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   12599篇
  免费   686篇
  国内免费   61篇
耳鼻咽喉   180篇
儿科学   256篇
妇产科学   201篇
基础医学   1699篇
口腔科学   1476篇
临床医学   991篇
内科学   2470篇
皮肤病学   288篇
神经病学   886篇
特种医学   525篇
外科学   1133篇
综合类   100篇
一般理论   4篇
预防医学   1462篇
眼科学   210篇
药学   942篇
中国医学   138篇
肿瘤学   385篇
  2023年   116篇
  2022年   268篇
  2021年   435篇
  2020年   286篇
  2019年   404篇
  2018年   466篇
  2017年   321篇
  2016年   336篇
  2015年   407篇
  2014年   593篇
  2013年   716篇
  2012年   985篇
  2011年   1002篇
  2010年   603篇
  2009年   475篇
  2008年   661篇
  2007年   687篇
  2006年   556篇
  2005年   512篇
  2004年   441篇
  2003年   360篇
  2002年   326篇
  2001年   248篇
  2000年   218篇
  1999年   174篇
  1998年   149篇
  1997年   102篇
  1996年   102篇
  1995年   75篇
  1994年   69篇
  1993年   73篇
  1992年   65篇
  1991年   96篇
  1990年   85篇
  1989年   115篇
  1988年   102篇
  1987年   90篇
  1986年   57篇
  1985年   59篇
  1984年   48篇
  1983年   38篇
  1982年   37篇
  1981年   43篇
  1980年   38篇
  1979年   35篇
  1978年   31篇
  1977年   33篇
  1975年   30篇
  1974年   33篇
  1973年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
To minimize bleeding during major liver resections or liver transplantation, surgical measures have been adopted that induce ischemia-reperfusion injury (I/R) which may significantly contribute to morbidity and mortality of partial liver resections. Several methods have sought to minimize I/R hepatic lesions. The present project assessed the protective role of ischemic preconditioning (IPC) in rat livers. The IPC was accomplished by clamping the hepatic pedicle for 5 minutes, followed by a 5-minute reperfusion (R) period before a 2-hour ischemia. Thereafter, reperfusions of 1, 3, and 24 hours were compared among IPC and control groups without IPC. Liver biopsy and blood samples were measured for mitochondrial respiratory control ratio (RCR), serum aspartate aminotransferase (AST), and alanine aminotransferase (ALT). IPC protected liver mitochondrial function. Serum aminotransferase levels were significantly lower among animals undergoing IPC compared with groups without IPC. Thus, we verified the effects of IPC for hepatocellular protection against I/R lesions.  相似文献   
92.
To examine the apoptosis expression in the intestinal mucosa in accordance of different periods of hyperbaric oxygen (HBO) treatment, rats were submitted to 60 min of mesenteric artery and vein ischemia and 60 min of reperfusion occlusion. A group (G-IR) was the control and HBO was applied in the ischemia (GHBO-I), reperfusion (GHBO-R), and ischemia and reperfusion time (GHBO-IR). After 60 min of reperfusion, samples of small bowel were prepared for immunohistochemical expression of caspase-3. The expression of caspase-3 was significantly inferior when HBO was administered in the ischemia (0.16 +/- 0.01) in comparison with the control (0.70 +/- 0.08), but HBO in the further reperfusion (0.84 +/- 0.03) or both ischemia and reperfusion time (0.42 +/- 0.05) was significantly worse. There was a connection between HBO, small bowel I/R injury, and mucosa apoptosis. The favorable effect was obtained when HBO was administered early in the ischemia time.  相似文献   
93.
Targeted muscle reinnervation (TMR) was initially designed to provide cortical control of upper limb prostheses through a series of novel nerve transfers. Early experience has suggested that TMR may also inhibit symptomatic neuroma formation. We present the first report of TMR performed at the time of a traumatic shoulder disarticulation. The procedure was done to prevent painful neuroma pain and allow for myoelecteric prosthetic use in the future. Eight months post-operatively, the patient demonstrates multiple successful nerve transfers and exhibits no evidence of neuroma pain on clinical exam. Using the Patient Reported Outcomes Measurement Information System (PROMIS), the patient demonstrates minimal pain interference or pain behavior. Targeted muscle reinnervation may be considered in the acute trauma setting to prevent neuroma pain and to prepare patients for myoelectric prostheses in the future.  相似文献   
94.
This case report assessed quality of life, activities of daily living, motor symptoms, functional ability, neuromuscular parameters and mRNA expression of selected genes related to muscle protein synthesis and degradation in a patient with Multiple System Atrophy (MSA). The patient underwent resistance training with instability devices (i.e., bosu, dyna disk, balance disk, Swiss ball) for six months twice a week. After the six months training, the patient’s left and right quadriceps muscle cross-sectional area and leg press one-repetition maximum increased 6.4%, 6.8%, and 40%, respectively; the patient’s timed up and go, sit to stand, dynamic balance, and activities of daily living improved 33.3%, 28.6%, 42.3%, and 40.1%, respectively; the patient’s severity of motor symptoms and risk of falls decreased 32% and 128.1%, respectively. Most of the subscales of quality of life demonstrated improvements as well, varying from 13.0% to 100.0%. mRNA expression of mechanogrowth factor and mammalian target of rapamycin increased 12.7-fold and 1.5-fold, respectively. This case report describes likely the first nonpharmacological therapeutic tool that might be able to decrease the severity of motor symptoms and risk of falls, and to improve functional ability, neuromuscular parameters, and quality of the life in a patient with MSA.

Key points

  • Six months of resistance training with instability alleviate the MSA-related effects and improve the quality of life in a patient with MSA.
  • High complexity exercise intervention (i.e., resistance training with instability) may be very beneficial to individuals with impaired motor control and function as MSA patients.
  • Caution should be exercised when interpreting our findings as they cannot be generalized to the entire MSA population and they do not allow establishing causal conclusions on the effects of this mode of exercise on MSA.
Key words: Exercise training, risk of falls, motor symptoms, cross-sectional area  相似文献   
95.
The purpose of this study was to sequentially monitor anti‐HLA antibodies and correlate the results with antibody‐mediated rejection (AMR), graft survival (GS), and graft function (GF). We collected sera from 111 kidney transplant recipients on transplant days 0, 7, 14, 30, 60, 90, 180, and 360 and analyzed PRA levels by ELISA. DSAs were analyzed by single‐antigen beads in rejecting kidneys. At pre‐transplant, 79.3% of the patients were non‐sensitized (PRA = 0%) and 20.7% were sensitized (PRA > 1%). After transplant, patients were grouped by PRA profile: no anti‐HLA antibodies pre‐ or post‐transplant (group HLApre?/post?; n = 80); de novo anti‐HLA antibodies post‐transplant (group HLApre?/post+; n = 8); sensitized pre‐transplant/increased PRA post‐transplant (group HLApre+/post↑; n = 9); and sensitized pre‐transplant/decreased PRA post‐transplant (group HLApre+/post↓; n = 14). De novo anti‐HLA antibodies were detected at 7–180 d. In sensitized patients, PRA levels changed within the first 30 d post‐transplant. Incidence of AMR was higher in HLApre?/post+ and HLApre+/post↑ than in HLApre?/post?, and HLApre+/post↓ (p < 0.001) groups. One‐yr death‐censored GS was 36% in group HLApre+/post↑, compared with 98%, 88% and 100% in groups HLApre?/post?, HLApre?/post+, and HLApre+/post↓, respectively (p < 0.001). Excluding first‐year graft losses, GF and GS were similar among the groups. In conclusion, post‐transplant antibody monitoring can identify recipients at higher risk of AMR.  相似文献   
96.

Background

Preoperative education is a key point in multimodal protocols of perioperative care. We investigated whether preoperative education for patients undergoing open cholecystectomy would reduce the incidence of perioperative symptoms.

Methods

This was a randomized, single-blinded, clinical trial that included adult (18–65 years old) candidates for elective open cholecystectomy. All patients took part in the ERAS/ACERTO protocol of perioperative care except that only the intervention group received preoperative education. The main endpoints of the study were the presence and intensity of postoperative symptoms (e.g., nausea, vomiting, pain) measured by a visual analogue scale, 24 h after the operation.

Results

A total of 74 patients (34 in the intervention group, 40 in the control group) completed the study. The intervention group had significantly lower median (interquartile range) scores for nausea [0 (4) vs. 2.5 (5.8), p = 0.04] and pain [0.2 (2.3) vs. 3.1 (3.45), p < 0.01] than the controls. High well-being (score ≥6) was reported by 79.4 % (27 patients) of the intervention group in contrast to 57.5 % (23 patients) of the controls (p = 0.04).

Conclusions

Preoperative education is highly effective in the context of a multimodal protocol for enhancing the recovery of patients submitted to open cholecystectomy.  相似文献   
97.
Hypofractionated radiotherapy (HF) in 15 or 16 daily fractions is well established as an alternative in early breast cancer after breast‐conserving surgery. Evidences for a whole‐breast treatment even shorter, in 5‐10 fractions, are still scarce. Women 50 years or older, with early breast tumor (pT1‐2pN0), after breast‐conserving surgery were eligible to enter in this phase II trial and received whole breast once‐weekly hypofractionated radiotherapy (wHF‐RT) to a total dose of 30 Gy, in 5 fractions of 6 Gy. During treatment and in post‐treatment follow‐up the toxicity was assessed and graduated according to the “Common Terminology Criteria for Adverse Events” (CTCAE), v3.0. Breast pictures for esthetic comparison were taken in 5 timepoints and 2 breast surgeons independently graduated the cosmetics changes. The trial was registered with ClinicalTrials.gov, number NCT01965483. From October 2013 to November 2015, 44 patients were enrolled in the trial and treated according to the protocol of wHF‐RT. The median age was 70.5 years (51‐88 years), and the median follow‐up was 22 months (9‐33 months). Skin erythema was the most common acute adverse event. At the end of radiation, 30 patients (68.2%) had any grade of radiation dermatitis. Concerning cosmetic appearance, there was no significant difference between pretreatment and 1 year assessments. The 2‐year overall survival and disease‐free survival were, respectively 96.8% and 97.7%. There was only one distant recurrence and no local or regional recurrence. Once‐weekly hypofractionated radiotherapy is a feasible and well tolerated alternative for early breast cancer adjuvant management with acceptable acute toxicity and esthetic outcomes.  相似文献   
98.
AIM:To examine surgical and medical outcomes for patients with cholangiocarcinoma using a populationbased cancer registry.METHODS:Using the California Cancer Registry’s Cancer Surveillance Program,patients with intrahepatic cholangiocarcinoma treated in Los Angeles County from 1988 to 2006 were identified and evaluated for clinical and pathologic factors and therapies received(surgery,radiation,and chemotherapy).The surgical cohort was further categorized into three treatment groups:patients who received adjuvant chemotherapy,adjuvant chemoradiation,or underwent surgery alone(no chemotherapy or radiation administered).Survival was assessed by Kaplan-Meier method;and Cox proportional hazard modeling was used in multivariate analysis.RESULTS:Of 825 patients,60.2% received no treatment.Of the remaining 328 patients,18.5% chemotherapy only,7.4% chemoradiation,and 13.8% underwent surgery.More male patients underwent surgical resection(P = 0.004).Surgical patients were younger than the patients receiving chemotherapy or chemoradiation(P < 0.001).Of the surgical cohort(n = 114),60.5% underwent surgery alone while 39.5% underwent surgery plus adjuvant therapy(chemotherapy n = 20;chemoradiation,n = 21)(P < 0.001).Median survival for all patients in the study was 6.6 mo.Median survival was highest for patients who underwent surgery(23 mo),whereas both chemotherapy(9 mo) and chemoradiation(8 mo) alone were each less effective(P < 0.001).By multivariate analysis,extent of disease,receipt of surgery,and administration of chemotherapy(with/without surgery) were independent predictors of overall survival.CONCLUSION:This study demonstrates that surgery is a critical treatment modality.Multimodality treatment has yet to be standardized,but play a role in optimal therapy for cholangiocarcinoma.  相似文献   
99.
目的探讨金属对金属(金对金)大头径假体微创全髋关节置换术(THA)治疗青中年股骨头坏死Ⅲ、Ⅳ期的临床疗效。方法本组32例(35髋)青中年股骨头缺血性坏死Ⅲ、Ⅳ期患者,年龄24~59岁,平均45岁,术前髋关节Harris评分平均(37.9±7.5)分;以改良后外侧小切口、肌间隙人路、充分保留关节动力性组织结构为特征的金对金大头径微创THA治疗。术中严格采取正确的假体植入技术,术中保留完整的软骨下骨和髋臼横韧带,击入臼杯时一次性安装成功,正确运用万古霉素预防感染。术后口服利伐沙班片抗凝,术后12h开放负压引流及卧床行功能锻炼,术后第2天拔除引流管后扶拐下地部分负重行走,术后2—3周患者即可弃拐完全负重行走。结果本组32例35髋患者均获随访,随访时间为12个月~6年,平均为4年。所有患者切口均一期愈合,无深静脉血栓形成、关节脱位、坐骨神经损伤、髋臼及股骨疲劳骨折、关节疼痛等严重并发症,X线片示髋关节假体位置均良好,无松动、移位、股骨柄下沉、假体周围骨折等表现。末次随访Harris评分由术前平均(37.9±7.5)分,提高至术后平均(92.2±4.6)分,前后比较有统计学意义(t=44.341,P〈0.05)。所有患者末次随访时髋关节功能明显优于术前,均对治疗效果满意,完全恢复正常生活及工作。结论采用金对金大头径微创THA治疗青中年股骨头坏死Ⅲ、Ⅳ期患者,能够明显降低手术风险,缩短卧床时问,迅速恢复髋关节功能,减少手术并发症,取得了满意的近期临床疗效。随着基础和临床研究的不断深入,金对金大头径髋关节假体的长期疗效还需要进一步探讨。  相似文献   
100.
The aim of this study was to assess the possible association between posttransplant diabetes mellitus (DM) and hepatitis C virus (HCV) infection in renal transplant recipients. This study included 124 patients who underwent renal transplantation between 1997 and 2002. Inclusion criteria were patients who were not diabetic prior to transplantation and posttransplant follow-up longer than 6 months. DM was defined as fasting blood glucose levels higher than 126 mg/dL on at least two occasions. HCV infection was detected using second- or third-generation ELISA methods and/or polymerase chain reactions for HCV-RNA. Twenty-five HCV positive (HCV+) patients were compared with 25 consecutive HCV negative (HCV-) transplant patients. Demographic and clinical data of the groups were compared. Posttransplantation DM was observed in 24% of the HCV+ patients. There were no statistical differences in age, gender, race, family history of DM, follow-up, or body mass index between the two groups. There was a higher prevalence of posttransplantation DM in HCV+ patients, but the difference did not reach statistical significance (24% vs 12%, P = NS). Alternatively, comparing patients of the two groups (n = 50) who did versus not develop DM, the incidence of posttransplantation DM was higher among HCV+ patients, but the difference did not reach statistical significance (66.6% vs 46.3%, P = NS). In conclusion, there was no association between HCV infection and the development of posttransplantation DM in this cohort of renal transplant recipients. However, there was a trend that suggested an association.  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