全文获取类型
收费全文 | 3358篇 |
免费 | 231篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 33篇 |
儿科学 | 117篇 |
妇产科学 | 53篇 |
基础医学 | 373篇 |
口腔科学 | 100篇 |
临床医学 | 263篇 |
内科学 | 719篇 |
皮肤病学 | 39篇 |
神经病学 | 243篇 |
特种医学 | 125篇 |
外科学 | 420篇 |
综合类 | 85篇 |
一般理论 | 1篇 |
预防医学 | 176篇 |
眼科学 | 220篇 |
药学 | 390篇 |
中国医学 | 54篇 |
肿瘤学 | 199篇 |
出版年
2023年 | 44篇 |
2022年 | 114篇 |
2021年 | 199篇 |
2020年 | 109篇 |
2019年 | 154篇 |
2018年 | 179篇 |
2017年 | 120篇 |
2016年 | 150篇 |
2015年 | 145篇 |
2014年 | 214篇 |
2013年 | 222篇 |
2012年 | 290篇 |
2011年 | 250篇 |
2010年 | 144篇 |
2009年 | 102篇 |
2008年 | 174篇 |
2007年 | 116篇 |
2006年 | 87篇 |
2005年 | 80篇 |
2004年 | 73篇 |
2003年 | 70篇 |
2002年 | 59篇 |
2001年 | 33篇 |
2000年 | 36篇 |
1999年 | 23篇 |
1998年 | 15篇 |
1997年 | 17篇 |
1996年 | 12篇 |
1995年 | 7篇 |
1993年 | 9篇 |
1992年 | 39篇 |
1991年 | 34篇 |
1990年 | 23篇 |
1989年 | 34篇 |
1988年 | 23篇 |
1987年 | 18篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 24篇 |
1983年 | 14篇 |
1980年 | 8篇 |
1979年 | 17篇 |
1978年 | 6篇 |
1976年 | 10篇 |
1975年 | 9篇 |
1974年 | 11篇 |
1973年 | 13篇 |
1972年 | 12篇 |
1971年 | 9篇 |
1969年 | 9篇 |
排序方式: 共有3610条查询结果,搜索用时 281 毫秒
31.
32.
Patrick M. Lec Abhishek Venkataramana Andrew T. Lenis Katherine E. Fero Vidit Sharma Vishnukamal Golla Kiran Gollapudi Jeremy Blumberg Karim Chamie 《Urologic oncology》2021,39(3):194.e17-194.e24
BackgroundHigh-risk ureteral tumors represent an understudied subset of upper tract urothelial carcinoma, whose surgical management can range from a radical nephroureterectomy (NU) to segmental ureterectomy (SU).ObjectivesTo evaluate contemporary trends in the management of high-risk ureteral tumors, the utilization of lymphadenectomy and peri-operative chemotherapy, and their impact on overall survival (OS).Design, setting, and participantsWe performed a retrospective cohort study of patients in the National Cancer Database from years 2006 to 2013 with clinically localized high-risk ureteral tumors treated with NU or SU.Outcome measurements and statistical analysisChi-squared tests were utilized to assess differences in clinicodemographic features and peri-operative treatment delivery between SU and NU cohorts. Cochran-Armitage tests and linear regressions were performed to evaluate temporal trends in treatment utilization. Multivariable logistic regression models were employed to assess predictors of treatment delivery. Multivariable Cox proportional hazards models evaluated associations with OS.ResultsOf the 1,962 patients included, NU was more commonly performed than SU (72.4%, 1,421/1,962 vs. 27.6%, 541/1,962). Only 22.7% (446/1,962) of the population underwent lymphadenectomy, and 24.8% (271/1,092) of those with advanced pathology (≥pT2 or pN+) received adjuvant chemotherapy. Lymphadenectomy was associated with improved OS in NU patients when more than 3 nodes were removed (hazard ratio [HR] 0.58, 95% confidence interval [CI] 0.39–0.89). Receipt of adjuvant chemotherapy for advanced pathology had no impact OS in both the NU (HR 1.10, 95% CI 0.84–1.44) and SU (HR 0.94, 95% CI 0.61–1.46) cohorts. Performance of SU was not associated with poorer OS on multivariable analysis (HR 1.02, 95% CI 0.89–1.21, P = 0.83).ConclusionOur study suggests that SU may be an appropriate alternative to NU for the management of high-risk ureteral tumors. Further, lymphadenectomy may play an important role at the time of NU, and adjuvant chemotherapy is infrequently utilized in patients with advanced pathology. 相似文献
33.
Abhishek Singh Kaushalendra Kumar Ajit Kumar Yadav K. S. James Lotus McDougal Yamini Atmavilas Anita Raj 《Studies in family planning》2021,52(1):41-58
Previous research on sex ratio at birth (SRB) in India has largely relied on macro‐analysis of census data that do not contain the breadth of factors needed to explain patterns in SRB. Additionally, no previous research has examined the differentiation of factors associated with SRB across birth orders, a key determinant in societies affected by son preference. This study aims to fill these gaps using micro‐data related to 553,461 births occurring between 2005 and 2016 collected as part of the 2015–2016 National Family Health Survey. Analyses used multivariable logistic regressions stratified by birth order to examine associations with SRB at the national level. The SRB at birth order 1 was outside the biological normal limit, and generally increased with birth order. First births in households with wealth in the middle and richest quintiles, with mothers who desired a higher ideal number of sons than daughters, and in lower fertility communities had a higher probability of being male. Most SRB correlates were visible at birth orders 3 or higher. Programs and policies designed to address India's male‐skewed SRB must consider the diverse factors that influence SRB, particularly for higher order births. 相似文献
34.
S K Kabra Y Jain R M Pandey T MadhulikaSinghal P Tripathi S Broor P Seth V Seth 《Transactions of the Royal Society of Tropical Medicine and Hygiene》1999,93(3):294-298
An epidemic of dengue haemorrhagic fever (DHF) occurred in Delhi in 1996. A total of 240 children between the age of 4 months to 13 years of either sex, admitted in one hospital, were evaluated. Two hundred and sixteen (90%) children were from Delhi. A clinical diagnosis of dengue fever (DF) was made in 25 (10%), dengue fever with unusual bleeding (DFB) in 22 (9%), DHF in 80 (33%) and dengue shock syndrome (DSS) in 113 (47%) of the children strictly according to the WHO classification. The age peaked at 8 years. There was no association between various grades of severity of illness and age-groups though girls suffered from more severe illness. No association between severity of malnutrition and severity of illness was observed. Tourniquet test was positive in 40% with DF, 18% with DFB, 62% with DHF and 64% with DSS. In DSS haematemesis was present in 55 (49%), epistaxis in 39 (35%), melaena in 27 (24%) and ecchymosis in 34 (30%) patients. Children diagnosed as DFB had haematemesis and epistaxis in 12 (55%) and 10 (45%) respectively. Intravenous fluid requirement was clearly less in DFB patients than in DHF/DSS patients. Unusual clinical features in the form of jaundice were present in 7 (6%), hepatic encephalopathy in 6 (5%) and dengue encephalopathy in 6 (5%) patients. Dengue 2 virus was isolated from 10 of the 50 patients for whom viral culture was done on C6/36 clone of Aedes albopictus cell line. Eighteen patients suffering from DSS died giving an overall case fatality of 7.5%. The mortality rate in DHF/DSS was 9.3%. It is further suggested that DFB is a distinct entity. Most patients could be classified by the WHO classification if a retrospective packed cell volume was used to assess haemoconcentration. We suggest that development of area-specific criteria for diagnosis and management is desirable. 相似文献
35.
36.
37.
Tripathi Siddhi Amarnath Gowdagere Shamanna Muddugangadhar Byrasandra Channapa Sharma Ashish Choudhary Suchismita 《Journal of Indian Prosthodontic Society》2014,14(1):110-114
The functional surfaces of the porcelain fused to metal fixed partial dentures are often abraded to adjust occlusion, such restorations are often found to fail in service. This study was therefore conducted to study the effect of surface abrasion on flexural strength of glazed porcelain fused to metal samples. It was also the aim of this study to find the effect of re-glazing on flexural strength of abraded samples. A total of ninety glazed porcelain fused to metal bar samples of the dimension 15 mm × 2 mm × 1.5 mm were fabricated. These samples were then divided into three groups (30 samples each) according to the surface treatments: group A-glazed (control); group B-abraded and group C-abraded and then re-glazed (self-glazed). Flexural strength was measured by using three point bend test on universal testing machine (texture analyser) with a cross-head speed of 0.6 mm/min. Peak force at the time of failure for all the samples was recorded. Statistical analysis found that mean flexural strength was highest for group A-80.65 ± 12.81 MPa; as compared to group B-74.18 ± 10.74 MPa and group C-77.85 ± 9.39 MPa. Student’s t test indicated that the difference in the flexural strength between groups A and B was significant while it was non-significant between groups B and C and also between groups A and C. The ‘f’ test indicated that the difference between the groups was non-significant. This study therefore showed that there is a marked decrease in the flexural strength of the porcelain fused to metal restorations after occlusal abrasion. The study also found that reglazing of these restorations may not restore their flexural strength significantly. 相似文献
38.
Trivendra Tripathi Mohammad Shahid Adil Raza Haris M. Khan Rahat Ali Khan Abbas Ali Mahdi Mashiatullah Siddiqui Abida Malik Aijaz Ahmed Khan 《Experimental and toxicologic pathology》2012,64(7-8):875-881
ObjectiveThe present study was designed to delineate the hepatotoxicological roles of histamine dose-dependently in immunized rabbits.MethodsThe cohort comprised of three groups (II, III and IV), containing 18 rabbits each, and received subcutaneous histamine 50 μg/kg, 100 μg/kg and 200 μg/kg, respectively for 10 days (b.i.d., starting from 3 days prior to immunization until 7 days after immunization). Group I (control, n = 18) received subcutaneous sterile distilled water for 10 days. They were subsequently immunized at day 3 with intravenous injection of SRBC (1 × 109 cells/ml). Blood samples were collected on pre-immunization (pre-I) day 0, as well as on days 7-, 14-, 21-, 28- and 58-post-immunization (post-I). Biochemical parameters aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and bilirubin [total bilirubin (TB), direct bilirubin (DB) and indirect bilirubin (IB)] were determined.ResultsGroups II and IV revealed a significant decrease (on day 0-pre-I) and a significant increase (on days 7-, 14-, 21-, 28- and 58-post-I) in ALT and AST levels, when compared with the corresponding values of groups I and III while group II showed a significant increase in ALT and AST levels as compared to group IV. ALP levels in groups II, III and IV showed a significant enhancement when compared with group I. Moreover, results of TB, DB and IB demonstrated increased levels in group III when compared with groups I, II and IV. The results were found statistically significant (p < 0.05).ConclusionShort-term treatment of histamine produces dose-dependent differential patterns of hepatic dysfunctions suggestive mild liver degeneration warranting further long-term studies. 相似文献
39.
40.