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   194435篇
  免费   2074篇
  国内免费   110篇
耳鼻咽喉   1355篇
儿科学   7025篇
妇产科学   3458篇
基础医学   18978篇
口腔科学   2102篇
临床医学   13851篇
内科学   35943篇
皮肤病学   1170篇
神经病学   18118篇
特种医学   9369篇
外科学   31794篇
综合类   2394篇
现状与发展   1篇
一般理论   4篇
预防医学   19447篇
眼科学   3090篇
药学   10394篇
中国医学   666篇
肿瘤学   17460篇
  2023年   154篇
  2022年   305篇
  2021年   811篇
  2020年   359篇
  2019年   720篇
  2018年   22636篇
  2017年   17740篇
  2016年   19884篇
  2015年   1427篇
  2014年   1518篇
  2013年   1791篇
  2012年   8583篇
  2011年   22466篇
  2010年   19631篇
  2009年   12318篇
  2008年   20719篇
  2007年   22959篇
  2006年   1779篇
  2005年   3385篇
  2004年   4352篇
  2003年   5270篇
  2002年   3364篇
  2001年   396篇
  2000年   475篇
  1999年   291篇
  1998年   337篇
  1997年   337篇
  1996年   201篇
  1995年   218篇
  1994年   198篇
  1993年   140篇
  1992年   105篇
  1991年   144篇
  1990年   160篇
  1989年   113篇
  1988年   85篇
  1987年   73篇
  1986年   60篇
  1985年   73篇
  1984年   57篇
  1983年   43篇
  1982年   53篇
  1980年   65篇
  1978年   44篇
  1976年   38篇
  1974年   43篇
  1969年   38篇
  1938年   63篇
  1932年   58篇
  1930年   48篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
We investigated the influence of control judgments and coping style on emotional reactions to domestic violence utilizing the framework of hopelessness theory. We assessed abuse severity, control attributions, coping, dysphoric symptoms, and hopelessness in 70 battered women recruited from 12 domestic violence agencies. Respondents reported dysphoria but not hopelessness. Increased reports of dysphoria were associated with higher levels of self-blame and avoidance coping and lower levels of problem-focused coping. Increased problem-focused coping was associated with decreased hopelessness. Perceived control over current abuse was not related to dysphoria. High expectations for control over future events were associated with decreased dysphoria. We discuss our results in terms of their application to attributional accounts of emotional reactions to battering.  相似文献   
992.
Claims regarding amnesia for childhood sexual abuse have often been based on studies of adults' responses to questions of the form, “Was there ever a period of time when you remembered less of the abuse than you do now?” In this experiment, 43 adult (mean age = 42) participants rated their current and prior memories of several nontraumatic childhood/adolescent events. Reports of prior periods of less memory were fairly common. Participants then engaged in “reminiscence” or “enhanced” retrieval activities directed toward remembering more about a selected target event. Following retrieval, 35% of the reminiscence condition participants reported prior poor memory for the target event, as did 70% of the enhanced condition. These results highlight the need for appropriate control conditions in retrospective studies of amnesia for childhood trauma.  相似文献   
993.
Objective To explore the relationship between expression of apoptosis-modulating proteins and histopathological grade and recurrence in meningioma. Methods Immunohistochemistry method (LSAB) was used to detect the expression of Bcl-2, Bax Bnd Bcl-XL in 80 cases of meningioma including benign group (38 cases), atypical group (26 cases) and malignant group (16 cases). Results Expression of Bcl-2 oncoprotein positive in 88% cases in malignant group was significantly higher than that of benign group (37%,P<0.05). There was no significant difference in the expression positive rate of Bax, Bcl-XL oncoprotein among benign, atypical and maligant groups (P>0.05), but Bcl-2+Bcl-XL/Bax was associated statistically with meningioma grade (P<0.01). There was no significant difference in the compare expression of Bcl-2, Bax, Bcl-XL oncoprotein positive in non-recurrent, initially resected recurrent and recurrent meningiomas (P>0.05). Conclusion Bcl-2, Bax and Bcl-XL might play important roles in meningiomas and BCL-2+BCL-XL/Bax is useful parameters for estimation of biological behavior of meningiomas.  相似文献   
994.
Esophageal cancer has a dismal prognosis and the surgical treatment only cures a small percentage of patients. The survival achieved by traditional surgical procedures is being improved with extended resections, but at the cost of greater morbidity. Concurrent radiochemotherapy can obtain results similar to those of surgery. Nowadays, locally advanced esophageal cancer should have a multimodal approach, because neoadjuvant chemotherapy, with or without radiotherapy, has demonstrated to improve the survival of chemosensitive patients. Recently, the role of hyperfractionated radiotherapy and new drugs such as paclitaxel, docetaxel and irinotecan in neoadjuvant treatment is being evaluated.  相似文献   
995.
Background A possible association between Helicobacter pylori seropositivity and tumor necrosis factor (TNF) A G-308A has been reported in Korea. The present study examined the associations of H. pylori with functional polymorphisms, TNF-A G-308A, C-857T, and T-1031C, and TNF-B A252G in Japanese subjects.Methods The total of 1374 study subjects included 241 outpatients who participated in an H. pylori eradication program (HPE), 679 first-visit outpatients (FVO) at a regional cancer hospital, and 454 local residents who received a health checkup examination (HCE).Results The frequency of the TNF-A -308A allele was only 1.3% of 480 chromosomes in the HPE group, so the FVO and HCE groups were not genotyped for that polymorphism. The genotype frequency of TNF-A C-857T was 69.2% CC, 27.7% CT, and 3.1% TT; that of TNF-A T-1031C was 69.4% TT, 28.1% TC, and 2.5% CC; and that of TNF-B A252G was 36.8% AA, 48.2% AG, and 15.0% GG. TNF-A -857T was tightly linked to TNF-A -1031T and TNF-B 252A. No significant associations between H. pylori seropositivity and polymorphisms of TNF-A C-857T and TNF-B A252G were observed. However, a reduced odds ratio adjusted for sex, age, and recruitment source was observed for TNF-A -1031CC (0.43; 95% confidence interval, 0.20–0.91) relative to TNF-A -1031TT. Subjects with TNF-A -857CC and -1031CC showed the lowest seropositivity (38.2% of 34 participants), while those with TNF-A -857TT and -1031TT showed the highest (66.7% of 42 participants).Conclusions This study suggests that the possibly high expression genotype of TNF-A may increase susceptibility to persistent H. pylori infection.  相似文献   
996.
Background: Many reconstruction procedures have been developed in efforts to resolve patients' complaints after total gastrectomy. However, there have been few reports of longterm comparisons between reconstruction procedures, especially with regard to the prevention of duodenal food passage. This study was undertaken to compare the longterm subjective and functional results among Roux-en-Y esophagojejunostomy (R-Y), R-Y with pouch (P-Y), and jejunal interposition with pouch (P-I) after total gastrectomy. Methods: Consecutive patients requiring curative total gastrectomy were enrolled in this prospective study by the envelope method. Results: Hospital stay was longer following a P-I than an R-Y or a P-Y. Over 50% of R-Y patients complained of heartburn, and 20% of R-Y patients showed dumping syndrome throughout the postoperative period, with this rate being significantly different from rates in the other two groups. P-Y patients complained of early satiety in the late postoperative period, while P-I patients complained of early satiety in the early postoperative period. The nutritional index in P-I patients was higher than those in patients with the other two procedures. Gastrointestinal and hepatobiliary dual scintigraphy (GHDS) showed that the rate of bile reflux with an R-Y was relatively high after surgery. Food reflux with a P-Y was increased (9.4% to 11.1%), but with a P-I food reflux was decreased at 3 years after surgery (13.3% to 9.9%). Patients with a P-Y had a faster recovery of body, weight in the early postoperative period; however, at 5 years after operation, body weight recovery with a P-I was greatest. Conclusion: Reconstruction should be performed with pouch formation after total gastrectomy with curative intent. Received: March 7, 2002 / Accepted: September 26, 2002 Acknowledgments This study was partly supported by the University of Tsukuba Research Project. Offprint requests to: S. Adachi  相似文献   
997.
BACKGROUND: Disorders of the DNA repair system that protects against alkylating mutagens are known to play an important role in carcinogenesis. METHODS: We investigated the expression of the DNA repair enzyme that protects against alkylating mutagens, O(6)-methylguanine DNA methyltransferase (MGMT), and the mismatch repair (MMR) enzymes, hMLH1 and hMSH2, in 135 gastric cancer specimens by immunohistochemical means. RESULTS: The immunoreactivity of MGMT and MMR proteins correlated significantly with several clinicopathologic factors. The survival curve in 116 patients showed that a loss of MGMT or hMLH1, but not of hMSH2, correlated with a poor prognosis. Combined evaluation of MGMT and hMLH1 revealed that the survival of patients with negative status for both MGMT and hMLH1 was shortest. However, this significant association between patient survival and MGMT or hMLH1 expression disappeared when early and advanced cancers were separately analyzed, indicating that synchronous losses of MGMT and hMLH1 increase during tumor progression and stage. Further evaluation according to histologic type revealed that loss of MGMT, hMLH1, and hMSH2 expression significantly differed between early and advanced cancer in differentiated-type cancers. In contrast, in undifferentiated-type cancer, loss of MGMT and MMR expression was frequently found even in intramucosal (m) cancer, and no significant difference was found in loss of hMLH1 and hMSH2 between early and advanced cancer. CONCLUSION: These findings demonstrate that the reduced expression of MGMT, hMLH1, and hMSH2 in differentiated-type cancer may play an important role during tumor progression between the early and advanced stage. On the other hand, in undifferentiated-type cancer, loss of MGMT and the MMR proteins appears to be an important event at carcinogenesis or at an earlier step of tumor progression.  相似文献   
998.
999.
逆行肝切除治疗难切性肝癌244例报道   总被引:3,自引:0,他引:3  
目的 逆行肝切除是治疗难切性肝癌的有效方法 ,本文报道了 2 44例临床经验。方法 常规肝切除方法切除困难的 2 44例巨大、显露困难或下腔静脉受累的肝癌采用逆行切肝法结合血管外科技术予以切除 (A组 ) ,同期临床特征类似的 31例肝癌采用常规切肝法切除 ,作为对照 (B组 )。结果 两组均无手术死亡 ,A组与B组相比 ,术中出血量较少 ( 12 90± 998ml比 2 2 86± 136 3ml)、术后胸水发生率 ( 2 6 /2 44比 10 /31)、腹水发生率 ( 72 /2 44比 19/31)、中度到重度黄疸率 ( 14 /2 44比 5 /31)、手术区积液率 ( 17/2 44比 7/31)、膈下感染率 ( 3/2 44比 1/31)、胆漏发生率 ( 2 /2 44比 1/31)、切口感染率 ( 3/2 44比 1/31)以及ALT恢复时间 ( 13.8± 5 .1天比 18.9± 8.9天 )均较低 ,差别具有统计学意义 (P <0 .0 1)。结论 对于难切性肝癌而言 ,逆行肝切除是安全有效的手术方法。  相似文献   
1000.
目的 探讨并总结包括腔静脉旁部肝尾叶切除的方法和经验。方法 分别采用右后途径和左侧途径行右尾叶和全尾叶切除;前者附加部分右后叶切除,后者可为单独全尾叶切除或附加左外叶或左半肝切除。结果 成功施行包括腔静脉旁部的肝尾叶切除13例,其中右尾叶切除7例,全尾叶切除6例;全组无手术死亡,术中、术后均无严重病发症发生;术后平均失血量为896.15ml,平均肝门阻断时间为25.40min,术后平均住院12.38天。结论 虽然解剖关系复杂,切除包括腔静脉旁部的肝尾叶安全可行。  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