全文获取类型
收费全文 | 15455篇 |
免费 | 1452篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 136篇 |
儿科学 | 482篇 |
妇产科学 | 303篇 |
基础医学 | 1993篇 |
口腔科学 | 318篇 |
临床医学 | 1601篇 |
内科学 | 3389篇 |
皮肤病学 | 144篇 |
神经病学 | 1272篇 |
特种医学 | 466篇 |
外国民族医学 | 1篇 |
外科学 | 2689篇 |
综合类 | 424篇 |
一般理论 | 21篇 |
预防医学 | 1554篇 |
眼科学 | 339篇 |
药学 | 972篇 |
中国医学 | 23篇 |
肿瘤学 | 824篇 |
出版年
2023年 | 118篇 |
2022年 | 155篇 |
2021年 | 349篇 |
2020年 | 203篇 |
2019年 | 311篇 |
2018年 | 377篇 |
2017年 | 303篇 |
2016年 | 290篇 |
2015年 | 365篇 |
2014年 | 479篇 |
2013年 | 730篇 |
2012年 | 888篇 |
2011年 | 976篇 |
2010年 | 592篇 |
2009年 | 477篇 |
2008年 | 819篇 |
2007年 | 910篇 |
2006年 | 829篇 |
2005年 | 804篇 |
2004年 | 758篇 |
2003年 | 720篇 |
2002年 | 675篇 |
2001年 | 289篇 |
2000年 | 271篇 |
1999年 | 268篇 |
1998年 | 196篇 |
1997年 | 154篇 |
1996年 | 120篇 |
1995年 | 131篇 |
1994年 | 119篇 |
1993年 | 104篇 |
1992年 | 212篇 |
1991年 | 212篇 |
1990年 | 198篇 |
1989年 | 155篇 |
1988年 | 152篇 |
1987年 | 136篇 |
1986年 | 147篇 |
1985年 | 150篇 |
1984年 | 142篇 |
1983年 | 118篇 |
1982年 | 103篇 |
1981年 | 90篇 |
1980年 | 85篇 |
1979年 | 103篇 |
1978年 | 108篇 |
1977年 | 75篇 |
1975年 | 78篇 |
1973年 | 90篇 |
1972年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A R Wright P T English H M Cameron J B Wilsdon 《Acta radiologica (Stockholm, Sweden : 1987)》1992,33(6):582-587
Pelvimetry remains a useful technique as part of the assessment of the term breech pregnancy where vaginal delivery is planned. MR pelvimetry is accurate, well tolerated and shows soft-tissue structures as well as bone. It avoids the potentially carcinogenic effects of ionising radiation and is thought to be completely safe for mother and fetus. A technique of MR pelvimetry is described which uses gradient-echo sequences. This quick, practical method makes minimal inroads into valuable scanning time, and may therefore be considered a potentially cost-effective alternative to conventional pelvimetry. 相似文献
42.
G T Mogavero B Jones J L Cameron J Coleman 《AJR. American journal of roentgenology》1992,159(5):1001-1003
OBJECTIVE. Our objective was to study the imaging findings in patients who had gastric and duodenal obstruction as a long-term complication of cholangiocarcinoma and to determine if the obstruction was associated with radiation therapy. MATERIALS AND METHODS. Between 1973 and 1989, 96 patients had either curative resection or palliative stenting for cholangiocarcinoma involving the hepatic duct bifurcation. Sixty-three (66%) also received adjuvant radiation therapy ranging from 4960 to 7220 rad (cGy). Gastric outlet or duodenal obstruction or both developed subsequently in seven of the 63 patients treated with radiation therapy. Radiographic studies, including upper gastrointestinal series and CT, and medical and surgical records for these seven patients were retrospectively reviewed. RESULTS. Upper gastrointestinal series in the seven patients with obstruction showed narrowing of the lumen, deformity and enlargement of gastric and duodenal mucosal folds, and delayed gastric emptying. CT performed in five of the seven patients showed thickening of the wall of the gastric antrum and small bowel and retained food and fluid within the stomach. All seven patients required gastrojejunostomy; at surgery, dense adhesions and fibrosis were found, and it was not evident whether the obstruction was due to the tumor or to radiation fibrosis. However, because this complication was seen only after radiotherapy, it was presumed to be radiation fibrosis. CONCLUSION. Our experience suggests that radiation therapy increases the risk of postoperative gastric and duodenal obstruction in patients undergoing surgery for cholangiocarcinoma. 相似文献
43.
Changes in the health care needs of American children over the past two centuries have engendered school health programs. Issues related to the role and responsibilities of school nurses within these programs have existed from the beginning. Current societal pressure for schools to assume even greater responsibility for providing health care has necessitated a precise definition of these roles and responsibilities. The purpose of this article is to review existing literature related to school nursing in this country and to describe the results of a study documenting state mandates for health education programs and the role of nurses within these programs. 相似文献
44.
45.
Cynthia S. Pomerleau Anne W. Garcia Ovide F. Pomerleau Oliver G. Cameron 《Psychoneuroendocrinology》1992,17(6):627-638
Nicotine intake, menstrual and smoking withdrawal symptomatology, and baseline cortisol and MHPG were assessed in nine women smokers under conditions of ad lib smoking and overnight abstinence in three menstrual phases (early follicular, mid-to-late follicular, and late luteal). A trend towards higher nicotine intake p <0.100 was observed in the mid-to-late follicular phase. Although me menstrual symptomatology was not significantly elevated during the smoking abstinence condition overall, abstinence appeared to prevent the normal reduction in symptomatology during the mid-to-late follicular phase that occurred under conditions of ad lib smoking. Menstrual and withdrawal symptoms were highly correlated, and both were most pronounced during the late luteal/abstinence condition. The smoking-specific item “craving” reflected this pattern, though in attenuated form, suggesting that the observed exacerbation of withdrawal symptomatology was not simply due to generalized dysphoria, as queried in both instruments. MHPG was significantly elevated in the late luteal phase, whereas cortisol was significantly higher during ad lib smoking than during abstinence and tended to be highest in the mid-to-late follicular phase. Further investigation will be needed to determine the functional significance of these findings for understanding and treating smoking in women. 相似文献
46.
47.
48.
49.
Functional changes in slow-twitch soleus and fast-twitch extensor digitorum longus muscles were assessed after 2 mo of streptozocin-induced diabetes in rats. For soleus, there was a slowing of twitch times both for contraction and relaxation and a reduction of maximum tetanic relaxation rate. There was little effect on strength performance assessed by maximal tetanic tension production. Treatment with the aldose reductase inhibitor ponalrestat largely prevented relaxation defects but had little effect on contraction. For the fast muscle, twitch times were relatively unaffected, but maximum tetanic relaxation rate was reduced. In addition, tetanic tension output decreased. These changes were largely prevented by ponalrestat treatment. The effects of partial insulin therapy were also investigated. This regimen reduced hypoinsulinemia, but sufficient hyperglycemia remained to stimulate the polyol pathway. It prevented the slowing of soleus twitch contraction but had no effect on relaxation. For extensor digitorum longus, insulin produced further deleterious effects on tetanic tension and maximum relaxation rate, which were antagonized by ponalrestat. A 1% dietary myo-inositol supplement had little effect on contractile function in slow or fast muscles. It was concluded that polyol-pathway activity is an important factor underlying skeletal muscle functional changes in diabetes, probably acting through disruption of Ca2+ handling. Hypoinsulinemia was considered a secondary factor causing atrophy, particularly of fast muscles. There was no evidence of effects dependent on neuropathy. 相似文献
50.
The pattern of cancer in white and Asian (Indian, Pakistani, and Bangladeshi) children living in the West Midlands Health Authority Region was investigated using age standardised incidence rates. Two sets of rates were calculated, a 10 year rate (1982-91) using survey based estimates of the ethnic population and a four year rate (1989-92) using the ethnic population counts from the 1991 census. The 10 year rates showed a significantly higher annual incidence of cancer in Asian (159.1/million/year) than in white (130.8) children. The pattern of cancers in Asian children was different, with an excess of lymphomas and germ cell tumours, and a deficit of rhabdomyosarcomas. These findings were confirmed by the four year rates. Although underestimation of the Asian population probably contributes to the apparent excess, there remains cause for concern that UK Asian children may be at higher risk of cancer. Accurate ethnic population figures and confirmatory studies are urgently required. 相似文献