全文获取类型
收费全文 | 172015篇 |
免费 | 6744篇 |
国内免费 | 446篇 |
专业分类
耳鼻咽喉 | 2253篇 |
儿科学 | 5039篇 |
妇产科学 | 4096篇 |
基础医学 | 24597篇 |
口腔科学 | 5563篇 |
临床医学 | 10032篇 |
内科学 | 38097篇 |
皮肤病学 | 4750篇 |
神经病学 | 13781篇 |
特种医学 | 4611篇 |
外国民族医学 | 1篇 |
外科学 | 19628篇 |
综合类 | 857篇 |
一般理论 | 27篇 |
预防医学 | 20385篇 |
眼科学 | 4411篇 |
药学 | 13358篇 |
2篇 | |
中国医学 | 692篇 |
肿瘤学 | 7025篇 |
出版年
2023年 | 842篇 |
2022年 | 785篇 |
2021年 | 2810篇 |
2020年 | 1595篇 |
2019年 | 3183篇 |
2018年 | 5092篇 |
2017年 | 3180篇 |
2016年 | 3173篇 |
2015年 | 3562篇 |
2014年 | 4110篇 |
2013年 | 6181篇 |
2012年 | 10356篇 |
2011年 | 10984篇 |
2010年 | 5604篇 |
2009年 | 4227篇 |
2008年 | 9002篇 |
2007年 | 9670篇 |
2006年 | 9240篇 |
2005年 | 8863篇 |
2004年 | 8163篇 |
2003年 | 7627篇 |
2002年 | 7261篇 |
2001年 | 5083篇 |
2000年 | 5630篇 |
1999年 | 4318篇 |
1998年 | 956篇 |
1992年 | 2320篇 |
1991年 | 2091篇 |
1990年 | 2073篇 |
1989年 | 1798篇 |
1988年 | 1679篇 |
1987年 | 1581篇 |
1986年 | 1639篇 |
1985年 | 1519篇 |
1984年 | 1086篇 |
1983年 | 938篇 |
1979年 | 1239篇 |
1978年 | 820篇 |
1977年 | 810篇 |
1976年 | 776篇 |
1975年 | 899篇 |
1974年 | 1137篇 |
1973年 | 1187篇 |
1972年 | 1130篇 |
1971年 | 1089篇 |
1970年 | 1021篇 |
1969年 | 1093篇 |
1968年 | 1115篇 |
1967年 | 989篇 |
1966年 | 887篇 |
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
91.
A study of 52 middle-aged males with essential hypertension, unaccompanied by cardiovascular disorders, is reported. The patients were divided into 2 groups with respect to the type of treatment they received: 30 patients on beta-adrenoblockers and 22 patients on methyldopa. The patients were treated continuously for 2 years under one-dimensional echocardiographic control. The greatest drop in arterial blood pressure and ventricular septum thickness was seen within the first 6 months of treatment, while posterior-wall hypertrophy disappeared altogether. Although there was no further drop in blood pressure after 6 months, the thickness of the ventricular septum remained reduced for at least 2 years. Regression of left-ventricular hypertrophy was not accompanied with any deterioration of left-ventricular performance, nor was it related to additional use of vasodilators. 相似文献
92.
Tumor recurrence in prostatic urethra following simultaneous resection of bladder tumor and prostate 总被引:4,自引:0,他引:4
A comparative retrospective study was performed on 100 patients who had undergone transurethral resection of a superficial bladder tumor (Ta-Tl) with no associated carcinoma in situ (group 1) and 100 patients who had undergone simultaneous transurethral resection of a superficial bladder tumor (Ta-Tl), with no associated carcinoma in situ, and benign prostatic hyperplasia (group II). Evaluation of the recurrences of prostatic urethral tumors in both groups showed that they appeared in 10 patients (12 recurrences) in group I and 10 patients (14 recurrences) in group II (p = not significant). These data enabled us to rule out the influence of simultaneous transurethral resection in cases of recurrences of prostatic urethral tumors. 相似文献
93.
94.
The effects of adrenergic activation on aggressiveness and the aggression induced endocrine changes were tested in rats. α2 adrenoceptor blockers were used for enhancing activation of the adrenergic system, and changes in aggressiveness were tested in resident-intruder contests. Three experiments were conducted. In experiment 1, saline injected rats responded to the presence of an opponent by aggression and the increase in plasma ACTH and corticosterone. Intraperitoneal administration of 1 mg/kg CH-38083 (an α2 adrenoceptor antagonist) produced a several fold increase in clinch fighting and mutual upright scores, and also further enhanced the plasma ACTH and corticosterone response. In experiment 2, the effect of three doses (0.5, 1 and 2 mg/kg) of three different α2 adrenoceptor blockers CH-38083, idazoxan and yohimbine were tested. All the substances increased aggression at 0.5 and 1 mg/kg; at 2 mg/kg the effect of idazoxan and yohimbine disappeared, while with CH-38083 an additional increase was obtained. In yohimbine treated animals the enhancement of aggression was reduced already at 1 mg/kg. In experiment 3, indomethacin, a potent inhibitor of the catecholamine-induced ACTH release completely abolished the effects of the α2 adrenoceptor antagonist CH-38083: the intensity of agonistic interactions, as well as ACTH and corticosterone plasma concentrations, returned to control levels. The possible role of catecholamines and the stress hormones in the activation of aggression is discussed. 相似文献
95.
Natriuretic peptide-induced cyclic GMP accumulation in adult guinea-pig cerebellar slices. 下载免费PDF全文
1. Second messenger responses to natriuretic peptides were studied in guinea-pig cerebellar slices by use of radioactive precursors. 2. The rank order of potency of the different natriuretic peptides in generating [3H]-guanosine 3':5'-cyclic monophosphate (cyclic GMP) was atrial natriuretic peptide (ANP) > brain natriuretic peptide (BNP) >> C-type natriuretic peptide (CNP) with EC50 values of 19.5 +/- 8.8 nM for ANP and 169 +/- 41 nM for BNP. CNP induced [3H]-cyclic GMP accumulation only at concentrations greater than 1 microM. 3. An additive response to ANP (1 microM) was observed in the presence of the adenosine receptor agonist, 5'-N-ethylcarboxamidoadenosine (NECA, 10 microM) or the soluble guanylyl cyclase activator, sodium nitroprusside (SNP, 100 microM) for [3H]-cyclic GMP accumulation. 4. ANP, BNP and CNP (all at 1 microM) failed to alter significantly either basal-, forskolin- (10 microM), isoprenaline- (100 microM), or NECA- (10 microM) induced [3H]-cyclic AMP generation. Natriuretic peptides also did not change the [3H]-cyclic AMP steady-state reached after 10 min of treatment with 10 microM forskolin. 5. Natriuretic peptides failed to elicit significant accumulation of [3H]-inositol phosphates at concentrations up to 10 microM. 6. These data are consistent with the presence of ANPA, rather than ANPB or clearance receptors (C-receptors), linked to second messenger cascades in guinea-pig cerebellar slices. 相似文献
96.
In order to study the possible regressive changes of left ventricular hypertrophy in treated hypertensive patients and to correlate them either with the drugs they received and/or the blood pressure reduction obtained, a long-term (6 years) echocardiographic follow-up study was performed in 61 patients. B and M mode echocardiographic septum and posterior wall thickness and left ventricular mass index were measured yearly and the type of ventricular hypertrophy, asymmetric septal or concentric (symmetric), were compared before and after the follow-up. Sixteen patients received only diuretics; 14, only propranolol, and associated therapy was used in the remaining 31 patients. Average blood pressure was significantly reduced in the whole group of patients, but, individually, 30 of them achieved normal levels for the diastolic (90 mmHg), remaining it over this value in the other, although all of them experienced an average reduction 10 mmHg with therapy. Those patients with concentric hypertrophy at entry showed a significant septal, posterior wall thickness and total ventricular mass reduction during the follow-up, those with initial asymmetric septal hypertrophy, a significant septal thickness and ventricular mass reduction, and those without hypertrophy on admission, showed an average paradoxical increase in septal thickness. We conclude that left ventricular hypertrophy disappeared or decreased in 48% of the patients and that treatment seems to prevent its progression or development in the 43% of all patients. The regressive or favorable changes were significantly more frequent among patients with normal blood pressure after treatment as well as among patients treated only with propranolol in comparison to those treated only with diuretics. 相似文献
97.
Mario González-Ulloa 《Aesthetic plastic surgery》1990,14(1):53-57
The author describes his surgical approach to the problems of the aging upper arm and elbow region. Surgery at an appropriate age can prevent the progressive wrinkling of the elbow which is further aggravated by aging of the upper arm. The author's operation is aimed at correcting both portions of the arm anatomy at the same time. 相似文献
98.
C Csonka G Gyurkó P Halász G Vekszler 《Magyar traumatológia, orthopaedia és helyreállító sebészet》1990,33(1):46-50
Authors report on arterial injuries in a 2-year material of hand injured. The combination of injuries observed and the methods of treatment are described. Attention is called to the fact, that because of anatomical characteristics of these regions, the diagnosis of arterial injuries is not always easy. Four cases of their own are briefly described in whom the arterial injury could be stated only at the development of complications (pulsating haematoma, false aneurysm, later bleeding). The importance of the primary careful treatment and the significance of the examination of the circulation (Allen's test, Doppler) are stressed. 相似文献
99.
T Juhás 《Ceskoslovenská oftalmologie》1990,46(5):367-370
Based on repeated fluoroangiographic examinations in a group of 28 children with type I diabetes mellitus the authors observed progressing diabetic retinal changes. At the end of the three-year observation period they found progress in 32% of the children. They investigated influence of risk factors such as age, duration of the basic disease, its metabolic compensation, sex and HLA typing on the development of diabetic retinopathy. 相似文献
100.
Study of the lens epithelial cell density in cataractous eyes operated on with extracapsular and intercapsular techniques 总被引:1,自引:0,他引:1
Epithelial cell counting was performed in 47 fragments from lens anterior capsules obtained during extracapsular and intercapsular surgery. Mean cell count was 3,277 cell/mm2; there was no correlation between cell number and age and no significant difference in cell counts between extracapsular and intercapsular surgery. There were, however, significant differences between advanced cataracts and the other cataract types (2,947 vs. 3,356). This may be important in explaining the differences in regenerative opacification of the posterior capsule in the different types of cataracts. 相似文献