全文获取类型
收费全文 | 609篇 |
免费 | 46篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 10篇 |
儿科学 | 9篇 |
妇产科学 | 18篇 |
基础医学 | 96篇 |
口腔科学 | 11篇 |
临床医学 | 67篇 |
内科学 | 114篇 |
皮肤病学 | 12篇 |
神经病学 | 27篇 |
特种医学 | 12篇 |
外科学 | 66篇 |
综合类 | 16篇 |
一般理论 | 3篇 |
预防医学 | 54篇 |
眼科学 | 7篇 |
药学 | 82篇 |
中国医学 | 19篇 |
肿瘤学 | 38篇 |
出版年
2023年 | 11篇 |
2022年 | 7篇 |
2021年 | 21篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 21篇 |
2017年 | 14篇 |
2016年 | 19篇 |
2015年 | 33篇 |
2014年 | 34篇 |
2013年 | 28篇 |
2012年 | 38篇 |
2011年 | 45篇 |
2010年 | 25篇 |
2009年 | 15篇 |
2008年 | 26篇 |
2007年 | 41篇 |
2006年 | 34篇 |
2005年 | 30篇 |
2004年 | 23篇 |
2003年 | 27篇 |
2002年 | 29篇 |
2001年 | 11篇 |
2000年 | 6篇 |
1999年 | 17篇 |
1998年 | 5篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 9篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1971年 | 2篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 2篇 |
排序方式: 共有661条查询结果,搜索用时 15 毫秒
1.
2.
3.
Melatonin was detected by radioimmunoassay in the gastrointestinal tract (GIT) of several species of fish (sturgeon, rainbow trout, carp), amphibians (axolotl, leopard frog, bullfrog), and one reptile (red-sided garter snake), which were sacrificed during the daytime. The highest levels of melatonin were detected in the snake [means = 1018 pg/g stomach, 328 pg/g proximal gut (PG), 511 distal gut (DG)] and carp (means = 102 pg/g stomach, 146 pg/g PG and 141 pg/g DG). Lowest levels were found in the axolotl (means = 44 pg/g stomach and PG, 92 pg/g DG) and the bullfrog (means = 73 pg/g esophagus, 78 pg/g stomach, 20 pg/g PG, and 152 pg/g DG). In most cases there were no statistically significant differences in the melatonin levels among various GIT tissues of the same species but there were differences in tissue levels between different species. 相似文献
4.
Hong Kong nurses' health-related behaviours: implications for nurses' role in health promotion 总被引:1,自引:0,他引:1
Patrick Callaghan RN BSc MSc Ma Kuk Fun RN BN Fung Ching Yee RN BN 《Journal of advanced nursing》1997,25(6):1276-1282
The health-related behaviours of a random sample (n=92) of Hong Kong nurses were assessed by a questionnaire written either in English or in English and Chinese. Hong Kong nurse reported negligible smoking or a alcohol use, low levels of breast self-examination, cervical screening behaviour and regular exercising, seat belt use and driving within the speed limit. The sample reported high levels of making efforts to avoid foods high in cholesterol, eating foods high in fibre and eating fruit daily. Dental hygiene was reported to be high. Just over half the sample reported sleeping 7–8 hours each night and eating breakfast daily. Most nurse reported maintaining their body weight at a healthy level and eating snacks between meals. The English language version of the questionnaire produced a slightly better response rate than the bilingual questionnaires. The results are discussed with reference to previous studies of females' health-related behaviours in Hong Kong and elsewhere. The implications for Hong Kong nurses' role in health promotion is discussed. 相似文献
5.
6.
Antibody against fusarochromanone (TDP‐1) was obtained from rabbits after immunization with TDP‐1 conjugated to bovine serum albumin (BSA). An indirect enzyme‐linked immunosorbent assay (ELISA) using TDP‐1‐ovalbumin conjugate as the antigen coated on to the microtiter plate was used for monitoring the antibody liter. For toxin detection, a direct competitive ELISA in which TDP‐1 was conjugated to horseradish peroxidase (HRP) was used. Competitive direct ELISA revealed that the antibody had about 5.6 and 4.5 times greater binding efficiency for monoacetyl fusarochromanone (TDP‐2) and diacetylated TDP‐1 than TDP‐1. The concentration causing 50% inhibition of binding of TDP‐1‐HRP to the antibody by TDP‐1, TDP‐2 and diacetyl‐TDP‐1 were 2.8, 0.5 and 0.62 ng/ml, respectively. For the analysis of fusarochromanones in wheat and barley, the toxins were first extracted from the commodities with 100% methanol. A small aliquot of the extract was dried, acetylated, diluted in buffer and then analyzed directly by ELISA. The overall recovery for fusarochromanone in the wheat and barley samples spiked with TDP‐1 in the concentration range of 20 to 500 ppb were found to be 97% and 103.4% with cv of 15% and 11.2% for barley and wheat, respectively. 相似文献
7.
Yang AH Chen JY Chen BF 《Virchows Archiv : an international journal of pathology》2004,445(3):305-314
While diffuse mesangial sclerosis is traditionally described as being the glomerulopathy of Denys–Drash syndrome (DDS), the podocyte proliferative lesions may be overlooked in these DDS cases. In the present study, an evolving process is extrapolated from a selected case of DDS that demonstrated glomerulopathy with conspicuous podocyte proliferation. The observation that podocytes express proliferation markers (Ki67, proliferating-cell nuclear antigen and topoisomerase II) in non-proliferative, mature-looking glomeruli suggests an initial pathogenic act to activate or to keep podocytes from quiescence. The subsequent proliferation of podocytes is in keeping with downregulation of WT1 and cyclin kinase inhibitors of p16 and p21. The emergence of cytokeratin-positive cells in glomeruli that show typical mesangial sclerosis implies elimination of podocytes and replacement with tubular and/or parietal epithelial cells. The final scene of evolving glomerulopathy displays apoptosis and expression of Fas-L and Bax in sclerotic mesangial lesions, which eventually end up with global sclerosis. This novel concept of DDS glomerulopathy implies complex molecular mechanisms involved in glomerular injury. 相似文献
8.
Yong Zhi Khow Graham S. Goh Jerry Yongqiang Chen Ngai Nung Lo Seng Jin Yeo Ming Han Lincoln Liow 《The Journal of arthroplasty》2021,36(6):1974-1979
BackgroundPrevious studies evaluating weight changes following total knee arthroplasty (TKA) were performed on heterogenous cohorts. However, no study has evaluated weight changes in a cohort of simultaneous-bilateral TKA (SB-TKA) patients. This study aimed to evaluate the prevalence of patients who lost or gained weight, determine if postoperative weight change influences functional outcome, and identify predictors of weight change after SB-TKA.MethodsProspectively collected registry data of 560 patients who underwent SB-TKA were reviewed. Patients were assessed preoperatively, at 6 months, and 2 years using the Knee Society Score, Oxford Knee Score, Short-Form 36, and range of motion. Change in body mass index (BMI) >5% was used to categorize patients into 3 groups: lost, maintained, or gained weight. Analysis of variance, Kruskal-Wallis test, and chi-squared test were used to compare functional outcomes between groups. Multivariable logistic regression evaluated predictors for postoperative weight changes.ResultsAt 2 years, 59% of patients maintained weight, 28% of patients gained weight, and 13% of patients lost weight. All groups experienced similar improvements in functional outcomes, rates of minimal clinically important difference attainment, and patient satisfaction (P > .05). Older patients were more likely to gain weight (P < .05). Patients with higher preoperative BMI were more likely to gain weight (P < .05) and less likely to lose weight (P < .05). Patients with greater preoperative comorbidities were less likely to lose weight (P < .05).ConclusionUp to 41% of patients experience significant weight changes after SB-TKA. Older patients with higher preoperative BMI were more likely to gain weight, while higher preoperative BMI with more comorbidities were less likely to lose weight following SB-TKA; however, postoperative weight changes do not appear to affect functional outcomes.Level of EvidenceIII, therapeutic study. 相似文献
9.
An attempt to estabilish the relationship between anti-cell adhesive action of phenylacetylshikonin anallogues and their cytotoxicity against A549 cells was done. In the one hour incubation with A549 cells, alpha-methoxyphenylacetyl-(9), alpha-acetoxyphenylacetyl-(13), 3,4-methylen-edioxyphenylacetyl-(15) and 4-(N,N-dimethylamino)-phenylacetylshikonin (17) analogues showed a high anti-cell adhesive activity (IC(100) value, 4-8 mug/ml), while halophenylacetyl-and dimethoxy-or trimethoxyphenylacetyl analogues expressed no activity at 40 mug/ml, indicating that the presence of a bulky group at C'-alpha and a polar group at C-4 of phenylacetyl moiety may be important. A similar structure activity relationship exists for the 48 hr cytotoxocity (ED(50)) of phenylacetylshikonin analogues in A 549 cells, but not in either K562 or L1210 cells. Furthermore, the difference between IC(100) values for anti-cell adhesive activity and ED(50) values for cytotoxicity of potent compound in A549 cells was not so great (1.5 to 3 times). Based on these observations, it is proposed that the anti-cell adhesive action of phenylacetylshikonins might be responsible for their cytotoxicity in A549 cells. 相似文献
10.