全文获取类型
收费全文 | 1398945篇 |
免费 | 106928篇 |
国内免费 | 6300篇 |
专业分类
耳鼻咽喉 | 17137篇 |
儿科学 | 44545篇 |
妇产科学 | 37657篇 |
基础医学 | 190166篇 |
口腔科学 | 37406篇 |
临床医学 | 127017篇 |
内科学 | 288069篇 |
皮肤病学 | 32571篇 |
神经病学 | 114822篇 |
特种医学 | 57201篇 |
外国民族医学 | 274篇 |
外科学 | 216611篇 |
综合类 | 32825篇 |
现状与发展 | 2篇 |
一般理论 | 480篇 |
预防医学 | 112907篇 |
眼科学 | 28926篇 |
药学 | 98000篇 |
26篇 | |
中国医学 | 2301篇 |
肿瘤学 | 73230篇 |
出版年
2018年 | 14265篇 |
2017年 | 11305篇 |
2016年 | 13550篇 |
2015年 | 15095篇 |
2014年 | 21032篇 |
2013年 | 31356篇 |
2012年 | 38495篇 |
2011年 | 41253篇 |
2010年 | 25665篇 |
2009年 | 25136篇 |
2008年 | 38529篇 |
2007年 | 40991篇 |
2006年 | 42086篇 |
2005年 | 40598篇 |
2004年 | 38671篇 |
2003年 | 37695篇 |
2002年 | 35639篇 |
2001年 | 67331篇 |
2000年 | 69187篇 |
1999年 | 57834篇 |
1998年 | 17370篇 |
1997年 | 15510篇 |
1996年 | 16489篇 |
1995年 | 16701篇 |
1994年 | 15510篇 |
1993年 | 14591篇 |
1992年 | 48079篇 |
1991年 | 46709篇 |
1990年 | 44897篇 |
1989年 | 42701篇 |
1988年 | 39570篇 |
1987年 | 38912篇 |
1986年 | 36702篇 |
1985年 | 35394篇 |
1984年 | 27038篇 |
1983年 | 22686篇 |
1982年 | 14261篇 |
1981年 | 12810篇 |
1980年 | 12041篇 |
1979年 | 24033篇 |
1978年 | 17493篇 |
1977年 | 14750篇 |
1976年 | 13514篇 |
1975年 | 14029篇 |
1974年 | 16508篇 |
1973年 | 15803篇 |
1972年 | 14537篇 |
1971年 | 13360篇 |
1970年 | 12209篇 |
1969年 | 11429篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
L R?stam R V Luepker M B Mittelmark D M Murray J S Slater H Blackburn 《American journal of preventive medicine》1988,4(5):249-254
To determine the potential effect of screening on referral patterns, an adult population sample (4,404 men, 5,164 women, 20-69 years of age) was systematically recruited and screened for hypercholesterolemia and then analyzed by different cholesterol referral recommendations. Using levels suggested by the Lipid Research Clinics Coronary Primary Prevention Trial (greater than or equal to 265 mg/dL), 7.3% of men and 5.8% of women would be referred for follow-up. With the suggested recommendations of the National Cholesterol Education Program (NCEP), (greater than or equal to 200 mg/dL), 49.2% of men and 40.2% of women would be referred. The use of age-related definitions of the NIH Consensus Conference on Lipid Lowering results in 28.0% referrals in men and 21.8% in women. From this population, hypercholesterolemia subjects (greater than or equal to 265 mg/dL at screening; n = 624) were invited for a second cholesterol determination (58% returned), which found 36% below the 265 mg/dL level. Population screening for cholesterol is likely to produce large numbers of patients for follow-up, with the actual numbers strongly dependent on cutoff levels and age-sex distributions. Referral and follow-up of these patients may place a significant load on an unprepared health care community. 相似文献
102.
103.
Juvenile hypocalcemia provokes persistent electroencephalographic change in renally compromised rats
J J Lipman D L White P L Lawrence P E Teschan 《Journal of the American College of Nutrition》1988,7(6):453-460
In view of the putative involvement of calcium in uremic encephalopathy and the critical importance of this element in juvenile development, we examined the effect of temporary restriction of dietary calcium intake on serum chemistry and the quantitative electroencephalogram (Q.EEG) in unilaterally 3/4 nephrectomized juvenile male Sprague-Dawley rats. Animals were renally infarcted at 22-26 days of age (50-74 g) and placed on one of two isocaloric dietary regimens: powdered normal rat diet (ND, n = 25) or low calcium diet (LCD, n = 8) for 30 days. At this time, ND animals showed normal serum chemistries, whereas LCD rats were hypocalcemic and azotemic with significantly elevated blood urea nitrogen (BUN) and serum creatinine concentrations and reduced renal creatinine clearance values. All animals thereafter received ND for 25-34 further days, during which time chronic Q.EEG electrodes were implanted. At the end of the common ND feeding period, serum chemistry values were equal and normal in both groups. The average theta/alpha ratio (TAR) of the overnight Q.EEG was assessed for 3 days. We found that the TAR of previously LCD animals was significantly elevated compared with ND rats. This indicates an encephalopathic slowing of the background rhythm of these animals. We conclude that, following restoration of a transient uremic and hypocalcemic episode induced by LCD feeding, the Q.EEG background frequency of juvenile renally impaired rats was abnormally slow after 30 days of ND feeding. 相似文献
104.
105.
D. Lothschütz M. Jennewein S. Pahl H.F. Lausberg A. Eichler W. Mutschler R.G. Hanselmann M. Oberringer 《Inflammation research》2002,51(8):416-422
OBJECTIVE AND DESIGN: Inflammatory and tumorous bronchi were screened in order to obtain new tumor relevant cytogenetic parameters. MATERIAL OR SUBJECTS: Bronchial cells of 32 patients were cultivated by standard cell culture procedures. METHODS: Tetraploidy and aneuploidy was determined by enumeration of chromosome 7 and 8 versus the number of centrosomes. The resulting data were correlated with histopathological data. RESULTS: Tetra- and aneuploidy of epithelial cells were detectable in 76% of tumor cell cultures, 75% of high grade inflammatory tissues and 40% of non- and low grade-inflammatory tissues. Additionally, we observed centrosome hyper-amplification and multipolar mitoses not only in the tumor but also in the early stages of inflammation. CONCLUSION: Inflammatory bronchi already show tumor-specific features and may consequently represent the preliminary genetic stage of cancer development in bronchi. 相似文献
106.
Andrew Williams 《The British journal of general practice》2002,52(484):940-941
107.
HLA-DR typing in identical twins with insulin-dependent diabetes: difference between concordant and discordant pairs 总被引:3,自引:0,他引:3
C Johnston D A Pyke A G Cudworth E Wolf 《British medical journal (Clinical research ed.)》1983,286(6361):253-255
A total of 106 pairs of identical twins, of whom 56 were concordant and 50 discordant for insulin-dependent diabetes, were typed for HLA-DR. In both the concordant and discordant groups there was a high prevalence of the antigens DR3 and DR4, a low prevalence of DR5 and DR7, and a virtual absence of DR2. The heterozygous phenotype DR3,DR4 was more prevalent in concordant than discordant pairs. This was therefore the first demonstration of a genetic difference between concordant and discordant identical twin pairs. These findings suggest that possession of both DR3 and DR4 antigens confers a greater genetic predisposition to insulin-dependent diabetes than does the possession of either antigen alone. 相似文献
108.
Chest radiographs of 43 consecutive diabetic patients were evaluated with a view to determine their role as a routine investigation of patients with diabetes mellitus. 22 (51.2%) patients had normal chest radiographs. The remaining 21 patients had 61 abnormalities found in their chest radiographs. 26 (42.6%) of these were significant abnormalities while 35 (57.4%) were non-significant. Of the former, 42.3% were due to cardiomegaly while in the latter group, aortic unfolding was the main finding. Radiological abnormalities were more commonly observed in patients aged 40 years and over, than in those below, with a ratio of 3:1. Chest radiographs corroborated clinical diagnosis in 19 of the 21 cases in whom abnormalities were observed. This study shows that routine chest radiograph in diabetic patients is useful in those with clinical symptoms and in older diabetics above the age of 40 years. 相似文献
109.
110.
C Caron J Goudemand A Marey D Beague G Ducroux F Drouvin 《Thrombosis and haemostasis》1991,66(4):410-414
The plasma levels of several haemostatic and fibrinolytic parameters were measured before and after delivery in 61 hypertensive pregnant women of whom 22 developed preeclampsia, and compared to the results obtained in 42 normal pregnant women. In the two last weeks before delivery (D less than or equal to -15) tPA antigen, PAI-1 activity, vWF:Ag/FVIII:C ratio, ATIII activity and platelet count were found to be significantly different in the hypertensive pregnant women with and without preeclampsia. Combined all together, an association of three of these five parameters were found to be pathological (i.e.:tPA:Ag greater than or equal to 19 ng/ml, PAI-1 activity greater than or equal to 58 IU/ml, vWF:Ag/FVIII:C ratio greater than or equal to 2.6, ATIII activity less than or equal to 73%) in none of the hypertensive women without preeclampsia and in only 35% of the preeclamptic group. A positive correlation was demonstrated between vWF:Ag/FVIII:C ratio and tPA:antigen levels suggesting that both tPA and vWF:Ag could be considered as early indicators of a possible micro angiopathy occurring in preeclampsia. However, due to the high dispersion of the results, it appears that the investigated haemostatic and/or fibrinolytic criteria give only presumptive arguments before assigning risk for preeclampsia development among hypertensive pregnant women. 相似文献