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   5836篇
  免费   229篇
  国内免费   49篇
耳鼻咽喉   179篇
儿科学   303篇
妇产科学   232篇
基础医学   411篇
口腔科学   288篇
临床医学   581篇
内科学   1397篇
皮肤病学   84篇
神经病学   325篇
特种医学   222篇
外科学   1201篇
综合类   101篇
预防医学   143篇
眼科学   237篇
药学   213篇
中国医学   5篇
肿瘤学   192篇
  2024年   5篇
  2023年   58篇
  2022年   81篇
  2021年   115篇
  2020年   87篇
  2019年   133篇
  2018年   143篇
  2017年   133篇
  2016年   155篇
  2015年   196篇
  2014年   213篇
  2013年   290篇
  2012年   412篇
  2011年   384篇
  2010年   232篇
  2009年   208篇
  2008年   465篇
  2007年   511篇
  2006年   498篇
  2005年   438篇
  2004年   348篇
  2003年   287篇
  2002年   228篇
  2001年   121篇
  2000年   108篇
  1999年   103篇
  1998年   31篇
  1997年   26篇
  1996年   19篇
  1995年   10篇
  1994年   9篇
  1993年   10篇
  1992年   12篇
  1991年   16篇
  1990年   8篇
  1988年   3篇
  1987年   4篇
  1984年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
  1973年   1篇
  1971年   3篇
  1970年   2篇
  1969年   1篇
排序方式: 共有6114条查询结果,搜索用时 0 毫秒
31.
32.
AIM: This study aims to investigate the existence of any relationship between homocysteine levels and insulin resistance in Turkish women with polycystic ovary syndrome. METHODS: A case-controlled, cross-sectional, observational study was undertaken in a total of 94 infertile Turkish women who required professional help in the Department of Infertility of Dr Zekai Tahir Burak Women's Health Research and Education Hospital. The correlation between serum homocysteine with age, body mass index, hormone profile, fasting insulin and glucose concentrations and insulin resistance were examined in patients with polycystic ovary syndrome and the results were compared to those of women with normal ovaries, who served as a control group. RESULTS: The mean serum fasting glucose and insulin levels, thus insulin resistance index of women with polycystic ovary syndrome, were significantly higher than those of the control subjects. The mean serum homocysteine levels were significantly higher in women with polycystic ovary syndrome than those in the control group. A positive correlation was detected between the mean homocysteine, the insulin resistance index determined by homeostasis model assessment and the fasting insulin levels in polycystic ovary syndrome patients. CONCLUSIONS: Serum homocysteine levels are elevated in women with polycystic ovary syndrome, and this elevation is associated with the serum insulin level rather than androgen excess. The intense treatment of hyperhomocysteinemia in women with polycystic ovary syndrome might improve reproductive outcome and contribute to protection from cardiovascular risks.  相似文献   
33.
34.
Purpose:To evaluate corneal densitometry (CD) of patients with arcus senilis (AS) and its association with the serum lipid markers.Methods:This is a cross-sectional, case-control study. The AS diagnosis was made clinically. Forty-five eyes of 45 patients with AS and 38 eyes of 38 age-matched control subjects with no noticeable AS were enrolled in the study. All participants underwent detailed ophthalmologic examination along with corneal Scheimpflug imaging with CD measurement. The evaluated serum lipid markers of the participants included total cholesterol, triglyceride, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and very-low-density lipoprotein (VLDL). The Spearman correlation analysis was used to correlate the serum lipid values and the CD. P < 0.05 was defined as statistically significant.Results:The male to female ratio was 26/19 and 14/24 in the study and control groups, respectively (P = 0.057). The mean age was 59.56 ± 8.7 and 56.47 ± 8.6 years in the study and control groups, respectively (P = 0.117). The mean total CD values in the zones extending from 2 to 12 mm were higher in the study group than in the control group (P < 0.001). The serum HDL level was found to be significantly decreased in the study group compared to the control group (P = 0.048 and Z = −1.976). There was a significant positive correlation between the serum triglyceride level and the CD value of the outermost zone (10–12 mm) (r = 0.334 and P = 0.025).Conclusion:The CD of patients with AS was found to increase not only in the peripheral zone but also in the cornea’s paracentral zone compared to the healthy controls. The serum triglyceride level should give an insight into the intensity of arcus senilis. The serum HDL levels were decreased in patients with AS.  相似文献   
35.
36.
The relation between cancer and coagulation is the subject of investigation since a relation between tumor and thrombosis has been determined. Antithrombin III is an important thrombin inhibitor, and increased thrombin?Cantithrombin (TAT) complex levels activate coagulation. Activated thrombin activatable fibrinolysis inhibitor (TAFI) inhibits the conversion of plasminogen to plasmin. In addition, it directly inactivates plasmin. Defective fibrinolysis increases the risk of thrombosis. In this study, we evaluated homeostatic parameters, TAFI, and TAT levels in patients with gastric cancer applying to the medical oncology outpatient clinic. Fifty-two patients and 35 healthy controls were included. ELISA was used to measure TAFI and TAT complex levels. These were statistically higher in the patient group (p?<?0.05 and p?=?0.001, respectively). D-dimer levels were higher in stage IV (p?=?0.05). Correlations between lymph nodes and TAFI and TAT levels were examined. Weak but positive correlation between lymph nodes and TAFI was detected (R?=?0.452, p?=?0.027). TAFI and TAT levels were evaluated using relative operating characteristic analysis to differentiate the disease. TAT was more specific than TAFI according to this analysis (TAFI area under curve (AUC), 0.676; TAT AUC, 0.874). Thrombotic events and bleeding disorders need to be borne in mind in gastric cancer. This situation is due to the impairment of the balance between coagulation and fibrinolysis. Further studies are now needed to evaluate the effects of TAFI and TAT on survey and prognosis as well as the potential of these parameters as tumor markers for gastric cancer.  相似文献   
37.
Ischemic stroke is a medical emergency requiring fast and effective collaboration of neurologists and radiologists. Currently there are promising new developments in the treatment of acute ischemic stroke with efforts being made to reduce the door-to-needle time and to improve recanalization of occluded vessels by new endovascular techniques. Clinical trials have also demonstrated the efficacy of thrombolysis up to 4.5?h and confirmed the importance of the time to treatment for positive outcome.  相似文献   
38.
Dr. U. Yilmaz 《Der Radiologe》2012,52(12):1095-1100
Intracranial arterial stenoses clinically present as acute, fluctuating or recurrent neurological deficits which are caused by hemodynamically impaired perfusion of the corresponding area of the brain. The type and the extent of the deficit, however, are not only determined by the location of the stenosis but also depend on the individual anatomical conditions of the patient, such as the degree of collateralization and variants of the circle of Willis.  相似文献   
39.
40.
This study was undertaken to examine the effects of leptin on testes in mice. For this purpose, 12 male mice were divided into two groups. Animals in Group I were designated as control. Mice in Group II were injected daily with leptin for 5 days. All animals were decapitated at the end of the experiment. The testes were removed and weighed out. Testicular tissue specimens were processed for light and electron microscopic examination and semi-quantitative evaluation of immunohistochemical testosterone staining. Intensity of immunostaining was determined on a scale between 0 (no staining) and 5 (heavy staining). For morphometric comparison, diameters of seminiferous tubules from each group were measured. In the leptin injected group, testicular weights and diameters of seminiferous tubules were significantly increased in comparison to control values. In light microscopic examination, an increase in secretory granules in the cytoplasm of Leydig cells was observed after leptin treatment. In the same group, distinct changes indicative of increased cell activation were seen in the ultrastructure of Leydig cells. Amount of mitochondria, lysosomes and cytoplasmic secretory granules were increased. Furthermore, an increase in extensiveness of rough endoplasmic reticulum was noted in this group. Immunohistochemical testosterone staining of the cytoplasm of Leydig cells was heavy (5 +) in the leptin treated mice compared to mild score (2 +) in the control mice. Additionally, heavy immunostaining of testosterone was also observed in the interstitial space after injection of leptin. The present findings indicate that testicular functions and synthesis of testosterone increase after administration of leptin.  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