全文获取类型
收费全文 | 27039篇 |
免费 | 2803篇 |
国内免费 | 72篇 |
专业分类
耳鼻咽喉 | 328篇 |
儿科学 | 827篇 |
妇产科学 | 519篇 |
基础医学 | 3581篇 |
口腔科学 | 549篇 |
临床医学 | 3229篇 |
内科学 | 4742篇 |
皮肤病学 | 251篇 |
神经病学 | 2893篇 |
特种医学 | 1012篇 |
外科学 | 4235篇 |
综合类 | 678篇 |
一般理论 | 5篇 |
预防医学 | 2990篇 |
眼科学 | 529篇 |
药学 | 1711篇 |
中国医学 | 12篇 |
肿瘤学 | 1823篇 |
出版年
2021年 | 356篇 |
2020年 | 218篇 |
2019年 | 402篇 |
2018年 | 497篇 |
2017年 | 346篇 |
2016年 | 344篇 |
2015年 | 418篇 |
2014年 | 584篇 |
2013年 | 960篇 |
2012年 | 1325篇 |
2011年 | 1283篇 |
2010年 | 723篇 |
2009年 | 716篇 |
2008年 | 1205篇 |
2007年 | 1190篇 |
2006年 | 1146篇 |
2005年 | 1070篇 |
2004年 | 1098篇 |
2003年 | 1043篇 |
2002年 | 904篇 |
2001年 | 895篇 |
2000年 | 924篇 |
1999年 | 743篇 |
1998年 | 360篇 |
1997年 | 314篇 |
1996年 | 333篇 |
1995年 | 310篇 |
1994年 | 281篇 |
1993年 | 298篇 |
1992年 | 639篇 |
1991年 | 631篇 |
1990年 | 600篇 |
1989年 | 620篇 |
1988年 | 581篇 |
1987年 | 592篇 |
1986年 | 527篇 |
1985年 | 525篇 |
1984年 | 398篇 |
1983年 | 347篇 |
1982年 | 243篇 |
1981年 | 210篇 |
1980年 | 208篇 |
1979年 | 367篇 |
1978年 | 206篇 |
1977年 | 209篇 |
1976年 | 228篇 |
1975年 | 184篇 |
1974年 | 240篇 |
1973年 | 228篇 |
1972年 | 187篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Richard B Thompson Ewout J van den Bos Bryce H Davis Yoshihisa Morimoto Damian Craig Brad S Sutton Donald D Glower Doris A Taylor 《The Journal of heart and lung transplantation》2005,24(2):205-214
BACKGROUND: Pre-clinical and clinical studies suggest that transplantation of bone marrow-derived stem cells can improve global cardiac function. However, no quantitative assessment of regional systolic contraction and correlation with phenotype has been made. Therefore, we used our model of cryoinfarcted rabbit myocardium for intracardiac transplantation of a mixed population of bone marrow-derived cells and assessed both regional function and myogenic conversion of the cells. METHODS: Nineteen New Zealand white rabbits underwent cryoinjury of the left ventricle. Autologous bone marrow (BM) cells were expanded in vitro. After 2 weeks, either 1 x 10(8) mixed BM-derived progenitor cells (BM group, n = 11) or vehicle (control group, n = 8) were injected into the cryoinjured region. Regional systolic function was measured using micromanometry and sonomicrometry before and 4 weeks after cell injection; cell phenotype was evaluated histologically. RESULTS: All animals in the BM group significantly improved both systolic shortening (0.11 +/- 0.7 vs -0.05 +/- 0.05 mm in the control group, p < 0.05) and regional stroke work when compared with control (9.6 +/- 2.4 vs -1.2 +/- 1.2 mm . mm Hg, p < 0.003). In addition, the BM group had improved global diastolic function, as measured by minimum dP/dt and end-diastolic pressure. On histologic assessment, BM cells differentiated toward a myogenic phenotype. CONCLUSIONS: Transplanting a mixed population of marrow-derived cells that can adopt a myogenic phenotype improves regional contractility and diastolic relaxation after myocardial infarction. 相似文献
42.
43.
44.
The many uses of the U tube 总被引:2,自引:0,他引:2
U tube placement was employed as an adjunct to complicated biliary procedures in 14 patients. We found the transhepatic tubes to be useful for stenting biliary anastomoses, maintaining biliary drainage, delivering localized irradiation, and acting as permanent external conduits. The tubes remained in placed an average of 15 months and as long as 40 months. The frequency of cholangitis was minimized by frequent tube exchange. The U-shaped configuration makes tube exchange easy and inexpensive to perform. 相似文献
45.
46.
M L Cibull M E Thompson L Smith C D Jennings M A Doukas E J Pavlik D E Powell 《American journal of hematology》1987,24(3):293-299
The emergence of a near-haploid clone of cells in blast phase chronic myelogenous leukemia is an unusual event. We report such a case and review eight other cases described in the English literature. The significance of the substantial loss of genetic material is discussed as is the phenotypic and genotypic heterogeneity observed in this group of patients. 相似文献
47.
The goal of the present study is to develop a technique for laparoscopic aortobifemoral bypass.Piglets weighing between 60 and 78 kg were anesthetized with halothane. The lateral retroperitoneal approach was preferred to the more familiar anterior transperitoneal approach and was successfully completed in 19 piglets. The piglets were placed in the right lateral decubitus position. The first port (2 cm) was inserted halfway between the tip of the 12th rib and the iliac crest. Four other trocars were placed in the retroperitoneum after balloon inflation had allowed creation of a space which permitted visualization of the aorta from the left renal artery down to the aorto-iliac junction. After evacuation of the retropneumoperitoneum, the cavity was maintained using an abdominal lift device and a retractor.Using this approach, we performed four aortobifemoral bypasses (end-to-end aortic anastomosis) after conventional intravenous heparinization (100 IU/kg) in less than 4 h. Blood loss did not exceed 250 ml and the hematocrit remained stable. Postmortem evaluation of the grafts revealed they were positioned as in a conventional bypass, their limbs having followed in the created retroperitoneal tunnels along the path of the native arteries. No mortality occurred before sacrifice of the animals. We believe that this first performed series of totally retroperitoneal laparoscopic aortobifemoral bypasses in the porcine model is useful in preparation for human application due to the anatomical similarities in the periaortic region. 相似文献
48.
G. Bradley Schaefer James N. Thompson John B. Bodensteiner James M. McConnell William J. Kimberling Charles T. Gay William D. Dutton David C. Hutchings Stanton B. Gray 《Annals of neurology》1996,39(3):382-385
There are conflicting reports on the relationship between cerebellar vermal lobule hypoplasia and autism. Using quantitative magnetic resonance image analysis, we measured the cerebellar vermis in 125 normal individuals with a broad age range and 102 patients with a variety of neurogenetic abnormalities. We conclude that hypoplasia of cerebellar vermal lobules VI and VII is a nonspecific finding that even occurs in several conditions without autistic behavior. This suggests that it is not a specific neuroanatomical marker for autism, nor is cerebellar dys- genesis likely to be solely responsible for clinical autistic behaviors. 相似文献
49.
Diagnostic distance of high grade prostatic intraepithelial neoplasia from normal prostate and adenocarcinoma.
下载免费PDF全文
![点击此处可从《Journal of clinical pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R Montironi R Pomante P Colanzi D Thompson P W Hamilton P H Bartels 《Journal of clinical pathology》1997,50(9):775-782
OBJECTIVE: To develop a distance measure based methodology to support the morphological evaluation of high grade prostatic intraepithelial neoplasia (PIN), a direct precursor of prostate cancer. METHODS: Eight morphological and cellular features were analysed in 20 cases of high grade PIN found in radical prostatectomy specimens from patients with adenocarcinoma. The diagnostic distance was evaluated to measure the extent to which the feature outcomes of the individual high grade PIN cases differed from the expected outcome profile of normal prostate, low and high grade PIN, and cribriform and large acinar adenocarcinoma. The belief value for high grade PIN was evaluated with a Bayesian belief network (BBN). RESULTS: Complete separation existed between the cumulative absolute diagnostic distances of these 20 cases from the prototype feature outcomes of high grade PIN and normal prostate the values for which were < or = 3 (range 0 to 3) and > or = 9 (range 9 to 15), respectively. The distances from low grade PIN (range 3 to 9), cribriform adenocarcinoma (range 2 to 8), and large acinar adenocarcinoma (range 5 to 10) were intermediate and showed overlap in their distribution. When taking into consideration whether the severity of feature changes was increasing or decreasing in comparison with the category prototype outcomes, the cumulative directional diagnostic distances from high grade PIN ranged from -3 to +3. Positive distance values were seen relative to low grade PIN (range +3 to +9) and relative to normal prostate (range +9 to +15). Negative values were found relative to cribriform adenocarcinoma (range -8 to +2). The distance values from large acinar adenocarcinoma ranged from -2 to +4 and partly overlapped with those from the high grade PIN category. A bivariate scattergram derived from both diagnostic distance measures showed excellent separation between the groups' distances. BBN analysis confirmed the morphology based diagnosis. The distance evaluation resulted in 18 cases whose belief value for high grade PIN ranged from 0.60 to 0.87. In the remaining two cases the results of the BBN analysis showed a belief value of 0.50 and 0.57 for low grade PIN and of 0.49 and 0.38 for high grade PIN, respectively. CONCLUSIONS: Distance measure based methodology represents a useful diagnostic decision support tool for the accurate evaluation of high grade PIN. 相似文献
50.