首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   931972篇
  免费   66373篇
  国内免费   1342篇
耳鼻咽喉   12958篇
儿科学   24359篇
妇产科学   23232篇
基础医学   132895篇
口腔科学   28247篇
临床医学   80559篇
内科学   183286篇
皮肤病学   19242篇
神经病学   72187篇
特种医学   36807篇
外国民族医学   79篇
外科学   152133篇
综合类   18042篇
现状与发展   1篇
一般理论   234篇
预防医学   61738篇
眼科学   21316篇
药学   72562篇
  3篇
中国医学   2163篇
肿瘤学   57644篇
  2018年   8967篇
  2017年   7031篇
  2016年   7762篇
  2015年   8878篇
  2014年   11989篇
  2013年   17500篇
  2012年   24091篇
  2011年   25049篇
  2010年   14820篇
  2009年   14270篇
  2008年   24609篇
  2007年   25694篇
  2006年   26485篇
  2005年   25428篇
  2004年   24561篇
  2003年   23608篇
  2002年   23154篇
  2001年   54726篇
  2000年   56544篇
  1999年   46951篇
  1998年   10730篇
  1997年   9464篇
  1996年   9594篇
  1995年   8926篇
  1994年   8280篇
  1993年   7594篇
  1992年   35491篇
  1991年   33917篇
  1990年   32735篇
  1989年   31870篇
  1988年   28994篇
  1987年   28253篇
  1986年   26290篇
  1985年   25145篇
  1984年   17835篇
  1983年   15142篇
  1982年   7797篇
  1981年   6773篇
  1979年   15782篇
  1978年   10599篇
  1977年   9052篇
  1976年   7871篇
  1975年   8628篇
  1974年   10466篇
  1973年   9858篇
  1972年   9357篇
  1971年   8853篇
  1970年   8427篇
  1969年   7924篇
  1968年   7200篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Immunoblotting of streptococcal antigens in guttate psoriasis   总被引:6,自引:0,他引:6  
Guttate psoriasis may be precipitated by acute streptococcal infection, usually of the upper respiratory tract. We have studied the immune response to streptococci in 26 patients presenting with a first or recurrent episode of acute guttate psoriasis (AGP), using immunoblotting. Eighteen of 26 patients studied had a demonstrable response to a wide range of streptococcal antigens using this approach, compared with 14 of 26 patients who demonstrated a response using more conventional anti-streptococcal antibody tests. Patients with AGP had a significantly higher antibody detection score using immunoblotting than did control subjects (P<0.005). We conclude that immunoblotting is a useful technique in studying this condition and may be of benefit in exploring the immunopathogene-sis of AGP.  相似文献   
992.
Trazodone hydrochloride is an oral antidepressant agent which has been associated with the improvement of erections in impotent men and the development of prolonged erections or priapism in potent men. An in vivo study in animal and human subjects was performed to gain experience with the effect of intracavernosal trazodone. In the anesthetized New Zealand White rabbit, intracavernosal trazodone or its major metabolite m-chlorophenylpiperazine (m-CPP) produced full penile erection in 76% and 84% of animals studied respectively with doses ranging from one to 15 mg. On the other hand, intracavernosal administration of five mg. papaverine resulted in a prolonged erection in 90% of animals studied. In 13 selected volunteer patients, intracavernosal trazodone caused tumescence but not full penile erection with corporal body pressures of 28.2 +/- 5.8 mm. Hg. Intracavernosal papaverine or papaverine and phentolamine in these subjects resulted in significantly higher corporal body pressures of 58 +/- 18 mm. Hg (p less than .05). Intracavernosal administration of alpha adrenoceptor agonists but not normal saline resulted in complete detumescence of trazodone- or m-CPP-induced prolonged erection in the animal studies. Intracavernosal trazodone results in erectile activity that appears in part based on its local alpha blocking activity but like other intracavernosal alpha-blocking agents is not as effective in initiating penile erections as are intracavernosal agents that directly induce smooth muscle relaxation.  相似文献   
993.
On the basis of analysis of surgical treatment of 753 patients with coxarthrosis during 1970-1987, the authors set forth the stages of arthroplasty development in the USSR, using the experience of the Kharkov research institute of orthopaedics and traumatology named after M. I. Sitenko on the problems of arthrodesis operations, endoprosthetics and biological arthroplasty. In the article are presented the peculiar features of diagnostic and surgical tactics in case of patients with idiopathic and dysplastic coxarthrosis; operation technique for each form is presented in details. The authors have developed a new perosseous access to the hip joint, which made a good showing and permits to preserve the integrity of periarticular muscles and neurovascular formations. Application of the given access made possible the extension of indications for arthroplasty in case of grave forms of coxarthrosis, met earlier in a reserved manner.  相似文献   
994.
995.
A 10-month-old child with achondroplasia with progressive head enlargement, ventriculomegaly, and wide subarachnoid spaces over the hemispheres was referred for evaluation. A steady-state lumbar infusion test revealed increased cerebrospinal fluid (CSF) outflow resistance (14 mm Hg/ml/min), and intra-arterial digital subtraction angiography (DSA) demonstrated bilateral venous outflow obstruction due to stenosis of the jugular foramen. Surgical decompression by opening the right jugular foramen relieved the clinical signs of intracranial hypertension. During the following year, the patient's head enlargement was moderate with relative normalization of size. Repeat DSA demonstrated improved venous runoff on the right side, and a steady-state lumbar infusion test demonstrated reduced CSF outflow resistance (10 mm Hg/ml/min). Venous decompression is causal therapy and may prove to be preferable to shunting in children with hydrocephalus and bilateral stenosis of the jugular foramen.  相似文献   
996.
997.
998.
Because of the lack of adequate strength and toughness, hydroxyapatite (HA) ceramic can not be used for a substitute for a bone and joint despite its excellent affinity for the bone. The present authors have succeeded in producing a new type of HA ceramic containing zirconia. This new ceramic material is superior to ordinary HA ceramic in quality and exceeds compact bone in bending strength and fracture toughness. The Young's modulus was about 3-4 times greater than that of compact bone. The new ceramic material contained either 1.6 or 50% of zirconia by volume and was produced using a special technique to disperse the metal dioxide. In order to assess their affinity for the bone, the new ceramic materials were implanted into rabbit femurs. Sections of the bones removed at different times after operation were prepared without decalcification and subjected to optical microscopy, scanning electronmicroscopy (SEM), and electron-probe X-ray microanalyser (EPMA). The formation of direct chemical bonds with the bone was seen without intervening membrane. Thus, the new ceramic material was shown to have an excellent affinity for the bone, comparable to that of ordinary HA ceramic.  相似文献   
999.
A case of Beh?et disease associated with aortic valve regurgitation treated with aortic valve replacement is reported. The patient was treated successfully with special surgical techniques for prevention of post operative paravalvular leakage and occurrence of pseudo aneurysm because the patient was under long-term steroid therapy for Beh?et disease.  相似文献   
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号