全文获取类型
收费全文 | 559篇 |
免费 | 19篇 |
国内免费 | 27篇 |
专业分类
儿科学 | 24篇 |
妇产科学 | 6篇 |
基础医学 | 36篇 |
口腔科学 | 1篇 |
临床医学 | 46篇 |
内科学 | 292篇 |
皮肤病学 | 2篇 |
神经病学 | 6篇 |
特种医学 | 63篇 |
外科学 | 25篇 |
综合类 | 23篇 |
预防医学 | 28篇 |
眼科学 | 4篇 |
药学 | 34篇 |
中国医学 | 1篇 |
肿瘤学 | 14篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 11篇 |
2014年 | 8篇 |
2013年 | 13篇 |
2012年 | 23篇 |
2011年 | 45篇 |
2010年 | 23篇 |
2009年 | 30篇 |
2008年 | 46篇 |
2007年 | 51篇 |
2006年 | 33篇 |
2005年 | 34篇 |
2004年 | 26篇 |
2003年 | 15篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 6篇 |
1999年 | 9篇 |
1998年 | 19篇 |
1997年 | 15篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 13篇 |
1993年 | 10篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 12篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1976年 | 3篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有605条查询结果,搜索用时 11 毫秒
1.
2.
Two modified helical basket extractors are described that have increased the success rate of removing ureteral calculi using fluoroscopy from 63% to 92%. Initially a rather stiff and expandable basket with a 20-cm filiform tip is used with coaxial catheters and sheath (stage 1). If this procedure is unsuccessful, a basket with two long cable ends is passed from the nephrostomy out through the urethra (stage 2). When used with coaxial bladder catheters, this technique allows dilatation of the vesicoureteric junction and retrograde catheterization and injection of fluids or gas to dislodge the stone prior to extraction. In a series of 38 patients, stones were removed in all but three (a success rate of 92%). In five cases small stones (less than 5 mm) were not retrieved but subsequent studies were normal. Ureteral stones were found in the abdominal ureter in 28 cases, in the pelvic ureter in seven cases, and in multiple sites in three cases. Stones were larger than 1 cm in 27.7% of cases. Postextraction mucosal edema with reduced ureteral patency was common but usually cleared in 2-3 days. Occasional complications were related to the nephrostomy. 相似文献
3.
4.
Retrorenal colon: implications for percutaneous diskectomy 总被引:1,自引:0,他引:1
It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary. 相似文献
5.
Problems arising from controlled ovarian hyperstimulation for intrauterine insemination, such as premature luteinization and asynchronous ovarian follicular development, are identical to those encountered with controlled ovarian hyperstimulation for in vitro fertilization (IVF) and gamete intrafallopian transfer (GIFT). It has been suggested that the adjunctive use of GnRH agonists for controlled ovarian hyperstimulation improves the efficiency of GIFT and IVF cycles. We hypothesized that adjunctive use of leuprolide acetate, a GnRH agonist, would have a similarly beneficial effect on cycle quality and cycle fecundity in subfertile women treated with controlled ovarian hyperstimulation and intrauterine insemination. We randomly assigned the first cycle of controlled ovarian hyperstimulation and intrauterine insemination for each of 97 subfertile women to include either human menopausal gonadotropins (hMGs) alone or hMGs following midluteal pre-treatment with leuprolide. If a pregnancy did not occur in the first cycle, the woman was given the other treatment in the second cycle. Although the cycles that included leuprolide required a larger amount of hMGs and more days of stimulation per cycle, the mean estradiol concentrations and numbers of follicles were not different. Despite prevention of premature luteinization with leuprolide, the cycle fecundity was not different between groups (0.11 with adjunctive leuprolide treatment and 0.22 with hMGs alone). We conclude that in unselected subfertile patients, the adjunctive use of leuprolide for controlled ovarian hyperstimulation and intrauterine insemination does not improve cycle fecundity compared with treatment cycles that do not include adjunctive leuprolide therapy. 相似文献
6.
7.
8.
Race and the response to adrenergic blockade with carvedilol in patients with chronic heart failure 总被引:9,自引:0,他引:9
Yancy CW Fowler MB Colucci WS Gilbert EM Bristow MR Cohn JN Lukas MA Young ST Packer M;U.S. Carvedilol Heart Failure Study Group 《The New England journal of medicine》2001,344(18):1358-1365
BACKGROUND: The benefits of angiotensin-converting-enzyme inhibitors and beta-blockers may be smaller in black patients than in patients of other races, but it is unknown whether race influences the response to carvedilol in patients with chronic heart failure. METHODS: In the U.S. Carvedilol Heart Failure Trials Program, 217 black and 877 nonblack patients (in New York Heart Association class II, III, or IV and with a left ventricular ejection fraction of no more than 0.35) were randomly assigned to receive placebo or carvedilol (at doses of 6.25 to 50 mg twice daily) for up to 15 months. The effects of carvedilol on ejection fraction, clinical status, and major clinical events were retrospectively compared between black and nonblack patients. RESULTS: As compared with placebo, carvedilol lowered the risk of death from any cause or hospitalization for any reason by 48 percent in black patients and by 30 percent in nonblack patients. Carvedilol reduced the risk of worsening heart failure (heart failure leading to death, hospitalization, or a sustained increase in medication) by 54 percent in black patients and by 51 percent in nonblack patients. The ratios of the relative risks associated with carvedilol for these two outcome variables in black as compared with nonblack patients were 0.74 (95 percent confidence interval, 0.42 to 1.34) and 0.94 (95 percent confidence interval, 0.43 to 2.05), respectively. Carvedilol also improved functional class, ejection fraction, and the patients' and physicians' global assessments in both the black patients and the nonblack patients. For all these measures of outcome and clinical status, carvedilol was superior to placebo within each racial cohort (P<0.05 in all analyses), and there was no significant interaction between race and treatment (P> 0.05 in all analyses). CONCLUSIONS: The benefit of carvedilol was apparent and of similar magnitude in both black and nonblack patients with heart failure. 相似文献
9.
Glycoproteins present in human follicular fluid that inhibit the zona- binding capacity of spermatozoa 总被引:1,自引:0,他引:1
Previous studies have suggested that human follicular fluid contains
factors that reduce the zona-binding capacity of spermatozoa. The present
study provides further evidence of the existence of such factors. Using the
hemizona binding assay (HZA), we have shown that the inhibitory effect of
human follicular fluid on the zona-binding capacity of spermatozoa is
concentration-dependent, an inhibitory effect being detected when the
concentration of human follicular fluid was > or = 10%. A 1%
concentration of human follicular fluid did not possess this inhibitory
activity. Heating human follicular fluid at 56 degrees C for 30 min did not
affect its inhibitory properties; treatment with proteinase-K abolished
such inhibition. Human follicular fluid was fractionated sequentially by
concanavalin-A affinity chromatography, Mono Q ion-exchange chromatography
and Superose-12 gel filtration. The zona binding inhibitory activity
resided in the fraction which bound to the lectin and Mono Q column and
contained molecules with native molecular weights of 32 and 192 kDa. Sodium
dodecyl sulphate-polyacrylamide gel electrophoresis analysis suggested that
the 192 kDa glycoprotein was a tetramer, while the 32 kDa glycoprotein
remained as a single molecular species under denaturing conditions. We
conclude that two glycoproteins were responsible for the zona binding
inhibitory activity of human follicular fluid. The physiological role of
these factors remains unclear.
相似文献
10.
Non-typhoid Salmonella gastroenteritis 总被引:2,自引:0,他引:2