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   2774篇
  免费   182篇
  国内免费   7篇
耳鼻咽喉   38篇
儿科学   90篇
妇产科学   63篇
基础医学   408篇
口腔科学   68篇
临床医学   221篇
内科学   428篇
皮肤病学   35篇
神经病学   187篇
特种医学   142篇
外科学   385篇
综合类   57篇
预防医学   159篇
眼科学   90篇
药学   306篇
中国医学   13篇
肿瘤学   273篇
  2023年   16篇
  2022年   28篇
  2021年   80篇
  2020年   42篇
  2019年   64篇
  2018年   67篇
  2017年   62篇
  2016年   63篇
  2015年   73篇
  2014年   106篇
  2013年   126篇
  2012年   184篇
  2011年   177篇
  2010年   103篇
  2009年   84篇
  2008年   141篇
  2007年   142篇
  2006年   152篇
  2005年   145篇
  2004年   114篇
  2003年   96篇
  2002年   84篇
  2001年   58篇
  2000年   64篇
  1999年   70篇
  1998年   21篇
  1997年   22篇
  1996年   26篇
  1995年   18篇
  1994年   14篇
  1993年   11篇
  1992年   57篇
  1991年   51篇
  1990年   47篇
  1989年   26篇
  1988年   39篇
  1987年   36篇
  1986年   30篇
  1985年   21篇
  1984年   15篇
  1983年   16篇
  1982年   12篇
  1981年   16篇
  1979年   9篇
  1978年   8篇
  1975年   8篇
  1974年   11篇
  1972年   9篇
  1970年   14篇
  1967年   7篇
排序方式: 共有2963条查询结果,搜索用时 31 毫秒
101.

Background:

Revised National Tuberculosis Control Programme (RNTCP) of Government of India provides intermittent thrice-a-week directly observed treatment short course (RNTCP regimen).

Objective:

Assessments of all-cause mortality and nine-month morbidity outcomes of patients with tuberculous meningitis (TBM) on RNTCP regimen.

Materials and Methods:

We prospectively followed up patients registered with RNTCP center, with a diagnosis of TBM from January 1st, 2010 to December 31st, 2011. Morbidity was assessed using modified Rankin Scale (mRS).

Results:

We had 43 patients with median duration for follow-up of 396 days and that of survivors of 425 days. Two patients defaulted. Fourteen patients (32.5%) had mRS score of 4 to 6 and 29 had mRS of 0 to 3 after 9-month treatment. Severe disability was not related to any factor on logistic regression. Severe disability was seen in one patient (6.66%) among the 15 patients with stage 1, nine (37.5%) out of 24 patients with stage 2 and three (75%) out of 4 patients with stage 3 disease. Eight patients died (18.6%) of whom 4 died during the intensive phase and 4 during the continuation phase of RNTCP regimen. Mortality was independently related to treatment failure with adjusted Hazard ratio of 8.29 (CI: 1.38-49.78) (P = 0.02). One patient (6.66%) died out of the 15 patients with stage 1 disease, 5 (20.8%) out of 24 patients with stage 2 disease and 2 (50%) out of the 4 with stage 3 disease.

Discussion and Conclusion:

RNTCP regimen was associated with good compliance, comparable mortality and morbidity.  相似文献   
102.
Accurate recognition of movement disorder phenomenology may differentiate children with anti‐N‐methyl D‐aspartate receptor (NMDAR) encephalitis, autoimmune basal ganglia encephalitis (BGE), and Sydenham's chorea (SC). Three neurologists blinded to the diagnoses recorded dominant and associated movement disorders seen on videos of 31 patients with anti‐NMDAR encephalitis (n = 10), BGE (n = 12), and SC (n = 9). Stereotypy was only seen in anti‐NMDAR encephalitis (8/10) and not in BGE and SC (P < 0.001). Perseveration was only seen in anti‐NMDAR encephalitis (5/10) and not in BGE and SC (P < 0.001). Akinesia was more commonly seen in BGE (5/12) than in anti‐NMDAR encephalitis (1/10, P = 0.097). Tremor was more commonly seen in BGE (5/12) than in anti‐NMDAR encephalitis (1/10, P = 0.097). Chorea was seen in all groups: anti‐NMDAR encephalitis (4/10), BGE (3/12), and SC (9/9). Likewise, dystonia was seen in all groups: anti‐NMDAR encephalitis (6/10), BGE (7/12), and SC (2/9). Stereotypies or perseveration are suggestive of anti‐NMDAR encephalitis, whereas their absence and the presence of akinesia and tremor is more suggestive of BGE. Chorea and dystonia are least discriminating. © 2014 International Parkinson and Movement Disorder Society  相似文献   
103.
ObjectiveThe objective of this study was to assess interobserver agreement, clinicopathologic correlation, and radiologic follow-up progression of complex cystic renal masses.Patients and methodsThe medical records of 143 patients with 154 complex cystic renal masses were retrieved. Primary outcomes were interobserver agreement between the radiologists, and malignancy rates following surgical extirpation with or without follow-up in Bosniak IIF, III, and IV categories. Secondary outcomes were correlation between histology and degree of enhancement on contrast-enhanced computed tomography scans and survival analysis of patients with or without surgical intervention using the Kaplan-Meier analysis.ResultsThe overall malignancy rate in patients who had surgery was 74.5% (29/39). Of 27 confirmed renal cell carcinoma on final histology, 9 were papillary renal cell carcinoma (incidence 33.3%). Assessment of interobserver agreement yielded a weighted kappa statistic value of 0.69 (95% confidence interval 0.56–0.82, P<0.0001). Radiologic progression rate of Bosniak IIF cysts over median follow-up of 18.5 months was 13% (10/78). There was no statistically significant difference between progression rate and regression rate of IIF cysts (13.8% vs. 11.5%) over the period of 24 months of follow-up. Most of the progression in complex cystic renal masses was seen in the first 2 years of follow-up. The malignancy rate on radiologic progression was 87.5% (8/9) and 75% (6/8) in Bosniak IIF and III cystic masses, respectively. The malignancy rate in Bosniak III cyst was 50% (4/8) without a period of initial observation or follow-up.ConclusionsA good degree of agreement exists between radiologists in classifying complex renal masses. Malignancy rate is considerably high in Bosniak IIF when they exhibit radiologic progression on systematic follow-up.  相似文献   
104.
105.
106.
The present study has analysed the numbers of argyrophilic nucleolar organizer regions (AgNOR) in normal tissues and in premalignant and malignant lesions of the oral mucosa in order to assess their potential as a biological marker for tumour progression. On comparison of AgNOR numbers in different lesions, carcinomas showed the highest number (4.65±0.98) compared to leukoplakias (2.38±0.47) and normal tissues (1.53±0.39). Spindle cell carcinomas and poorly differentiated squamous cell carcinomas had higher AgNOR counts than well-differentiated carcinomas. In various clinically different types of oral leukoplakia, the lowest AgNOR counts were observed in homogenous leukoplakia and the highest in speckled leukoplakia. No significant difference in AgNOR number was observed between non-dysplastic and dysplastic leukoplakia, although a significant difference was evident between dysplastic leukoplakia and normal oral mucosa. Correlating the AgNOR count and tumour progression, a significantly high positive correlation coefficient (r=0.7969,P=0.0000) was observed.  相似文献   
107.
BACKGROUND AND AIM OF THE STUDY: The Ultracor valve is a recent introduction in the evolution of the tilting disc valve. This report summarizes a single surgeon's experience with the valve in the aortic position over a nine-year period. METHODS: Between 1990 and 1999, 94 patients received an Ultracor heart valve prosthesis in the aortic position. Forty-five patients (48%) had associated procedures, of which 32 (34%) were coronary artery grafts. Mean follow up was 2.6 years; total follow up was 229 patient-years. Follow up was 100% complete. RESULTS: The actuarial survival rate, including operative mortality rate, at five years was 82%. Actuarial freedom from valve-related death was 96% at five years. The linearized complication rate was 1.7%/year for late valve-related mortality, 1.7%/year for thromboembolism, 2.2%/year for anticoagulant-related hemorrhage (ACH), 1.3%/year for prosthetic valve endocarditis (PVE), and 1.7%/year for reoperation. The estimates of actuarial freedom from complications at five years were thromboembolism 89%, ACH 90%, PVE 96% and reoperation 96%. No structural failure or valve thrombosis was observed. CONCLUSION: Our experience over nine years showed the Ultracor heart valve prosthesis in the aortic position to be comparable with other currently evaluated mechanical heart valves in terms of durability and clinical results. Further study in this area should concentrate on the impact of valve type on left ventricular recovery post-implantation to provide additional information to the surgeon when selecting a valve from the plethora of choices available.  相似文献   
108.
Our studies investigated functional interactions between calreticulin, an endoplasmic reticulum chaperone, and major histocompatibility complex (MHC) class I molecules. Using in vitro thermal aggregation assays, we established that calreticulin can inhibit heat-induced aggregation of soluble, peptide-deficient HLA-A2 purified from supernatants of insect cells. The presence of HLA-A2-specific peptides also inhibits heat-induced aggregation. Inhibition of heat-induced aggregation of peptide-deficient HLA-A2 by calreticulin correlates with a rescue of the HLA-A2 heavy chain from precipitation, by forming high-molecular-weight complexes with calreticulin. Complex formation between HLA-A2 heavy chains and calreticulin occurs at 50 degrees C but not 37 degrees C, suggesting polypeptide-based interactions between the HLA-A2 heavy chain and calreticulin. Once complexes are formed, the addition of peptide is not sufficient to trigger efficient assembly of heavy chain/beta2m/peptide complexes. Using a fluorescent peptide-based binding assay, we show that calreticulin does not enhance peptide binding by HLA-A2 at 37 degrees C. We also show that calreticulin itself is converted to oligomeric species on exposure to 37 degrees C or higher temperatures, and that oligomeric forms of calreticulin are active in inhibiting thermal aggregation of peptide-deficient HLA-A2. Taken together, these results suggest that calreticulin functions in the recognition of misfolded MHC class I heavy chains in the endoplasmic reticulum. However, in the absence of other endoplasmic reticulum components, calreticulin by itself does not enhance the assembly of misfolded MHC class I heavy chains with beta2m and peptides.  相似文献   
109.
Sperm of the Pacific herring, Clupea pallasi, are unique in that they are immotile upon spawning in the environment. Herring sperm have evolved to remain motionless for up to several days after spawning, yet are still capable of fertilizing eggs. An egg chorion ligand termed "sperm motility initiation factor" (SMIF) induces motility in herring sperm and is required for fertilization. In this study, we show that SMIF induces calcium influx, sodium efflux, and a membrane depolarization in herring sperm. Sperm motility initiation by SMIF depended on decreased extracellular sodium (<350 mM) and could be induced in the absence of SMIF in very low sodium seawater. Motility initiation depended on > or =1 mM extracellular calcium. Calcium influx caused by SMIF involved both the opening of voltage-gated calcium channels and reverse sodium-calcium (Na(+)/Ca(2+)) exchange. Membrane depolarization was slightly inhibited by a calcium channel blocker and markedly inhibited by a Na(+)/Ca(2+) exchange inhibitor. Sodium efflux caused by SMIF-initiated motility was observed when using both extracellular and intracellular sodium probes. A Na(+)/Ca(2+) exchange antigen was shown to be present on the surface of the sperm, primarily over the midpiece, by using an antibody to the canine Na(+)/Ca(2+) exchanger. This antibody recognized a 120-kDa protein that comigrated with the canine myocyte Na(+)/Ca(2+) exchanger. Sperm of Pacific herring are now shown to use reverse Na(+)/Ca(2+) exchange in motility initiation. This mechanism of regulation of motility initiation may have evolved for both maintenance of immotility after spawning as well as ligand-induced motility initiation.  相似文献   
110.
The term gossypiboma is used to describe a mass of cotton matrix left behind in a body cavity intraoperatively. The most common site reported is the abdominal cavity. It can present with abscess, intestinal obstruction, malabsorption, gastrointestinal hemorrhage, and fistulas. A 37-year-old woman presented with pain in the right hypochondrium for 2 months following open cholecystectomy. As she did not improve with proton pump inhibitors, an esophagogastroduodenoscopy (EGD) was done, which showed a possible gauze piece stained with bile in the first part of the duodenum. Contrast-enhanced computed tomography (CECT) of the abdomen revealed an abnormal fistulous communication of the first part of duodenum with proximal transverse colon, with a hypodense, mottled lesion within the lumen of the proximal transverse colon plugging the fistula, suggestive of a gossypiboma. Excision of the coloduodenal fistula, primary duodenal repair, and feeding jejunostomy was done. The patient recovered well and is now tolerating normal diet. Coloduodenal fistula is usually caused by Crohn''s disease, malignancy, right-sided diverticulitis, and gall stone disease. Isolated coloduodenal fistula due to gossypiboma has not been reported in the literature so far to the best of our knowledge. We report this case of coloduodenal fistula secondary to gossypiboma for its rarity and diagnostic challenge.Key words: Surgical sponges, Intestinal fistula, Multidetector computed tomographyThe first report of a coloduodenal fistula was by Haldane in 1862, and it was malignant from the hepatic flexure.1 Coloduodenal fistula is caused by Crohn''s disease, malignancy, right-sided diverticulitis, and gall stone disease, but isolated coloduodenal fistula due to gossypiboma has not been reported in the literature to the best of our knowledge. Gossypiboma is known to present as intra-abdominal abscess, intestinal obstruction, and fistulization, but coloduodenal fistula has not been reported as a mode of presentation. We report this case of coloduodenal fistula secondary to gossypiboma for its rarity and diagnostic challenge.  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