全文获取类型
收费全文 | 24055篇 |
免费 | 2034篇 |
国内免费 | 803篇 |
专业分类
耳鼻咽喉 | 219篇 |
儿科学 | 396篇 |
妇产科学 | 624篇 |
基础医学 | 2977篇 |
口腔科学 | 450篇 |
临床医学 | 2673篇 |
内科学 | 4980篇 |
皮肤病学 | 301篇 |
神经病学 | 1452篇 |
特种医学 | 624篇 |
外国民族医学 | 4篇 |
外科学 | 3161篇 |
综合类 | 2137篇 |
现状与发展 | 3篇 |
一般理论 | 9篇 |
预防医学 | 1354篇 |
眼科学 | 819篇 |
药学 | 2053篇 |
10篇 | |
中国医学 | 785篇 |
肿瘤学 | 1861篇 |
出版年
2024年 | 53篇 |
2023年 | 315篇 |
2022年 | 624篇 |
2021年 | 914篇 |
2020年 | 610篇 |
2019年 | 666篇 |
2018年 | 754篇 |
2017年 | 678篇 |
2016年 | 639篇 |
2015年 | 828篇 |
2014年 | 995篇 |
2013年 | 1164篇 |
2012年 | 1700篇 |
2011年 | 1797篇 |
2010年 | 1127篇 |
2009年 | 914篇 |
2008年 | 1316篇 |
2007年 | 1340篇 |
2006年 | 1356篇 |
2005年 | 1324篇 |
2004年 | 1122篇 |
2003年 | 1045篇 |
2002年 | 1021篇 |
2001年 | 686篇 |
2000年 | 643篇 |
1999年 | 563篇 |
1998年 | 250篇 |
1997年 | 236篇 |
1996年 | 204篇 |
1995年 | 141篇 |
1994年 | 138篇 |
1993年 | 96篇 |
1992年 | 230篇 |
1991年 | 202篇 |
1990年 | 185篇 |
1989年 | 158篇 |
1988年 | 125篇 |
1987年 | 119篇 |
1986年 | 99篇 |
1985年 | 68篇 |
1984年 | 48篇 |
1983年 | 40篇 |
1982年 | 51篇 |
1981年 | 51篇 |
1980年 | 39篇 |
1979年 | 42篇 |
1978年 | 38篇 |
1977年 | 22篇 |
1975年 | 22篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
This study evaluated the role of insulin, glucagon and the epidermal growth factor (EGF) on liver regeneration after partial hepatectomy. Male Wistar rats, weighing approximately 200 g, were used. A partial hepatectomy, with resection of the medial and left lateral lobes (67.31%), was performed on the control group and seven hormone-treated groups: insulin, glucagon, EGF, insulin plus glucagon, insulin plus EGF, glucagon plus EGF, and a combination of the three hormones. The hormones were administered subcutaneously two days prior to the partial hepatectomy. The groups administered insulin were allowed to drink 20% glucose in water. Another group of rats received simulated operations, i.e., only a laparotomy was performed. The rats were killed at six, 24, 48 and 72 hours after the operation. Remnant liver weight, deoxyribonucleic acid (DNA) content, rate of DNA synthesis, mitotic index, blood glucose and serum insulin levels were measured. The results showed that: 1) the effects of single hormone administration on posthepatectomy liver regeneration were not obvious; 2) combined administration of insulin and glucagon increased the weight of the remnant liver, the DNA content, and the rate of DNA synthesis; 3) the combined administration of insulin, glucagon, and EGF increased the regeneration based on the remnant liver weight and mitotic index; and 4) there was no concordance between the change in blood glucose levels and the effect of hormones during liver regeneration. 相似文献
42.
Toddlers who ingest the drug of abuse 3,4-methylenedioxymethamphetamine (MDMA; 'Ecstasy') are at particularly high risk of serious neurological and cardiovascular side effects. We report of a 20-month-old male toddler who accidentally ingested Ecstasy. He presented with fever and seizures, tachycardia, hypertension, and hyperthermia. Urine amphetamine level was 2111 ng/mL. Treatment included rapid cooling, hydration, and support measures. Vital signs were regularly monitored. His condition became stable on day 2 and urine amphetamine level returned to normal on day 3 of hospitalization. His behavior, activity, and appetite had returned to their usual levels upon follow-up at our outpatient clinic. The incidence of drug abuse with MDMA has increased dramatically over the last decade in developed countries. It can be expected that accidental Ecstasy poisoning in children will increase as well. This case illustrates the need to consider the possibility of accidental Ecstasy ingestion in the differential diagnosis of a child suffering from convulsions with fever. 相似文献
43.
44.
45.
46.
Joe I-Chiang Chou Hwai-Jen Fong Shou-Hsin Kuang Lin-Yang Gi Fang-Yi Hwang Yu-Chieng Lai Richard Che-Shoa Chang Shou-Yen Kao 《Journal of oral and maxillofacial surgery》2005,63(3):355-361
PURPOSE: This study was an analysis of the soft and hard tissue changes of the facial profile after bilateral sagittal splitting osteotomy for mandibular setback of Taiwanese patients. PATIENTS AND METHODS: We collected pre- and postsurgical lateral cephalographs of 64 patients (28 males, 36 females) with skeletal Class III malocclusion who received combined orthodontic-surgical treatment with bilateral sagittal splitting osteotomy mandibular setback at Taipei Veterans General Hospital between 1994 and 2000. Nineteen cephalometric parameters of (14 linear, 4 angular, and the BS index) soft and hard tissues were measured at 1 week before treatment, and 2 months and 1 year after surgery, and analyzed by paired t test. RESULTS: Mean patient age was 20.0 +/- 1.6 years. The patients underwent an average of 7 mm mandibular setback at the osseous pogonion (Pog). Average setbacks at Pog and soft tissue pogonion (pog) were 5.54 mm and 4.85 mm, respectively, at 1 year after surgery. The setback ratio of Pog/pog was 1:0.88. The hard tissue relapse at Pog was 21% at 1 year after surgery. Improvement in prognathic profile was demonstrated by significant changes in the positions of Pog and pog, ANB angle, the distance from lower lip to esthetic line (E-L lip), and the BS index after surgery. However, compared with parameters obtained from a normal Taiwanese population, the cephalometric data of Pog, pog, and BS index still indicated mild prognathism. CONCLUSION: Although mandibular prognathism could be grossly improved by bilateral sagittal splitting osteotomy mandibular setback, a significant amount of relapse occurred within 1 year after surgery. The extent of the postoperatively preserved features showing mandibular prognathism should be a concern for both patients and physicians. 相似文献
47.
48.
S. T. Fan Q. S. Wang C. M. Lo K. W. Tam Yu E. C. S. Lai J. Wong 《ANZ journal of surgery》1994,64(11):759-762
Impaired hepatic function is a major contributory factor to the high incidence of postoperative morbidity and mortality in patients with malignant biliary obstruction. Dynamic hepatic function tests such as indocyanine green (ICG) retention and aminopyrine breath tests were evaluated in such patients to define whether they were clinically useful for prediction of postoperative morbidity and mortality. Forty-four patients with malignant biliary obstruction undergoing surgery for relief of obstructive jaundice were recruited into the study. Indocyanine green retention and aminopyrine breath tests were carried out in all patients pre-operatively and repeated in 36 patients postoperatively. The ICG retention was abnormal in all patients before surgery and there was significant improvement 2 weeks after surgery (32.8 ± 2.5%vs 18.3 ± 2.8%, P= 0.001). The change in ICG retention levels correlated with the serum bilirubin levels but the pre-operative ICG retention value could not predict postoperative morbidity and mortality. The aminopyrine breath test was abnormal in all but one patient. It correlated with pre-operative prothrombin time of the patients before surgery but it did not improve significantly after surgery and was not predictive of postoperative outcome. It is concluded that both ICG retention and aminopyrine breath tests have limited clinical value in the pre-operative evaluation of patients with malignant biliary obstruction. 相似文献
49.
Benzo(a)pyrene inhibits epidermal growth factor binding and receptor autophosphorylation in human placental cell cultures 总被引:1,自引:0,他引:1
H J Guyda L Mathieu W Lai D Manchester S L Wang S Ogilvie K T Shiverick 《Molecular pharmacology》1990,37(2):137-143
Studies investigated the effects of benzo(a)pyrene (BP) treatment on epidermal growth factor (EGF) receptor binding and kinase activity in human placental cell cultures. Specific binding of 125I-EGF to cells from early gestation placentae was significantly decreased by 37 and 60% following exposure to 1 and 10 microM BP, respectively, for 24 hr. In contrast, cells cultured from term placentae showed no inhibitory effect of either concentration of BP. Specific binding of 125I-labeled insulin and insulin-like growth factors-I and -II to early gestation cells was decreased only 15-18% at 10 microM BP, which indicates that loss of membrane receptors appears to be selective for EGF. Scatchard analysis of early gestation cells revealed that BP was associated with a dose-dependent loss in the number of high affinity EGF binding sites. Evidence from cross-linking and autophosphorylation experiments confirmed that the Mr 170,000 binding protein was decreased in a dose-dependent manner following BP treatment. In comparison, term placental cells exhibit a 26% loss of EGF receptor autophosphorylation without alteration in binding following exposure to 10 microM BP. Thus, early gestation cells exhibit a BP-related down-regulation of EGF receptors, whereas term placental cells show receptor desensitization. No adverse effect of BP treatment was observed on the incorporation of [35S] methionine into proteins secreted by early gestation cells. Further experiments compared the effects of BP with the related poly-cyclic compounds beta-naphthoflavone, alpha-naphthoflavone, and 3-methylcholanthrene. In early gestation cells, EGF binding and receptor autophosphorylation were measurably decreased at 10 microM concentrations of these polycyclic compounds, but to a lesser extent than observed with BP. In term placental cells, however, EGF binding was unchanged or increased, whereas receptor autophosphorylation was decreased 10-26%. Thus, exposure of term placental cells to these polycyclic compounds leads to a dissociation between EGF binding and receptor protein kinase activity. Finally, aryl hydrocarbon hydroxylase activity was induced 20- to 200-fold in early placental cells exposed to BP, beta-naphthoflavone, and 3-methylcholanthrene. In summary, the direct effects of BP and related compounds observed on placental EGF receptors may indicate altered function of EGF in the regulation of cell growth and differentiation in the human placenta. 相似文献
50.
Identifying potential indicators of the quality of end-of-life cancer care from administrative data.
Craig C Earle Elyse R Park Bonnie Lai Jane C Weeks John Z Ayanian Susan Block 《Journal of clinical oncology》2003,21(6):1133-1138
PURPOSE: To explore potential indicators of the quality of end-of-life services for cancer patients that could be monitored using existing administrative data. METHODS: Quality indicators were identified and assessed by literature review for proposed indicators, focus groups with cancer patients and family members to assess candidate indicators and generate new ideas, and an expert panel ranking the meaningfulness and importance of each potential indicator using a modified Delphi approach. RESULTS: There were three major concepts of poor quality of end-of-life cancer care that could be examined using currently-available administrative data (such as Medicare claims): institution of new anticancer therapies or continuation of ongoing treatments very near death; a high number of emergency room visits, inpatient hospital admissions, or intensive care unit days near the end of life; and a high proportion of patients never enrolled in hospice, only admitted in the last few days of life, or dying in an acute-care setting. Concepts such as access to psychosocial and other multidisciplinary services and pain and symptom control are important and may eventually be feasible, but they cannot currently be applied in most data systems. Indicators based on limiting the use of treatments with low probability of benefit or indicators based on economic efficiency were not acceptable to patients, family members, or physicians. CONCLUSION: Several promising claims-based quality indicators were identified that, if found to be valid and reliable within data systems, could be useful in identifying health-care systems in need of improving end-of-life services. 相似文献