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   20342篇
  免费   1564篇
  国内免费   40篇
耳鼻咽喉   162篇
儿科学   909篇
妇产科学   698篇
基础医学   2530篇
口腔科学   324篇
临床医学   2298篇
内科学   3758篇
皮肤病学   376篇
神经病学   2220篇
特种医学   583篇
外国民族医学   7篇
外科学   2135篇
综合类   213篇
一般理论   12篇
预防医学   2590篇
眼科学   282篇
药学   1161篇
  1篇
中国医学   37篇
肿瘤学   1650篇
  2023年   201篇
  2022年   353篇
  2021年   702篇
  2020年   448篇
  2019年   679篇
  2018年   816篇
  2017年   580篇
  2016年   554篇
  2015年   607篇
  2014年   825篇
  2013年   1098篇
  2012年   1589篇
  2011年   1726篇
  2010年   882篇
  2009年   761篇
  2008年   1167篇
  2007年   1193篇
  2006年   1110篇
  2005年   1030篇
  2004年   933篇
  2003年   803篇
  2002年   731篇
  2001年   212篇
  2000年   194篇
  1999年   196篇
  1998年   119篇
  1997年   119篇
  1996年   83篇
  1995年   60篇
  1994年   67篇
  1993年   57篇
  1992年   136篇
  1991年   113篇
  1990年   127篇
  1989年   113篇
  1988年   117篇
  1987年   116篇
  1986年   105篇
  1985年   106篇
  1984年   88篇
  1983年   79篇
  1982年   51篇
  1980年   51篇
  1979年   69篇
  1978年   62篇
  1976年   50篇
  1975年   53篇
  1974年   58篇
  1973年   74篇
  1972年   84篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
231.
232.

Objective

The goal of this study was to determine the prevalence of severe nausea and vomiting of pregnancy/hyperemesis gravidarum among relatives of affected individuals.

Study design

Family history data were obtained on 1224 self-reported cases of hyperemesis gravidarum. Cases completed an online survey administered by the Hyperemesis Education and Research Foundation between 2003 and 2006.

Results

Approximately 28% of cases reported their mother had severe nausea and vomiting or hyperemesis gravidarum while pregnant with them. Of the 721 sisters with a pregnancy history, 137 (19%) had hyperemesis gravidarum. Among the most severe cases, those requiring total parenteral nutrition or nasogastric feeding tube, the proportion of affected sisters was even higher, 49/198 (25%). Nine percent of cases reported having at least two affected relatives including sister(s), mother, grandmother, daughters, aunt(s), and cousin(s).

Conclusion

There is a high prevalence of severe nausea and vomiting of pregnancy/hyperemesis gravidarum among relatives of hyperemesis gravidarum cases in this study population. Because the incidence of hyperemesis gravidarum is most commonly reported to be 0.5%, this study provides strong but preliminary evidence for a genetic component to extreme nausea and vomiting of pregnancy.  相似文献   
233.
234.
The authors compare perspectives of intimate partner violence (IPV) survivors and emergency department (ED) nurses on types of social support IPV victims need at different stages of readiness to disclose and leave a relationship. Qualitative interviews (16 IPV survivors, 10 ED nurses) center on women's responses to vignettes that illustrate different stages of readiness. Survivors mention fear as a barrier for action, whereas nurses are more likely to say that the woman is in denial. Survivors emphasize emotional support and respect, whereas nurses emphasize informational and instrumental support. IPV victims desire appropriate, respectful responses by nurses, suitable to their stage of readiness. Nurses need more insight into women's decisions to disclose and leave a relationship and skills to provide emotional support.  相似文献   
235.
OBJECTIVE: Brain metastasis from uterine cancer is a rare event. Consequently, the optimal management strategy is not defined. We reviewed our institution's experience with brain metastasis from endometrial cancer along with the extant medical literature to develop management recommendations. METHODS: Twenty patients with CNS metastasis were identified. Information regarding symptoms, treatment, and survival was collected. The Kaplan-Meier method was used to compare survival data. RESULTS: The incidence of CNS metastasis was 0.97%. Median patient age at initial diagnosis of endometrial cancer was 62.0 years and 64.0 years at diagnosis of brain metastasis. Most patients initially presented with advanced FIGO stage: 9 stage IVB, 4 stage IIIC, 4 stage IIIA, 2 stage IB, and 1 stage IA. The median interval from diagnosis of endometrial cancer to diagnosis of brain metastasis was 11.5 months (range 0.6-73.6). Median survival after diagnosis of brain metastasis was 2.0 months (range 0.1-39.2). Improved survival was seen in patients treated with multimodal therapy compared to patients who only received whole brain radiotherapy (WBRT) (p=0.0001) or compared to patients who received no treatment (p=0.009). No difference in survival was seen between patients treated with WBRT versus no therapy. The survival advantage associated with multimodal therapy was also supported by case reports and case series in the literature. CONCLUSIONS: Based upon the data presented along with the medical literature, multimodal therapy appears to improve the survival of patients with CNS metastasis from uterine cancer.  相似文献   
236.
OBJECTIVES: To determine the importance of margin status and other prognostic factors associated with the recurrence and survival of patients with squamous cell vulvar carcinoma. METHODS: Data were analyzed using Kaplan-Meier methods and Cox proportional hazards regression. All slides were re-reviewed by two gynecologic pathologists. RESULTS: Ninety patients (median age: 69) were treated for vulvar carcinoma from 1984 to 2002, including 28 FIGO stage I, 20 stage II, 26 stage III and 16 with stage IV disease. Sixty-three (70%) patients underwent complete radical vulvectomies and 27 (30%) had modified radical vulvectomies. Nineteen (20%) patients received adjuvant radiotherapy. Five-year disease-specific survival rates were 100%, 100%, 86% and 29% for stages I-IV, respectively. None of the 30 patients with a pathologic margin distance >8 mm had local recurrence. Of the 53 women with tumor-free pathologic margin of <8 mm, 12 (23%) had a local recurrence. Moreover, women with >2 positive groin nodes had significantly higher recurrence risk compared to those with <2 metastatic groin nodes (p<0.001). On multivariate analysis, positive groin nodes and margin distance were important prognostic factors for recurrence. Moreover, stage, tumor size, margin distance, and depth of invasion were significant independent predictors for disease-specific survival. The median follow-up was 58 months (range: 2-188). CONCLUSIONS: Pathologic margin distance is an important predictor of local vulvar recurrence. Our data suggest that a > or =8-mm pathologic margin clearance leads to a high rate of loco-regional control.  相似文献   
237.
OBJECTIVE: To study if spontaneous contractions augmented by proteinase-activated receptor-2 (PAR-2)-activating peptide serine-leucine-isoleucine-glycine-arginine-leucine (SLIGRL) involve coactivation of membrane chemoceptors and are associated with expression of PAR-2 mRNA in non-pregnant and pregnant rat myometrium. MATERIALS AND METHODS: Non-pregnant, mid-pregnant, and late pregnant rat uterine horn and small intestine segments were snap-frozen in liquid nitrogen to determine PAR-2 mRNA levels by real time polymerase chain reaction (PCR). Uterine rings were used for isometric tension recording. Effect of SLIGRL (0.1 mM) on spontaneous contractions before and after exposure to ibuprofen (cyclooxygenase inhibitor, 1.0 microM), SQ-29548 (thromboxane A(2) receptor inhibitor, 1.0 microM), ketotifen (histamine 1 receptor inhibitor, 10 microM), WEB-2170BS (platelet-activating factor (PAF) receptor inhibitor, 10 microM), atropine (muscarinic receptor inhibitor, 0.1 microM), or ketanserin (serotonin receptor inhibitor, 10 microM) were compared. Paired t-test and one-way ANOVA followed by Dunnett's or Newman-Keuls post hoc tests were used for statistical analysis when appropriate. SIGNIFICANCE: P<0.05. RESULTS: The agents did not significantly affect time-associated decay in spontaneous contractile activity in any group of the tissues. Activation of spontaneous contractions induced by SLIGRL in non-pregnant rat myometrium did not involve coactivation of membrane chemoceptors, while in mid-pregnant rat myometrium coactivation of prostanoid, histamine, and serotonin receptors and in late pregnant rat myometrium coactivation of thromboxane receptors was noted. Expression of PAR-2 mRNA was similar in non-pregnant, mid-pregnant, and late pregnant rat myometrium. CONCLUSIONS: Expression of PAR-2 in rat myometrium is not dependent on gestational age. Stimulation of PAR-2 is associated with production/release of cyclooxygenase pathway product(s) activating thromboxane/prostaglandin H2 receptors, partial involvement of histamine H1 receptors and serotonin receptors in midpregnancy and thromboxane A2/prostaglandin H2 receptors in late pregnancy.  相似文献   
238.
OBJECTIVE: To compare the clinical behavior and outcomes of low- and high-grade endometrial stromal sarcomas (LGESS and HGESS), respectively. METHODS: Patients with endometrial stromal sarcoma from five different institutions were identified and reviewed for clinicopathologic variables, surgical management and outcomes. Statistical calculations including Chi-square, t-test and survival using the Kaplan-Meier method with the log rank test were performed. RESULTS: One hundred and five patients were identified with 72 having LGESS, 31 with HGESS and 2 having unclassified tumors. The mean age was 50 years for patients with LGESS and 64 years for those with HGESS (p<0.0001). In patients with LGESS, 68% (49 patients) had disease confined to the uterine corpus or cervix compared to 39% (12 patients) in HGESS (p=0.002). The median overall survival was 53 months for HGESS and had not yet been reached in LGESS with 87.8% alive at 80 months (p<0.0001). In HGESS patients with extrauterine disease, the presence of residual disease greater than 2 cm had a significant effect on median survival. Median survival was 52 months for those who underwent optimal cytoreduction versus 2 months for those with suboptimal residual disease (p=0.007). The impact of cytoreduction was not seen in LGESS patients with extrauterine disease with 82.1% alive at 78 months. CONCLUSIONS: Low-grade and high-grade endometrial stromal sarcomas represent two distinct clinical entities and should be treated as such. Survival in patients with high-grade tumors appears to be related to amount of residual disease at the completion of initial surgery and would suggest the need for aggressive cytoreduction. The role of surgical staging and optimal adjuvant therapy remains unclear.  相似文献   
239.
Human breast milk is known to contain numerous biologically active components which protect breast fed infants against microbes, viruses, and toxins. The purpose of this study was to purify and characterize the breast milk mucin and determine its anti-poxvirus activity. In this study human milk mucin, free of contaminant protein and of sufficient quantity for further analysis, was isolated and purified by Sepharose CL-4B gel filtration and cesiumchloride density-gradient centrifugation. Based on the criteria of size and appearance of the bands and their electrophoretic mobility on sodium dodecyl sulfate polyacrylamide-gel electrophoresis, Western blotting together with the amino acid analysis, it is very likely that the human breast milk mucin is MUC1. It was shown that this breast milk mucin inhibits poxvirus activity by 100% using an inhibition assay with a viral concentration of 2.4 million plaque-forming units/ml. As the milk mucin seems to aggregate poxviruses prior to their entry into host cells, it is possible that this mucin may also inhibit other enveloped viruses such as HIV from entry into host cells.  相似文献   
240.
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