全文获取类型
收费全文 | 27038篇 |
免费 | 1997篇 |
国内免费 | 66篇 |
专业分类
耳鼻咽喉 | 246篇 |
儿科学 | 798篇 |
妇产科学 | 553篇 |
基础医学 | 3312篇 |
口腔科学 | 404篇 |
临床医学 | 2678篇 |
内科学 | 5342篇 |
皮肤病学 | 722篇 |
神经病学 | 2379篇 |
特种医学 | 1046篇 |
外国民族医学 | 1篇 |
外科学 | 4121篇 |
综合类 | 420篇 |
一般理论 | 60篇 |
预防医学 | 2314篇 |
眼科学 | 860篇 |
药学 | 1819篇 |
中国医学 | 31篇 |
肿瘤学 | 1995篇 |
出版年
2022年 | 212篇 |
2021年 | 403篇 |
2020年 | 260篇 |
2019年 | 391篇 |
2018年 | 477篇 |
2017年 | 411篇 |
2016年 | 435篇 |
2015年 | 491篇 |
2014年 | 768篇 |
2013年 | 1088篇 |
2012年 | 1623篇 |
2011年 | 1672篇 |
2010年 | 954篇 |
2009年 | 848篇 |
2008年 | 1584篇 |
2007年 | 1621篇 |
2006年 | 1599篇 |
2005年 | 1652篇 |
2004年 | 1609篇 |
2003年 | 1505篇 |
2002年 | 1481篇 |
2001年 | 409篇 |
2000年 | 318篇 |
1999年 | 352篇 |
1998年 | 345篇 |
1997年 | 317篇 |
1996年 | 290篇 |
1995年 | 272篇 |
1994年 | 238篇 |
1993年 | 236篇 |
1992年 | 281篇 |
1991年 | 251篇 |
1990年 | 229篇 |
1989年 | 230篇 |
1988年 | 204篇 |
1987年 | 193篇 |
1986年 | 188篇 |
1985年 | 224篇 |
1984年 | 215篇 |
1983年 | 217篇 |
1982年 | 248篇 |
1981年 | 256篇 |
1980年 | 212篇 |
1979年 | 168篇 |
1978年 | 178篇 |
1977年 | 169篇 |
1976年 | 115篇 |
1975年 | 132篇 |
1974年 | 143篇 |
1973年 | 110篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
The gustatory and olfactory basis of learned alcohol aversions was examined by testing rats with either gustatory neocortex ablations, olfactory bulb ablations, or a combination of both ablations. In the first experiment operated rats were compared with control rats in the acquisition of a learned alcohol aversion. In the second experiment, the effect of ablations on preoperatively-learned alcohol aversions was examined. Rats lacking gustatory neocortex learned and retained alcohol aversions normally although these rats extinguished the aversions faster than normal rats. Olfactory bulb ablation alone failed to disrupt normal aversion learning but completely eliminated retention of a previously acquired aversion. Combination ablations produced severe deficits both in acquisition and retention of learned alcohol aversions. The results indicate that, besides having gustatory qualities, the odor quality of alcohol is important in determining the associative and memorial characteristics of alcohol. 相似文献
92.
Induction of islet cytodifferentiation by fetal mesenchyme in adult pancreatic ductal epithelium. 总被引:4,自引:0,他引:4
Recombinant tissue consisting of adult ductal epithelium isolated from pancreas and fetal mesenchyme was transplanted subcutaneously in the inguinal region of nude mice or epididymal fat pads of rats with a tissue chamber device for short-term (8-day) or long-term (6- to 12-wk) duration. We found that recombinant tissue underwent morphogenesis and cytodifferentiation, thereby forming islets that contained cells immunocytochemically positive for insulin and glucagon. Islet cytodifferentiation occurred in approximately 20% of the recombinants. In recombinants that developed into islets, the tissue was always in close association with an extracellular matrix, nerves, and blood vessels. Controls consisting of mesenchyme alone or duct epithelium alone showed no evidence of morphogenesis of cytodifferentiation. Pancreatic rudiments were also implanted to serve as positive controls. This is the first demonstration of islet cytodifferentiation from adult duct epithelium. 相似文献
93.
94.
95.
Lawrence G. Raisz MD 《Clinical reviews in bone and mineral metabolism》2006,4(2):123-127
Prostaglandins, particularly PGE2, have been shown to stimulate bone formation in a number of circumstances. Endogenous prostaglandins may be important in
heterotopic ossification and fracture healing. The major source of prostaglandins in bone is the inducible form of cyclooxygenase
(COX)-2 and inhibition of COX-2 may impair bone formation. Recent studies using selective agonists for the prostaglandin EP2
and EP4 receptors, which stimulate cAMP in bone cells, have suggested that these might be used clinically to accelerate bone
formation, particularly when used locally. 相似文献
96.
Dr. Joseph A. Kuhn MD Lawrence D. Wagman MD John A. Lorant MD Fredrick W. Grannis MD Mordecai Dunst MD William R. Dougherty MD Daniel I. Jacobs MD 《Annals of surgical oncology》1994,1(4):353-359
Background: A radical forequarter amputation with partial chest wall resection (one to four ribs) has been reported for benign and malignant
lesions involving the shoulder and chest wall region. Concerns about reconstruction and postoperative pulmonary function have
previously limited more extensive chest wall resections. The current report describes the first case in which a complete unilateral
anterior and posterior chest wall resection and pneumonectomy (hemithoracectomy) accompany a forequarter amputation. A novel
reconstructive technique used the full circumference of the forearm tissue with an intact ulna as a free osseomyocutaneous
flap.
Methods: In this case, a 21-year-old patient presented with an extensive recurrent desmoid tumor that involved the shoulder, brachial
plexus, subclavian vein, and chest wall from the lateral sternal border to the midportion of the scapula and down to the eighth
rib. The operative technique involved removal of the entire right hemithorax from the midline sternum to the transverse process
posteriorly, down to the ninth rib inferiorly. Due to the absence of a rigid hemithorax, the uninvolved ipsilateral lung was
also removed. The forearm flap was prepared before final separation of the specimen and division of the subclavian vessels.
Results: Postoperatively, the patient maintained excellent oxygenation without atelectasis or fever and was extubated on the 15th
postoperative day. As expected after pneumonectomy, significant decreases from preoperative to immediate postoperative values
were noted for the vital capacity (VC) (from 4.87 L to 1.29 L), forced 1-s expiratory volume (FEV1) (from 3.77 L to 1.02 L),
and inspiratory capacity (IC) (3.33 1 to 0.99 1). Rehabilitation included a specially designed external prosthesis to provide
cosmesis and prevent scoliosis. By the 15th postoperative week the patient had returned to normal social and physical activities,
with a gradual improvement in all respiratory parameters: VC 1.52 L, FEV1 1.29 L, IC 1.04 L. There has been no evidence of
tumor recurrence at 1 year.
Conclusions: This report provides evidence that a complete hemithoracectomy, pneumonectomy, and forequarter amputation can be safely performed
for selective tumors involving the shoulder region with extensive chest wall invasion. Reconstruction may be achieved with
an extended forearm osseomyocutaneous free flap with an excellent functional outcome.
Presented at the 46th Annual Cancer Symposium of The Society of Surgical Oncology, Los Angeles, California, March 18–21, 1993. 相似文献
97.
E. Eric Muirhead David H. P. Streeten Bennie Brooks Edward T. Schroeder Lawrence W. Byers 《Blood pressure》1992,1(3):138-148
A new syndrome is described in a patient with advanced renal insufficiency. This consists of severe and persistent hypotension causing weakness but associated with a clear mental status. Also present is evidence for decreased vascular reactivity. The hypotension was not orthostatic. The hypotension was associated with a circulating vasodepressor substance having the characteristics of medullipin I. The medullipin appears to have been derived from the remaining right kidney. Hypotension existed despite the presence of major prohypertensive mechanisms, including an endstage kidney, hyperreninemia and hyperaldosteronemia. It is likely that hypotension due to hypermedullipinemia is an entity occurring in the human being. 相似文献
98.
99.
100.
L G Arlian D L Vyszenski-Moher A T Lawrence K R Schrotel H L Ritz 《The Journal of allergy and clinical immunology》1992,89(4):866-876
The outer portions (husk) of psyllium seeds are a concentrated source of natural fiber used in some bulk-fiber laxatives and cereals. They are known to elicit respiratory allergic reactions after inhalation or ingestion among sensitized individuals. Antigenic and allergenic characterization of three psyllium-seed fractions (husk, endosperm, and embryo) was conducted with crossed immunoelectrophoresis (CIE), crossed radioimmunoelectrophoresis, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis to determine the source of psyllium allergenicity. Homologous CIE demonstrated psyllium endosperm and embryo extracts contained seven and four antigens, respectively. Husk extracts were too gelatinous to react by CIE. However, heterologous CIE profiles of endosperm or embryo extracts, reacted with antihusk antibodies, resulted in antigen-antibody precipitin peaks that matched the heavy staining precipitin lines of homologous reactions for endosperm and embryo, respectively. These results indicated that commercial-grade husk, endosperm, and embryo contained similar antigens. Extracts of all three seed components contained antigens that bound IgE antibodies in the sera of 11 psyllium RAST-positive individuals, as determined by crossed radioimmunoelectrophoresis. The few prominent husk protein/peptide bands resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were common in either embryo or endosperm. Immunoblots revealed common IgE reactive bands in all three seed fractions. Microscopic examination of the powdered commercial-grade psyllium (95% pure) revealed it contained endosperm and embryo particles. These immunologic, biochemical, and microscopic findings suggest that other contaminating seed components are primarily responsible for the allergenicity of commercial-grade psyllium-husk powder rather than the husk itself. 相似文献