全文获取类型
收费全文 | 3885篇 |
免费 | 234篇 |
国内免费 | 132篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 33篇 |
妇产科学 | 44篇 |
基础医学 | 321篇 |
口腔科学 | 1篇 |
临床医学 | 416篇 |
内科学 | 913篇 |
皮肤病学 | 2篇 |
神经病学 | 83篇 |
特种医学 | 102篇 |
外国民族医学 | 2篇 |
外科学 | 781篇 |
综合类 | 622篇 |
预防医学 | 75篇 |
眼科学 | 5篇 |
药学 | 320篇 |
4篇 | |
中国医学 | 182篇 |
肿瘤学 | 341篇 |
出版年
2023年 | 34篇 |
2022年 | 86篇 |
2021年 | 122篇 |
2020年 | 112篇 |
2019年 | 102篇 |
2018年 | 87篇 |
2017年 | 89篇 |
2016年 | 116篇 |
2015年 | 121篇 |
2014年 | 191篇 |
2013年 | 185篇 |
2012年 | 174篇 |
2011年 | 205篇 |
2010年 | 168篇 |
2009年 | 168篇 |
2008年 | 173篇 |
2007年 | 164篇 |
2006年 | 176篇 |
2005年 | 182篇 |
2004年 | 166篇 |
2003年 | 148篇 |
2002年 | 132篇 |
2001年 | 107篇 |
2000年 | 105篇 |
1999年 | 92篇 |
1998年 | 75篇 |
1997年 | 64篇 |
1996年 | 95篇 |
1995年 | 75篇 |
1994年 | 76篇 |
1993年 | 57篇 |
1992年 | 45篇 |
1991年 | 43篇 |
1990年 | 47篇 |
1989年 | 32篇 |
1988年 | 36篇 |
1987年 | 31篇 |
1986年 | 20篇 |
1985年 | 18篇 |
1984年 | 23篇 |
1983年 | 9篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 12篇 |
1979年 | 17篇 |
1977年 | 5篇 |
1976年 | 6篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1972年 | 4篇 |
排序方式: 共有4251条查询结果,搜索用时 15 毫秒
41.
42.
Tadashi Terada 《Pathology international》2008,58(12):806-809
Carcinoma arising from Rokitansky–Aschoff sinus (RAS) is extremely rare; only eight cases have been reported in the literature. Herein is reported a case of minute adenocarcinoma arising in RAS. A 77‐year‐old Japanese man with gallbladder stones underwent cholecystectomy. A tiny submucosal tumor (1 cm × 1 cm) was incidentally recognized. Histologically, the submucosal tumor was located in the subserosa and, to a lesser extent, in the fibromuscular layer. It was adenocarcinoma. RAS were recognized within the tumor, and there was a gradual transition between RAS and the adenocarcinoma. Mucin histochemistry indicated neutral and acidic mucins in the cytoplasm and lumens of the adenocarcinoma cells. Immunohistochemistry showed that the adenocarcinoma cells were positive for cytokeratin, epithelial membrane antigen, carbohydrate antigen 19‐9, K‐i67 (labeling = 80%), MUC1, MUC5AC and MUC6. In contrast, the adenocarcinoma cells were negative for CEA, c‐erbB2, p53 protein, MUC2 and CD10. In summary, minute subserosal adenocarcinoma, which arose in RAS, was found incidentally; therefore careful examination of resected gallbladders is necessary. 相似文献
43.
Cystic duct and Heister's "valves" 总被引:2,自引:0,他引:2
The anatomy and physiology of the cystic duct have been relatively neglected by anatomists and the function of the spiral mucosal folds or "valves" of Heister, first described in 1732, remains obscure. The gross and microscopic anatomy of the cystic duct is reviewed together with results from laboratory investigations into the function of the cystic duct and its spirally arranged folds. The duct and spiral folds contain muscle fibers responsive to pharmacologic, hormonal, and neural stimuli. There is, however, no convincing evidence of a discrete muscular sphincter within the duct. Although the cystic duct is unlikely to play a major role in gallbladder filling and emptying, it appears to function as more than a passive conduit. Coordinated, graded muscular activity in the cystic duct in response to hormonal and neural stimuli may facilitate gallbladder emptying. The principal function of the internal spiral folds that are found in man and other animals may be to preserve patency of this narrow, tortuous tube rather than to regulate bile flow. 相似文献
44.
Optimizing the embryo transfer technique 总被引:7,自引:0,他引:7
The technique of embryo transfer is very crucial and great attention and time should be given to this step. In order to optimize the embryo transfer technique, several precautions should be taken. The first and most important is to avoid the initiation of uterine contractility. This can be achieved by the use of soft catheters, gentle manipulation and by avoiding touching the fundus. Secondly, proper evaluation of the uterine cavity and utero-cervical angulation is very important, and can be achieved by performing dummy embryo transfer and by ultrasound evaluation of the utero-cervical angulation and uterine cavity length. Another important step is the removal of cervical mucus so that it does not stick to the catheter and inadvertently remove the embryo during catheter withdrawal. Finally, one has to be absolutely sure that the embryo transfer catheter has passed the internal cervical os and that the embryos are delivered gently inside the uterine cavity. 相似文献
45.
The goal of this study was to investigate whether cruzipain, a Trypanosoma cruzi immunodominant antigen, was able to induce antibodies reactive to the cardiac M(2) muscarinic acetylcholine receptor (M(2) mAChR). Immunization with cruzipain that was devoid of enzyme activity triggered IgG antibodies against cardiac M(2) mAChR. By radioligand competition assay we proved that the anti-cruzipain IgG fraction, purified from serum, inhibited binding of the specific M(2) mAChR radioligand [(3)H]quinuclidinyl benzilate. We also demonstrated that anti-cruzipain IgG reacted against the second extracellular loop of the M(2) mAChR. The corresponding affinity-purified serum anti-M(2)e2 IgG (reacting against a synthetic peptide corresponding to this loop in humans) displayed agonist-like activity associated with specific M(2) mAChR activation - increase of cGMP, inositol phosphate accumulation and nitric oxide synthase activity - triggering a decrease in myocardial contractility. Moreover, the same IgG fraction decreased heart frequency, related to inhibition of adenylate cyclase activity. These results imply that cruzipain plays a role in the production of antibodies against M(2) mAChR, which have been related to the pathogenesis of dysautonomic syndrome described in Chagas' disease. 相似文献
46.
目的 探讨原发性胆囊癌的CT诊断与鉴别诊断要点。方法 回顾性分析23例原发性胆囊癌CT征象,并与手术和病理对照。结果 本组23例胆囊癌术前CT正确诊断18例,5例误诊,根据CT表现可分为:腔内型8例、厚壁型5例、肿块型10例;其中共8例并肝门和腹膜后淋巴结转移;3例肝内转移;病理结果:腺癌20例,鳞癌3例。结论 原发性胆囊癌CT的诊断价值较高,但仍容易误诊,早期的诊断仍有一定困难,掌握其CT征象,注意鉴别诊断可以提高本病的诊断水平。 相似文献
47.
Inger B. Schipper Paul Steendijk Robert J. M. Klautz Enno T. van der Velde Jan Baan 《Pflügers Archiv : European journal of physiology》1993,425(5-6):426-433
It has been shown that in the intact canine heart the left-ventricular end-systolic pressure/volume relation (ESPVR) depends on loading conditions: an increase in arterial vascular resistance causes a leftwards shift and a steeper slope of the ESPVR, suggesting an increased inotropic state. Our purpose was to investigate the possible contribution of the sympathetic nervous system to this load sensitivity of the ESPVR, using intact, but denervated, hearts with normal coronary perfusion and afterload. We used two types of loading intervention: venous volume infusion and gradual occlusion of the descending aorta. ESPVRs were obtained in six anaesthetized open-chest dogs, both before and after bilateral ablation of the stellate ganglia. To exclude the influence of heart rate changes, bilateral vagotomy was performed and the heart was paced. The absence of (unpaced) heart rate changes in response to pressure alterations was used to confirm total denervation. Left ventricular pressure was measured with a micromanometer and volume with a conductance catheter. ESPVRs were essentially linear and characterized by their slope (E
es) and volume intercept at 12 kPa (V
12). We found that E
es (P<0.0001) and V12 (P<0.05) were both significantly different during pressure and volume interventions (0.67±0.29 and 0.41±0.18 kPa/ml for E
es and 16.2±8.2 and 18.2±8.4ml for V12 respectively). Denervation did not significantly affect the parameters of the ESPVR obtained by either volume infusion or aortic occlusion. Two-way analysis of variance revealed no significant interactive effect between denervation and intervention, indicating that the sympathetic nervous system does not influence the load dependency of the ESPVR. The dP/dt
max: EDV relationship behaved similarly. These results suggest that load dependency is an intrinsic property of the myocardium. 相似文献
48.
Tkachenko BI Evlakhov VI Poyasov IZ 《Bulletin of experimental biology and medicine》2003,136(3):213-215
Experiments on cats treated with nitroglycerin showed dynamic relationship between changes in caval venous flows: blood flow increased in the superior vena cava and decreased in the inferior vena cava. Blood pressure in the right atrium either decreased, or increased. No significant changes in total venous return were observed during maximum shifts in right atrial pressure, while contractility of the right ventricular myocardium usually decreased. Our findings suggest that the direction of the right atrial pressure shifts induced by nitroglycerin does not depend on venous return, but is determined by the prevalence of flow changes in the superior vena cava or inferior vena cava. 相似文献
49.
50.
Markus M. Nthen Gisela Knpfle Hans-Jrg Fdisch Klaus Zerres 《American journal of medical genetics. Part A》1993,46(4):467-470
We report on a fetus with alobar holoprosencephaly, microphthalmia, midline cleft lip and palate, absent nose, dysplastic ears, radial defects, pentalogy of Fallot, unilateral renal aplasia, absent gallbladder, vertebral anomalies, and absence of ribs. The father had a cleft palate, bilateral colobomas of the iris and retina, a bifid uvula, vertebral anomalies, and unilateral congential hearing loss. His sister had a cleft lip. On the basis of this family and the family reported by Steinfeld [1982], this malformation syndrome can be defined as a rare autosomal dominant syndrome whose main component manifestations are holoprosencephaly, predominantly radial limb deficiency, heart defects, kidney malformations, absence of gallbladder, and vertebral anomalies. © 1993 Wiley-Liss, Inc. 相似文献