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   2241篇
  免费   211篇
  国内免费   38篇
耳鼻咽喉   9篇
儿科学   81篇
妇产科学   110篇
基础医学   381篇
口腔科学   107篇
临床医学   224篇
内科学   371篇
皮肤病学   31篇
神经病学   128篇
特种医学   255篇
外科学   226篇
综合类   70篇
一般理论   1篇
预防医学   172篇
眼科学   79篇
药学   165篇
肿瘤学   80篇
  2023年   18篇
  2022年   16篇
  2021年   44篇
  2020年   19篇
  2019年   25篇
  2018年   33篇
  2017年   21篇
  2016年   19篇
  2015年   26篇
  2014年   36篇
  2013年   78篇
  2012年   77篇
  2011年   81篇
  2010年   58篇
  2009年   46篇
  2008年   79篇
  2007年   110篇
  2006年   99篇
  2005年   102篇
  2004年   108篇
  2003年   63篇
  2002年   82篇
  2001年   83篇
  2000年   82篇
  1999年   76篇
  1998年   46篇
  1997年   36篇
  1996年   35篇
  1995年   36篇
  1994年   37篇
  1993年   30篇
  1992年   43篇
  1991年   63篇
  1990年   53篇
  1989年   70篇
  1988年   58篇
  1987年   52篇
  1986年   49篇
  1985年   45篇
  1984年   28篇
  1983年   22篇
  1982年   25篇
  1981年   19篇
  1979年   18篇
  1978年   24篇
  1976年   22篇
  1975年   14篇
  1971年   21篇
  1970年   16篇
  1969年   17篇
排序方式: 共有2490条查询结果,搜索用时 15 毫秒
91.
Clinical trials comparing nonsurgical transfer techniques with laparoscopic directed methods are needed to determine the most successful and cost-effective approach for gamete and ET. We report the successful nonsurgical transfer of frozen-thawed embryos into the fallopian tube after our initial attempt resulting in an ongoing IUP. The process is relatively simple, safe, and avoids the risks of general anesthesia. Unlike US-guided tubal cannulation, this technique offers direct, clear visualization of the tubal ostium, assuring the desired catheter placement. As well, hysteroscopic guidance allows an accurate estimate of the depth of catheter insertion within the fallopian tube, which may be a critical factor in successful tubal deposition of gametes or embryos. Whether prolonged carbon dioxide exposure of the tubal microenvironment and/or direct endometrial trauma limits the efficacy of this technique remains to be determined. Finally, outpatient hysteroscopic directed tubal cannulation holds promise as a methodological technique that ultimately assists in the examination of the best site for embryo deposition (tubal versus uterine) and/or method of delivery (nonsurgical versus surgical).  相似文献   
92.
BACKGROUND: Although early enteral feeding clearly reduces septic morbidity after blunt and penetrating trauma, data for head-injured patients are conflicting. This study examines the effects of early vs delayed enteral feedings on outcome in patients with severe closed-head injuries with a Glasgow Coma Scale (GCS) score greater than 3 and less than 11. METHODS: Thirty patients were prospectively randomized to receive an immune-enhancing diet (Impact with fiber) early (initiated < 72 hours after trauma) delivered via an endoscopically placed nasoenteric tube (Stay-Put) or late (administered after gastric ileus resolved). This formula was continued for 14 days or until the patient tolerated oral feeding. Goal rate of nutrition was 21 nonprotein cal/kg/d and 0.3 g N/kg/d. RESULTS: Two patients in the early group were excluded due to inability to place the tube, and one patient in the late group died before 72 hours. Five of the remaining 27 died, 1 in the early group and 4 in the late group. There were no significant differences between the groups in length of stay, intensive care unit (ICU) days, significant infection, or GCS score. However, major infection correlated inversely with admission GCS score (R = -0.6, p < .003). Time to reach a GCS score of 14 was significantly longer in patients with significant infections compared with those without (p < .02). CONCLUSIONS: No difference in length of stay or infectious complications is shown in patients with severe closed-head injury when they are given early vs delayed feeding using an immune-enhancing formula. Severity of the head injury is closely associated with significant infection.  相似文献   
93.
CA-125 levels in endometriosis   总被引:4,自引:1,他引:4  
CA-125 is a cellular antigen detected in many patients with ovarian cancer, but it has also been detected in patients with endometriosis. Preoperative CA-125 levels were drawn from 113 patients before they underwent laparoscopy. Patients were categorized into diagnostic groups on the basis of pathologic findings. CA-125 levels in patients with evidence of intraabdominal adhesions were not statistically different from those in patients with normal pelvic anatomy. However, patients with advanced endometriosis had significantly elevated levels of CA-125 when compared with patients with normal pelvic anatomy (P less than 0.05). The clinical and immunologic implications of elevated CA-125 levels in patients with advanced endometriosis are discussed.  相似文献   
94.
Fourteen healthy young women were studied through a control and a treatment menstrual cycle in two series of experiments. In the first series, they were given one of four doses of deglycosylated human chorionic gonadotropin (hCG) as a 24-hour infusion during the mid-luteal phase of the cycle. In these studies, there were no significant alterations of the length of the luteal phase of the treatment cycle, and there was no decrease in serum progesterone (P) during the infusion. In fact, serum P increased during the infusion. In the second series of studies, five subjects were given a 48-hour infusion of normal saline during the control cycle, and a 48-hour infusion of deglycosylated alpha-intact beta-hCG during the treatment cycle, both being administered during the mid-luteal phase. Treatment did not alter luteal phase duration and, again, increased serum P. It is concluded that deglycosylated preparations of hCG are not clinically useful as luteinizing hormone antagonists, probably because of residual agonist activity.  相似文献   
95.
After biochemical and radiographic studies, enzyme replacement therapy in three patients with the infantile form of hypophosphatasia was attempted by weekly intravenous infusions of bone alkaline phosphatase-rich (BAP) plasma from patients with Paget bone disease. Subsequently, circulating BAP activity was substantially increased in each patient, and in one was maintained in the normal range for nearly 2 months. Despite partial or complete correction of the deficiency of circulating BAP activity, we observed no radiographic evidence for arrest of progressive osteopenia or improvement in rachitic defects in any of the patients. Failure of infants with hypophosphatasia to show significant healing of rickets on correction of circulating BAP activity supports the hypothesis that this isoenzyme functions in situ during normal skeletal mineralization.  相似文献   
96.
Stevens-Johnson syndrome and toxic epidermal necrolysis (TEN) are mild-to-life-threatening adverse reactions that have been described after exposure to fluoroquinolones. No published reports, however, exist of exfoliative disease after treatment with levofloxacin. A 78-year-old woman with many medical problems, including chronic obstructive pulmonary disease, was treated with parenteral levofloxacin for community-acquired pneumonia. She was discharged with oral levofloxacin to complete an additional 3 days of treatment as an outpatient. Two days after completing this regimen, the patient developed a rash with blistering. The rash progressed to TEN in 7 days, and she was transferred to a burn treatment center. She was treated with fluid resuscitation, wound dressing, and antibiotics. Her condition improved, and she was discharged after 22 days. To our knowledge, this case is the first published report of levofloxacin-induced TEN.  相似文献   
97.
OBJECTIVE: To examine the characteristics of 'diagnostic orphans' among cannabis users-those who report one or two symptoms of DSM-IV dependence but do not meet diagnostic criteria for DSM-IV abuse or dependence. METHOD: Data were collected from a representative population cohort of 1601 young adults aged 20-21 years. Those who reported that they had used cannabis at least weekly at some point within the past year were assessed for symptoms of DSM-IV cannabis abuse and dependence using the Composite International Diagnostic Interview. RESULTS: Approximately 2.8% of the cohort could be classified as diagnostic orphans, with another 3.0 and 7.5% meeting criteria for abuse and dependence, respectively. Diagnostic orphans were: similar to those who met criteria for cannabis abuse or dependence in terms of demographic characteristics; similar to those who met criteria for cannabis abuse in terms of cannabis use patterns; and similar to those who met criteria for abuse and dependence in their rates of heavy alcohol use and DSM-IV alcohol dependence. However, they did not appear to have elevated rates of illicit drug use or mental health problems compared to non users. CONCLUSIONS: Diagnostic orphans reported using cannabis in a manner similar to persons meeting criteria for cannabis abuse, and had similar rates of alcohol dependence and other illicit drug use. Strict adherence to DSM-IV diagnoses of abuse and dependence may overlook a substantial proportion of young persons who experience cannabis-related problems. There is a need to consider (a) subthreshold levels of cannabis-related problems among those seeking treatment for other problems; and (b) interventions for this group to prevent escalation of such problems.  相似文献   
98.
Ballistics is the science of thrown or projected objects. The consequences of ballistic injuries to the face may be devastating and lead to considerable disability and disfigurement. Reconstructive techniques for maxillofacial injuries have improved greatly since World War II; however, the basic principles for the initial, early and reconstructive phases of treatment have stood the test of time. This paper gives an overview of the management of ballistic injuries to the face and jaws.  相似文献   
99.
BACKGROUND: Our aim was to assess long-term results after less than total parathyroidectomy for hyperparathyroidism in multiple endocrine neoplasia type 1. METHODS: Of 1888 patients undergoing operation at our institution for primary hyperparathyroidism between 1972 and 2001, 83 (4.4%) had multiple endocrine neoplasia type 1. Outcome data were available for 79; 66 underwent subtotal parathyroidectomy, 55 (83%) of these with bilateral thymectomy. In 13 patients, only grossly enlarged glands were resected (mean 1.1 per patient) as the syndrome of multiple endocrine neoplasia type 1 was not yet evident or the initial exploration was performed elsewhere. RESULTS: Follow-up has been 48 +/- 51 months (mean + SD). Intraoperative serum PTH assay decay in 20 patients was suggestive of cure in 18 patients, none of whom required reoperation. Nine patients (11%) required reoperation (3 required reoperation twice) after a mean interval of 77 +/- 53 months. Subtotal parathyroidectomy resulted in a lesser reoperation rate than resection of grossly enlarged glands (7% vs 30%, P =.02). At the time of review, 63 patients (80%) were normocalcemic, 10 (13%) hypocalcemic (2 after unsuccessful delayed autograft), and 7% hypercalcemic (none after reoperation). By Kaplan-Meier analysis, the rate of surgical cure (patients who are nonhypercalcemic) is 60% and 51% at 10 and 15 years, respectively. CONCLUSION: Subtotal parathyroidectomy reduces the need for reoperation. Selective reoperation leads to long-lasting biochemic cure.  相似文献   
100.
Current issues in trauma   总被引:2,自引:0,他引:2  
  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