全文获取类型
收费全文 | 2648091篇 |
免费 | 204593篇 |
国内免费 | 4048篇 |
专业分类
耳鼻咽喉 | 38018篇 |
儿科学 | 90072篇 |
妇产科学 | 74430篇 |
基础医学 | 377396篇 |
口腔科学 | 76348篇 |
临床医学 | 234295篇 |
内科学 | 516094篇 |
皮肤病学 | 57773篇 |
神经病学 | 214422篇 |
特种医学 | 105757篇 |
外国民族医学 | 1064篇 |
外科学 | 402485篇 |
综合类 | 60395篇 |
现状与发展 | 4篇 |
一般理论 | 899篇 |
预防医学 | 202640篇 |
眼科学 | 60870篇 |
药学 | 198451篇 |
5篇 | |
中国医学 | 4892篇 |
肿瘤学 | 140422篇 |
出版年
2018年 | 27056篇 |
2017年 | 21065篇 |
2016年 | 23629篇 |
2015年 | 26320篇 |
2014年 | 35877篇 |
2013年 | 55754篇 |
2012年 | 75481篇 |
2011年 | 80333篇 |
2010年 | 47579篇 |
2009年 | 44283篇 |
2008年 | 77173篇 |
2007年 | 81820篇 |
2006年 | 82536篇 |
2005年 | 80415篇 |
2004年 | 78440篇 |
2003年 | 75610篇 |
2002年 | 74085篇 |
2001年 | 122452篇 |
2000年 | 127761篇 |
1999年 | 107507篇 |
1998年 | 29921篇 |
1997年 | 26988篇 |
1996年 | 27157篇 |
1995年 | 26127篇 |
1994年 | 24663篇 |
1993年 | 23080篇 |
1992年 | 86475篇 |
1991年 | 84296篇 |
1990年 | 82465篇 |
1989年 | 79150篇 |
1988年 | 73367篇 |
1987年 | 72336篇 |
1986年 | 68208篇 |
1985年 | 65925篇 |
1984年 | 49538篇 |
1983年 | 42414篇 |
1982年 | 25086篇 |
1981年 | 22564篇 |
1979年 | 46301篇 |
1978年 | 32408篇 |
1977年 | 27379篇 |
1976年 | 25740篇 |
1975年 | 27460篇 |
1974年 | 33003篇 |
1973年 | 31749篇 |
1972年 | 29170篇 |
1971年 | 27066篇 |
1970年 | 25160篇 |
1969年 | 23361篇 |
1968年 | 21373篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Kaposi's sarcoma. CT-radiographic correlation 总被引:1,自引:0,他引:1
The role of CT in the diagnosis of intrathoracic Kaposi's sarcoma (KS) was evaluated retrospectively in 24 patients, in the absence of coexistent opportunistic infections. In all cases the diagnosis of KS was initially established by histologic evaluation of extrathoracic disease: 15 patients had verified parenchymal KS and nine patients endobronchial KS. (Chest roentgenograms were analyzed separately for each group: in 14 patients serial films were available for review. The predominant radiographic findings was the presence of nonspecific, bilateral, perihilar infiltrates in 22 of 24 cases (92 percent). Corresponding CT scans documented the presence of abnormal hilar densities characteristically extending into the adjacent pulmonary parenchyma along distinctly perivascular and peribronchial pathways. Discrete, poorly marginated nodules were identified radiographically in ten cases (42 percent); these proved to be randomly distributed throughout the parenchyma on CT. Radiographic evidence of mediastinal adenopathy was distinctly unusual, seen in only two cases (8 percent). While CT typically demonstrated shotty adenopathy, significantly enlarged nodes (greater than 1 cm) were rarely identified. We concluded that CT is more specific than routine roentgenograms for identifying pulmonary KS. While not pathognomonic, peribronchial and perivascular disease is sufficiently characteristic to obviate more invasive diagnostic procedures, especially in patients with established KS. 相似文献
992.
As a result of policy changes and developments on the demand side, the importance of technology in primary health care will grow fast. An approach to the implementation of new technologies in primary health care is presented in this article. First we describe the main problems in Dutch primary health care. The second step is to identify new technologies which are becoming available. Subsequently, the interface between these problems and their possible technological resolution has to be found. The fact that a technological innovation appears to be a solution is not sufficient reason for introducing it. There are all kinds of reasons why an innovation that has proved useful in the hospital situation, for example, might be of doubtful use in primary health care. Accordingly, the next step is to assess whether a technological solution to a problem in primary health care is indeed an improvement. To acknowledge the particular situation of primary health care, a scheme has been developed that may be used to determine criteria of evaluation. 相似文献
993.
We studied the parathyroid function in patients with advanced renal failure by determining their plasma concentrations of ionized calcium (iCa), intact parathyroid hormone (PTH) and its inactive metabolites (PTH-MM). The suppressibility of the parathyroidism was studied with a calcium infusion test. The intact PTH values of the nondialysis and dialysis patients did not statistically differ from each other. The concentrations of PTH-MM were, however, higher in the dialysis patients than in the nondialysis patients (p less than 0.05). The ratio of PTH-MM to intact PTH was lowest in healthy reference subjects and highest in dialysis patients (p less than 0.01), and did not correlate with the degree of intact PTH elevation in the patient groups. The calcium infusion test was carried out on 15 patients. All showed suppression in the elevated plasma intact PTH concentration and in 6 the intact PTH value normalized. The PTH-MM value did not normalize in any of the patients. During oral calcium treatment the degree of intact PTH suppression at an achieved concentration of plasma iCa was predictable from the infusion test. Three patients were parathyroidectomized after the calcium infusion test. In 2 of these elevated intact PTH normalized within 24 h while in 1 no change took place. In this latter case on clinical improvement was noted. We conclude that the determination of plasma intact PTH concentration especially of combined with plasma iCa value is a reliable means of studying the hyperparathyroidism associated with chronic renal failure. 相似文献
994.
1. The action of (1-28) alpha-human atrial natriuretic peptide (ANP) was studied on human isolated resistance arteries. 2. Renal, skeletal muscle, omental and subcutaneous resistance arteries were taken from tissue removed at surgery and isometric tension responses were measured with a myograph. 3. ANP (10(-9)-10(-6) M) relaxed precontracted segments of renal and skeletal muscle arteries in a concentration-dependent manner. ANP failed to relax isolated omental or subcutaneous arteries. 4. The effect of ANP on human isolated resistance arteries varies depending on the site of origin of the artery. 相似文献
995.
996.
The authors report their experience of anterolateral bilateral approach of cervical spine. They underline the advantages and inconvenience of this route and discuss the indications. 相似文献
997.
998.
Cancer risk after evaluation for infertility 总被引:3,自引:0,他引:3
L A Brinton L J Melton G D Malkasian A Bond R Hoover 《American journal of epidemiology》1989,129(4):712-722
To evaluate cancer risk by various causes of infertility, the authors conducted a retrospective cohort study among 2,335 women evaluated for infertility at the Mayo Clinic between 1935 and 1964. Most cancers occurred at expected frequencies, with the exception of cancers of the thyroid (standardized incidence ratio (SIR) = 2.6) and other endocrine glands (SIR = 6.7), although analyses were based on small numbers. Patients with progesterone deficiencies (31 per cent of the study subjects) had a 20 per cent higher cancer risk than did those with other causes of infertility, with excesses deriving primarily from cancers of the lung, cervix, ovary, and thyroid and from melanoma. Breast cancer risk, however, was not elevated in either patients with progesterone deficiencies (SIR = 0.9) or patients with other causes of infertility (SIR = 1.0). Examination of other parameters of infertility, including age at evaluation, type of infertility (primary vs. secondary), and years of attempted conception, showed no elevated risks of breast cancer in any subgroup. These results fail to support previous studies that have linked progesterone deficiencies among infertile women to elevated breast cancer risk. However, the data suggest a possible involvement of a progesterone deficiency in the etiology of other cancers, particularly thyroid cancer and melanoma. 相似文献
999.
C M Bijleveld R Verwer R H Houwen M J Slooff 《Nederlands tijdschrift voor geneeskunde》1989,133(28):1401-1406
Between 1-1-1982 and 1-1-1988 52 children with an end-stage liver disease were evaluated to determine whether orthotopic liver transplantation (OLT) would be appropriate. 24 children were accepted as candidates in the long term. Twelve were not accepted as potential recipients. The parents of 3 decided not to accept OLT as treatment for their children. Two children died before a suitable donor liver was available, so that OLT was carried out in 11 children. Two of these children needed a second transplant. In 3 children only a part of a donor liver was transplanted. Shortage of donor livers of small size is partly alleviated by using a part of a larger liver. The underlying diseases of the transplanted children were cryptogenic cirrhosis (1x), biliary atresia with a hepatoportoenterostomy (8x) and cirrhosis following neonatal hepatitis (2x). Ten children with OLT are clinically and physically well. Postoperatively a primary graft dysfunction occurred in one child. He was retransplanted. The median waiting time for a donor liver was 5 months. The timing for OLT has to take this in account. In treating children with end-stage liver disease (partial) OLT should be considered. 相似文献
1000.
R N Hensinger 《The Orthopedic clinics of North America》1987,18(4):597-616
Early management of congenital dislocation of the hip has been necessary and has resulted in a high percentage of normal-appearing and functioning hips. The risk of complications and problems has been lessened. Further, the techniques employed are simpler and less demanding or difficult for patients, family, or physicians. 相似文献