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   2947篇
  免费   144篇
  国内免费   13篇
耳鼻咽喉   90篇
儿科学   61篇
妇产科学   8篇
基础医学   353篇
口腔科学   156篇
临床医学   172篇
内科学   799篇
皮肤病学   42篇
神经病学   186篇
特种医学   131篇
外科学   524篇
综合类   13篇
预防医学   99篇
眼科学   39篇
药学   157篇
中国医学   5篇
肿瘤学   269篇
  2022年   32篇
  2021年   41篇
  2020年   32篇
  2019年   39篇
  2018年   52篇
  2017年   50篇
  2016年   44篇
  2015年   61篇
  2014年   79篇
  2013年   84篇
  2012年   120篇
  2011年   145篇
  2010年   72篇
  2009年   75篇
  2008年   117篇
  2007年   137篇
  2006年   130篇
  2005年   123篇
  2004年   139篇
  2003年   144篇
  2002年   147篇
  2001年   68篇
  2000年   69篇
  1999年   69篇
  1998年   42篇
  1997年   46篇
  1996年   46篇
  1995年   34篇
  1994年   25篇
  1993年   31篇
  1992年   52篇
  1991年   60篇
  1990年   73篇
  1989年   80篇
  1988年   66篇
  1987年   55篇
  1986年   64篇
  1985年   46篇
  1984年   44篇
  1983年   26篇
  1982年   22篇
  1981年   13篇
  1980年   10篇
  1979年   42篇
  1978年   13篇
  1977年   19篇
  1976年   14篇
  1975年   16篇
  1972年   12篇
  1968年   11篇
排序方式: 共有3104条查询结果,搜索用时 15 毫秒
91.
92.
We report FDG PET of two cases of cold abscess due to Mycobacterium tuberculosis. Case 1 had colon cancer; FDG PET showed high FDG uptake in the colon lesion and low uptake in the inguinal lesion. The latter was a tuberculous cold abscess confirmed by CT/MRI and biopsy. Case 2 received radiotherapy for lung cancer and presented with suspected vertebral metastasis. Further studies revealed tuberculosis of the vertebra and a tuberculous cold abscess in the iliopsoas muscle. FDG PET showed moderate uptake in the third lumbar spine and low uptake in the abscess center of iliopsoas lesion. Both tuberculous cold abscesses showed moderate FDG uptake in the capsule and low uptake in the center. These features are unique compared with non-tuberculous abscess and typical tuberculosis lesions, which are characterized by high FDG uptake. Pathologically, tuberculous cold abscess is not accompanied by active inflammatory reaction. Our findings suggested that the FDG uptake by tuberculous lesion varies according to the grade of inflammatory activity. The new diagnostic features of tuberculous cold abscess may be useful in the evaluation of such lesions by FDG PET.  相似文献   
93.
Ileal conduits have long been accepted as a standard method for urinary diversion, but conventional ileal conduits are not always suitable for patients whose ureters are for the greater part compromised by neoplasm or preoperative irradiation, resulting in a shortening of the ureters. Bowel migration into the large cavity, which develops after pelvic organ removal, appears to cause tension on the ureteroileal anastomotic site. Dextrotransmesenteric placement of an ileal conduit may provide easy access to the shortened ureters without exerting pressure on the anastomosis. We employed this procedure in seven patients undergoing pelvic exenteration with relatively minimal morbidity.  相似文献   
94.
Serum prostatic acid phosphatase (PAP), γ-seminoprotein (γ-Sm), and prostate-specific antigen (PA) levels were measured in 63 untreated patients with prostatic cancer. The sensitivities of PAP, γ-Sm, and PA as markers of malignancy were 68%, 83%, and 77%, respectively. The latter two markers were more sensitive than PAP, especially in stage B disease. The specificities of PAP, γ-Sm, and PA were 95%, 93%, and 93%, respectively. Patients with multiple positive markers were very likely to have prostatic cancer. In reactivation of the disease, positive rates for γ-Sm and PA were higher than for PAP, indicating that the former two markers are more reliable for monitoring prostatic cancer.  相似文献   
95.
 We have developed an antegradely insertable aortic balloon occlusion catheter for aortic arch repair, and review our experiences of using it. The purpose of the present study was to examine the usefulness of the balloon for surgical treatment of aortic arch aneurysm. In 30 patients with aortic arch aneurysm, including 22 with a non-ruptured and 8 with a ruptured aneurysm, the catheter was antegradely inserted into the descending thoracic aorta through the aortic arch or the aneurysm without opening the pleural space after establishing antegrade selective cerebral perfusion and obtaining cardiac arrest. During distal anastomosis, the catheter occluded the aorta with continuous perfusion of the lower half of the body through an arterial cannula inserted into the femoral artery. Among the patients with a nonruptured aneurysm, two deaths (9.1%) occurred because of aorto-broncho-esophageal fistulae or cardiac arrest due to severe asthma attack within 30 days, and the other three hospital deaths were due to aspiration pneumonia, multiple organ failure with preoperative renal dysfunction, or low cardiac output syndrome due to perioperative myocardial infarction. Among the patients with a ruptured aneurysm, three deaths (37.5%) were due to acute myocardial infarction, respiratory failure, or intractable arrhythmia within 30 days, and another hospital death was caused by mediastinitis. No paraplegia was caused in any patient excluding one of the patients with a ruptured aneurysm who could not be weaned from the extracorporeal circulation due to perioperative myocardial infarction. There was no early postoperative serious visceral organ dysfunction except for two patients with postoperative low cardiac output syndrome or preoperative severe renal dysfunction. This catheter was effective in protecting the visceral organs and the spinal cord in the repair of an aortic arch aneurysm. Received: March 7, 2002 / Accepted: November 29, 2002  相似文献   
96.
97.
BACKGROUND: Actinobacillus actinomycetemcomitans is considered a major etiologic agent of aggressive periodontitis. Other periodontopathic bacteria such as Porphyromonas gingivalis are also suspected of participating in aggressive periodontitis, although the evidence is controversial. The aim of the present study was to investigate the prevalence of periodontopathic bacteria and to clarify the microbiological features of aggressive periodontitis in Japanese patients. METHODS: Subgingival plaque was collected from 50 aggressive periodontitis (AgP) patients (localized 10, generalized 40). Samples from 35 generalized chronic periodontitis (CP) patients and 18 healthy subjects were examined as controls. Plaque samples were examined using culture and polymerase chain reaction (PCR) method. RESULTS: The prevalence of A. actinomycetemcomitans was relatively low in the localized (20%) and generalized (17.5%) AgP patients, with no significant difference observed in detection frequencies between AgP and the control groups (CP 8.6%, healthy 0%). On the other hand, Tannerella forsythensis (formerly Bacteroides forsythus), Campylobacter rectus, P. gingivalis, and Treponema denticola were frequently detected in localized as well as generalized aggressive periodontitis patients. The prevalence and proportion of P. gingivalis correlated with severity of clinical attachment loss in both localized and generalized aggressive periodontitis. CONCLUSIONS: T. forsythensis, C. rectus, P. gingivalis, and T. denticola were the predominant periodontopathic bacteria of aggressive periodontitis patients in Japan. Although A. actinomycetem- comitans was also detected in AgP patients, the prevalence of this bacterium was much lower than that of P. gingivalis.  相似文献   
98.
To retrospectively investigate the effects of indigo carmine intravenous injection on oxygen reserve index (ORi?) in 20 patients who underwent elective gynecologic surgery under general anesthesia. The study subjects were patients who underwent elective gynecologic surgery under general anesthesia between April 2016 and January 2017, and were administered a 5-ml intravenous injection of 0.4% indigo carmine for clinical purposes during surgery with ORi monitoring. Changes in ORi within 20 min after indigo carmine injection were observed. A relevant decrease in ORi was defined as ≥?10% reduction in ORi from pre-injection level. ORi rapidly decreased after indigo carmine intravenous injection in all patients. In 10 of 19 patients, ORi decreased to 0 after indigo carmine injection. The median lowest value of ORi was 0 (range 0–0.16) and the median time to reach the lowest value of ORi was 2 min (range 1–4 min) after injection. ORi values returned to pre-injection levels within 20 min in 13 of 19 patients, and the median time to return to pre-injection levels was 10 min (range 6–16 min) after injection. During ORi monitoring it is necessary to consider the rapid reduction in ORi after intravenous injection of indigo carmine.  相似文献   
99.
We semiquantitatively analysed radionuclide cisternography in three patients with spontaneous cerebrospinal fluid (CSF) leakage diagnosed by typical symptoms and magnetic resonance imaging findings before and several months after treatment with epidural blood patch. Radioactivity in the whole CSF space was measured immediately after and at 1, 5, 7 and 24 h after intrathecal injection of (111)In-diethylenetriaminepentaacetic acid (DTPA). Initial findings included the vague appearance of leakage in the thoracic spine in two patients, early bladder filling at 1 h in one and a lack of tracer filling into the high cranial convexity in all three. The radioactivity count rapidly decreased within several hours after injection and reached 20% of the initial value at 24 h. In contrast, no rapid decrease was observed after treatment and more than 50% of tracer remained at 24 h after injection. Semiquantitative analysis of tracer clearance may provide additional information in the diagnosis of CSF leakage, especially with no obvious qualitative findings.  相似文献   
100.
In contrast to Caucasians, Japanese people have a relatively high incidence of malignant melanoma in the oral cavity and volar-subungual skin. The classification of oral melanoma has not been established. We report 7 new cases of oral melanoma, with a review of 36 cases, published in Japan, between 1970 and 1984. Most of the cases reviewed have radial growth phases, and their gross and microscopic features seem to correspond to those of acral lentiginous melanoma of the skin. However, 1 of our cases and 3 previously reported cases of oral nodular melanoma suggest the presence of melanoma heterogeneity in the oral cavity.  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