全文获取类型
收费全文 | 6271篇 |
免费 | 273篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 187篇 |
儿科学 | 325篇 |
妇产科学 | 240篇 |
基础医学 | 428篇 |
口腔科学 | 294篇 |
临床医学 | 644篇 |
内科学 | 1504篇 |
皮肤病学 | 102篇 |
神经病学 | 333篇 |
特种医学 | 318篇 |
外科学 | 1238篇 |
综合类 | 119篇 |
预防医学 | 170篇 |
眼科学 | 241篇 |
药学 | 221篇 |
中国医学 | 5篇 |
肿瘤学 | 229篇 |
出版年
2024年 | 5篇 |
2023年 | 61篇 |
2022年 | 75篇 |
2021年 | 127篇 |
2020年 | 94篇 |
2019年 | 135篇 |
2018年 | 151篇 |
2017年 | 141篇 |
2016年 | 156篇 |
2015年 | 209篇 |
2014年 | 236篇 |
2013年 | 322篇 |
2012年 | 407篇 |
2011年 | 386篇 |
2010年 | 259篇 |
2009年 | 220篇 |
2008年 | 480篇 |
2007年 | 522篇 |
2006年 | 503篇 |
2005年 | 442篇 |
2004年 | 353篇 |
2003年 | 290篇 |
2002年 | 234篇 |
2001年 | 132篇 |
2000年 | 113篇 |
1999年 | 116篇 |
1998年 | 55篇 |
1997年 | 57篇 |
1996年 | 48篇 |
1995年 | 26篇 |
1994年 | 27篇 |
1993年 | 22篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 14篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 5篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 6篇 |
1975年 | 6篇 |
排序方式: 共有6598条查询结果,搜索用时 15 毫秒
101.
102.
To determine the stage of the disease, performance status of the patients on admission and treatment modalities, records of 226 patients with lung cancer diagnosed between January 1992 and December 1999 were evaluated retrospectively. The mean age of the patients were 61.3 +/- 10.3 years (mean +/- standard deviation) and 217 (96%) were men and 9 (4%) were women. Of the 192 cases with non-small cell lung cancer 22.9% were stage 4, 40.6% were stage 3b, 22.4% were stage 3a, 4.2% were stage 2, 9.9% were stage 1. Of the 34 (15.1%) patients with small cell lung cancer, 26.5% were extensive and 73.5% were in limited stages. The performance status according to European Cooperative Oncology Group (ECOG) was between 0-2 in 88.4% and 3-4 in 11.6% of the cases. A positive correlation between the performance status and the stage of the disease was observed (p= 0.0331). It was detected that the performance status of the patients who underwent surgery was better than the patients who treated with radiotherapy (p= 0.0008). Radiotherapy (RT), chemotherapy (CT), surgery, combined therapy (RT + CT), adjuvant RT and palliative therapy were performed in 27%, 20.4%, 11.5%, 1.3%, 1.8% and 14.6% of the cases respectively. No information about treatment protocol was able to obtained in 23.4% of the patients, probably due to referrals, early deaths etc. In conclusion, more than half of our cases with lung cancer were diagnosed in advanced stages as a possible result of late admission to physician and surgery were performed in only a small part of the cases. It was detected that performance status of the patients operated was better than the patients treated with radiotherapy. On the other hand, combination therapy was applied in few cases. 相似文献
103.
STUDY OBJECTIVE: QT dispersion (QTd) and late potentials derived from signal-averaged ECG (SAECG) have been proposed as noninvasive predictors of cardiac arrhythmias that occur in patients with COPD. In this study, we aimed to investigate QTd and SAECG in patients with COPD. DESIGN: Cross-sectional study. SETTING: Teaching chest disease hospital and cardiology center in a university hospital. PATIENTS: Thirty patients with COPD (28 men and 2 women; mean +/- SD age, 60 +/- 9 years) and 31 age- and sex-matched control subjects (28 men and 3 women; mean age, 57 +/- 7 years) were included. Measurements and results: Respiratory function tests, arterial blood gas analyses, echocardiographic examinations, rhythm Holter recordings, and heart rate variability (HRV) analyses were performed in addition to the measurements of QT intervals and SAECG. Patients with COPD had higher rate of ventricular premature beats (VPBs) as compared to control subjects (924 +/- 493 beats vs 35 +/- 23 beats, p = 0.009). Eight patients with COPD (27%) had nonsustained runs of ventricular tachycardia (VT). QTd rates were significantly increased in patients with COPD as compared to control subjects (57.7 +/- 9.9 ms vs 37.5 +/- 8.2 ms, p < 0.001). On comparing patients with COPD with and without runs of VT, patients with VT had longer QTd (67 +/- 10 ms vs 55 +/- 8 ms, p = 0.001). However no difference in any HRV and late potential parameters were found between patients with COPD with and without runs of VT. VPB rates were strongly correlated with QTd in patients with COPD (r = 0.61, p < 0.001). On SAECG analysis, patients with COPD had significantly increased total QRS duration as compared to control subjects. Nine of the 30 patients with COPD (30%) had positive late potentials. However, QTd and VPB rates were also similar between patients with COPD with and without late potentials. CONCLUSIONS: The development of ventricular arrhythmia in patients with COPD was associated with increased QTd. Increased QTd may be associated with autonomic changes seen in patients with COPD. 相似文献
104.
105.
A new variant of type II von Willebrand disease with aberrant multimeric structure of plasma but not platelet von Willebrand factor (type IIF) 总被引:2,自引:0,他引:2
A patient with a lifelong bleeding disorder was diagnosed as having Type II von Willebrand disease. The larger multimers of von Willebrand factor were absent from her plasma but present in platelets. A high- resolution electrophoretic technique was used to study the complex structure of individual von Willebrand factor multimers. In normal plasma, each multimer could be resolved into five bands: a more intense central one and four less intense, two moving faster and two slower than the central band. In normal platelets, each multimer could also be resolved into five bands. The central one had a mobility similar to that in plasma, whereas the four satellite bands had a mobility that differed from that of the corresponding plasma bands. In the patient, platelet von Willebrand factor antigen content and ristocetin cofactor activity were normal, and von Willebrand factor showed the same structure of individual multimers as seen in normal platelets. On the other hand, plasma von Willebrand factor antigen and ristocetin cofactor activity were decreased, and the structure of individual von Willebrand factor multimers was different from that of normal plasma and similar to that seen in normal and patient's platelets. After infusion of 1-deamino-8-D-arginine vasopressin, the largest von Willebrand factor multimers, as well as new satellite bands with a mobility similar to those in normal plasma, appeared in the patient plasma, and the levels of von Willebrand factor antigen and ristocetin cofactor activity became normal. Yet no relevant change in the prolonged bleeding time was observed. This new variant of von Willebrand disease, therefore, is characterized by the presence of a dysfunctional von Willebrand factor molecule that exhibits unique structural abnormalities in plasma but appears to be normal in platelets. The designation of Type IIF is proposed for this type of von Willebrand disease in accordance with the terminology that has been previously used. 相似文献
106.
Dr. Erica A. Brotschi MD Carol L. Hilbinger BA Elizabeth A. Kahl AB William A. Vaules AB Nicholas A. Midis AB J. Krzysztof Blusztajn PhD Stephen H. Zeisel MD PhD 《Digestive diseases and sciences》1995,40(9):1982-1989
Acetylcholine may be released from gallbladder intrinsic nerves in response to cholecystokinin stimulation. This study characterized metabolites of [14C]choline produced in the gallbladder and released during incubation, with or without cholecystokinin-octapeptide. Radiolabeled [14C]choline was applied to the mucosal or muscle surface of intact guinea pig gallbladders in an organ bath. After radiolabeling, gallbladders were incubated with or without the contractile agonist cholecystokinin-octapeptide. Metabolites of [14C]choline were identified in gallbladder tissue and incubation buffers using HPLC and thin-layer chromatography. The major metabolites of [14C]choline were betaine and phosphocholine. [14C]Phosphocholine was incorporated slowly into [14C]phosphatidylcholine. [14C]Choline was released into buffers during incubation. [14C]Acetylcholine constituted less than 1% of radiolabel in the gallbladder. There was no identifiable [14C]acetylcholine released in buffers. Cholecystokinin-octapeptide did not affect choline metabolism. These studies showed that choline in the gallbladder is metabolized along pathways similar to those in the liver. Gallbladders released mostly choline, rather than acetylcholine, even during hormonally induced contraction.This project was supported by the Research and Development Office of the Department of Veterans Affairs. 相似文献
107.
Association of granulocyte-macrophage colony-stimulating factor with the crystalloid granules of human eosinophils 总被引:3,自引:1,他引:3
Levi-Schaffer F; Lacy P; Severs NJ; Newman TM; North J; Gomperts B; Kay AB; Moqbel R 《Blood》1995,85(9):2579-2586
We have previously shown that normal-density human peripheral blood eosinophils transcribe and translate mRNA for granulocyte-macrophage colony-stimulating factor (GM-CSF) and that the intracellular distribution was granular as assessed by light microscopy immunocytochemistry. The present study was conducted to confirm this apparent association between GM-CSF and the crystalloid granule using a subcellular fractionation method for human eosinophils and immunogold electron microscopy (EM). Highly purified (> 99%, by negative selection using anti-CD16 immunomagnetic microbeads) human peripheral blood eosinophils were obtained from four asthmatic subjects (not taking systemic medication), homogenized and density fractionated (5 x 10(7) cells/subject) on linear Nycodenz gradients. Twenty-four fractions were collected from each cell preparation and analyzed for marker enzyme activities as well as total protein. Dot blot analysis with specific monoclonal antibodies (MoAbs) was used to detect the eosinophil granule proteins major basic protein (MBP) and eosinophil cationic protein (ECP). An anti-CD9 MoAb was used as an eosinophil plasma membrane marker. Lactate dehydrogenase (LDH) was used as a cytosolic marker. Immunoreactivity for GM-CSF was detected by a specific enzyme-linked immunosorbent assay using a polyclonal antihuman GM-CSF antibody and confirmed by dot blot. GM-CSF coeluted with the cellular fractions containing granule markers (MBP, ECP, eosinophil peroxidase, hexosaminidase, and arylsulphatase), but not those containing cytoplasm (LDH+) or membrane (CD9+) markers. EM examination of pooled fractions associated with the peak of GM-CSF immunoreactivity confirmed that they contained crystalloid and small granules, but not plasma membrane. In addition, quantification, using immunogold labeling with an anti/GM-CSF MoAb, indicated preferential localization of gold particles over the eosinophil granule cores of intact cells. Thus, our results indicate that GM-CSF resides as a granule-associated, stored mediator in unstimulated human eosinophils. 相似文献
108.
Gumurdulu Y Serin E Ozer B Kayaselcuk F Ozsahin K Cosar AM Gursoy M Gur G Yilmaz U Boyacioglu S 《World journal of gastroenterology : WJG》2004,10(5):668-671
AIM:The eradication rate of Helicobacter pylori (H pylon) shows variation among countries and regimens of treatment.We aimed to study the eradication rates of different regimens in our region and some factors affecting the rate of eradication.METHODS:One hundred and sixty-four Hpylori positivepatients (68 males, 96 females; mean age:48±12 years)with duodenal or gastric ulcer without a smoking history were included in the study. The patients were divided into three groups according to the treatment regimens. Omeprazole 20mg, clarithromycin 500mg, amoxicillin 1g were given twice daily for 1 week (Group I) and 2 weeks (Group Ⅱ).Patients in Group Ⅲ received bismuth subsitrate 300mg,tetracyline 500 mg and metronidazole 500mg four times daily in addition to Omeprazole 20mg twice daily.Two biopsies each before and after treatment were obtained from antrum and corpus, and histopathologically evaluated.Eradication was assumed to be successful if no Hpylorus was detected from four biopsy specimens taken after treatment. The effects of factors like age, sex, Hpyloridensity on antrum and corpus before treatment, the total Hpylori density, and the inflammation scores on the rate of Hpylori eradication were evaluated.RESULTS:The overall eradication rate was 42%. The rates in groups Ⅱ and Ⅲ were statistically higher than that in group I (P<0.05). The rates of eradication were 24.5%,40.7% and 61.5% in groups Ⅰ, Ⅱ and Ⅲ, respectively. The eradication rate was negatively related to either corpus Hpylori density or total Hpyloridensity (P<0.05).The median age was older in the group in which the eradication failed in comparison to that with successful eradication (55yr vs 39yr, P<0.001). No correlation between sex and Hpylori eradication was found.CONCLUSION: Our rates of eradication were significantly lower when compared to those reported in literature.We believe that advanced age and high Hpyloridensity are negative predictive factors for the rate of Hpylorieradication. 相似文献
109.
110.
Kerem M Ferahkose Z Yilmaz UT Pasaoglu H Ofluoglu E Bedirli A Salman B Sahin TT Akin M 《World journal of gastroenterology : WJG》2008,14(23):3633-3641
AIM: To investigate the roles of the adipocytokines, ghrelin and leptin in gastric cancer cachexia.
METHODS: Resistin, ghrelin, leptin, adiponectin, insulin and insulin-like growth factor (IGF-Ⅰ), were measured in 30 healthy subjects, and 60 gastric cancer patients of which 30 suffered from cancerinduced cachexia and 30 served as a control group. The relationships between hormones, body mass index (BMI) loss ratio, age, gender, and Glasgow Prognostic Score (GPS) were investigated.
RESULTS: Cachexia patients had higher tumor stage and GPS when compared with non-cachexia patients (P 〈 0.05). Ghrelin, resistin, leptin, adiponectin and IGF- Ⅰ, showed a significant correlation with BMI loss ratio and GPS (P 〈 0.05). A strong correlation was seen between GPS and BMI loss (R = -0.570, P 〈 0.0001). Multivariate analysis indicated that BMI loss was significantly independent as a predictor of ghrelin, resistin, leptin and IGF-Ⅰ (P 〈 0.05). Existence of an important significant relationship between resistin and insulin resistance was also noted.
CONCLUSION: These results showed that serum ghrelin, leptin, adiponectin, and IGF-Ⅰ play important roles in cachexia-related gastric cancers. No relationship was found between resistin and cancer cachexia. Also, because of the correlation between these parameters and GPS, these parameters might be used as a predictor factor. 相似文献
METHODS: Resistin, ghrelin, leptin, adiponectin, insulin and insulin-like growth factor (IGF-Ⅰ), were measured in 30 healthy subjects, and 60 gastric cancer patients of which 30 suffered from cancerinduced cachexia and 30 served as a control group. The relationships between hormones, body mass index (BMI) loss ratio, age, gender, and Glasgow Prognostic Score (GPS) were investigated.
RESULTS: Cachexia patients had higher tumor stage and GPS when compared with non-cachexia patients (P 〈 0.05). Ghrelin, resistin, leptin, adiponectin and IGF- Ⅰ, showed a significant correlation with BMI loss ratio and GPS (P 〈 0.05). A strong correlation was seen between GPS and BMI loss (R = -0.570, P 〈 0.0001). Multivariate analysis indicated that BMI loss was significantly independent as a predictor of ghrelin, resistin, leptin and IGF-Ⅰ (P 〈 0.05). Existence of an important significant relationship between resistin and insulin resistance was also noted.
CONCLUSION: These results showed that serum ghrelin, leptin, adiponectin, and IGF-Ⅰ play important roles in cachexia-related gastric cancers. No relationship was found between resistin and cancer cachexia. Also, because of the correlation between these parameters and GPS, these parameters might be used as a predictor factor. 相似文献