全文获取类型
收费全文 | 11752篇 |
免费 | 843篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 165篇 |
儿科学 | 397篇 |
妇产科学 | 239篇 |
基础医学 | 1426篇 |
口腔科学 | 202篇 |
临床医学 | 1128篇 |
内科学 | 2426篇 |
皮肤病学 | 245篇 |
神经病学 | 1004篇 |
特种医学 | 544篇 |
外科学 | 1693篇 |
综合类 | 166篇 |
一般理论 | 6篇 |
预防医学 | 1147篇 |
眼科学 | 255篇 |
药学 | 626篇 |
中国医学 | 7篇 |
肿瘤学 | 943篇 |
出版年
2022年 | 106篇 |
2021年 | 216篇 |
2020年 | 130篇 |
2019年 | 194篇 |
2018年 | 233篇 |
2017年 | 176篇 |
2016年 | 172篇 |
2015年 | 200篇 |
2014年 | 268篇 |
2013年 | 434篇 |
2012年 | 695篇 |
2011年 | 719篇 |
2010年 | 372篇 |
2009年 | 344篇 |
2008年 | 603篇 |
2007年 | 658篇 |
2006年 | 620篇 |
2005年 | 595篇 |
2004年 | 555篇 |
2003年 | 493篇 |
2002年 | 456篇 |
2001年 | 251篇 |
2000年 | 232篇 |
1999年 | 220篇 |
1998年 | 129篇 |
1997年 | 86篇 |
1996年 | 82篇 |
1995年 | 80篇 |
1994年 | 80篇 |
1993年 | 83篇 |
1992年 | 179篇 |
1991年 | 157篇 |
1990年 | 150篇 |
1989年 | 167篇 |
1988年 | 158篇 |
1987年 | 160篇 |
1986年 | 175篇 |
1985年 | 174篇 |
1984年 | 119篇 |
1983年 | 122篇 |
1982年 | 72篇 |
1981年 | 76篇 |
1980年 | 88篇 |
1979年 | 121篇 |
1978年 | 87篇 |
1977年 | 86篇 |
1975年 | 71篇 |
1974年 | 72篇 |
1973年 | 84篇 |
1972年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Samuel Szomstein Orit Kaidar-Person Kristoff Naberezny Marcia Cruz-Correa Raul Rosenthal 《Surgery for obesity and related diseases》2006,2(6):617-621
BACKGROUND: Anastomotic stenosis presents as one of the most common late complications in the postoperative period after bariatric surgery. It is often diagnosed by upper gastrointestinal series (UGIS) and/or upper endoscopy (UE). The aim of this study was to determine whether a correlation exists between the Gastrografin UGIS and UE findings in the determination of gastrojejunal anastomotic strictures after Roux-en-Y gastric bypass (RYGB). METHODS: Between July 2001 and October 2003, all medical records of patients who underwent RYGB at our institution were retrospectively reviewed. The medical records of patients who underwent UE because of symptoms suggestive of gastric outlet obstruction and those of patients who were initially evaluated by Gastrografin UGIS before UE were evaluated further. RESULTS: Of 535 morbidly obese patients who underwent RYGB, 52 (9.7%) had UE and were included in this study. The mean number of UEs performed per patient was 2.67. Of these 52 patients, 30 underwent Gastrografin UGIS before UE. The mean diameter of the anastomosis on the first UE was 5.97 mm and on Gastrografin UGIS was 6.83 mm. A good correlation was found between the Gastrografin UGIS and UE findings using Pearson's correlation coefficient (0.44, P = .02) and single linear regression analysis using the endoscopic diameter as the outcome and radiographic findings as the predictor (beta = 0.27, P = .025, 95% confidence interval 0.30-0.49). CONCLUSION: In our study, the Gastrografin UGIS findings correlated positively with the endoscopic gastrojejunal anastomosis findings in patients with anastomotic stricture who had undergone RYGB. 相似文献
32.
Joe I-Chiang Chou Hwai-Jen Fong Shou-Hsin Kuang Lin-Yang Gi Fang-Yi Hwang Yu-Chieng Lai Richard Che-Shoa Chang Shou-Yen Kao 《Journal of oral and maxillofacial surgery》2005,63(3):355-361
PURPOSE: This study was an analysis of the soft and hard tissue changes of the facial profile after bilateral sagittal splitting osteotomy for mandibular setback of Taiwanese patients. PATIENTS AND METHODS: We collected pre- and postsurgical lateral cephalographs of 64 patients (28 males, 36 females) with skeletal Class III malocclusion who received combined orthodontic-surgical treatment with bilateral sagittal splitting osteotomy mandibular setback at Taipei Veterans General Hospital between 1994 and 2000. Nineteen cephalometric parameters of (14 linear, 4 angular, and the BS index) soft and hard tissues were measured at 1 week before treatment, and 2 months and 1 year after surgery, and analyzed by paired t test. RESULTS: Mean patient age was 20.0 +/- 1.6 years. The patients underwent an average of 7 mm mandibular setback at the osseous pogonion (Pog). Average setbacks at Pog and soft tissue pogonion (pog) were 5.54 mm and 4.85 mm, respectively, at 1 year after surgery. The setback ratio of Pog/pog was 1:0.88. The hard tissue relapse at Pog was 21% at 1 year after surgery. Improvement in prognathic profile was demonstrated by significant changes in the positions of Pog and pog, ANB angle, the distance from lower lip to esthetic line (E-L lip), and the BS index after surgery. However, compared with parameters obtained from a normal Taiwanese population, the cephalometric data of Pog, pog, and BS index still indicated mild prognathism. CONCLUSION: Although mandibular prognathism could be grossly improved by bilateral sagittal splitting osteotomy mandibular setback, a significant amount of relapse occurred within 1 year after surgery. The extent of the postoperatively preserved features showing mandibular prognathism should be a concern for both patients and physicians. 相似文献
33.
Ahsan Y Khan Joe Carrithers Sheldon H Preskorn Rex Lear Stephen R Wisniewski A John Rush Diane Stegman Colleen Kelley Karen Kreiner Andrew A Nierenberg Maurizio Fava 《Annals of clinical psychiatry》2006,18(2):91-98
BACKGROUND: The purpose of this paper is to use demographic and clinical data from a large diverse group of outpatients diagnosed with non-psychotic major depression to investigate the validity of the DSM-IV concept of melancholic depression. METHODS: Baseline clinical and demographic data were collected on 1500 outpatients (1456 of whom melancholia could be determined) with non-psychotic major depressive disorder (MDD) participating in the Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study. Depressive symptom severity was assessed by clinical telephone interview using the 17-item Hamilton Rating Scale for Depression (HRS-D17) and the 30-item Inventory of Depressive Symptomatology (IDS-C30). The types and degrees of concurrent psychiatric symptoms were measured using a self report, the Psychiatric Diagnostic Screening Questionnaire (PDSQ), by recording the number of items relevant to each diagnostic category endorsed by study participants. RESULTS: Adjusting for severity of depression (as measured by the total HRS-D17 scores), no differences were found in the rate of melancholic depression by race, marital status, education, employment status, family history of depression, primary care versus specialty care, monthly income, and degree of psychiatric and medical co-morbidity. Melancholic depression was significantly more likely in men than women. Melancholic depression after adjustment for severity was associated with a slightly younger age at study entry, as well as with greater illness severity, and slightly shorter duration of current episode. Hispanic ethnicity was associated with lower melancholic depression rates at the .06 level of significance. CONCLUSIONS: Among outpatients with MDD, melancholic features were less likely in Hispanic patients, but more likely in slightly younger patients and in men. Melancholic features were also related to a slightly shorter current episode. These findings are consistent with the notion that external socio-demographic factors do not play an important role in the pathophysiology of melancholic depression. 相似文献
34.
Joe Pixler 《Journal of healthcare risk management》2004,24(1):29-29
35.
M J Rosenthal D Smith L Yaguez V Giampietro D Kerr E Bullmore M Brammer S C R Williams S A Amiel 《Diabetic medicine》2007,24(7):720-727
AIMS: Caffeine enhances counterregulatory responses to acute hypoglycaemia. Our aim was to explore its effects on cortical function, which are not known at present. METHODS: Regional brain activation during performance of the four-choice reaction time (4CRT) at different levels of complexity was measured using functional magnetic resonance imaging (fMRI) at euglycaemia (5 mmol/l) and hypoglycaemia (2.6 mmol/l) in the presence and absence of caffeine in six healthy right-handed men. RESULTS: During hypoglycaemia, caffeine enhanced adrenaline responses to hypoglycaemia (2.5 +/- 0.7 nmol/l to 4.0 +/- 1.0 nmol/l, P = 0.01) and restored the brain activation response to the non-cued 4CRT, the linear increases in regional brain activation associated with increased task complexity and the ability to respond to a cue that were lost in hypoglycaemia alone. CONCLUSIONS: Caffeine can sustain regional brain activation patterns lost in acute hypoglycaemia, with some restoration of cortical function and enhanced adrenaline responsiveness. A methodology has been established that may help in the development of therapies to protect against severe hypoglycaemia in insulin therapy for patients with diabetes and problematic hypoglycaemia. 相似文献
36.
Insulin inhibition of endothelial prostacyclin production 总被引:7,自引:0,他引:7
Graft thrombosis is a common cause of early graft failure in pancreatic transplantation, even in the absence of rejection. Altered endothelial cell (EC) production of thromboactive substances may play a primary role in this and other settings of thrombosis where intraluminal insulin concentrations are high. We therefore investigated the effect of insulin on EC production of prostacyclin (PGI2), a potent endogenous antagonist of platelet aggregation and vasodilator. Confluent monolayers of human umbilical vein endothelial cells (HUVEC) were incubated for 15 min in Hanks'/Hepes buffer containing 0, 50, 250, or 500 microU/ml of human insulin or 0, 500, 1000, or 2000 microU/ml of porcine insulin. PGI2 production was assessed by exposing the monolayers to either 20 microM arachidonic acid (stimulated) or arachidonic acid vehicle (basal) for an additional 15 min. Test buffers were then assayed by RIA for 6-keto-PGF1 alpha, the stable metabolite of PGI2. The results of these experiments indicate that human insulin inhibits both basal and arachidonic acid-stimulated production of PGI2 from HUVEC in a dose-dependent manner. Inhibition of stimulated production was significant at concentrations of 250-500 microU/ml. Porcine insulin also inhibited arachidonic acid-stimulated production of PGI2 from HUVEC in a dose-dependent manner. However, HUVEC were less sensitive to porcine insulin than to human insulin and a concentration of 2000 microU/ml was required for significant inhibition. We therefore conclude that insulin, in locally high concentrations, inhibits endothelial PGI2 production in vitro. The ability of insulin to alter the production of thromboresistant substances from endothelium may facilitate thrombosis in circumstances where counterregulatory mechanisms are disturbed by injury or transplantation. 相似文献
37.
38.
Kohsuke Sasaki Daniel Pinkel Masato Tsukahara Ichiro Murano Joe W Gray 《Pathology international》1994,44(2):145-150
A human chromosomal translocation t(8;9) was detected using two-color fluorescence in situ hybridization with probes capable of staining the entire lengths of each of these chromosomes. The chromosome 8 probe was labeled with biotin and detected with Texas red, while the chromosome 9 probe was labeled with AAF and detected with FITC . In normal metaphase spreads, two metaphases from the proband, two red, one green and one part red and part green derivative chromosome were seen. The bicolor chromosome corresponded to translocation of a chromosome 8 segment to the distal part of the q region of one chromosome 9, as originally indicated by banding analysis. In interphase nuclei of the proband, four domains with bright fluorescence were recognized in many nuclei. Two were red, one was green, and the fourth had portions of both colors, indicating the presence of the translocation. 相似文献
39.
Major fragment of soluble peptidoglycan released from growing Bordetella pertussis is tracheal cytotoxin. 总被引:5,自引:2,他引:3 下载免费PDF全文
R S Rosenthal W Nogami B T Cookson W E Goldman W J Folkening 《Infection and immunity》1987,55(9):2117-2120
Bordetella pertussis is known to release a factor which promotes the loss of ciliated respiratory epithelium and copurifies with a soluble peptidoglycan (PG) fragment termed tracheal cytotoxin (TCT). The objective of this study was to determine whether pertussis organisms turn over and release PG derivatives in addition to TCT. B. pertussis Tohama (phase III) was grown in liquid Stainer-Scholte medium containing [3H]diaminopimelic acid (DAP) to label PG specifically, washed to remove free label, and suspended in fresh medium without [3H]DAP. Molecular sieve chromatography of supernatants obtained from such cultures revealed a single included peak of 3H, the elution volume of which corresponded roughly to a disaccharide peptide monomer standard (ca. 10(3) daltons). This material (i) contained [3H]DAP in acid-hydrolyzable linkage, (ii) comigrated with 1,6-anhydro-N-acetylmuramic acid-containing disaccharide peptides on paper chromatography, (iii) was resistant to degradation by mild alkali, and (iv) was indistinguishable from authentic TCT by high-voltage paper electrophoresis and two reversed-phase high-performance liquid chromatography systems. Together, the data suggest that B. pertussis releases a markedly homogeneous set of PG fragments, consisting principally of TCT, and that TCT is possibly a nonreducing, anhydromuramic acid-containing fragment or a cyclic PG derivative. 相似文献
40.
G J Rosenthal W A Craig E Corsini M Taylor M I Luster 《Toxicology and applied pharmacology》1992,112(2):222-228
Pentamidine isethionate, an antiprotozoal agent with therapeutic value against Pneumocystis carinii pneumonia, has been used for over 30 years without a precise understanding of its mechanism of pharmacologic action. We have previously reported that pentamidine has the capacity to inhibit the release of cytokines from macrophages through a post-translational processing event. The present studies were undertaken to assess the ability of pentamidine to modulate the detrimental effects of murine endotoxemia, a disease with a pathophysiology clearly linked to host-produced cytokines. Under conditions where normal B6C3F1 mice succumbed to the lethal effects of endotoxin, mice pretreated with pentamidine were significantly protected from both mortality and loss of thermoregulatory control. The EC50 for protection from mortality by pentamidine was approximately 11.4 mg/kg. These observations correlated with decreased serum levels of tumor necrosis factor (TNF) and interleukin 6. Inhibition of cytokines was not manifested as part of a generalized inhibition of protein synthesis as demonstrated by the lack of significant modulation of serum albumin in pentamidine-treated animals. In addition to decreased serum concentrations of cytokines, lungs isolated from mice treated with both pentamidine and endotoxin exhibited a decreased release of TNF compared to lungs isolated from mice treated with vehicle and endotoxin. The lower levels of TNF released from lung tissue in pentamidine-treated mice correlated with a lesser degree of alveolar deterioration than was observed in vehicle-treated mice. These data indicate that following endotoxin administration, pentamidine has a protective and antiinflammatory role both systemically and in the lung and suggest that inhibition of inflammatory cytokines may be one mechanism operable in the therapeutic activity of the drug against P carinii pneumonia. 相似文献