全文获取类型
收费全文 | 1706篇 |
免费 | 87篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 34篇 |
儿科学 | 134篇 |
妇产科学 | 215篇 |
基础医学 | 119篇 |
口腔科学 | 25篇 |
临床医学 | 129篇 |
内科学 | 380篇 |
皮肤病学 | 28篇 |
神经病学 | 104篇 |
特种医学 | 58篇 |
外科学 | 299篇 |
综合类 | 34篇 |
一般理论 | 1篇 |
预防医学 | 39篇 |
眼科学 | 33篇 |
药学 | 88篇 |
中国医学 | 5篇 |
肿瘤学 | 74篇 |
出版年
2023年 | 13篇 |
2022年 | 23篇 |
2021年 | 24篇 |
2020年 | 19篇 |
2019年 | 26篇 |
2018年 | 50篇 |
2017年 | 32篇 |
2016年 | 49篇 |
2015年 | 52篇 |
2014年 | 57篇 |
2013年 | 97篇 |
2012年 | 118篇 |
2011年 | 121篇 |
2010年 | 63篇 |
2009年 | 62篇 |
2008年 | 124篇 |
2007年 | 151篇 |
2006年 | 123篇 |
2005年 | 139篇 |
2004年 | 116篇 |
2003年 | 113篇 |
2002年 | 88篇 |
2001年 | 37篇 |
2000年 | 26篇 |
1999年 | 26篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1982年 | 1篇 |
1975年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1799条查询结果,搜索用时 15 毫秒
61.
Hydatid cyst disease is encountered in Turkey frequently. Rupture of a pulmonary cyst into the pleural cavity is rare, but represents the most serious complication of the hydatid disease. Surgical intervention was carried out in all cases in our clinic when expansion of the lungs could not be achieved. Open ends of the bronchus were closed and the pericyst layer was sutured after the removal of the germinative layer. We here present 5 cases of hydatid cysts with the above mentioned complication. 相似文献
62.
Color Doppler tissue imaging to evaluate left atrial appendage function in mitral stenosis 总被引:4,自引:0,他引:4
Eryol NK Topsakal R Kiranatli B Abaci A Ciçek Y Oguzhan A Başar E Ergin A Cetin S 《Echocardiography (Mount Kisco, N.Y.)》2003,20(1):29-35
Two-dimensional color Doppler tissue imaging (CDTI) has so far been used, in general, to evaluate ventricular function. This study examined if the left atrial appendage tissue velocity could reproducibly be measured with CDTI and if they have any predictive value for left atrial appendage (LAA) function and former thromboembolism. Thirty-six patients (24 women, 12 men; mean age 45 +/- 12 years; 18 AF; 11 former thromboembolic stroke) with mitral stenosis undergoing transesophageal echocardiography were examined with CDTI. Peak systolic tissue velocity (m/sec, peak systolic velocity [PSV]) was measured at the tip of the LAA in the basal short-axis view. LAA flow emptying (LAAEV) and filling (LAAFV) velocities (m/sec) were also recorded 1 cm immediately below the orifice of the appendage. Interobserver and intraobserver variabilities were determined for the PSV. LAA ejection fraction was measured by Simpson's method. Mitral regurgitation, AF, transmitral mean gradient, left ventricular ejection fraction, mitral valve area, and left atrial diameter were used as a covariant for adjustment. The intraobserver and interobserver correlation coefficients for the PSV using CDTI was 0.64 and 0.60, respectively (bothP = 0.01). LAAEV(0.29 +/- 0.09 vs 0.19 +/- 0.04, P = 0.001)and LAA ejection fraction(44 +/- 12 vs 29 +/- 14, P = 0.004)were found to be significantly decreased in the patients with decreased PSV (<0.05 m/sec), even after adjustment. The decreased PSV was positively correlated with the low LAAEV (<0.25 m/sec) and history of thromboembolism (r = 0.59, r = 0.38, respectively), and remained a significant determinant of the low LAAEV (OR 50.03, CI 1.46-1738.11,P = 0.02), but not of history of thromboembolism (OR 4.29, CI 0.52-35.01,P = 0.08) after adjustment. In conclusion, these results suggest that CDTI provides a reproducible method for quantification of contraction at the tip of the LAA. Decreased PSV may be predictive of poor LAA function. 相似文献
63.
Levent Ozgonenel Esra Cetin Sule Tutun Pinar Tonbaklar Hale Aral Guvenc Guvenen 《Clinical rheumatology》2010,29(5):473-477
Vascular endothelial growth factor (VEGF) is known to be involved in the pathogenesis of rheumatoid arthritis (RA). In order
to elucidate the association between VEGF levels and RA disease activity, VEGF concentrations were measured in RA patients
at different phases and severity levels. Thirty-eight healthy subjects and 40 patients with RA were prospectively included
in the study. Subjects were further categorized into four subgroups (high, moderate, low, or remission) using the disease
activity score-28 (DAS28) scoring system. VEGF levels were significantly higher in patients than controls (p < 0.001). VEGF levels differed significantly in controls, early and late-phase RA patients (p = 0.002). A significant difference was found between controls and patients with high RA disease activity scores (p < 0.0001). VEGF levels were not correlated with age (r = −0.016; p = 0.921) or sex (r = 0.209; p = 0.921). VEGF values were correlated with erythrocyte sedimentation rate (r = 0.445; p = 0.004), but was not correlated with serum rheumatoid factor levels (r = −0.130; p = 0.424) in the patient group. In conclusion, higher VEGF levels are associated with late phase and high disease activity
in RA, independent of age and sex. 相似文献
64.
Sel?uk Kaya Recep Süt?ü Emel Sesli Cetin Buket Cicioglu Aridogan Namik Deliba? Mustafa Demirci 《International journal of infectious diseases》2007,11(3):251-255
OBJECTIVE: In this study, we investigated the relationship between fascioliasis and serum malondialdehyde (MDA) levels, superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activities. We also investigated whether there are significant differences in MDA levels and antioxidant enzymatic activities between acute and chronic fascioliasis. METHODS: Forty fascioliasis patients who were diagnosed by ES-ELISA positivity were included in this study. The patients were classified as 18 with acute and 22 with chronic fascioliasis. RESULTS: In patients with fascioliasis, levels of MDA were statistically higher and erythrocyte SOD and GPx activities were statistically lower than in healthy controls. MDA levels were found to be higher in patients with acute fascioliasis than in patients with chronic fascioliasis although MDA levels were significantly higher in patients with chronic fascioliasis than in controls. There was no statistically significant difference between the two groups for the antioxidant enzyme activities. CONCLUSION: The results of this study may indicate that fascioliasis produces specific effects on the antioxidant defense mechanisms due to its inflammatory character. Our results also allow us to suggest that oxidative stress has an important role in the pathogenesis of fascioliasis and the persistence of this oxidative stress can be one of the underlying factors in the pathogenesis of the chronic disease. 相似文献
65.
Guanylin-like peptides regulate electrolyte/water transport through the epithelia. Moreover, these peptides possess antiproliferative activity and regulate the turnover of epithelial cells. In an earlier study we localized guanylin immunoreactivity in secretory ducts of adult rodent salivary glands. In this study we investigated the appearance and distribution pattern of this peptide during the development of rat salivary glands. Guanylin immunoreactivity appeared at the beginning of cell differentiation from solid bud, on embryonic day 17 in the submandibular and sublingual glands and after day 18 in the parotid gland. Guanylin immunoreactivity appeared first in ductal and acinar anlage: its cell distribution pattern and fate differed in these two compartments. In the duct cells guanylin immunoreactivity spread after the duct system developed, whereas in acinar cells it disappeared after cell differentiation. The guanylin immunoreactivity we detected in adult salivary duct cells accords with guanylins role in regulating electrolyte and water transport through the various epithelia. It does so by activating guanylate cyclase-C receptor, increasing intracellular cGMP concentration, and phosphorylating the cystic fibrosis transmembrane conductance regulator (CFTR) protein by the cGMP-dependent protein kinase II. This signaling cascade couples to the ductal electrolyte/water secretion and modulates finally the electrolyte composition of the saliva. On the other hand, CFTR is also involved in mechanisms of cell growth, by regulating apoptosis, and promoting cell differentiation. The early diffuse guanylin immunoreactivity we observed in ducts and acinar anlage, before the secretory set is operative, suggests guanylin has a role in cell differentiation. 相似文献
66.
Targeted vessel reconstruction in non‐contrast‐enhanced steady‐state free precession angiography 下载免费PDF全文
Efe Ilicak Suheyla Cetin Elif Bulut Kader Karli Oguz Emine Ulku Saritas Gozde Unal Tolga Çukur 《NMR in biomedicine》2016,29(5):532-544
Image quality in non‐contrast‐enhanced (NCE) angiograms is often limited by scan time constraints. An effective solution is to undersample angiographic acquisitions and to recover vessel images with penalized reconstructions. However, conventional methods leverage penalty terms with uniform spatial weighting, which typically yield insufficient suppression of aliasing interference and suboptimal blood/background contrast. Here we propose a two‐stage strategy where a tractographic segmentation is employed to auto‐extract vasculature maps from undersampled data. These maps are then used to incur spatially adaptive sparsity penalties on vascular and background regions. In vivo steady‐state free precession angiograms were acquired in the hand, lower leg and foot. Compared with regular non‐adaptive compressed sensing (CS) reconstructions (CSlow), the proposed strategy improves blood/background contrast by 71.3 ± 28.9% in the hand (mean ± s.d. across acceleration factors 1–8), 30.6 ± 11.3% in the lower leg and 28.1 ± 7.0% in the foot (signed‐rank test, P < 0.05 at each acceleration). The proposed targeted reconstruction can relax trade‐offs between image contrast, resolution and scan efficiency without compromising vessel depiction. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
67.
Can Yücel Karabay M.D. Regayip Zehir M.D. Ahmet Güler M.D. Vecih Oduncu M.D. Arzu Kalayci M.D. Soe Moe Aung M.D. Ali Karagoz M.D. Ibrahim Halil Tanboga M.D. Ozkan Candan M.D. Cetin Gecmen M.D. Ayhan Erkol M.D. Ali Metin Esen M.D. Cevat Kirma M.D. 《Echocardiography (Mount Kisco, N.Y.)》2013,30(5):572-581
The aim of this study was to evaluate left atrial deformations using speckle tracking echocardiography for predicting left atrial appendage (LAA) thrombus in patients with suspected cardioembolic stroke who were in normal sinus rhythm. A total of 153 ischemic stroke patients (89 males, 64 females) in sinus rhythm who were suspected of having cardioembolism were included in the study. The patients underwent conventional two‐dimensional (2D) echocardiogram and 2D speckle tracking echocardiogram of the left atrium. Left atrial peak strain (LA‐4C‐RES) and left atrial precontraction strain (LA‐4C‐PUMP) were measured. Patients were divided into 2 groups according to the presence of thrombus in the LAA in transesophageal echocardiography. Both LA‐4C‐RES and LA‐4C‐PUMP values were found to be significantly lower in patients with LAA thrombus (11.8 ± 1.4% vs. 33 ± 12%, P < 0.001 and 5.8 ± 1.3% vs. 14.2 ± 5.3%, P < 0.001, respectively). A good inverse correlation was present between LA‐4C‐RES values and LAA morphologic parameters (with LAA area: r = ?0.70, P < 0.001, with LAA length: r = ?0.60, P < 0.001), and a good positive correlation was present with LAA emptying velocity with pulse Doppler (r = 0.74, P < 0.001). The area under the receiver‐operating characteristic curve of the LA‐4C‐RES was 0.94 (0.90–0.98, P < 0.001), for the LA‐4C‐PUMP, the area was 0.92 (0.87–0.96, P < 0.001) to predict LAA thrombus. Left atrial deformation parameters measured by 2D speckle tracking method was found to predict impaired LAA functions and the presence of LAA thrombus in ischemic stroke patients with suspected cardioembolism, but who are in sinus rhythm. 相似文献
68.
69.
Muge Gokce Murat Tuncer Mualla Cetin Fatma Gumruk 《Indian journal of hematology & blood transfusion》2013,29(3):161-163
A three-month-old boy presented with growth failure, skeletal abnormalities, otitis media and pancytopenia. Exocrine pancreatic insufficiency was confirmed by low levels of fecal elastase. He was diagnosed as Shwachman-Diamond syndrome by clinical and laboratory findings. The diagnosis was confirmed by sequence analysis for SBDS gene on chromosome seven revealing compound heterozygous mutation, which are c.258+2T-C and c.183-184TA-CT. Matched unrelated donor screening for hematopoietic stem cell transplantation was initiated. Unfortunately, he died of respiratory difficulty at 5 months of age. Our case is the youngest patient whose presumptive Shwachman-Diamond syndrome diagnosis was confirmed by molecular analysis. 相似文献
70.
Anaphylaxis and acute allergic reactions may sometimes be fatal. They occur within minutes in a sensitized individual. So quick diagnosis and management are necessary issues. In the literature, cases are widely reported against allergens found in drugs, foods and their additives, radiocontrast material, bee stings, and many other materials. Here, we present a 37-year-old woman who developed an anaphylactic reaction to normal saline infusion during evaluation for her acute abdominal pain. We found only one report about normal saline allergy in the literature (Litvin ME, Shemchuck AS, Lisetskii VA. Anaphylactic shock caused by intravenous injection of isotonic solution of sodium chloride. Klin Khir 1976;(7):59-61). 相似文献