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   1925篇
  免费   51篇
  国内免费   14篇
耳鼻咽喉   22篇
儿科学   122篇
妇产科学   192篇
基础医学   140篇
口腔科学   97篇
临床医学   136篇
内科学   427篇
皮肤病学   17篇
神经病学   131篇
特种医学   33篇
外科学   421篇
综合类   13篇
一般理论   3篇
预防医学   41篇
眼科学   39篇
药学   79篇
中国医学   4篇
肿瘤学   73篇
  2023年   8篇
  2022年   25篇
  2021年   31篇
  2020年   28篇
  2019年   23篇
  2018年   29篇
  2017年   25篇
  2016年   51篇
  2015年   64篇
  2014年   91篇
  2013年   114篇
  2012年   146篇
  2011年   144篇
  2010年   91篇
  2009年   95篇
  2008年   129篇
  2007年   136篇
  2006年   140篇
  2005年   140篇
  2004年   117篇
  2003年   87篇
  2002年   81篇
  2001年   38篇
  2000年   28篇
  1999年   24篇
  1998年   18篇
  1996年   7篇
  1995年   3篇
  1994年   7篇
  1993年   8篇
  1992年   8篇
  1991年   15篇
  1990年   6篇
  1989年   7篇
  1987年   2篇
  1986年   2篇
  1984年   1篇
  1982年   2篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1977年   1篇
  1976年   1篇
  1974年   2篇
  1973年   1篇
  1972年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有1990条查询结果,搜索用时 15 毫秒
71.
1,2,4‐triazole‐functional PGMA polymers have been synthesized and their anhydrous proton‐conducting properties were investigated after doping with phosphoric acid and triflic acid. PGMA was prepared by solution polymerization and then modified with 1H‐1,2,4‐triazole (Tri) and 3‐amino‐1,2,4‐triazole (ATri). FT‐IR, 13C NMR and elemental analysis verify the high immobilization of the triazoles in the polymer chain. Phosphoric‐acid‐doped polymers showed lower Tg and higher proton conductivities. PGMA‐Tri 4 H3PO4 showed a maximum water‐free proton conductivity of approximately 10?2 S · cm?1 while that of PGMA‐ATri 2 H3PO4 was 10?3 S · cm?1. The structure and dynamics of the polymers were explored by 1H MAS and 13C CP‐MAS solid‐state NMR.

  相似文献   

72.

Objectives

To investigate the low sexual function and its associated risk factors in pre- and postmenopausal women without clinically significant depression.

Methods

Cross-sectional study with 180 women aged between 19 and 60 years who admitted to our outpatient clinic. Sexual function was assessed by female sexual function index and clinically significant depression was measured by Beck depression inventory test.

Results

The rate of low sexual function was 85.9% in postmenopausal (OR 2.9, 95% CI 1.8–4.8) and 47.7% in premenopausal women (OR 0.4, 95% CI 0.3–0.5) (p < 0.0001). The postmenopausal group reported significantly lower desire, arousal, lubrication, orgasm, satisfaction and pain scores than controls (p < 0.0001, for all of them). Low sexual function was positively correlated with age (r = 0.37, p < 0.0001), menopausal status (r = 0.40, p < 0.0001), gravidity (r = 0.44, p < 0.0001), parity (r = 0.43, p < 0.0001), abortion rates (r = 0.27, p = 0.001) and marriage period (r = 0.40, p < 0.0001). There were also significant negative correlations between low sexual function and education (r = −0.39, p < 0.0001) and family income (r = −0.29, p < 0.0001). However, multivariate regression analysis demonstrated that education, family income and menopausal status were the only independent variables for low sexual function after adjusted for age, gravidity, parity, abortion, marriage period and menopausal status.

Conclusion

Low sexual function was relatively high in postmenopausal women without clinically significant depression. Education, family income and menopausal status were the independent risk factors for low sexual function. Investigation of female sexuality was essential for these patients.  相似文献   
73.

Objective(s)

To evaluate a modified Ferriman-Gallwey (mFG) scoring system and serum total testosterone (tT) and dehydroepiandrosterone sulfate (DHEAS) levels, in women with polycystic ovary syndrome (PCOS) and in control subjects.

Study design

Women with any gynecological problem who presented to the Kahramanmaras Sutcuimam University Medical Faculty Gynecology and Obstetric Outpatient Clinic in the Mediterranean region of Turkey were assessed prospectively. Oligo-anovulation, clinical and biochemical hyperandrogenism, and PCO appearance on ultrasound that met the 2003 Rotterdam Consensus Criteria were used for PCOS diagnosis. Group 1 consisted of 43 cases with a diagnosis of PCOS and group 2 (control group) consisted of 75 age and BMI matched control subjects without PCOS.

Results

In groups 1 and 2, clinical hyperandrogenism (hirsutism) appearance ratio was 86.0% (37/43) and 18.0% (15/75) (p < 0.001); while biochemical hyperandrogenism (high serum tT or DHEAS level) was 65.1% (28/43) and 36% (27/75) (p < 0.05), respectively. In groups 1 and 2, mean serum tT levels were 115.2 and 73.4 ng/dL (p < 0.001), mean serum DHEAS levels were 256.1 and 177.7 ng/dL (p < 0.001), and mean hirsutism scores were 11.2 and 5.5 (p < 0.001), respectively. Serum mean tT, DHEAS and hirsutism scores for group 1 were significantly higher than those of group 2 (<0.001). No correlation was observed between BMI and the hirsutism scores or the biochemical hyperandrogenism in both groups.

Conclusion(s)

In our study, mean serum androgen levels and hirsutism ratio in the PCOS group were higher than the control group. These values were also substantially higher than those previously published in the literature.  相似文献   
74.

Background  

Spontaneous tubal twin pregnancy is a rare condition with an incidence of 1 in every 125,000 pregnancies. We present the case of a unilateral tubal twin ectopic pregnancy treated with single-dose methotrexate.  相似文献   
75.
76.

Purposes

The aims of this study were to review the frequency, characteristics, and the clinical course of primary immunodeficiency (PID) patients admitted to pediatric intensive care unit (PICU) and attempt to identify factors related with mortality that might predict a poor outcome.

Methods

We performed a retrospective review of children with PID aged 1 month to 18 years and admitted to PICU from January 2002 to January 2012 in our tertiary teaching children’s hospital.

Results

There were a total of 51 patients accounting for 71 admissions to the PICU. The most common diagnosis was severe combined immunodeficiency. Respiratory problems were the leading cause for admission. A total of 20 patients received hematopoietic stem cell transplantation. Immune reconstitution was achieved in 9 (45 %) patients and eight of them did survive. In all 56 % of all admission episodes resulted in survival. Risk factors for mortality included requirement of mechanical ventilation (P?<?.001), number of organ system failure (P?=?.013), need for renal replacement therapy (P?<?.001), use of inotropes (P?<?.001), higher Pediatric Logistic Organ Dysfunction (PELOD) score (P?=?.005), and length of PICU stay (P?<?.001).

Conclusions

This is the first study regarding the outcome and mortality-related risk factors for PID patients requiring PICU admission. We suggest that PICU management is as important as early diagnosis and treatment for these patients. Prediction of those at risk for poorer outcome might be beneficial for accurate intensive care management and survival.  相似文献   
77.
We intended to reevaluate the morphologic prognostic factors for early-stage ovarian carcinomas. We reviewed 111 patients diagnosed with early-stage ovarian cancer who had undergone primary surgery at Hacettepe Hospital between 1984 and 2001, using diagnostic criteria from the WHO-2003 classification. We applied the Universal grading system suggested by Shimizu/Silverberg and noted FIGO-stage, histotype, tumor size, bilaterality, and endometriosis. These features were compared with each other and survival. The survival analysis was carried out by Kaplan–Meier curves. Of the cases, 52 were reclassified as ‘borderline tumor’ or ‘cystadenoma with borderline foci’ and 59 as ‘invasive carcinoma’. FIGO-stage and mitotic count were significant for survivals of 59 patients with cancer. Mitotic index was also significant for the probability of metastasis. The patients with stage-II cancer had 5.65 times more risk of recurrence than stage-I cancer. The 5-year overall and disease-free survivals rates were 90.6% and 87.5% for stage-I, 54.7% and 39.3% for stage-II, respectively. Universal grade did not reach statistical significance for survivals but it was related to FIGO-stage significantly. In conclusion, FIGO-stage is the most reliable prognosticator. Although prognostic value of universal grade is not significant, mitotic count may provide important prognostic information for early-stage ovarian carcinomas.  相似文献   
78.
Osteoporosis is a multifactorial disease in which genetic determinants are modulated by hormonal, environmental and nutritional factors. The balance between bone resorption and bone formation seems to be regulated by a variety of growth factors and cytokines. An important clinical risk factor in the pathogenesis of osteoporosis is the presence of genetic polymorphisms in susceptibility genes. In this study, we investigated the association between osteoporosis and interleukin 10 (IL-10) −597 C>A and transforming growth factor β1 (TGF-β1) T869C (also named Leu10>Pro) polymorphisms in Turkish postmenopausal women. Genomic DNA obtained from 255 individuals (152 osteoporotic and 103 healthy controls). The DNA sample was isolated from peripheral bloods by salting-out method and analyzed by the techniques of PCR-RFLP. Genotype and allele frequencies were calculated and data were analyzed using the χ2 test. We found a statistically significant difference between the groups with respect to IL-10 genotype distribution (p = 0.001) and allele frequencies (p < 0.0002). However, we did not found any difference between the groups with regarding TGF-β1 genotype distribution and allele frequencies (p > 0.05). In the combined genotype analysis, IL-10/TGF-β1 CCCC combine genotype was also estimated risk factor for osteoporosis in Turkish postmenopausal women (p = 0.026). To our knowledge, this is the first report to examine IL-10 gene −597 C>A polymorphism and osteoporosis in Turkish population.  相似文献   
79.
Objective: To determine the role of serum procalcitonin levels in predicting ascites infection in hospitalized cirrhotic and non-cirrhotic patients.Methods: A total of 101 patients (mean age: 63.4±1.3, 66.3% were males) hospitalized due to cirrhosis (n=88) or malignancy related (n=13) ascites were included in this study. Spontaneous bacterial peritonitis (SBP, 19.8%), culture-negative SBP (38.6%), bacterascites (4.9%), sterile ascites (23.8%) and malign ascites (12.9%) groups were compared in terms of procalcitonin levels in predicting ascites infection. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of procalcitonin levels and predicting outcome of procalcitonin levels was compared with C-reactive protein (CRP).Results: Culture positivity was determined in 26.7% of overall population. Serum procalcitonin levels were determined to be significantly higher in patients with positive bacterial culture in ascitic fluid compared to patients without culture positivity (median (min-max): 4.1 (0.2-36.4) vs. 0.4 (0.04-15.8), p<0.001). Using ROC analysis, a serum procalcitonin level of <0.61 ng/mL in SBP (area under curve (AUC): 0.981, CI 95%: 0.000-1.000, p<0.001), <0.225 ng/mL in culture-negative SBP (AUC: 0.743, CI 95%: 0.619-0.867, p<0.001), <0.42 ng/mL in SBP and culture-negative SBP patients (AUC: 0.824, CI 95%: 0.732-0.916, p<0.001), and <1.12 ng/mL in bacterascites (AUC: 0.837, CI 95%: 0.000-1.000, p=0.019) were determined to accurately rule out the diagnosis of bacterial peritonitis. Predictive power of serum procalcitonin levels in SBP + culture-negative SBP group (AUCs: 0.824 vs 0.622, p=0.004, Fig 4), culture-positive SBP (AUCs: 0.981 vs 0.777, p=0.006, Fig 5) and (although less powerfull) in culture-negative SBP (AUCs: 0.743 vs 0.543, p=0.02, Fig 6) were found significantly higher than CRP.Conclusion: According to our findings determination of serum procalcitonin levels seems to provide satisfactory diagnostic accuracy in differentiating bacterial infections in hospitalized patients with liver cirrhosis related ascites.  相似文献   
80.
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