全文获取类型
收费全文 | 646篇 |
免费 | 51篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 15篇 |
妇产科学 | 40篇 |
基础医学 | 74篇 |
口腔科学 | 1篇 |
临床医学 | 59篇 |
内科学 | 157篇 |
皮肤病学 | 5篇 |
神经病学 | 37篇 |
特种医学 | 16篇 |
外科学 | 61篇 |
综合类 | 14篇 |
预防医学 | 87篇 |
眼科学 | 37篇 |
药学 | 53篇 |
肿瘤学 | 40篇 |
出版年
2022年 | 5篇 |
2021年 | 7篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 25篇 |
2012年 | 26篇 |
2011年 | 33篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 28篇 |
2007年 | 32篇 |
2006年 | 38篇 |
2005年 | 24篇 |
2004年 | 18篇 |
2003年 | 28篇 |
2002年 | 18篇 |
2001年 | 20篇 |
2000年 | 25篇 |
1999年 | 21篇 |
1998年 | 7篇 |
1996年 | 7篇 |
1995年 | 8篇 |
1994年 | 12篇 |
1993年 | 7篇 |
1992年 | 10篇 |
1991年 | 16篇 |
1990年 | 8篇 |
1989年 | 18篇 |
1988年 | 13篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1975年 | 5篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 9篇 |
1970年 | 6篇 |
1969年 | 5篇 |
1968年 | 4篇 |
1962年 | 5篇 |
1924年 | 6篇 |
1923年 | 4篇 |
1919年 | 5篇 |
排序方式: 共有697条查询结果,搜索用时 11 毫秒
1.
Benjamin Clapp Melba Jarmillo Valeria Vigil Luis Macias Marcia Bouton Cuatemoc Gallardo Andrew Kassir 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2007,11(2):242-245
BACKGROUND AND OBJECTIVES: The purpose of this study was to determine patient recall and comprehension after laparoscopic appendectomy in an underserved population. Laparoscopic surgery can lead to diagnostic uncertainty secondary to poor recall and variable port placement. METHODS: After institutional review board approval, we identified a cohort of patients who underwent laparoscopic appendectomy from 2000 to 2004 at a single institution. We then attempted to contact the patients to conduct a 10-question telephone survey, which determined whether the patient spoke English or Spanish as a primary language, ethnicity, educational level, and questions about recall of perioperative events and diagnoses. If we could not reach the patient, we tried to call back on 2 different occasions. RESULTS: Between 2000 and 2004, 186 patients underwent laparoscopic appendectomy. Of these, 65% were Hispanic. We found that only 17% of these patients returned for a postoperative visit. Only 19.3% could be contacted by phone. Forty-seven percent of the patients contacted by phone spoke Spanish exclusively. Overall 92% of patients contacted knew what operation they had, and gave their correct diagnosis. CONCLUSIONS: The low percentage of patients available to follow-up makes this study statistically insignificant. However, we believe that fact in itself is important. In Southwestern states, we see a large migrant population. This highlights the need to communicate effectively with the patients at the time of surgery, which we speculate we did based on the percentage of patients that knew their diagnosis. 相似文献
2.
Magnetic resonance imaging and clinical correlates of intellectual impairment in myotonic dystrophy 总被引:4,自引:0,他引:4
S J Huber J T Kissel E C Shuttleworth D W Chakeres L E Clapp M A Brogan 《Archives of neurology》1989,46(5):536-540
Although intellectual impairment is common in patients with myotonic dystrophy, this aspect of the disease has received relatively little research attention. We examined 41 patients with myotonic dystrophy using objective neuropsychological procedures and magnetic resonance imaging. Ten patients (24%) had severe and generalized intellectual dysfunction, while lesser or no cognitive impairment characterized the remaining patients. Degree of intellectual impairment was not related to neuromuscular status or sex. Patients with severe intellectual disturbance had significantly earlier onset of both myotonia and weakness and were more likely to inherit the disease from their mother. Magnetic resonance imaging findings indicated that while degree of cerebral atrophy was not related to severity of intellectual impairment, skull thickness, focal white matter lesions, and anterior temporal lobe abnormalities were significantly more common in patients with severely disturbed intellect. This study reports a number of previously unreported cerebral magnetic resonance imaging findings associated with intellectual impairment in myotonic dystrophy, but the etiology of these changes awaits neuropathologic examination. 相似文献
3.
Identifying environmental factors reflected to alcohol use is important for program planning and evaluation in college alcohol and drug prevention programs. Little has been written concerning uses of data in environmental prevention efforts. This paper presents four brief interrelated case studies of how environmental modifications were used by a college alcohol prevention project to 1) change the marketing practices and service policies of a student-oriented bar, 2) alter the sales practices of a campus bookstore concerning alcohol paraphernalia, 3) to develop a campaign with the goal of reducing risk factors related to heavy drinking at private student parties, and 4) stop an unsafe bus from transporting students to bars in Mexico. Creative use of such environmental prevention approaches has potential benefit to colleges and universities concerned with the primary prevention of alcohol-related problems experienced by students. 相似文献
4.
5.
The physical attractiveness of 25 pairs of monozygotic (MZ) twins was rated independently for twins A and B. The MZ twins were rated alike in their physical attractiveness (r=0.54; corrected for attenuation,r=0.94). Physical attractiveness was uncorrelated with verbal intelligence but was associated, controlling statistically for the sex difference in attractiveness favoring females, with three of the eight traits in the Comrey inventory: Conformity, Extraversion, and Emotional Stability. In both sexes, greater emotional stability was associated with attractiveness; in males greater extraversion; and in females, greater conformity. When these twin correlations were adjusted for this association with attractiveness, the mean change in the value ofr was only 0.03, indicating that physical attractiveness does not appear to bias conclusions from twin studies. 相似文献
6.
The normal once-a-day frequency of suckling in the rabbit was increased on day 31 (late lactation) by the addition of two extra sucklings (8 and 16 hr after) the daily suckling. In confirmation of previous data, two additional sucklings significantly decreased milk yield acutely on day 31 in comparison with the average 4-day milk yield before and after day 31. The decrease in milk secretion after the two additional sucklings was prevented by a single injection of 3 mg prolactin (given 24 hr before the two extra sucklings) and/or by injections of the beta-adrenergic-blocking drug, propranolol (100 micrograms/kg b. wt. given 30 min before each additional suckling). Since prolactin secretion is decreased in these species and the mammary gland is less responsive to the hormone during late lactation, the present results suggest that in addition to these factors, suckling-induced activation of sympathetic influences may contribute to the decline in milk production at this stage of lactation. Taken together, these results suggest that suckling may regulate lactation in the rabbit through antagonistic mechanisms at different stages of lactation. 相似文献
7.
N. K. Clapp M. A. Henke R. M. Hansard R. E. Walsh D. L. Widomski C. P. Anglin D. J. Fretland T. S. Gaginella 《Inflammation research》1991,34(1-2):178-180
Spontaneous colitis in CTT's presents cytological characteristics similar to chronic ulcerative colitis in humans, e.g. inflammatory cell infiltrate and crypt abscesses. To better characterize CTT colitis as a potential model for human inflammatory bowel disease (IBD), inflammatory mediators identified in colonic tissue of human IBD patients and/or experimental colitis models were assayed. Inflammatory mediator changes in plasma and colon from tamarins with acute (n=10) and chronic (n=10) colitis (by mucosal biopsy) were assayed by RIAs. Similar inflammatory mediators were found in the CTT's with acute colitis. In the plasma, PAF and PGE2 levels were lower in acute colitis CTT's, no LTB4 was detected, and histamine levels were not different from chronic colitic animals. In the colon, myeloperoxidase and interleukin-1 were significantly higher in acute colitis, PGE2 and LTB4 were higher but not significantly, and PAF was not different from chronic CTT's. These data suggest that a combination of events are occurring in the pathogenesis of tamarin colitis that involves some of the same mediators that are found in the human disease and in other experimental models. The importance of these findings to human IBD remains for further investigation; however, the spontaneous primate model offers an exciting approximation of the disease development and merits further investigation for understanding the pathogenesis of human IBD as well as to aid in development of targeted therapeutics. 相似文献
8.
This study was designed to determine the effects of four well-characterized dietary brans on large bowel tumorigenesis induced in mice with 1,2-dimethylhydrazine (DMH). Eight-week-old barrier-derived male Balb/c mice were fed a semisynthetic diet with 20% bran added (either corn, soybean, soft winter wheat, or hard spring wheat) or a no-fiber-added control diet. Half of each group was given DMH (20 mg/kg body weight/week, subcutaneously for 10 weeks) beginning at 11 weeks of age. Surviving mice were killed 40 weeks after the first DMH injection. Tumors were not found in mice not subjected to DMH. In DMH-treated mice, tumors were found almost exclusively in the distal colon. Tumor incidences were as follows: controls, 11%; soybean group, 44%; soft winter wheat group, 48%; hard spring wheat group, 58%; and corn group, 72%. Tumors per tumor-bearing mouse ranged from 1.4 to 1.6, except in the corn group, which had 2.1. A positive correlation was found between percentage of neutral detergent fiber in the brans and tumor incidences but not between the individual components of cellulose, hemicellulose, or lignin. The enhancement of DMH-induced large bowel tumorigenesis by all four bran types may reflect a species and/or mouse strain effect that is bran-source related. These data emphasize the importance of using well-defined bran in all "fiber" studies. 相似文献
9.
Inhibition of rat corneal angiogenesis by 16-kDa prolactin and by endogenous prolactin-like molecules. 总被引:4,自引:0,他引:4
Z Due?as L Torner A M Corbacho A Ochoa G Gutiérrez-Ospina F López-Barrera F A Barrios P Berger G Martínez de la Escalera C Clapp 《Investigative ophthalmology & visual science》1999,40(11):2498-2505
PURPOSE: The cornea is an avascular organ, where induction of new blood vessels involves the turn-on of proangiogenic factors and/or the turn-off of antiangiogenic regulators. Prolactin (PRL) fragments of 14 kDa and 16 kDa bind to endothelial cell receptors and inhibit angiogenesis. This study was designed to determine whether antiangiogenic PRL-like molecules are involved in cornea avascularity. METHODS: Sixteen-kDa PRL and basic fibroblast growth factor (bFGF) or anti-PRL antibodies were placed into rat cornea micropockets and neovascularization evaluated by the optical density associated with capillaries stained by the peroxidase reaction and by the number of vessels growing into the implants. Prolactin receptors in corneal epithelium were investigated by immunocytochemistry. RESULTS: bFGF induced a dose-dependent stimulation of corneal neovascularization. This effect was inhibited by coadministration of 16-kDa PRL, as indicated by a 65% reduction in vessel density and a 50% decrement in the incidence of angiogenic responses. Corneal angiogenic reactions of different intensities were induced by implantation of polyclonal and monoclonal anti-PRL antibodies. Corneal epithelial cells were labeled by several anti-PRL receptor monoclonal antibodies. CONCLUSIONS: These findings show that exogenous 16-kDa PRL inhibits bFGF-induced corneal neovascularization and suggest that PRL-like molecules with antiangiogenic actions function in the cornea. PRL receptors in the corneal epithelium may imply that PRL in the cornea derives from lacrimal PRL internalized through an intracellular pathway. These observations are consistent with the notion that members of the PRL family are potential regulators of corneal angiogenesis. 相似文献
10.
We use data from the two rounds of the NLSY97 and the corresponding QED data to examine the effectiveness of school endowments and curricula in targeting juvenile use of tobacco, alcohol, and marijuana. Our results support the notion that schools matter in reducing juvenile involvement in substance use. Higher discretionary dollars per pupil are linked to reduced rates of juvenile initiation and repetitive use rates of cigarettes and marijuana. Additionally, school curricula, as indicated by the implementation of year round classes and some innovative and after-school programs--such as gifted and talented, attendance monitoring, homework hotline, international baccalaureate, extended-day, and mentoring, programs, affect both juvenile initiation to tobacco and alcohol use and juvenile repetitive use of tobacco and alcohol. In particular, we find that juvenile initiation to cigarette use is approximately between 2 percentage points and 3 percentage points lower among youths attending schools with gifted and talented and international baccalaureate programs. In addition, juvenile repetitive cigarette use is approximately 54%, 52%, and 48% lower among youths attending schools offering year round classes, international baccalaureate, and twenty-first century programs, respectively. Finally, juvenile initiation to alcohol use and juvenile repetitive use of alcohol are approximately 3% and 20% lower, respectively, among youths in schools offering gifted and talented programs. In sum, while these programs are not implemented to address substance use problems among the student body, we find that the implementation of these programs is often accompanied by a reduction in juvenile initiation and repetitive substance use. 相似文献