全文获取类型
收费全文 | 6374篇 |
免费 | 513篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 74篇 |
儿科学 | 133篇 |
妇产科学 | 175篇 |
基础医学 | 873篇 |
口腔科学 | 67篇 |
临床医学 | 720篇 |
内科学 | 1461篇 |
皮肤病学 | 78篇 |
神经病学 | 937篇 |
特种医学 | 168篇 |
外科学 | 831篇 |
综合类 | 89篇 |
现状与发展 | 1篇 |
一般理论 | 6篇 |
预防医学 | 473篇 |
眼科学 | 104篇 |
药学 | 359篇 |
中国医学 | 8篇 |
肿瘤学 | 347篇 |
出版年
2023年 | 27篇 |
2022年 | 47篇 |
2021年 | 111篇 |
2020年 | 75篇 |
2019年 | 101篇 |
2018年 | 146篇 |
2017年 | 99篇 |
2016年 | 106篇 |
2015年 | 126篇 |
2014年 | 169篇 |
2013年 | 306篇 |
2012年 | 431篇 |
2011年 | 434篇 |
2010年 | 225篇 |
2009年 | 219篇 |
2008年 | 361篇 |
2007年 | 378篇 |
2006年 | 400篇 |
2005年 | 376篇 |
2004年 | 355篇 |
2003年 | 342篇 |
2002年 | 374篇 |
2001年 | 74篇 |
2000年 | 50篇 |
1999年 | 68篇 |
1998年 | 73篇 |
1997年 | 67篇 |
1996年 | 59篇 |
1995年 | 58篇 |
1994年 | 42篇 |
1993年 | 60篇 |
1992年 | 38篇 |
1991年 | 47篇 |
1990年 | 33篇 |
1989年 | 36篇 |
1988年 | 32篇 |
1987年 | 31篇 |
1986年 | 33篇 |
1985年 | 31篇 |
1984年 | 51篇 |
1983年 | 54篇 |
1982年 | 77篇 |
1981年 | 80篇 |
1980年 | 61篇 |
1979年 | 37篇 |
1978年 | 46篇 |
1977年 | 51篇 |
1976年 | 37篇 |
1975年 | 28篇 |
1973年 | 28篇 |
排序方式: 共有6904条查询结果,搜索用时 15 毫秒
41.
42.
Jerome L. Belinson M.D. R.G. Pretorius M.D. Maura McClure R.N. Takamaru Ashikaga Ph.D. 《Gynecologic oncology》1986,23(3):304-309
Thirty-three patients were treated with HexAF after previous treatment with cyclophosphamide (C), Adriamycin (A), and cisplatin (P). The patients had either progressed on CAP, had persistent disease after CAP, or recurred after a negative second look. Treatment schedule was hexamethylmelamine (Hex) 150 mg po qd days 1-14, methotrexate (A) 40 mg/m2 IV days 1 and 8, and 5-fluorouracil (F) 600 mg/m2 IV days 1 and 8. Courses were repeated every 4 weeks. Thirty-one of 33 patients were evaluable for response. Three of 31 patients had partial responses, 7 of 31 had stable disease, and 21 of 31 progressed. Median survival of the responders (n = 3) was 23 months and the nonresponders (n = 28) was 6 months (p = 0.027). Patients with less than 1 cm disease (n = 12) had a median survival of 20 months, and those with greater than 1 cm (n = 21) had a median survival of 6 months (p = 0.004). Toxicity was mild. Even with a statistically significant survival advantage for HexAF responders, we consider a response rate of less than 10% unacceptable. 相似文献
43.
44.
45.
Iqbal S Kriebs J Harman C Gungor S Alger L Turan O Kopelman J Malinow A Baschat AA 《American journal of perinatology》2008,25(6):335-339
Our objective was to test if protease inhibitors (PIs) increase the incidence of fetal growth restriction (FGR). Human immunodeficiency (HIV)-seropositive women were studied. At birth the neonatal weight percentile was assigned by predicted growth potential (GP), accounting for race, parity, weight, height, gestational age, birthweight, and gender (Gardosi, 1992). FGR was defined as GP < 10% percentile. Maternal age, CD4 count, viral load, weight gain, prenatal care, tobacco, alcohol, substance abuse, and PI use were related to FGR using chi-square and multiple regression analysis. Ninety-three of 191 women received PI. In these, FGR occurred in 27 (29%) compared with 15 (15.3%) in the non-PI group ( P = 0.02). Maternal CD4 count ( P < 0.0001) was the primary determinant, and smoking ( P = 0.037) was an independent cofactor for FGR (Nagelkerke r2 = 0.24). Twenty-six of 82 (31.7%) smokers had FGR, versus 16 of 109 (14.7%) of nonsmokers (odds ratio, 2.69; 95% confidence interval, 1.33 to 5.46; P = 0.005). After exclusion of the CD4 count, PI became a cofactor for FGR ( P = 0.021 and Nagelkerke r2 = 0.104). We concluded that maternal HIV status and smoking determine the risk for FGR. Although PIs increase the risk for FGR, this effect appears to depend on maternal disease severity. 相似文献
46.
47.
48.
Sainikitha Prattipati Francis M. Sakita Tumsifu G. Tarimo Godfrey L. Kweka Jerome J. Mlangi Amedeus V. Maro Lauren A. Coaxum Sophie W. Galson Alexander T. Limkakeng Anzibert Rugakingira Sarah J. Urasa Nwora L. Okeke Blandina T. Mmbaga Gerald S. Bloomfield Julian T. Hertz 《Global Heart》2022,17(1)
Introduction:HIV confers increased risk of myocardial infarction (MI), but there has been little study of ischemic electrocardiogram (ECG) findings among people with HIV in sub-Saharan Africa.Objectives:To compare the prevalence of ischemic ECG findings among Tanzanians with and without HIV and to identify correlates of ischemic ECG changes among Tanzanians with HIV.Methods:Consecutive adults presenting for routine HIV care at a Tanzanian clinic were enrolled. Age- and sex-matched HIV-uninfected controls were enrolled from a nearby general clinic. All participants completed a standardized health questionnaire and underwent 12-lead resting ECG testing, which was adjudicated by independent physicians. Prior MI was defined as pathologic Q-waves in contiguous leads, and myocardial ischemia was defined as ST-segment depression or T-wave inversion in contiguous leads. Pearson’s chi-squared test was used to compare the prevalence of ECG findings among those with and without HIV and multivariate logistic regression was performed to identify correlates of prior MI among all participants.Results:Of 497 participants with HIV and 497 without HIV, 272 (27.8%) were males and mean (sd) age was 45.2(12.0) years. ECG findings suggestive of prior MI (11.1% vs 2.4%, OR 4.97, 95% CI: 2.71–9.89, p < 0.001), and myocardial ischemia (18.7% vs 12.1% OR 1.67, 95% CI: 1.18–2.39, p = 0.004) were significantly more common among participants with HIV. On multivariate analysis, ECG findings suggestive of prior MI among all participants were associated with HIV infection (OR 4.73, 95% CI: 2.51–9.63, p = 0.030) and self-reported family history of MI or stroke (OR 1.96, 95% CI: 1.08–3.46, p = 0.023).Conclusions:There may be a large burden of ischemic heart disease among adults with HIV in Tanzania, and ECG findings suggestive of coronary artery disease are significantly more common among Tanzanians with HIV than those without HIV. 相似文献
49.
Mechanical strain, induced noninvasively in the high-frequency domain, is anabolic to cancellous bone, but not cortical bone 总被引:5,自引:0,他引:5
Departing from the premise that it is the large-amplitude signals inherent to intense functional activity that define bone morphology, we propose that it is the far lower magnitude, high-frequency mechanical signals that continually barrage the skeleton during longer term activities such as standing, which regulate skeletal architecture. To examine this hypothesis, we proposed that brief exposure to slight elevations in these endogenous mechanical signals would suffice to increase bone mass in those bones subject to the stimulus. This was tested by exposing the hind limbs of adult female sheep (n = 9) to 20 min/day of low-level (0.3g), high-frequency (30 Hz) mechanical signals, sufficient to induce a peak of approximately 5 microstrain (micro epsilon) in the tibia. Following euthanasia, peripheral quantitative computed tomography (pQCT) was used to segregate the cortical shell from the trabecular envelope of the proximal femur, revealing a 34.2% increase in bone density in the experimental animals as compared with controls (p = 0.01). Histomorphometric examination of the femur supported these density measurements, with bone volume per total volume increasing by 32% (p = 0.04). This density increase was achieved by two separate strategies: trabecular spacing decreased by 36.1% (p = 0.02), whereas trabecular number increased by 45.6% (p = 0.01), indicating the formation of cancellous bone de novo. There were no significant differences in the radii of animals subject to the stimulus, indicating that the adaptive response was local rather than systemic. The anabolic potential of the signal was evident only in trabecular bone, and there were no differences, as measured by any assay, in the cortical bone. These data suggest that subtle mechanical signals generated during predominant activities such as posture may be potent determinants of skeletal morphology. Given that these strain levels are three orders of magnitude below strains that can damage bone tissue, we believe that a noninvasive stimulus based on this sensitivity has potential for treating skeletal complications such as osteoporosis. 相似文献
50.