全文获取类型
收费全文 | 118616篇 |
免费 | 7168篇 |
国内免费 | 1580篇 |
专业分类
耳鼻咽喉 | 1575篇 |
儿科学 | 2970篇 |
妇产科学 | 4107篇 |
基础医学 | 18296篇 |
口腔科学 | 3608篇 |
临床医学 | 9277篇 |
内科学 | 21614篇 |
皮肤病学 | 2436篇 |
神经病学 | 8002篇 |
特种医学 | 4018篇 |
外国民族医学 | 3篇 |
外科学 | 16748篇 |
综合类 | 5213篇 |
一般理论 | 34篇 |
预防医学 | 8690篇 |
眼科学 | 2818篇 |
药学 | 10204篇 |
中国医学 | 818篇 |
肿瘤学 | 6933篇 |
出版年
2021年 | 984篇 |
2019年 | 1045篇 |
2018年 | 1610篇 |
2017年 | 1167篇 |
2016年 | 1197篇 |
2015年 | 1443篇 |
2014年 | 1883篇 |
2013年 | 2442篇 |
2012年 | 3546篇 |
2011年 | 3796篇 |
2010年 | 2285篇 |
2009年 | 2048篇 |
2008年 | 3380篇 |
2007年 | 3613篇 |
2006年 | 3599篇 |
2005年 | 3163篇 |
2004年 | 2975篇 |
2003年 | 2772篇 |
2002年 | 2627篇 |
2001年 | 6730篇 |
2000年 | 6921篇 |
1999年 | 5695篇 |
1998年 | 1829篇 |
1997年 | 1378篇 |
1996年 | 935篇 |
1995年 | 862篇 |
1992年 | 3728篇 |
1991年 | 3806篇 |
1990年 | 3550篇 |
1989年 | 3552篇 |
1988年 | 3428篇 |
1987年 | 3277篇 |
1986年 | 3091篇 |
1985年 | 2967篇 |
1984年 | 2053篇 |
1983年 | 1792篇 |
1982年 | 985篇 |
1979年 | 1909篇 |
1978年 | 1184篇 |
1977年 | 986篇 |
1976年 | 918篇 |
1975年 | 1191篇 |
1974年 | 1358篇 |
1973年 | 1413篇 |
1972年 | 1357篇 |
1971年 | 1247篇 |
1970年 | 1137篇 |
1969年 | 1121篇 |
1968年 | 1024篇 |
1967年 | 897篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Oncologic screenings of the populations in the areas with increased incidence of esophageal cancer have revealed Barrett's ulcer in 1 percent of the examinees. Endoscopic and cytologic characteristics of this condition are presented. Precancer changes--severe dysplasia--are most frequent in male Kazakhs (14.1 percent) aged 50 to 59 (14.7 percent). Subjects with Barrett's ulcer developing severe dysplasia, as evidenced by cytograms, should be included in the group of subjects at risk for carcinoma of the lower third of the esophagus and cardia. 相似文献
72.
E Maquarre C Artus Z Gadhoum C Jasmin F Smadja-Joffe J Robert-Lézénès 《Leukemia》2005,19(12):2296-2303
We have recently reported that ligation of the CD44 cell surface antigen with A3D8 monoclonal antibody (mAb) triggers incomplete differentiation and apoptosis of the acute promyelocytic leukemia (APL)-derived NB4 cells. The present study characterizes the mechanisms underlying the apoptotic effect of A3D8 in NB4 cells. We show that A3D8 induces activation of both initiator caspase-8 and -9 and effector caspase-3 and -7 but only inhibition of caspase-3/7 and caspase-8 reduces A3D8-induced apoptosis. Moreover, A3D8 induces mitochondrial alterations (decrease in mitochondrial membrane potential DeltaPsi m and cytochrome c release), which are reduced by caspase-8 inhibitor, suggesting that caspase-8 is primarily involved in A3D8-induced apoptosis of NB4 cells. However, the apoptotic process is independent of TNF-family death receptor signalling. Interestingly, the general serine protease inhibitor 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF) decreases A3D8-induced apoptosis and when combined with general caspase inhibitor displays an additive effect resulting in complete prevention of apoptosis. These results suggest that both caspase-dependent and serine protease-dependent pathways contribute to A3D8-induced apoptosis. Finally, A3D8 induces apoptosis in all-trans-retinoic acid-resistant NB4-derived cells and in APL primary blasts, characterizing the A3D8 anti-CD44 mAb as a novel class of apoptosis-inducing agent in APL. 相似文献
73.
A modified technique for the repair of moderate to severe cicatricial entropion has been developed. This method is unique, as it involves the creation of a bipedicled tarsoconjunctival advancement flap. The technique avoids the causes of surgical failure seen with standard tarsal fracturing procedures. 相似文献
74.
Smoking and stroke. 总被引:2,自引:0,他引:2
The purpose of this review is to evaluate literature published since 1978 on the association between smoking and stroke. Two cohort studies found a dose-response relationship between the amount of cigarettes smoked per day and the relative risk of stroke. Also, two of the cohort studies found that when smoking ceased, the risk of stroke lessened (p less than 0.001). Nine case-control studies found a significant association between smoking and stroke for men and women. The biological association between smoking and stroke is plausible and several epidemiologic studies are supportive of this thesis. Additional, well-designed epidemiologic studies with a sufficient sample size to detect reasonably small odds ratios or relative risks (thus providing adequate statistical power) are warranted. 相似文献
75.
Following administration of phenothiazines for schizophrenia, a 25-year-old patient developed a malignant neuroleptic syndrome followed by bilateral periarticular ossification of the knees, with severely limited motion. Two years later, the patient regained useful motion after bilateral excision of the ossified tissue and intensive physiotherapy. No recurrence of ossification was observed 3 years after operation, and the patient has maintained almost normal motion. 相似文献
76.
77.
78.
Both dopamine D1 and D2 receptors are present in rat retina. D1 receptors are positively coupled to adenylyl cyclase, while D2 receptors are negatively coupled. After intraocular administration of the neurotoxin 6-hydroxydopamine (6-OHDA) there is depletion of retinal dopamine by about 90%, as well as a decrease of the number of D1 and D2 receptor binding sites. Following the 6-OHDA lesion, there is an enhancement of the D1 receptor-stimulated accumulation of cyclic-AMP and a loss of D2 receptor-inhibited accumulation of cyclic-AMP. Our results suggest that some of the retinal D2 receptors are coupled to adenylyl cyclase and some are not. 相似文献
79.
The effect of the traditional Chinese medicinal herbs enema and enteric-coated capsules in the treatment of ulcerative colitis (UC) were compared in 260 cases. The immune complexes and the dynamic change of autoantibodies were monitored in 28 out of the 260 cases before and after treatment. The following results were observed. (1) There was no significant difference in the total effective rate between the enema group and the oral capsule group (93.3% and 87.5% respectively), but the recovery rates of purulent hemafecia, mucusfecia and erosion accompanying colitis, etc. in the former group were higher than those in the latter (P less than 0.01). (2) The circulating immune complexes were found 43 times above the normal range in 17 cases with positive rate 60.7%, and tended to decrease as the condition became better after treatment. Antinuclear antibodies were determined by the indirect fluorescent immune method and the indirect enzyme labelling method and the positive rates were 53.6% and 64.7% respectively, both being much higher than those in the controls (P less than 0.01). 相似文献
80.
W F Rayburn M Z Johnson K L Hoffman S M Donn R M Nelson 《American journal of perinatology》1987,4(2):98-101
A goal for the obstetrician and neonatologist is to screen for risk factors associated with intraventricular hemorrhage (IVH) in the low-birthweight infant. Perinatal events that lead to neonatal metabolic and cardiovascular derangements seem to provoke IVH, and conflicting reports have implicated labor as being contributory. A fetal heart rate (FHR) abnormality during premature labor may be a predictor of subsequent neonatal IVH. For this reason, 5 years of FHR tracings at two university medical centers were reviewed for inborn infants who were delivered after premature labor and weighed less than or equal to 2000 gm. Sixty-four infants developed IVH, but pre-existing labor with a discernible FHR pattern was recorded in only 38 (59%) cases. Interpretations were reassuring in 17 (45%) cases, suspicious in 7 (18%) cases, and ominous in 14 (37%) cases. This proportion of FHR patterns was not significantly different from a matched group of premature infants without IVH during the same period. Interpretations of intrapartum FHR patterns of low-birthweight infants are limited, especially before 30 weeks gestation, and not useful in predicting neonatal IVH. 相似文献