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   90141篇
  免费   6343篇
  国内免费   1874篇
耳鼻咽喉   3207篇
儿科学   975篇
妇产科学   2553篇
基础医学   3583篇
口腔科学   3434篇
临床医学   8612篇
内科学   8269篇
皮肤病学   803篇
神经病学   2807篇
特种医学   1603篇
外国民族医学   20篇
外科学   28120篇
综合类   13187篇
现状与发展   8篇
一般理论   10篇
预防医学   4470篇
眼科学   4894篇
药学   4226篇
  191篇
中国医学   1490篇
肿瘤学   5896篇
  2024年   1374篇
  2023年   2698篇
  2022年   3839篇
  2021年   4941篇
  2020年   4862篇
  2019年   3897篇
  2018年   3628篇
  2017年   3242篇
  2016年   3224篇
  2015年   3229篇
  2014年   6552篇
  2013年   6262篇
  2012年   5111篇
  2011年   5429篇
  2010年   4274篇
  2009年   4036篇
  2008年   3816篇
  2007年   3802篇
  2006年   3425篇
  2005年   3001篇
  2004年   2598篇
  2003年   2123篇
  2002年   1674篇
  2001年   1535篇
  2000年   1343篇
  1999年   1215篇
  1998年   976篇
  1997年   931篇
  1996年   726篇
  1995年   623篇
  1994年   546篇
  1993年   431篇
  1992年   355篇
  1991年   347篇
  1990年   257篇
  1989年   235篇
  1988年   234篇
  1987年   237篇
  1986年   197篇
  1985年   214篇
  1984年   193篇
  1983年   133篇
  1982年   128篇
  1981年   115篇
  1980年   92篇
  1979年   52篇
  1978年   47篇
  1977年   45篇
  1976年   32篇
  1975年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Summary The width of the third ventricle, the length of the anterior commissure-posterior commissure line (AC-PC line), the spatial position of the midplane of the third ventricle, and the co-ordinates of the AC, the PC, and of 17 brain targets in the thalamus, hypothalamus and pallidum, were assessed on a pre-operative Stereotactic computed-tomography (CT) study and compared to measurements on intra-operative air-ventriculography, using a non-invasive relocatable Stereotactic frame.There were no significant differences in the length of the ACPC line, in the position of the midsagittal plane of the third ventricle, or in the vertical or lateral co-ordinates of the AC, the PC and the cerebral targets, between measurements on CT and on air-ventriculography. However, the width of the third ventricle was significantly larger, and the spatial positions of both AC and PC were significantly more anterior on air-ventriculography than on the CT study. This anterior dislocation of the commissures was presumably due to the insufflation of air into the ventricles of patients being in the supine position during surgery.  相似文献   
92.
93.
Between November 1967 and December 1994, 242 patients with gestational trophoblastic disease (GTD) were treated with chemotherapy by the Gynecology Service of Memorial Hospital. Eighty-seven of the patients (35.9%) underwent at least one major operation during the course of their illness. Twenty-six patients underwent two major operations, and in five patients, three major operations were performed, for a total of 118 procedures. The most frequent procedures were: hysterectomy, 56 (47.4%); hysterotomy, 15 (12.7%); thoracotomy, 13 (11%); and craniotomy, 5 (4.2%). Twenty-nine additional procedures ranging in complexity from oophorectomy to segmental liver resection were also performed. Twenty-nine operations (24.5%) were considered to be beyond the scope of most gynecologic surgeons. The overall complete remission rate for 242 patients was 90.4%. The rate for patients who underwent a major surgical procedure was 79.3% compared to 96.7% for patients whose treatment was with chemotherapy alone.
The data demonstrate that the integration of surgery in the management of GTD patients often requires a multidisciplinary approach that in many cases can best be achieved at specialized treatment centers.  相似文献   
94.
Day care is generally accepted in anterior segment eye-surgery. In the Rotterdam Eye Hospital this option was also considered for posterior segment surgery. We were interested in the opinion, of patients on this matter and therefore asked patients, who were admitted for posterior segment eye-surgery, to answer a questionnaire. The major question was: ‘If your physician had given his permission, do you think it would have been possible for you to go home on the evening after surgery?’. Other questions evaluated problems in organising assistance at home and transportation to the out-patient clinic as well as circumstances after the operation, such as pain, nausea, dizziness and anxiety. Eighty-one out of 87 patients responded: 56% answered ‘eyes’ and 44% ‘no’ to the major question. Relating the answer to the major question to medical data and to answers to the other questions, we found organizational problems at home and anxiety to have a statistical significant relation with a negative answer. Clinical factors like age, American Society of Anesthesiologists (ASA)-class, diabetes mellitus (including insulin-dependant), type of anesthesia, time of the day the surgery was finished, duration of surgery, pain, nausea or dizziness were not signficantly related. The number of patients involved in this study, however, is too small to draw conclusions on specific subgroups of patients.  相似文献   
95.
A comprehensive neuropsychological test battery was administered to 10 consecutive patients undergoing neurosurgical intervention, capsulotomy, as a last resort treatment for chronic, incapacitating, and otherwise intractable illness, either obsessive-compulsive disorder (OCD; n= 5) or non-OCD anxiety disorder (n= 5). The aim was to study the neuropsychology of severe anxiety disorders before and after a defined neurosurgical intersection of connections between the frontal lobes and related brain regions. Although extremely disabled by their illness before surgery, the patients performed within the normal range on most tests. After capsulotomy, there was significant improvement on measures of clinical morbidity and of psychosocial functioning, and the general neuropsychological performance remained remarkably intact. In a subgroup of 5 patients, however, perseverative responses were more common postoperatively, possibly indicating dysfunction of systems involving the frontal lobes. Although admittedly sparse, these data can be interpreted as suggesting that in vulnerable individuals, capsulotomy may give rise to increased perseverative behaviour in the laboratory, and possibly in the real world as well. This risk must be weighed against the potential clinical benefit of capsulotomy in this extremely disabled, sometimes suicidal patient population.  相似文献   
96.
The distribution of mannan binding protein (MBP) in blood donorsera was determined by enzyme-linked immunosorbent assay toestablish normal concentrations. Abnormally low MBP concentrationswere found in 16% (21 out of 135) of female partners and 14%(15 out of 108) of male partners of couples experiencing recurrentmiscarriage, compared with <5% of obstetrically normal controls(P < 0.005). This relationship was even stronger (9.5 versus1.0%) and more significant (P < 0.002) when only subjectspresumed to be homozygous for the mutant allele responsiblefor MBP deficiency were considered. By immunohistochemistry,MBP could be demonstrated in first trimester placenta. We suggestthat low concentrations of MBP within the feto-placental unitincrease susceptibility to fetal loss, possibly via an infection-inducedplacental cytokine imbalance.  相似文献   
97.
This study compares the incidence of local tumor recurrence following primary excision with the CO2 laser, Nd:YAG laser (contact), Argon Beam Coagulator, or electrocautery. One hundred eight Fisher 344 rats with R3230AC mammary tumors (1.6 +/- 0.04 [SD] cm diameter) were used. All animals were randomized into groups of similar tumor size. In groups C and CS, excision was performed with a Sharplan 1060 CO2 laser (TEMoo, 25 W, continuous wave [CW], 0.2-mm spot size). Wounds in group CS were "sterilized" (0.5-mm spot size, 25 W, CW) by gently heating the wound without causing blanching or charring. In group N, a 0.4-mm contact Laser Blade and a Cooper 8000 Nd:YAG laser at 20 W CW was used. In groups SA1 and SA2, tumors were excised with the scalpel, and hemostasis and wound "sterilization" were accomplished with the Bard System 6000 Argon Beam Coagulator (ABC) at 40 W and 4 liters/min argon gas flow in SA1 and 12 liters/min in SA2. In group E, excision was accomplished at 40 W blend mode, 10 W spray mode. In group EA, excision was accomplished at 60 W cutting current, and hemostasis was achieved with the ABC. The animals were examined for evidence of recurrence for 34 days postoperatively. Mortalities were excluded from analysis. The incidence of recurrence was 11/14 (79%) in C, 6/16 (38%) in CS, 10/14 (71%) in SA1, 6/13 (46%) in SA2, 6/15 (40%) in N, 7/10 (70%) in EA, and 3/15 (20%) in E. Group E is statistically different (P less than .01) from groups EA, C, and SA1. Group C was different (P less than .01) from groups E, CS, and N. These results demonstrate an inverse relationship between tumor recurrence and local thermal effects at the surgical site. The ABC did not increase tumor recurrence. Contact YAG surgery was similar to CO2 laser excision and "sterilization." An attempt to study the influence of gas flow and pressure on local tumor recurrence and metastases should be made.  相似文献   
98.
We reviewed the records of 110 consecutive patients with advanced-stage epithelial ovarian carcinoma treated at the Soroka Medical Center, Beer-Sheva, Israel, from 1961-1987. Twenty patients (18.1%) had optimal debulking at initial laparotomy, 30 patients (27.2%) had nonoptimal debulking at initial laparotomy, 20 patients (18.1%) had an "inoperable" disease at initial laparotomy, and 40 patients (36.3%) had such poorly written records that no information about the degree of resectability at initial laparotomy could be obtained. Four patients, in whom the residual tumor left at initial laparotomy had responded to chemotherapy, had a second laparotomy. In all four patients optimal debulking surgery at second laparotomy was easy to perform and was successful. The value of a second laparotomy after a few cycles of chemotherapy in order to optimally debulk the residual tumor left at initial laparotomy is discussed. It is concluded that a second attempt of debulking surgery after chemotherapy has a respectable place in the management of patients with advanced-state epithelial ovarian carcinoma, but further research is needed.  相似文献   
99.
This surgical anatomy study aimed to evaluate the possibility of identifying the external laryngeal nerve during thyroid surgery and the possible variations of nerves at risk. Fifty patients underwent total thyroidectomies during a period of 12 months. Using a neurostimulator, the distal motor branch of the external laryngeal nerve was searched. Electrical stimulation of a nervous branch aimed to provoke a global contraction of the cricothyroid in order to identify with certitude the external laryngeal nerve. The external laryngeal nerve was identified in 20% of cases. Its course was, with almost equal frequency, either (1) between the vessels of the superior thyroid pedicle or (2) superficial and anterior to the fascia of the cricothyroid muscle. The external laryngeal nerve is hard to find during thyroid surgery, even with a neurostimulator. It can be vulnerable during thyroid surgery but only in cases of anatomic variations. Searching for the nerve systematically during thyroid surgery does not seem to be useful. Several precautions when dissecting the superior pole of the thyroid gland seem to be necessary and sufficient to respect the external laryngeal nerve.  相似文献   
100.
PROBLEM: Infection has been proposed to initiate abortion, and the role of viruses in spontaneous resorption in mice has not been tested. METHOD: The anti-viral drug ribavirin (1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) was fed to CBA/J and C3H/HeJ female mice beginning on the morning after mating with DBA/2J males. RESULTS: Ribavirin treatment increased the rate of abortion (resorption) on day 13.5, and this was associated with retardation of the rate of embryo development and hypoplasia of the trophoblast. There was a reduction in trophoblast-dependent decidua-associated soluble suppressor activity, but there was no maternal mononuclear cell infiltrate of the type reported in association with resorption of semiallogeneic and xenogeneic mouse embryos. This may be due to an immunosuppressive effect of ribavirin. Ribavirin was able to potently suppress proliferation of mouse trophoblast and mastocytoma cell lines in vitro. CONCLUSIONS: There are several drug-induced murine abortion models that provide useful insights into potential mechanisms underlying spontaneous pregnancy failure, but in the ribavirin model, a direct impairment of trophoblast development appears to be responsible.  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