全文获取类型
收费全文 | 401775篇 |
免费 | 12551篇 |
国内免费 | 404篇 |
专业分类
耳鼻咽喉 | 4130篇 |
儿科学 | 13770篇 |
妇产科学 | 7674篇 |
基础医学 | 49270篇 |
口腔科学 | 6809篇 |
临床医学 | 30135篇 |
内科学 | 81557篇 |
皮肤病学 | 6895篇 |
神经病学 | 36735篇 |
特种医学 | 15522篇 |
外国民族医学 | 101篇 |
外科学 | 56900篇 |
综合类 | 3232篇 |
一般理论 | 66篇 |
预防医学 | 38425篇 |
眼科学 | 7223篇 |
药学 | 25463篇 |
中国医学 | 1337篇 |
肿瘤学 | 29486篇 |
出版年
2023年 | 1264篇 |
2022年 | 940篇 |
2021年 | 3583篇 |
2020年 | 2105篇 |
2019年 | 4012篇 |
2018年 | 28381篇 |
2017年 | 21350篇 |
2016年 | 23474篇 |
2015年 | 6352篇 |
2014年 | 6489篇 |
2013年 | 9970篇 |
2012年 | 22728篇 |
2011年 | 36061篇 |
2010年 | 25978篇 |
2009年 | 17003篇 |
2008年 | 32363篇 |
2007年 | 35466篇 |
2006年 | 14044篇 |
2005年 | 15507篇 |
2004年 | 15850篇 |
2003年 | 15662篇 |
2002年 | 13192篇 |
2001年 | 6370篇 |
2000年 | 6607篇 |
1999年 | 5693篇 |
1998年 | 1095篇 |
1997年 | 951篇 |
1996年 | 805篇 |
1995年 | 748篇 |
1992年 | 3241篇 |
1991年 | 2959篇 |
1990年 | 2857篇 |
1989年 | 2570篇 |
1988年 | 2417篇 |
1987年 | 2233篇 |
1986年 | 2113篇 |
1985年 | 1912篇 |
1984年 | 1418篇 |
1983年 | 1210篇 |
1979年 | 1208篇 |
1978年 | 856篇 |
1977年 | 799篇 |
1975年 | 806篇 |
1974年 | 1004篇 |
1973年 | 996篇 |
1972年 | 936篇 |
1971年 | 923篇 |
1970年 | 879篇 |
1969年 | 926篇 |
1968年 | 804篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Background
While the mortality of esophageal surgery has decreased due to technological advancements, there is still a complication rate of about 30%. One of the main complications is the anastomotic leakage associated with a significant rate of morbidity and mortality. To close the leakage the efficacy of self-expanding stents (SES) has been shown in different studies. However, the high rate of stent migration limits the use of commercial available stents. In our case we were faced with the problem that the diameter of all available stents was too small to attach tightly to the mucosal wall of the esophagogastric anastomosis. 相似文献993.
Objective To describe dislocation of the elbow with articular fracture of the distal humerus,a type of elbow fracture-dislocation about which little has been written.Methods Four patients with a dislocation of the elbow and fracture of the distal humerus were identified.Three had dislocation and complex intraarticular fracture of the capitellum,trochlea,and lateral epicondyle.Results Two patients(one treated with a second operation to address avascular necrosis of the capitellum)achieved a functional arc of elbow motion and one patient was lost after removal of the implants 3 months after fracture with documented healing.The fourth patient had a complex open fracture dislocation involving the entire articular surface.An attempt to salvage the articular surface resulted in deep infection.Extensive heterotopic bone led to arthrodesis of the elbow.Conclusions Dislocations of the elbow with articular fracture of the humerus are uncommon.Most injuries involve the capitellum,lateral trochlea,and lateral epicondyle.Open reduction and internal fixation of the distal humerus fracture can restore stability without repairing the medial collateral ligament. 相似文献
994.
Susceptibility to invasive amebiasis has been suggested to be due to intrinsic amebic factors and/or to such host factors as intestinal microflora, mucus and colonic redox potential. We investigated the effect of rat colon components on the growth of axenically cultured E. histolytica trophozoites. Extracts of rat colon tissue produced a 57% amebic growth inhibition. The main growth inhibitory components were precipitated by 65% ammonium sulfate and were heat-sensitive. These components were partially separated by ultrafiltration and gel filtration chromatography. Thus, we found colonic components (Mr 50-100 kDa) that produced strong growth inhibition (75%). These results suggest that rat colonic products may play an active role in resistance to amebic infection. 相似文献
995.
D Modrowski L Miravet M Feuga F Bannié P J Marie 《Journal of bone and mineral research》1992,7(8):961-969
To evaluate whether treatment with a mitogenic agent may increase bone formation and bone mass in osteopenia induced by estrogen deficiency, we determined the effect of oral fluoride treatment on bone and bone cells in ovariectomized rats. Sodium fluoride (NaF) was administered to 3-month-old ovariectomized rats 1 day after ovariectomy (OVX) for 1, 3, and 6 months. NaF was given in drinking water at the dose of 1 mg/kg body weight per day. Fluoride administration led to a partial prevention of the bone loss induced by OVX as shown by histologic analysis of tibial metaphysis and by evaluation of femoral calcium content. These beneficial effects of fluoride were more striking at early time points (1 and 3 months postovariectomy) than after 6 months of treatment. The increase in trabecular bone volume in OVX rats treated with fluoride was associated with a rise in the osteoblast surface, which was increased by 60, 72, and 235% at 1, 3, and 6 months postovariectomy compared to untreated OVX rats. In OVX rats and in sham-operated rats plasma osteocalcin was increased in correlation with the osteoblast surface. However, these two parameters were not correlated in OVX rats treated with fluoride. The heat-labile bone-specific alkaline phosphatase in plasma was decreased in OVX rats treated with fluoride compared to OVX rats, suggesting that both the number and the activity of osteoblasts were affected by NaF treatment. To examine the effect of fluoride on the osteocalcin production and the proliferative capacity of bone cells, osteoblastic cells were isolated by collagenase digestion from the bone surface of tibia in treated and untreated OVX rats.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
996.
R Karlsson S Edén L Eriksson B von Schoultz 《Gynecologic and obstetric investigation》1992,34(4):197-201
The interpretation of previous data on osteocalcin during pregnancy has been complicated by the fact that serum levels, at least in nonpregnant women, display a significant circadian variation. In the present study, serum concentrations of osteocalcin were recorded for 24 h in 12 individual women. In 4 nonpregnant women, there were striking diurnal fluctuations during the sampling period, with values ranging from 0.5 to 4.0 ng/ml. One woman who was investigated in the 11th week of pregnancy showed similar fluctuations in osteocalcin concentrations whereas in the 15th and 17th week values were much lower with minor fluctuations. In 4 women investigated during late pregnancy (weeks 34-38), osteocalcin serum levels were extremely low (range 0.2-0.4 ng/ml), often below the detection limit of the assay, and there was no diurnal variation. Also, in 1 lactating woman, osteocalcin serum levels were low (0.3-0.8 ng/ml) and stable. Low osteocalcin values during pregnancy may indicate a reduced bone turnover possibly mediated via an altered estrogen and growth hormone secretion. 相似文献
997.
A combination of psyllium fiber with nutrients in a commercially available wafer (Fiberall-Ciba Consumer Pharmaceutical) was evaluated for its effectiveness in reducing food intake and appetite. Each of 15 nonobese healthy women received no wafers and four different amounts (39, 104, 169, and 234 kcal) of the fiber wafer with water, in a ratio of 13 kcal (and 0.565 g psyllium) wafer per 41.67 g water, 30 minutes prior to a test meal of macaroni and beef, on nonconsecutive days. Intake of the test meal and hunger ratings were both significantly reduced after intake of the two largest wafer amounts (169 and 234 kcal, respectively), in comparison with the two smaller amounts and none at all. The reduction produced by the largest amount compared to none at all was 122 kcal (about half the energy of the amount given). There were no significant differences in intake and hunger ratings among the two smaller amounts and none at all. Thus the threshold for intake reduction by this product with water lies between 104 and 169 kcal. Methodologically, this work underscores the importance of testing the satiating effects of foods at multiple levels before conclusions are drawn about their satiating effectiveness, and suggests that the threshold for significant reduction should be considered as a measure of the product's satiating effectiveness. The relative contributions of the nutrients, the fiber, and the water to the satiating effect still need to be determined. 相似文献
998.
Charles J. Coté Alfred L. Daniels Michelle Connolly Stanislaw K. Szyfelbein Charles D. Wickens 《Journal canadien d'anesthésie》1992,39(5):454-457
We undertook a prospective study of standard peripheral pulse oximetry versus a modified pulse oximeter probe applied to the tongue in order to determine the efficacy of this alternative monitoring site in children with thermal injuries. Ten patients with a mean age (± SD) of 7.5 ± 4.5 yr were studied on 15 occasions. The mean weight +- SD) was 31.4+- 13.7 kg and percent surface area burn (± SD) was 56+- 21%. A total of 1,992 min of anaesthesia time was monitored. Both sites functioned simultaneously 47% of the time; the lingual but not the peripheral site functioned 28% of the time and only the peripheral site and not the lingual functioned 22% of the time. Neither site functioned 3% of the time. The tongue oximeter provided 563 min more monitoring time than the peripheral sites. The tongue oximeter also functioned in children with peripheral vasoconstriction when the peripheral sensor failed and was less susceptible to electrocautery interference. The tongue oximeter is a reasonable adjunct but not a substitute for peripheral oximetry since its application is limited to paralyzed, intubated patients. 相似文献
999.
Michelle McKerral Pierre Lachapelle François Tremblay Robert C. Polomeno Marie-Sylvie Roy Raquel Beneish Franco Leporé 《Documenta ophthalmologica. Advances in ophthalmology》1995,91(2):181-193
The contribution of each monocular pathway to the timing of the binocular pattern visual evoked potential was assessed in situations where a significant interocular timing discrepancy was observed. Monocular and binocular pattern visual evoked potentials to 0.5° checks were recorded from normal subjects, normal subjects in whom one eye was blurred, patients with monocular amblyopia, and patients with resolved unilateral optic neuritis. Normal subjects showed facilitation, while suppression was evidenced in subjects with monocular blurring. In patients with amblyopia, the affected pathway had no effect on binocular pattern visual evoked potential latency, suggesting that the amblyopic eye was suppressed. In contrast, all patients with optic neuritis showed binocular averaging. Our results show that different forms of binocular interaction are evidenced in normal subjects, in amblyopia and in optic neuritis, and suggest that a comparative analysis of monocular and binocular pattern visual evoked potential peak times brings valuable information to the clinical evaluation that could be used to distinguish disease processes further.Abbreviation BPVEP
binocular pattern visual evoked potential 相似文献
1000.