全文获取类型
收费全文 | 414篇 |
免费 | 22篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 20篇 |
妇产科学 | 5篇 |
基础医学 | 39篇 |
口腔科学 | 7篇 |
临床医学 | 71篇 |
内科学 | 103篇 |
皮肤病学 | 2篇 |
神经病学 | 18篇 |
特种医学 | 55篇 |
外科学 | 24篇 |
综合类 | 11篇 |
预防医学 | 37篇 |
眼科学 | 3篇 |
药学 | 36篇 |
肿瘤学 | 8篇 |
出版年
2022年 | 4篇 |
2021年 | 8篇 |
2019年 | 5篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 13篇 |
2013年 | 14篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 11篇 |
2009年 | 6篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 19篇 |
2004年 | 8篇 |
2003年 | 10篇 |
2002年 | 7篇 |
2001年 | 7篇 |
1999年 | 10篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 19篇 |
1992年 | 15篇 |
1991年 | 20篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 3篇 |
1969年 | 6篇 |
1968年 | 3篇 |
1962年 | 2篇 |
排序方式: 共有440条查询结果,搜索用时 15 毫秒
1.
B F Gilchrist T E Lobe K P Schropp G A Kay S D Hixson E L Wrenn P G Philippe R S Hollabaugh 《Journal of pediatric surgery》1992,27(2):209-12; discussion 212-4
Although laparoscopic procedures are currently in vogue in general surgery, the role of this approach in children has not been prospectively evaluated in the United States using the new instrumentation now available to us. To assess the value of laparoscopic appendectomy (LA) in childhood, we prospectively compared 14 LAs with 50 open appendectomies (OA) over 6 months in a single children's hospital. Antibiotic usage was at the discretion of the surgeon regardless of the procedure performed and was not different between groups. LA was performed under the direction of a single laparoscopy-trained surgeon and patient selection was based on parental consent. A three-puncture LA technique was used; children from this group were allowed to return to full activities as soon as they were comfortable. There were no significant differences between groups for severity of disease, age, weight, hospital cost, or complications. The types of complications that developed were comparable in both groups. The percent of complicated appendicitis (gangrene or perforation) was 32% in the OA group and 36% in the LA group. Patients in the LA group spent significantly fewer days in the hospital and returned to unrestricted activities (school, athletics, etc) faster than patients in the OA group. LA is approximately $1,000 more expensive than OA, the differences being easily explainable by the cost of the disposable supplies necessary for the procedure (laser fibers, trocars, etc), but because of the shorter hospital stay in the LA group the mean total cost for each group was comparable. These data suggest that although there appears to be no cost advantage, LA shortens the hospital stay and allows children to return to unrestricted activity sooner than OA.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
2.
3.
4.
Image-directed percutaneous biopsies with a biopsy gun 总被引:3,自引:0,他引:3
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method. 相似文献
5.
6.
Evaluation of COBAS AMPLICOR (Roche): accuracy in detection of Chlamydia trachomatis and Neisseria gonorrhoeae by coamplification of endocervical specimens 总被引:5,自引:0,他引:5
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We evaluated further the accuracy of the COBAS AMPLICOR (Roche) (CA) PCR-based system in detection of Chlamydia trachomatis and Neisseria gonorrhoeae in endocervical specimens. Endocervical specimens collected for any indication for testing for C. trachomatis and N. gonorrhoeae among a university hospital health system population were included. Testing for C. trachomatis was done by two PCR methods, CA and manual microwell AMPLICOR (Roche) (MWA), and by culture; testing for N. gonorrhoeae was done by CA and culture. Discrepancy resolution was performed. Reproducibility testing and hands-on labor time measurements for CA were done. Among 654 C. trachomatis samples, the prevalence of true positivity was 9.2%, and among the 618 N. gonorrhoeae samples, the prevalence of true positivity was 4.4%. For detection of C. trachomatis, the sensitivity, specificity, and negative and positive predictive values were, respectively, as follows for each test: CA, 93.3, 99.7, 99.3, and 96.4%; MWA, 91.7, 99.7, 99.2, and 96.5%; and culture, 65.0, 100, 96.6, and 100%. For detection of N. gonorrhoeae those values were as follows: CA, 96.3, 100, 99.8, and 100%; and culture, 92.6, 100, 99.7, and 100%. Hands-on labor time for each clinical result was estimated to be at 7.5 min. The prevalence of inhibitory specimens was 3.5%, including two positive C. trachomatis samples which would have been missed otherwise. The direct cost of each clinical result with CA was estimated to be $9.09. Our methods include a diverse range of indications for testing among women, using endocervical swabbing samples, 2 M sucrose phosphate transport medium, and discrepancy resolution for comparison. Under our test conditions, the CA system is an accurate, rapid, and cost- and labor-efficient method for detection of C. trachomatis and N. gonorrhoeae. 相似文献
7.
8.
Naturally soluble rat germ cell adenylate cyclase was inhibited by adenosine and the adenosine analogs, 9-beta-D-arabinofuranosyl adenine (AFA) and 2',5'-dideoxyadenosine (DDA), all of which inhibited hormone-sensitive adenylate cyclases at the "P" site. The IC50 values for adenosine and DDA were approximately 0.1 and for AFA, 4.0 mM. The onset of adenosine inhibition was very rapid whether adenosine was added to the enzyme reactant mixture at time zero concomitantly with the addition of substrate or after the enzyme had been activated by the addition of substrate. The adenosine analogs, N6-methyladenosine (MeA) and N6-phenylisopropyl adenosine (PIA), which interact with plasma membrane receptors ("R" receptors) for hormone-sensitive adenylate cyclase, had little effect on the activity of the cytosolic adenylate cyclase. Additionally, aminophylline, which has been shown to competitively antagonize adenosine interactions with the plasma membrane "R" receptors but not "P" site interactions, had no effect upon substrate activation of the soluble enzyme and did not prevent adenosine from inhibiting the activity of the enzyme. These data provide evidence for an adenosine regulatory site on the cytosolic enzyme which resembles the "P" site described for membrane bound-adenylate cyclase. 相似文献
9.
Fecal impaction 总被引:3,自引:0,他引:3
K Wrenn 《The New England journal of medicine》1989,321(10):658-662
Fecal impaction is a common disorder with variable presentation and many potential complications. Its pathophysiology is complex, and the treatment is often difficult and frustrating. Preventive measures are likely to be cost effective in populations at high risk, such as institutionalized or debilitated elderly people, mentally ill patients, those with chronic renal failure or cancer, and those who are neurologically impaired. 相似文献
10.
Osteosarcomatosis 总被引:10,自引:0,他引:10
Hopper KD; Moser RP Jr; Haseman DB; Sweet DE; Madewell JE; Kransdorf MJ 《Radiology》1990,175(1):233-239
A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized. 相似文献