全文获取类型
收费全文 | 594篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 56篇 |
妇产科学 | 9篇 |
基础医学 | 69篇 |
口腔科学 | 12篇 |
临床医学 | 64篇 |
内科学 | 105篇 |
皮肤病学 | 8篇 |
神经病学 | 26篇 |
特种医学 | 148篇 |
外科学 | 28篇 |
综合类 | 8篇 |
一般理论 | 2篇 |
预防医学 | 28篇 |
眼科学 | 5篇 |
药学 | 29篇 |
肿瘤学 | 21篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 12篇 |
2017年 | 5篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 14篇 |
2013年 | 23篇 |
2012年 | 8篇 |
2011年 | 11篇 |
2010年 | 28篇 |
2009年 | 19篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 12篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 8篇 |
2000年 | 14篇 |
1999年 | 10篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 29篇 |
1995年 | 29篇 |
1994年 | 27篇 |
1993年 | 22篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 14篇 |
1989年 | 18篇 |
1988年 | 18篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 18篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 20篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 15篇 |
1975年 | 12篇 |
1973年 | 4篇 |
1966年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有621条查询结果,搜索用时 15 毫秒
61.
62.
A new method is proposed to derive the size of the interspecies uncertainty factor (UF) that is toxicologically and statistically based. The method involves quantifying interspecies variation in susceptibility to numerous toxic substances via the use of binary interspecies comparisons that are converted to a 95% UF. This interspecies UF represents an estimate of the upper 95% of the population of 95% prediction intervals (PI) for binary interspecies comparisons within four categories of phylogenetic relatedness (species within genus, genera within family, families within order, orders within class). The 95% interspecies UFs range from a low of 10 for species within genus up to 65 for orders within class. Most mammalian toxicology studies involving mice, rats, cats, dogs, gerbils, and rabbits are orders-within- class categories for human risk assessment and would be provided a 65-fold UF. Larger or smaller interspecies UF values could be selected on the level of protection desired. 相似文献
63.
Most care received by cancer patients is provided in the community by informal or unpaid caregivers. The unrelenting care demands can lead to physical, emotional, social, and financial reactions; furthermore, studies indicate that the effects of caregiving may endure after the patient's death. A need therefore exists for instruments measuring both caregiving and post-caregiving reactions. Among available instruments, the Caregiver Reaction Assessment (CRA) is a multidimensional, 5-factor measure designed to assess the negative and positive aspects of caregiving. The current study examined the psychometric properties and factor structure of responses to a modified Hebrew version of the CRA aimed at measuring caregiving and post-caregiving reactions. Although the scale was modified, it was assumed that, similar to the original CRA, a 5-factor structure would be supported by means of confirmatory factor analysis. A total of 236 bereaved primary caregivers of cancer patients from central and southern regions of Israel were recruited over a period of 18 months. As hypothesized, results provide support for a 5-factor structure of responses to this modified version of the CRA. The concurrent validity of responses to the scale was also supported. Replication of the findings with randomly derived and larger sample sizes is needed. 相似文献
64.
Marjolein EJ Oerlemans Marjan van den Akker Agnes G Schuurman Eliane Kellen Frank Buntinx 《Clin Pract Epidemiol Ment Health》2007,3(1):29
Background
The authors tested the hypothesis that depression is a possible factor influencing the course of cancer by reviewing prospective epidemiological studies and calculating summary relative risks.Methods
Studies were identified by computerized searches of Medline, Embase and PsycINFO. as well as manual searches of reference lists of selected publications. Inclusion criteria were cohort design, population-based sample, structured measurement of depression and outcome of cancer known for depressed and non-depressed subjectsResults
Thirteen eligible studies were identified. Based on eight studies with complete crude data on overall cancer, our summary relative risk (95% confidence interval) was 1.19 (1.06–1.32). After adjustment for confounders we pooled a summary relative risk of 1.12 (0.99–1.26).No significant association was found between depression and subsequent breast cancer risk, based on seven heterogeneous studies, with or without adjustment for possible confounders. Subgroup analysis of studies with a follow-up of ten years or more, however, resulted in a statistically significant summary relative risk of 2.50 (1.06–5.91).No significant associations were found for lung, colon or prostate cancer.Conclusion
This review suggests a tendency towards a small and marginally significant association between depression and subsequent overall cancer risk and towards a stronger increase of breast cancer risk emerging many years after a previous depression.65.
To investigate the suggestion that von Willebrand factor (vWf) can substitute for fibrinogen in supporting ADP-induced aggregation of human platelets, we studied platelet reactions in two media: (1) a high calcium medium, Tyrode-albumin solution containing calcium ions in the physiological range of 2 mmol/L, and (2) a low calcium medium, modified Tyrode-albumin solution from which calcium salt was omitted (calcium ion concentration approximately 20 mumol/L). In the high calcium medium vWf even at concentrations up to six times as high as physiological, showed little or no potentiation of ADP-induced platelet aggregation, whereas fibrinogen strongly potentiated reversible aggregation without thromboxane formation or release of granule contents. In the low calcium medium, either vWf or fibrinogen supported biphasic aggregation in response to ADP, with thromboxane formation and release of granule contents. Aspirin and the thromboxane receptor blocker BM 13.177 inhibited these secondary responses to von Willebrand factor, indicating that they require thromboxane A2 formation and feedback amplification by thromboxane A2. A monoclonal antibody, 10E5, to the platelet glycoprotein IIb/IIIa complex inhibited both primary and secondary aggregation. Although vWf supports ADP-induced aggregation when the concentration of ionized calcium is in the micromolar range, it does not support ADP-induced aggregation in the presence of a concentration of ionized calcium in the physiological range, indicating that vWf probably cannot substitute for fibrinogen in supporting ADP- induced aggregation in vivo. 相似文献
66.
Diaziquone given as a bolus has not been effective in patients with relapsed or refractory leukemia. Because of in vitro data suggesting enhancement of diaziquone-induced cytotoxicity for human and murine leukemia cells with increased duration of drug exposure and the relatively short terminal plasma half-life of diaziquone, 49 patients (34 acute nonlymphocytic leukemia [ANLL], six chronic myelogenous leukemia in blast crisis [CML-B], five acute lymphocytic leukemia [ALL], four 2 degrees ANLL) with leukemia were given diaziquone as a continuous infusion for seven days. The maximum tolerated dose was 28 mg/m2/d for seven days. The dose-limiting toxicity was the duration of bone marrow aplasia (median, 49 days to greater than 500 PMNs in responders; range, 28 to 101 days). Nonhematologic toxicity was minimal. Responses occurred only in patients with relapsed ANLL, of whom 26 were treated at effective doses. There were six complete responses (CR) (23%) and two partial responses (PR) (8%), although five of eight responders never achieved platelet counts greater than 100,000/microL. Thrombocytopenia in these patients was felt to be a manifestation of diaziquone effect, not persistence of leukemia. The median duration of CR was 195 days (range, 88 to 860+). One patient had active CNS leukemia at the start of treatment and has had a durable (28+ month) CR in both sites of disease. Diaziquone produced prolonged aplasia in patients with secondary ANLL and CML-B (five of ten patients died aplastic), whereas patients with ALL all had regrowth of leukemia and two failed to become aplastic. The lack of significant nonhematologic toxicity and the activity in patients with relapsed ANLL render diaziquone of interest as second-line therapy or consolidation therapy in first remission for patients with ANLL. 相似文献
67.
Targeting ASCT2‐mediated glutamine uptake blocks prostate cancer growth and tumour development 下载免费PDF全文
Qian Wang Rae‐Anne Hardie Andrew J Hoy Michelle van Geldermalsen Dadi Gao Ladan Fazli Martin C Sadowski Seher Balaban Mark Schreuder Rajini Nagarajah Justin J‐L Wong Cynthia Metierre Natalia Pinello Nicholas J Otte Melanie L Lehman Martin Gleave Colleen C Nelson Charles G Bailey William Ritchie John EJ Rasko Jeff Holst 《The Journal of pathology》2015,236(3):278-289
68.
69.
Serial evaluations of lymphocytotoxic antibody (LCTAb) and responsiveness to random donor platelet transfusion were reviewed in 234 patients who had developed LCTAb at some time during their treatment course. Seventy (30%) of these patients had significant falls in antibody levels. In 44 patients these declines occurred after further antigenic exposure was reduced either because no transfusions were administered or only histocompatible platelets were transfused. Forty patients with declines in LCTAb levels who were previously refractory to platelet transfusion were rechallenged with random donor platelets. Thirty-four of 35 clinically evaluable patients had good responses to these unmatched transfusions for 2 weeks to 36 months, and in 21 patients antibody did not return despite repeated transfusions. Thus, serial LCTAb measurements are helpful in the management of alloimmunized patients. Many patients will have decreases or a loss of LCTAb, either permanently or transiently, and can be successfully supported with more easily available unmatched random donor platelet transfusions. 相似文献
70.
Cobalamin (vitamin B12) deficiency detection by urinary methylmalonic acid quantitation 总被引:2,自引:0,他引:2
A study was made to assess the value of cobalamin deficiency detection through quantitation of urinary methylmalonic acid (MMA). Urinary MMA was measured in 1118 patients suffering from megaloblastic anemia, other anemias, elevated red cell mean corpuscular volume, or unexplained neurologic disorders. Patients without proven cobalamin deficiency had urinary MMA levels less than 20 micrograms/ml. All patients (n = 27) confirmed to have cobalamin deficiency showed MMA levels greater than 20 micrograms/ml. Data are presented showing the Schilling test results, the comparison of serum cobalamin to urinary MMA levels, and other basic hematologic data. MMA levels are a good indication of cobalamin distribution and function since they are directly related to a cobalamin-dependent metabolic pathway. With rapid, reliable quantitation by mass spectrometry, urinary MMA can now be a useful clinical test. 相似文献