 | 44篇 |
1990年 | 40篇 |
1989年 | 31篇 |
1988年 | 31篇 |
1987年 | 34篇 |
1986年 | 41篇 |
1985年 | 28篇 |
1984年 | 19篇 |
1983年 | 19篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1979年 | 19篇 |
1978年 | 12篇 |
1975年 | 9篇 |
1969年 | 14篇 |
1968年 | 13篇 |
1967年 | 10篇 |
1966年 | 16篇 |
排序方式: 共有5501条查询结果,搜索用时 15 毫秒
51.
Koji Tanaka MD Isao Miyashiro MD Masahiko Yano MD Kentaro Kishi MD Masaaki Motoori MD Yousuke Seki MD Shingo Noura MD Masayuki Ohue MD Terumasa Yamada MD Hiroaki Ohigashi MD Osamu Ishikawa MD 《Annals of surgical oncology》2009,16(6):1520-1525
Background The effect of obesity on gastrectomy in patients with gastric cancer is controversial. The degree of abdominal fat increases
the technical difficulty of abdominal surgery. This study examined the effect of visceral fat on total gastrectomy and risk
factors associated with the formation of pancreatic fistula.
Methods Between February 2001 and April 2007, 191 patients with gastric cancer underwent total gastrectomy. The visceral fat area
(VFA) was calculated from computed tomography (CT) scans taken at the level of the umbilicus using FatScan Software. Patients
were divided into high- (≥100 cm2, n = 52) and low-VFA groups (<100 cm2, n = 139), and also into high- (≥25 kg/m2, n = 47) and low-BMI groups (<25 kg/m2, n = 144).
Results Blood loss and incidence of pancreatic fistula were significantly higher in the high- than low-VFA group. However, only blood
loss was significantly different between the high- and low-BMI groups. VFA, blood loss, and splenectomy were identified as
significant risk factors for pancreatic fistula formation on univariate analysis, and multivariate logistic regression analysis
of these factors identified VFA (p = 0.0001) and splenectomy (p = 0.0014) as significant predictors of pancreatic fistula.
Conclusions VFA is a better indicator for pancreatic fistula formation after total gastrectomy than is BMI. Lymph node dissection must
be performed carefully, especially in patients with visceral fat accumulation during total gastrectomy with splenectomy. 相似文献
52.
Ryoji Kawano Enjo Hata Shingo Ikeda Toshiya Yokota 《The Japanese Journal of Thoracic and Cardiovascular Surgery》2005,53(11):611-614
We describe a resected pulmonary blastoma in an 84-year-old male, the oldest of previously reported patients. A chest X-ray showed a 2 cm-sized abnormal shadow in the left lung field. Five months later computed tomography demonstrated a well-demarcated heterogenous mass, measuring 12 cm in diameter, in the left lower lobe of the lung. This mass was diagnosed as a carcinoma using echo-guided percutaneous biopsy. The patient underwent a left lower lobectomy. The resected specimen revealed the tumor to be a pulmonary blastoma arising from lung tissue. Preoperative diagnosis of pulmonary blastoma is extremely difficult because of the histological heterogeneity of tumor. Since it has been noted that pulmonary blastoma rapidly progresses in a short period of time, surgical treatment should be undertaken as quickly as possible when such a tumor is suspected. 相似文献
53.
Shingo Yamamoto Masao Tanooka Kumiko Ando Toshiko Yamano Reiichi Ishikura Michio Nojima Shozo Hirota Hiroki Shima 《International urology and nephrology》2009,41(4):785-790
To evaluate the diagnostic accuracy of computed tomography (CT)-based imaging methods for assessing renal vascular anatomy,
imaging studies, including standard axial CT, three-dimensional volume-rendered CT (3DVR-CT), and a 3DVR-CT movie, were performed
on 30 patients who underwent laparoscopic donor nephrectomy (10 right side, 20 left side) for predicting the location of the
renal arteries and renal, adrenal, gonadal, and lumbar veins. These findings were compared with videos obtained during the
operation. Two of 37 renal arteries observed intraoperatively were missed by standard axial CT and 3DVR-CT, whereas all arteries
were identified by the 3DVR-CT movie. Two of 36 renal veins were missed by standard axial CT and 3DVR-CT, whereas 1 was missed
by the 3DVR-CT movie. In 20 left renal hilar anatomical structures, 20 adrenal, 20 gonadal, and 22 lumbar veins were observed
during the operation. Preoperatively, the standard axial CT, 3DVR-CT, and 3DVR-CT movie detected 11, 19, and 20 adrenal veins;
13, 14, and 19 gonadal veins; and 6, 11, and 15 lumbar veins, respectively. Overall, of 135 renal vascular structures, the
standard axial CT, 3DVR-CT, and 3DVR-CT movie accurately detected 99 (73.3%), 113 (83.7%), and 126 (93.3%) vessels, respectively,
which indicated that the 3DVR-CT movie demonstrated a significantly higher detection rate than other CT-based imaging methods
(P < 0.05). The 3DVR-CT movie accurately provides essential information about the renal vascular anatomy before laparoscopic
donor nephrectomy. 相似文献
54.
55.
Y Nakamoto T Saga S Fujishiro M Washida M Churiki K Matsuda 《The British journal of radiology》1998,71(852):1320-1322
We report a case of gallstone ileus in which the stone impacted at the neck of a Meckel's diverticulum. CT demonstrated the gallstone as a calcified mass in the lower abdomen. Gallstone ileus was diagnosed although a more accurate diagnosis was not obtained pre-operatively. The site of impaction was not typical and a blind loop filled with contrast materials was evident. We believe that this is the first report demonstrating this rare condition with imaging. 相似文献
56.
Postoperative cytology for drained fluid from the pancreatic bed after "curative" resection of pancreatic cancers: does it predict both the patient's prognosis and the site of cancer recurrence? 总被引:1,自引:0,他引:1 下载免费PDF全文
Ishikawa O Wada H Ohigashi H Doki Y Yokoyama S Noura S Yamada T Sasaki Y Imaoka S Kasugai T Matsunaga T Takenaka A Nakaizumi A 《Annals of surgery》2003,238(1):103-110
OBJECTIVE: To evaluate the postoperative cytology of drained fluid from the pancreatic bed as a predictive indicator of local recurrence after curative (R0) resection of pancreatic cancer. SUMMARY BACKGROUND DATA: The pancreatic bed offers a common site of cancer recurrence (local recurrence), even after curative (R0) resection is performed for pancreatic cancer. If local recurrence is thereby predicted precisely, soon after surgery, we have a chance to treat it by adding radiation or some other locoregional therapy before it can grow or spread beyond the pancreatic bed. However, there have been no previous reports of cytology performed on the drained fluid after pancreatectomy. METHODS: This study includes 94 patients who had shown negative results in the peritoneal washing cytology before resection and subsequently received pancreatectomies for pancreatic tumors. They consisted of 12 benign tumors, 17 noninvasive or minimally invasive carcinomas and 65 invasive ductal carcinomas (R0 = 58; R1/2 = 7). Postoperatively, the drained fluid from the pancreatic bed was collected for 24 hours and used for cytologic examination. The cytologic results were examined in association with the histopathology of the resected tumor, patient's survival, and mode of cancer recurrence, including local recurrence. RESULTS: Patients with benign tumors or noninvasive/minimally invasive carcinomas had negative result in cytology, and none of them have died of local recurrence (limited to the pancreatic bed) to date. However, patients with invasive ductal carcinoma revealed higher cytology-positive rates: 28% (16/58) in curative (R0) resection; and 71% (5/7) in noncurative (R1/2) resection. Among 58 patients with R0 resection, the 3-year survival rate was 14% in 16 cytology-positive patients and 55% in 42 cytology-negative patients (P < 0.05). The 3-year cumulative rate of local recurrence was 85% and 23%, respectively (P < 0.05). Compared with other histopathologic parameters obtained from the resected specimens, the drain cytology was more specific in predicting the subsequent development of local recurrence. CONCLUSIONS: Drain-cytology was a quick examination that enabled us to specifically indicate both minute residual cancer and subsequent development of local recurrence even after R0 resection of pancreatic cancer. 相似文献
57.
We investigated the possibility of using computer analysis of high-resolution CT images to radiologically classify the shape of pulmonary nodules. From a total of 107 HRCT images of solid, solitary pulmonary nodules with prior differentiation as benign (n=55) or malignant (n=52), we extracted the desired pulmonary nodules and calculated two quantitative parameters for characterizing nodules: circularity and second central moment. Using discriminant analysis for two thresholds in differentiating malignant from benign states resulted in a sensitivity of 76.9%, a specificity of 80%, a positive predictive value of 78.4%, and a negative predictive value of 78.6%. 相似文献
58.
Nakamoto T Taguchi A Ohtsuka M Suei Y Fujita M Tsuda M Sanada M Kudo Y Asano A Tanimoto K 《Dento maxillo facial radiology》2008,37(5):274-281
OBJECTIVES: An eroded inferior cortex of the mandible detected on dental panoramic radiographs is useful for identifying post-menopausal women with low skeletal bone mineral density (BMD) or osteoporosis. The purposes of this study were to develop a computer-aided diagnosis (CAD) system that automatically determines cortical erosion of the mandible on dental panoramic radiographs and to assess the validation of this CAD system. METHODS: A CAD system was developed based on mathematical morphology for identifying post-menopausal women with low skeletal BMD or osteoporosis, based on World Health Organization criteria, by identifying whether the endosteal margin of mandibular cortical bone was eroded. The sensitivity, specificity, predictive value, accuracy and likelihood for a positive risk result were calculated using dichotomous 2 x 2 tables using 100 panoramic radiographs. RESULTS: For identifying women with low skeletal BMD, the sensitivity and specificity were 76.8% and 61.1%, respectively, the positive and negative predictive values were 90.0% and 36.7%, accuracy was 74.0% and the likelihood for positive risk was 1.96. The respective values for identifying women with osteoporosis were 94.4% and 43.8%, the positive and negative predictive values were 48.6% and 93.3%, respectively, the accuracy was 62.0% and the likelihood for positive risk was 1.68. CONCLUSION: Our results suggest that a CAD system applied to dental panoramic radiographs may be useful for identifying post-menopausal women with low skeletal BMD or osteoporosis. 相似文献
59.
MRA of intracranial aneurysms embolized with platinum coils: a vascular phantom study at 1.5T and 3T
Kakeda S Korogi Y Hiai Y Sato T Ohnari N Moriya J Kamada K 《Journal of magnetic resonance imaging : JMRI》2008,28(1):13-20
PURPOSE: To analyze the influence of matrix and echo time (TE) of three-dimensional time-of-flight (3D TOF) magnetic resonance angiography (MRA) on the depiction of residual flow in aneurysms embolized with platinum coils at 1.5T and 3T. MATERIALS AND METHODS: A simulated intracranial aneurysm of the vascular phantom was loosely packed to maintain the patency of some residual aneurysmal lumen with platinum coils and connected to an electromagnetic flow pump with pulsatile flow. MRAs were obtained altering the matrix and TE of 3D TOF sequences at 1.5T and 3T. RESULTS: The increased spatial resolution and the shorter TE offered better image quality at 3T. For the depiction of an aneurysm remnant, the high-spatial-resolution 3T MRA (matrix size of 384 x 224 and 512 x 256) with a short TE of < or =3.3 msec were superior to the 1.5T MRA obtained with any sequences. CONCLUSION: 3T MRA is superior to 1.5T MRA for the assessment of aneurysms embolized with platinum coils; the combination of the 512 x 256 matrix and short TE (3.3 msec or less) seems feasible at 3T. 相似文献
60.
Ishii K Kanda T Harada A Miyamoto N Kawaguchi T Shimada K Ohkawa S Uemura T Yoshikawa T Mori E 《European radiology》2008,18(11):2678-2683
The utility of measuring the corpus callosal angle (CA) for the diagnosis of idiopathic normal pressure hydrocephalus (INPH)
was investigated. Three-dimensional magnetic resonance imaging (MRI) was performed in 34 INPH patients, 34 Alzheimer’s disease
(AD) patients, and 34 normal control (NC) subjects. Measurement of the CA on the coronal MR images of the posterior commissure
perpendicular to the anteroposterior commissure plane was performed for all subjects. The CA of the INPH group (mean ± SD,
66 ± 14°) was significantly smaller than those of the AD (104 ± 15°) and NC (112 ± 11°) groups. When using the threshold of
the mean − 2SD value of the NC group (= 90°), an accuracy of 93%, sensitivity of 97%, and specificity of 88% were observed
for discrimination of INPH from AD patients. Measuring the CA helps in differentiating INPH patients from AD and normally
aged subjects. 相似文献