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   63328篇
  免费   4575篇
  国内免费   333篇
耳鼻咽喉   635篇
儿科学   1602篇
妇产科学   1539篇
基础医学   7843篇
口腔科学   1537篇
临床医学   6357篇
内科学   14386篇
皮肤病学   809篇
神经病学   4999篇
特种医学   1916篇
外国民族医学   2篇
外科学   9741篇
综合类   1010篇
现状与发展   1篇
一般理论   103篇
预防医学   5254篇
眼科学   1858篇
药学   4428篇
中国医学   139篇
肿瘤学   4077篇
  2023年   292篇
  2022年   463篇
  2021年   1155篇
  2020年   724篇
  2019年   1010篇
  2018年   1244篇
  2017年   848篇
  2016年   968篇
  2015年   1137篇
  2014年   1774篇
  2013年   2809篇
  2012年   3775篇
  2011年   4116篇
  2010年   2346篇
  2009年   2191篇
  2008年   4008篇
  2007年   4192篇
  2006年   4021篇
  2005年   4114篇
  2004年   3842篇
  2003年   3454篇
  2002年   3415篇
  2001年   730篇
  2000年   623篇
  1999年   722篇
  1998年   741篇
  1997年   609篇
  1996年   492篇
  1995年   491篇
  1994年   466篇
  1993年   440篇
  1992年   532篇
  1991年   509篇
  1990年   417篇
  1989年   438篇
  1988年   396篇
  1987年   373篇
  1986年   355篇
  1985年   419篇
  1984年   432篇
  1983年   394篇
  1982年   528篇
  1981年   443篇
  1980年   485篇
  1979年   301篇
  1978年   322篇
  1977年   321篇
  1976年   261篇
  1975年   287篇
  1974年   246篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Transabdominal sacrocolpopexy has been shown, in multiple long-term studies of its success and durability, to be the definitive treatment option for post-hysterectomy vaginal vault prolapse. It is, however, associated with greater morbidity than vaginal repair. We describe a minimally invasive technique for vaginal vault prolapse repair and present our experience with a minimum of one-year follow-up. The surgical technique involves five laparoscopic ports—three for the da Vinci robot and two for the assistant. After appropriate dissection a polypropylene mesh is attached to the sacral promontory and to the vaginal apex by use of Gore-Tex sutures. The mesh material is then covered by the peritoneum. Patient analysis focused on complications, urinary continence, patient satisfaction, and morbidity, with a minimum of 12 months follow-up. Forty-two patients with post-hysterectomy vaginal vault prolapse underwent robot-assisted laparoscopic sacrocolpopexy at our institute and 35 have a minimum of 12 months follow-up, with a mean follow-up of 36 months (range 12–48) in the group. Mean age was 67 (47–83) years and mean operating time was 3.1 (2.15–4.75) h for the entire cohort. All but one patient were discharged home on postoperative day one; one patient left on postoperative day two. One developed recurrent grade three rectocele, one had recurrent vault prolapse, and two suffered from vaginal extrusion of mesh. All patients were satisfied with their outcome. The robot-assisted laparoscopic sacrocolpopexy is a minimally invasive technique for vaginal vault prolapse repair, combining the advantages of open sacrocolpopexy with the reduced morbidity of laparoscopy. We observed reduced hospital stay, low occurrence of complications, and high patient satisfaction, with a minimum of 1-year follow-up. Most importantly, the long-term results of the robotic repair are similar to those of open repair, but with significantly less morbidity.  相似文献   
53.

Background  

There are few effective strategies reported for the primary prevention of low back pain (LBP). Core stabilization exercises targeting the deep abdominal and trunk musculature and psychosocial education programs addressing patient beliefs and coping styles represent the current best evidence for secondary prevention of low back pain. However, these programs have not been widely tested to determine if they are effective at preventing the primary onset and/or severity of LBP. The purpose of this cluster randomized clinical trial is to determine if a combined core stabilization exercise and education program is effective in preventing the onset and/or severity of LBP. The effect of the combined program will be compared to three other standard programs.  相似文献   
54.
Tuberculosis involving the soft tissue from adjacent bone or joint is well recognized. However, primary tuberculous pyomyositis, tuberculous bursitis, and tuberculous tenosynovitis are rare entities constituting 1% of skeletal tuberculosis. Tuberculous tenosynovitis involves most commonly the tendon sheaths of the hand and wrist, and tuberculous bursitis occurs most commonly around the hip. The greater trochanteric bursa and the greater trochanter are the most frequent sites of tuberculous bursitis. Cases of primary tuberculous pyomyositis and tenosynovitis of the tendons of the ankle and foot are seldom reported in the radiology literature. All imaging modalities-plain radiography, bone scan, computed tomography, and magnetic resonance imaging (MRI)--provide information that is helpful in determining therapy. MRI in particular, with its multiplanar capabilities and superb contrast of soft tissue, can demonstrate the extent of the soft tissue mass and access the adjacent bones and joints. However, MRI has no diagnostic specificity in regard to tuberculosis, and in nonendemic areas, biopsy is strongly recommended. All patients in this review were permanent residents of North America or Western Europe and were immunocompetent. Examples of atypical presentations of the above entities are demonstrated.  相似文献   
55.
56.
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences.  相似文献   
57.
58.
A survey was carried out to ascertain the preference for donor site scar orientation in patients undergoing pedicled latissimus dorsi breast reconstruction and their views on breast reconstruction in general. One hundred twelve women (59 Chinese, 53 Western) completed the questionnaire. Participants were asked to state their preferred scar orientation (i.e., oblique, horizontal, or vertical) based on photographs showing the position of the scars. Demographic information and views on issues surrounding breast reconstruction in general were also collected. Data was analyzed non-parametrically with chi-square test and t test. The mean age of participants was 39.5 years (20–73 years). Seventy-seven percent of the participants would opt for an immediate breast reconstruction if offered (p < 0.001). Eighty-six percent would have objection to the use of silicone implant as a whole or part of a reconstruction (p < 0.001). Vertical and horizontal scars were the preferred orientation, with no women choosing the oblique orientation as their first choice (p < 0.001). The non-Chinese of 40 years or older, as well as Chinese women from all age groups, preferred the horizontal scar (p < 0.05). We demonstrated that both culture and age impact on the preferred scar orientation in breast reconstruction. Women in the age group we commonly reconstruct favored the horizontal scar. However, the younger women of non-Chinese origin tended to favor the vertical scar.  相似文献   
59.
OBJECTIVE: The more atherogenic lipid profile seen in peritoneal dialysis (PD) patients cannot fully explain the increased incidence of atherosclerosis in this population. Oxidative modification of low-density lipoproteins (LDL) is considered to play a central role in the atherogenic process, whereas high-density lipoprotein (HDL) protects LDL from oxidation. On the other hand, it has been suggested that the LDL and HDL of PD patients are more resistant to oxidation than those of control subjects, while PD-HDL equally protects LDL from oxidation compared to control-HDL. Two HDL-associated enzymes have been shown to protect both LDL and HDL from oxidation: paraoxonase (PON1) and HDL-associated platelet-activating factor acetylhydrolase (HDL-PAF-AH). Furthermore, low PON1 activity and high total plasma PAF-AH concentration, which represents mainly the LDL-associated enzyme, have been shown to be independent risk factors for coronary artery events in the general population. However, there are limited data regarding possible alterations of these enzymes in PD patients. The aim of our study was to examine the possible alterations of PON1 and PAF-AH activities in patients undergoing PD. DESIGN: A cross-sectional study. SETTING: A university medical center. PARTICIPANTS: 56 PD patients of Caucasian origin and 86 matched controls were studied. MEASUREMENTS: In all subjects, serum PON1 activity toward paraoxon (paraoxonase) and phenylacetate (arylesterase), as well as total serum and HDL-PAF-AH activities were measured; PON1 genetic polymorphisms known to influence PON1 activity (Q192R and M55L) were determined. RESULTS: The PD patients exhibited significantly increased serum PON1 (paraoxonase) and PON1 (arylesterase) activities compared to controls, regardless of the PON1 polymorphisms or the levels of HDL cholesterol. Additionally, PD patients had significantly elevated activities of total serum PAF-AH and HDL-PAF-AH, independently of the levels of LDL or HDL cholesterol. The ratio of HDL-PAF-AH/ total PAF-AH, which has recently been suggested to be a potential marker of atherogenicity, was decreased in these patients compared to controls. Moreover, no difference in the prevalence of PON1 polymorphisms between PD patients and controls was found. CONCLUSION: The elevated activities of PON1 and HDL-PAF-AH could explain the increased resistance of PD-HDL to oxidation; the higher activity of total PAF-AH and the decreased HDL-PAF-AH/ total PAF-AH ratio could contribute to the increased incidence of atherosclerosis in these patients.  相似文献   
60.
Background. Accepted practices of informed consent often result in suboptimal patient understanding of research studies.Methods. This pilot study aimed to assess trial-specific tailored materials, compared to a widely used generic booklet about clinical trials, randomly assigned to 118 candidates for cancer clinical trials. Study outcomes were: satisfaction with decision-making; satisfaction with materials; and subjective understanding of the clinical trial.Results. There were no major differences between groups. Participants rated tailored materials higher as a useful reference.Conclusions. Trial-specific materials hold utility for reference during clinical trials. Studies of informed consent are feasible, although important factors limit research.  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