全文获取类型
收费全文 | 630篇 |
免费 | 38篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 19篇 |
妇产科学 | 3篇 |
基础医学 | 46篇 |
口腔科学 | 20篇 |
临床医学 | 97篇 |
内科学 | 136篇 |
皮肤病学 | 19篇 |
神经病学 | 8篇 |
特种医学 | 96篇 |
外科学 | 35篇 |
综合类 | 64篇 |
预防医学 | 57篇 |
眼科学 | 2篇 |
药学 | 28篇 |
1篇 | |
中国医学 | 19篇 |
肿瘤学 | 21篇 |
出版年
2023年 | 2篇 |
2022年 | 6篇 |
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 15篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 30篇 |
2014年 | 25篇 |
2013年 | 30篇 |
2012年 | 30篇 |
2011年 | 29篇 |
2010年 | 42篇 |
2009年 | 31篇 |
2008年 | 25篇 |
2007年 | 27篇 |
2006年 | 8篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 14篇 |
2002年 | 5篇 |
2001年 | 8篇 |
1999年 | 4篇 |
1998年 | 27篇 |
1997年 | 23篇 |
1996年 | 29篇 |
1995年 | 23篇 |
1994年 | 22篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1990年 | 4篇 |
1989年 | 14篇 |
1988年 | 17篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有673条查询结果,搜索用时 0 毫秒
591.
O Sjaastad C Saunte TA Fredriksen D de Souza Carvalho YD Fragoso LG Dale I Hørven 《Cephalalgia : an international journal of headache》1988,8(2):111-120
A 56-year-old, previously reported woman with cluster headache-like headache with bouts of unilateral (the side of predominance changing through the years) severe headache had a familial history (three generations) of partial Hageman factor deficiency and bleeding episodes. A giant aneurysm was found to be lodged in the anterior communicating artery on the left side. Clinically, the features were atypical for cluster headache: onset at a young age (14 years), episodes of retrobulbar neuritis appearing at the side of pain, etc. Studies of forehead sweating indicated that the right side was the pathologic one, from an autonomic point of view, as did pupillometric studies. However, during attacks, which were left-sided at the time, forehead sweating was marked laterally on the left side and on the upper eyelid, but not on the right. The "signal" usually reaching the autonomically stigmatized side during attacks of cluster headache, therefore, did not seem to reach the sweat glands on that (the right) side during the attack in the present case. This headache may, therefore, be distinct from cluster headache, both from a clinical and from an autonomic function point of view. 相似文献
592.
ES Perry ; RH Moore ; TA Berger ; LC Billups ; DA Maybee ; KF Salata ; LE Lippert 《Transfusion》1996,36(4):318-321
BACKGROUND: Reticulocytes are important in the phenotyping of transfused patients. Reticulocytes can persist in blood units for the shelf life of the unit. STUDY DESIGN AND METHODS: Temperature dependence of reticulocyte persistence was examined in vitro at 4, 24, and 37 degrees C by using thiazole orange staining and flow cytometric analysis. Two-color flow cytometric analysis was used to evaluate the persistence of donor reticulocytes in transfused patients. RESULTS: Flow cytometric analysis using thiazole orange demonstrated that persistence of reticulocytes in units of stored CPDA-1 blood was temperature-dependent. Reticulocytes disappeared over 13 and 6 days at 24 degrees C and 37 degrees C, respectively, but at 4 degrees C the reticulocyte count changed little over 35 days. Two-color flow cytometric analysis of reticulocyte antigens was used to follow donor reticulocytes in 14 transfusion events in nine different patients. Donor reticulocytes persisted through 24 hours in 75 percent of the patients and were detectable at 48 hours in three patients. CONCLUSION: This study demonstrates that reticulocytes persist during refrigerated storage; they are detectable in the circulation of most recipients for the first 24 hours after transfusion and in the circulation of a few recipients after 48 hours. These findings may have relevance for separation techniques based on reticulocyte density in samples drawn shortly after transfusion and for evaluation of reticulocyte counts in patients with hematologic abnormalities. 相似文献
593.
Reduction in the toxicity of a component of an artificial blood substitute by supercritical fluid fractionation 总被引:1,自引:0,他引:1
Artificial blood substitutes (ABS) containing the surfactant Pluronic F68 (F68) are reported to be cytotoxic to cell lines. Because of F68's reported impairment of granulocyte function, it was hypothesized that F68 was also responsible for the cytotoxicity of ABS, possibly as a result of a separable fraction of the F68, separation of which could be achieved using supercritical fluid fractionation (SFF). SFF employs gases, such as carbon dioxide, under high pressure to dissolve the parent compound, a process that is followed by step-by-step precipitation and recovery of the dissolved material. The toxicity of F68 to human and animal cells was investigated by culturing Hela and B16 cells in the presence or absence of F68. Cells were grown for 4 days, harvested, and counted. Hela and B16 growth were markedly inhibited by F68. Four lots of F68 at 20 mg per ml inhibited Hela growth by 54 +/- 10 percent (p less than 0.05). In four dose-response experiments, three lots of F68 caused 50 percent inhibition of cell growth at 25 +/- 17 mg per ml. Four lots of F68 were also processed by SFF. Hela cells were grown in the presence of control media, parent (unextracted) F68, the early fractions of SFF extraction (XT), and the residual (partially purified) (RES F68). All parent F68, XT, and RES F68 were at 20 mg per ml. In 11 studies, the XT were 77 +/- 25 percent more toxic than the parent F68 (p less than 0.02), and the RES F68 were 30 +/- 11 percent less toxic than parent F68 (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
594.
Wayne TA Enanoria Alan E Hubbard Mark J van der Laan Mi Chen Juan Ruiz John M ColfordJr 《BMC public health》2007,7(1):127
Background
For individuals with AIDS, data exist relatively soon after diagnosis to allow estimation of "early" survival quantiles (e.g., the 0.10, 0.15, 0.20 and 0.30 quantiles, etc.). Many years of additional observation must elapse before median survival, a summary measure of survival, can be estimated accurately. In this study, a new approach to predict AIDS median survival is presented and its accuracy tested using AIDS surveillance data. 相似文献595.
DL Jacobson I Bica TA Knox C Wanke E Tchetgen D Spiegelman M Silva S Gorbach IB Wilson 《Clinical infectious diseases》2003,37(10):1349-1356
In human immunodeficiency virus (HIV) disease, symptoms of underlying illness may promote weight loss through decreased caloric intake, increased metabolic needs, or nutrient malabsorption. We evaluated disease symptoms as predictors of acute weight loss (i.e., loss of > or =5% of weight). HIV-infected men and women (n=415) were telephoned every 5 weeks to obtain information about weight and recent symptoms. Weight change between each pair of consecutive calls (telephone intervals, 2814) was calculated. Acute weight loss occurred across 4.5% of intervals and among 24% of individuals. Patients reported > or =1 symptom before 58% of telephone intervals. The most common symptoms or symptom complexes before intervals were diarrhea (21% of patients), anorexia (17%), upper respiratory symptoms (16%), skin symptoms (12%), and abdominal pain (12%). Trouble swallowing (6%) and oral symptoms (7%) were less common. Risk of acute weight loss was significantly increased when oral symptoms or trouble swallowing were present, and it was decreased when highly active antiretroviral therapy (HAART) was used or when diarrhea was not present. Even when HAART is being administered, clinicians should remain vigilant regarding weight loss, oral symptoms, and trouble swallowing. 相似文献
596.
Foss FM; Borkowski TA; Gilliom M; Stetler-Stevenson M; Jaffe ES; Figg WD; Tompkins A; Bastian A; Nylen P; Woodworth T 《Blood》1994,84(6):1765-1774
597.
598.
Mackall CL; Fleisher TA; Brown MR; Magrath IT; Shad AT; Horowitz ME; Wexler LH; Adde MA; McClure LL; Gress RE 《Blood》1994,84(7):2221-2228
Recently we have observed an increased incidence of opportunistic infections in patients treated with intensive chemotherapy for cancer. Because T-cell depletion is associated with similar clinical events in human immunodeficiency virus infection and after bone marrow transplantation, we have analyzed peripheral blood lymphocyte populations in a series of patients during treatment with intensive chemotherapy for cancer. Although neutrophil, monocyte, and platelet numbers consistently recovered to greater than 50% of pretreatment values after each sequential cycle of therapy, lymphocyte numbers did not recover within the same time period. B cells decreased rapidly from a mean value of 149 +/- 46/mm3 before chemotherapy to 4 +/- 1/mm3 during chemotherapy (P = .01). CD4+ T cells decreased from a mean of 588 +/- 76/mm3 before chemotherapy to 105 +/- 28/mm3 during chemotherapy (P = .0002) and CD8+ T cells decreased from a mean of 382 +/- 41/mm3 before chemotherapy to 150 +/- 46/mm3 during chemotherapy (P = .0009). Natural killer cell numbers did not show significant declines (171 +/- 30/mm3 before, 114 +/- 24/mm3 during, P = .19). Based on the history of opportunistic complications in patients with other disorders who display similar degrees of CD4+ T-cell lymphopenia and preliminary observations in this population, immune incompetence could surface as a dose-limiting toxicity for highly dose-intensive chemotherapy regimens. 相似文献
599.
Prenatal diagnosis of beta-thalassemias by amniocentesis: linkage analysis using multiple polymorphic restriction endonuclease sites 总被引:10,自引:0,他引:10
In order to assess the applicability of multiple restriction endonuclease analyses of amniocyte DNA to the prenatal diagnosis of beta-thalassemias in general, we studied 12 consecutive couples at risk. DNA of both members of the 12 couples and a previous offspring of each was analyzed for the presence of 4 polymorphic restriction endonuclease sites: the Hpa I site 3' to the beta-globin gene, the Hind III site in the G gamma gene, the Hind III site in the A gamma gene, and the Bam HI site 3' to the beta-gene. Linkage disequilibrium between these sites and beta A or beta thal genes was not found, presumably due to the heterogeneity of beta thal genes. However, the high frequency of polymorphism at these sites allowed differentiation of beta A-bearing chromosomes from beta thal or beta S-bearing chromosomes in both members of 6 couples. In these couples, complete prenatal diagnosis by linkage analysis of amniocyte DNA would be possible. In the remaining 6 couples, beta A and beta thal chromosomes could be discriminated in one member. In about 50% of the pregnancies of these couples, exclusion of beta-thalassemia is possible by this analysis. These data suggest that when linkage analysis of polymorphic restriction endonuclease sites is carried out, prenatal diagnosis of beta-thalassemia states can be accomplished by amniocentesis alone in 75% of pregnancies at risk. 相似文献