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   9721篇
  免费   538篇
  国内免费   81篇
耳鼻咽喉   94篇
儿科学   182篇
妇产科学   91篇
基础医学   1233篇
口腔科学   211篇
临床医学   636篇
内科学   2711篇
皮肤病学   238篇
神经病学   560篇
特种医学   355篇
外科学   1752篇
综合类   40篇
预防医学   194篇
眼科学   193篇
药学   601篇
中国医学   20篇
肿瘤学   1229篇
  2024年   11篇
  2023年   149篇
  2022年   266篇
  2021年   416篇
  2020年   225篇
  2019年   322篇
  2018年   377篇
  2017年   275篇
  2016年   302篇
  2015年   285篇
  2014年   380篇
  2013年   412篇
  2012年   713篇
  2011年   678篇
  2010年   399篇
  2009年   333篇
  2008年   549篇
  2007年   639篇
  2006年   580篇
  2005年   589篇
  2004年   562篇
  2003年   504篇
  2002年   485篇
  2001年   78篇
  2000年   64篇
  1999年   90篇
  1998年   98篇
  1997年   77篇
  1996年   74篇
  1995年   52篇
  1994年   48篇
  1993年   42篇
  1992年   37篇
  1991年   40篇
  1990年   33篇
  1989年   28篇
  1988年   25篇
  1987年   16篇
  1986年   8篇
  1985年   11篇
  1984年   10篇
  1983年   9篇
  1982年   19篇
  1981年   6篇
  1980年   8篇
  1978年   4篇
  1977年   6篇
  1976年   2篇
  1974年   2篇
  1969年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Renal tubular cell injury induced by oxalate plays an important role in kidney stone formation. Water containing oxygen nano-bubbles (nanometer-sized bubbles generated from oxygen micro-bubbles; ONB) has anti-inflammatory effects. Therefore, we investigated the inhibitory effects of ONB water on kidney stone formation in ethylene glycol (EG)-treated rats. We divided 60 rats, aged 4 weeks, into 5 groups: control, the water-fed group; 100 % ONB, the 100 % ONB water-fed group; EG, the EG treated water-fed group; EG + 50 % ONB and EG + 100 % ONB, water containing EG and 50 % or 100 % ONB, respectively. Renal calcium oxalate (CaOx) deposition, urinary excretion of N-acetyl-β-d-glucosaminidase (NAG), and renal expression of inflammation-related proteins, oxidative stress biomarkers, and the crystal-binding molecule hyaluronic acid were compared among the 5 groups. In the control and 100 % ONB groups, no renal CaOx deposits were detected. In the EG + 50 % ONB and EG + 100 % ONB groups, ONB water significantly decreased renal CaOx deposits, urinary NAG excretion, and renal monocyte chemoattractant protein-1, osteopontin, and hyaluronic acid expression and increased renal superoxide dismutase-1 expression compared with the EG group. ONB water substantially affected kidney stone formation in the rat kidney by reducing renal tubular cell injury. ONB water is a potential prophylactic agent for kidney stones.  相似文献   
82.

Background

The present study aimed to clarify the clinicopathologic features of long-term disease-fee survival after resection of hepatocellular carcinoma (HCC).

Methods

This retrospective study identified 940 patients who underwent curative resection of HCC between 1991 and 2000 at five university hospitals. Seventy-four patients with 10 years of recurrence-free survival were identified and followed up. They were divided into two groups, 60 recurrence-free and 14 with recurrence after a 10-year recurrence-free period.

Results

Overall survival rates of recurrence and non-recurrence groups were 68 and 91 % at 16 years, and 34 and 91 % at 20 years (p = 0.02), respectively. There were five (36 %), and two deaths (3 %), respectively, after 10 recurrence-free years. A second resection for recurrence was performed in four patients (29 %), and mean survival was 15.3 years after the first hepatectomy. Although three patients in the non-recurrence group (5 %) developed esophageal and/or gastric varices, seven patients in the recurrence group (50 %) developed varices during 10 years (p < 0.0001). In multivariate analysis, preoperative and 10-year platelet count was identified as a favorable independent factor for maintained recurrence-free survival after a 10-year recurrence-free period following curative hepatic resection of HCC.

Conclusions

Recurrence of HCC may occur even after a 10-year recurrence-free period. Long-term follow-up after resection of HCC is important, and should be life-long. Patients with higher preoperative and 10-year platelet counts are more likely to have long-term survival after resection. A low platelet count, related to the degree of liver fibrosis, is a risk factor for recurrence and survival of HCC after curative resection.  相似文献   
83.
We developed an easy method of measuring the presampling modulation transfer function (MTF) using the square wave chart in digital radiography. In this method, the presampling MTF is measured by Fourier transform of image data of the square wave chart. When Fourier analysis of the sampling data of a square wave is carried out, it is generally difficult to find the starting point and terminal point of the periodic data that should be extracted because of an insufficient number of data. To solve this problem, interpolated data were calculated by using a window function of the frequency domain. The aliasing error was avoided using a characteristic such that the square wave has discrete frequency components. The accuracy of this method was investigated by computer simulation study. Actual measurement of the presampling MTF by this method was also performed with a CR system. These studies indicated the effectiveness of our proposed method in terms of accuracy and ease of use.  相似文献   
84.
BACKGROUND: Donor asthma has been regarded as a contraindication to lung transplantation (LTx) because of concerns that pre-existing airway inflammation will predispose to early and late graft dysfunction. The aim of this study was to describe LTx outcomes in which lungs had been transplanted from donors with a history of asthma. METHODS: A retrospective chart review was undertaken of 743 consecutive donor lung referrals to the Alfred Hospital between 1990 and September 2002. Seventy-four were noted to have a history of asthma, including 18 in whom asthma was the cause of death. Twenty-seven patients became lung donors, of whom 16 were on asthma treatment (on-treatment group) and 11 were not (no-treatment group). RESULTS: From 27 lung donors, 35 LTx procedures were performed (16 double LTx [DLTx], 19 single LTx [SLTx]). Five recipients died at <30 days (including 3 of early graft failure in the no-treatment group), and 7 died at >30 days (only 1 due to BOS). The 30-day, 1-year and 5-year survival rates in the on- and no-treatment donor groups were 90% vs 76%, 74% vs 69% and 74% vs 60%, respectively, and were not significantly different from our overall LTx survival rates. There were no significant differences in percent predicted forced expiratory volume in 1 second, ICU stay or hospital stay overall, or when analyzed according to on treatment vs no treatment and SLTx vs DLTx. Only 2 procedures LTx were performed from fatal asthma donors, both of whom had subsequent graft dysfunction and died on Days 73 and 484, respectively. CONCLUSIONS: The use of lungs from carefully selected lung donors with a history of asthma may increase the donor pool with acceptable long-term outcomes. The use of fatal asthma donors remains problematic.  相似文献   
85.
A 47-year-old woman who had been diagnosed as having aortitis syndrome underwent aortic root replacement for an ascending aortic aneurysm and aortic regurgitation. Because the patient has been treated with steroids for more than 20 years, a Freestyle stentless valve was used to avoid the risk of valve detachment. There were no complications observed during the postoperative course. Although long-term follow-up will be necessary to observe the valve durability, the Freestyle stentless valve seems to be useful for aortic root replacement in patients at high risk of valve detachment due to aortitis syndrome.  相似文献   
86.
Japan's prototype of depression was traditionally a melancholic depression based on the premorbid personality known as shūchaku‐kishitsu proposed by Mitsuzo Shimoda in the 1930s. However, since around 2000, a novel form of depression has emerged among Japanese youth. Called ‘modern type depression (MTD)’ by the mass media, the term has quickly gained popularity among the general public, though it has not been regarded as an official medical term. Likewise, lack of consensus guidelines for its diagnosis and treatment, and a dearth of scientific literature on MTD has led to confusion when dealing with it in clinical practice in Japan. In this review article, we summarize and discuss the present situation and issues regarding MTD by focusing on historical, diagnostic, psychosocial, and cultural perspectives. We also draw on international perspectives that begin to suggest that MTD is a phenomenon that may exist not only in Japan but also in many other countries with different sociocultural and historical backgrounds. It is therefore of interest to establish whether MTD is a culture‐specific phenomenon in Japan or a syndrome that can be classified using international diagnostic criteria as contained in the ICD or the DSM. We propose a novel diagnostic approach for depression that addresses MTD in order to combat the current confusion about depression under the present diagnostic systems.  相似文献   
87.
Purpose

JWH-424, (8-bromo-1-naphthyl)(1-pentyl-1H-indol-3-yl)methanone, is a synthetic cannabinoid, which is a brominated analogue of JWH-018, one of the best-known synthetic cannabinoids. Despite the structural similarity to JWH-018, little is known about JWH-424 including its metabolism. The aim of the study was to compare human liver microsomes (HLM) and the fungus Cunninghamella elegans as the metabolism catalysts for JWH-424 to better understand the characteristic actions of the fungus in the synthetic cannabinoid metabolism.

Methods

JWH-424 was incubated with HLM for 1 h and Cunninghamella elegans for up to 72 h. The HLM incubation mixtures were diluted with methanol and fungal incubation mixtures were extracted with dichloromethane and reconstituted in methanol before analyses by liquid chromatography–high-resolution mass spectrometry (LC-HRMS).

Results

HLM incubation resulted in production of ten metabolites through dihydrodiol formation, hydroxylation, and/or ipso substitution of the bromine with a hydroxy group. Fungal incubation led to production of 23 metabolites through carboxylation, dihydrodiol formation, hydroxylation, ketone formation, glucosidation and/or sulfation.

Conclusions

Generally, HLM models give good predictions of human metabolites and structural analogues are metabolised in a similar fashion. However, major hydroxy metabolites produced by HLM were those hydroxylated at naphthalene instead of pentyl moiety, the major site of hydroxylation for JWH-018. Fungal metabolites, on the other hand, had undergone hydroxylation mainly at pentyl moiety. The metabolic disagreement suggests the necessity to verify the human metabolites in authentic urine samples, while H9 and H10 (hydroxynaphthalene), H8 (ipso substitution), F22 (hydroxypentyl), and F17 (dihydroxypentyl) are recommended for monitoring of JWH-424 in urinalysis.

  相似文献   
88.
Annals of Nuclear Medicine - Amyloid positron emission tomography (PET) can reliably detect senile plaques and fluorinated ligands are approved for clinical use. However, the clinical impact of...  相似文献   
89.
Objectives: To report our initial experience with transumbilical laparo‐endoscopic single‐site adrenalectomy for adrenal tumors by using a single port with a multichannel cannula and bent laparoscopic instrumentation. Methods: Between December 2009 and December 2010, 30 patients underwent transumbilical laparo‐endoscopic single‐site adrenalectomy at our hospital. The procedure was carried out for adrenal cortical adenoma in 17 patients, adrenal pheochromocytoma in seven patients and other types of tumors in six patients. A multichannel port, bent laparoscopic instruments and Opti4 laparoscopic electrodes were used in all patients. The intraperitoneal space was approached through the umbilicus. The multichannel port was placed through a 2‐cm incision at the inner edge of the umbilicus. A 5‐mm flexible laparoscope was introduced to maintain an adequate laparoscopic view, and surgical specimens were extracted using an Endocatch bag. Results: All procedures were successfully completed, with only one incision through the umbilicus, and without conversion to a standard laparoscopic approach. Mean operative time was 120.1 ± 34.7 min. Tumor laterality and patient body mass index did not affect surgical morbidity. The initial 15 patients had a significantly longer mean pneumoperitoneum time (95.8 ± 37.5 min) than the last 15 patients (70.5 ± 18.7 min). Only one postoperative complication was observed (postoperative hematoma). Conclusions: A transumbilical approach for laparo‐endoscopic single‐site adrenalectomy is safe and feasible, and it results in superior cosmesis. Improvements in surgical devices might facilitate further development of this approach.  相似文献   
90.
We report a case of adrenal pheochromocytoma in a patient with neurofibromatosis type 1 (NF1). A 65-year-old female patient was admitted to our hospital for examination of a right adrenal mass. The adrenal tumor was incidentally discovered by abdominal computed tomography during examination for hypertension in another hospital. She had large multiple neurofibromatous lesions and café-au-lait spots on the trunk. We thought that it was difficult to make a skin incision on normal skin. Serum and urinary catecholamines were markedly increased. Magnetic resonance imaging revealed a solid round tumor 3 cm in diameter, located in the right adrenal gland. Laparoscopic right adrenalectomy was performed. Serum and urinary catecholamines returned to the normal range on post-operative day 10. Laparoscopic surgery may be a good option for NF1 patients with pheochromocytoma, especially those who had multiple neurofibromatosis on the trunk.  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