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   3175篇
  免费   201篇
  国内免费   27篇
耳鼻咽喉   23篇
儿科学   163篇
妇产科学   142篇
基础医学   312篇
口腔科学   72篇
临床医学   394篇
内科学   453篇
皮肤病学   76篇
神经病学   261篇
特种医学   225篇
外科学   341篇
综合类   156篇
一般理论   1篇
预防医学   267篇
眼科学   34篇
药学   211篇
中国医学   16篇
肿瘤学   256篇
  2022年   17篇
  2021年   42篇
  2020年   32篇
  2019年   36篇
  2018年   44篇
  2017年   48篇
  2016年   44篇
  2015年   52篇
  2014年   65篇
  2013年   145篇
  2012年   138篇
  2011年   126篇
  2010年   96篇
  2009年   83篇
  2008年   123篇
  2007年   146篇
  2006年   128篇
  2005年   129篇
  2004年   109篇
  2003年   117篇
  2002年   102篇
  2001年   102篇
  2000年   104篇
  1999年   100篇
  1998年   73篇
  1997年   69篇
  1996年   55篇
  1995年   36篇
  1994年   48篇
  1993年   51篇
  1992年   55篇
  1991年   61篇
  1990年   69篇
  1989年   96篇
  1988年   79篇
  1987年   57篇
  1986年   54篇
  1985年   42篇
  1984年   31篇
  1983年   22篇
  1982年   18篇
  1981年   24篇
  1980年   19篇
  1979年   16篇
  1978年   16篇
  1975年   21篇
  1970年   15篇
  1969年   14篇
  1968年   14篇
  1967年   16篇
排序方式: 共有3403条查询结果,搜索用时 31 毫秒
1.
Twenty two patients (age range: 1 month to 11 years) were treated for congenital diaphragmatic defects (excluding hiatus hernia) in the six year period 1983-8. Presenting features were failure to thrive (n = 7), abdominal pain and vomiting (n = 4), chronic respiratory symptoms (n = 3), and inability to wean from ventilatory support (n = 3). The defect was an incidental finding in five patients. Operative repair was performed with no mortality or serious postoperative morbidity. Dramatic improvement occurred in 15 of the 17 symptomatic patients. Awareness of the differential diagnosis should avoid delay in diagnosis or inappropriate treatment. Surgical correction is strongly recommended in all cases.  相似文献   
2.
Five infants with biopsy proved juvenile xanthogranuloma of the iris were reviewed. Early treatment with subconjunctival injection of steroids and topical steroid drops resulted in regression of the lesion in four patients. One patient, reviewed at the age of 8 months after glaucoma which had developed secondary to the iris xanthogranuloma, had been treated by surgery alone: the visual outcome was very poor.  相似文献   
3.
Background. Extensive questioning of patients with a wide variety of skin disorders led to the impression that nocturnal overheating was probably an important factor in the initiation and the perpetuation of many skin disorders. Methods. In order to test the hypothesis, 12 “clean-skinned” subjects (6M/6F) aged 18 to 45 years were monitored electronically every 30 seconds during an 8 hour sleep period (2300 to 0700 hours), sleeping under a standard 10 tog duvet. Results. All the subjects were too hot by 3 to 4°C. All showed changes in their EEG patterns with reduced REM sleep, increased awakenings, and all showed changes in their sleep stage patterns. In addition, they all showed evidence of increased sweating in the “heat-sink” area. Conclusions. The mechanisms where by such changes could be implicated in the precipitation and perpetuation of skin disease are discussed. “Lifestyle” modification as a very effective, noninvasive, therapeutic regime is recommended. Further research along these lines would probably be very valuable and instructive.  相似文献   
4.
Experience with the P.A.S.-PORT, a peripherally implanted central venous access device, is evaluated in a retrospective review of 154 patients from July 1991 to June 1994. Blood could not be aspirated from six patients. Complications included temporary minor thrombophlebitis in seven patients (4.5%), symptomatic axillary or subclavian vein thrombosis in five patients (3.2%), clotted port in two patients (1.2%), port pocket cellulitis in two patients (1.2%), and fungal sepsis in two patients (1.2%). In six patients (3.8%) the P.A.S.-PORT had to be removed because of complications. The P.A.S.-PORT facilitated delivery of chemotherapy, parenteral nutrition, blood products, antibiotics, hydration, and blood sampling. It was demonstrated that the P.A.S.-PORT may be inserted and used with a low incidence of complications in gynecologic cancer patients.  相似文献   
5.
Renal angiomyolipoma: 6 case reports and literature review   总被引:4,自引:0,他引:4  
We report 6 cases of renal angiomyolipomas and review the pertinent literature concerning this disease. One case involved the rare association of tuberous sclerosis and pregnancy. Another patient without tuberous sclerosis had renal cell carcinoma and later suffered a contralateral angiomyolipoma. The pathological conditions of renal angiomyolipomas with and without tuberous sclerosis are discussed. Since angiomyolipomas present with multiple clinical similarities to renal cell carcinoma, the primary task for the clinician is to differentiate this hamartoma from carcinoma. The distinguishing characteristics and the clinical management of renal angiomyolipomas are discussed.  相似文献   
6.
Human peripheral mononuclear cells responded chemotactically to 4-carboxyl-L-glutamic acid. The maximal chemotactic response occurred at 0.1 nM. No chemotactic response was found with neutrophils or fetal bovine fibroblasts. Glutamic acid, a neuroexcitatory dicarboxylic amino acid and the parent compound of 4-carboxyglutamic acid, did not stimulate chemotaxis in any of the cells tested. However, it functioned as an antagonist to 4-carboxyglutamic acid (ED50 approximately 2 pM; ED100 approximately 10 pM). In contrast to the lack of response to glutamic acid, its dicarboxylic cyclic analogue, kainic acid, excited a chemotactic response in mononuclear cells. The data suggest that mononuclear phagocytes have receptors for dicarboxylic neuroexcitatory amino acids, and we speculate that 4-carboxyglutamic acid, a tricarboxylic acid, may have a previously unrecognized role as a neuroexcitatory amino acid.  相似文献   
7.
This paper presents a mathematical model of in-mouth volatile release from gelled emulsion particles dispersed in a continuous aqueous phase. Data based on APCI MS-Breath analysis is presented to demonstrate the effect of particle size, oil content and oil-water partition coefficients. It is shown that in-mouth release of aroma from the dispersion of gelled emulsion particles follows a two-component kinetic equation with fast and slow components. Both the fast and slow rate constants depend on the particle size, oil content and oil water partition coefficient of the aroma. The relative amount of aroma contributing to the fast and slow components also depends on the size of the particles. In order to understand this unexpected behaviour, an analytical model was developed that considers the interplay between the mass transfer of flavour across the interface of the particles and that across the air-liquid interface. Analytical expressions for the two rate constants and the relative ratio of aroma contributing to the fast component have been derived. From this model, three regimes of in-mouth release of aroma from the dispersion of gelled emulsion particles were identified including, the emulsion regime, the transition regime and the gel particle regime. In the emulsion regime, changes in the size of gelled emulsion particles had negligible impact on the overall release. In the transition regime, the release was controlled by the interaction of flavour transfer from the particles with that across the air-water interface. In the gel particle regime, aroma release at long times was governed by the particles and that at short times was governed by the air-water interface, and the two processes were fully decoupled. A simple relationship was derived for the critical size above which the release of aroma from the dispersion of gelled emulsion particles is affected by the size of the particles.  相似文献   
8.
9.
Traumatic pseudoaneurysms of the superior mesenteric artery (SMA) are extremely rare. We describe two cases of posttraumatic proximal SMA pseudoaneurysms with symptoms of gastric outlet obstruction. Repair was accomplished by aorta-SMA bypass with saphenous vein. Injuries to the proximal SMA are easily missed at laparotomy, especially if intestinal ischemia or hematomas are absent. Recognition and repair are stressed to avoid the complications associated with pseudoaneurysm formation.  相似文献   
10.
Ten thrombocytopenic patients (platelets < 10–24 × 10(9)/L) who were refractory to platelet transfusion were investigated for their responsiveness to staphylococcal protein A column therapy. Nine patients had previously been treated with steroids, intravenous immune globulin, and/or other forms of immunosuppressive therapy without improvement in their transfusion response. All patients were receiving multiple platelet transfusions without achieving 1-hour corrected count increments (CCIs) > or = 7500. Eight patients had antibodies that reacted with platelets and were directed against HLA class I antigens, ABO antigens, and/or platelet-specific alloantigens. Plasma (500-2000 mL) from each patient was passed over a protein A silica gel column and then returned to the patient. Patients received from 1 to 14 treatments. A positive response to protein A therapy was defined as at least a doubling of the pretreatment platelet count and/or two successive 10- to 120-minute posttransfusion CCIs > or = 7500. Following plasma treatments, 6 of 10 patients responded with daily platelet counts that averaged 48 +/− 11 × 10(9) per L as compared with counts of 16 +/− 7 × 10(9) per L (p < 0.0005) before treatment. Posttransfusion CCI values determined in four of these patients averaged 2480 +/− 810 and 10,010 +/− 3540 (p < 0.005) before and after treatment, respectively. In contrast, among the four unresponsive patients, platelet counts averaged 10 +/− 9 and 13 +/− 10 × 10(9) per L (p = NS), respectively, while posttransfusion CCIs were 700 +/− 1410 and 1520 +/− 2460 (p = NS), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
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